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Alaska Blind Child Discovery

A cooperative, charitable research project to vision screen every preschool Alaskan

ABCD Publications


Arnold, R. W. (1993). Retinopathy of prematurity in Alaska: Treating the vast expanse. the International Conference on Retinopathy of Prematurity, Chicago, Illinois, USA, Kugler Publications (Amsterdam/New York).

Arnold, R. W. (1993). "Vision Screening in Alaska: Experience with Enhanced Brückner Test." Alaska Med 35(2): 204-208.

Arnold, R. W. (1994). "Posterior retinopathy of prematurity cryotherapy from a limbal reference." J Pediatr Ophthalmol Strabismus 31: 303-305.

Arnold RW, Gionet EG, Jastrzebski AI, Kovtoun TA, Machida CJ, Armitage MD, et al. (2000) The Alaska Blind Child Discovery project: rationale, methods and results of 4000 screenings. Alaska Med. 2000;42(3):58-72.

BACKGROUND: Photoscreening allows lay persons to adapt the Enhanced Bruckner Test to preschoolers in an attempt to identify refractive amblyopia. The Alaska Blind Child Discovery (ABCD) project is charitably funded and administered. METHODS: MTI photoscreening was offered to children in rural and urban communities in southern Alaska from 1996 through June 1999. Parents answered questions concerning the child's health, family ocular history and whether the child had any eye "Warning Signs." The MTI images were interpreted by two eye doctors using a modification in MTI published guidelines. RESULTS: Out of 4000 screenings performed on 3930 children, there was an overall "not normal" interpretation of 9% and an inconclusive rate of 1%. The mean S.D. age was 3.9 2 years. Only 6% had had a prior eye exam. The average number of Polaroid pictures per screening was 1.16. Follow-up data on "not normal" results was obtained on just over 50%. The positive predictive value during the first two years was 77% but improved to 92% from 1998-1999. Affirmative answers to the questions concerning previous eye exam, child's health, siblings eye health and positive "Warning Signs" were significantly associated with "not normal" interpretations but affirmative answers about eye health of mother, father and relatives were not. Community penetrance of photoscreening to the target age-group ranged from only 5% for Anchorage to almost 100% for the Bristol Bay public health nurses. Five percent of parents of "positive" results surveyed would not have recommended screening for their friends. Equipment functioned dependably even in remote Alaska. CONCLUSION: Charitable volunteer Polaroid photoscreening detected amblyopia and significant pediatric eye disease in over 300 children during the first 3.5 years of ABCD.

Arnold, R. W. (2002). "Use of a consumer video system to enhance low vision in children and adults." JPOS 39(4): 245-247.

Arnold, R. W. (2003). "Highly specific photoscreening at the Alaska State Fair: Valid Alaska Blind Child Discovery photoscreening and interpretation." Alaska Med 45(2): 34-40.

Arnold, R. W. (2003). "The phoropter trapeze. A portable refractive support for remote clinics." Binocul Vis Strabismus Q 18(1): 26-7.
A trapeze was engineered using inexpensive pre-threaded commercial polyvinyl chloride ("PVC") plumbing pipe. This was suspended from a convenient overhead point and the phoropter was clamped to it. It was stabilized by the patient holding on two attached handles. Illustrated in photographs.

Arnold, R. W. (2004). "Pseudo-false positive eye/vision photoscreening due to accommodative insufficiency. A serendipitous benefit for poor readers?" Binoc Vis and Strabismus Quart 19(2): 75-80.
BACKGROUND: Children whose eyes and vision are otherwise normal and who should screen negatively as normals, but who fail to compensate for their normal mild hyperopia (i.e. by normally accommodating, or rather actually failing to accommodate) will generate hyperopic crescents in a photoscreen test that can be interpreted as "positive" (for pathology) because high and asymmetric levels of hyperopia are common risk factors for amblyopia. This would therefore usually be considered a "false positive" and no further care would be offered. However, this failure to compensate, may in fact be a pathological disorder, accommodative insufficiency, making this apparently "false positive" situation actually a actually a "false-positive-false- negative positive test", or more simply a "false- false positive test". METHODS: The Alaska Blind Child Discovery Project photoscreened just under 16,000 children referring 6% as "positive", of which, after examination, the false positive rate was just 6% of those referred (0.4% of the total number screened). RESULTS: Ten (42%) of the 24 false positives had evidence of accommodative insufficiency inspite of only average (for age) amounts of cycloplegic hyperopia and a lag of accommodation on dynamic retinoscopy. Eight of the 10 were boys of kindergarten age. Most of these subsequently benefitted from prescription and use of reading glasses of low plus sphere correction. CONCLUSION: About 0.15% of photoscreened children, or 2.5% of those screening positive, and 42% (10/24) found initially on exam to be falsely positive, yielding hyperopic interpretations despite low and usually acceptably normal for age amounts of hyperopia, are in fact suffering from a pathological accommodative insufficiency. Identification of such false- false positives by a combination of photoscreening and dynamic retinoscopy may be used to determine which students might be helped with enforced reading glasses. Confirmatory exams on photoscreen positive-hyperopia cases should include an assessment of accommodation to identify these children.
Arnold, R. W. (2004). "Vision in Preschoolers Study (letter)." Ophthalmol 111(12): 2313.

Arnold, R. W., M. D. Armitage, et al. (2005). "The cost and yield of photoscreening: Impact of photoscreening on overall pediatric ophthalmic costs." JPOS 42(2): 103-111.
Approximately 5% of preschool children suffer from amblyopia. Many of them have high or unequal hyperopia. Amblyogenic risk factors can frequently be detected by photoscreening.
MTI™ photoscreening was offered free-of-charge to a target group of children aged 1-4 from urban and rural screening hubs. Their parents provided a brief family and health history before consenting to the flash photography. Packets of screened images were mailed to the ABCD coordinating center for physician photoscreen interpretation, specifically seeking latent or anisometropic hyperopia. Parents and screeners were then mailed results and information about amblyopia. Follow-up exam data were then tallied. A Cost-Consequence Analysis was developed for vision screening and eye care.
In 1998 and 1999, 5166 screenings were performed with a “positive” interpretation rate of 4.5% in the 3046 urban children and 6.2% in the 2120 rural children. The penetrance of screening was 13% in urban communities and 49% in rural communities. The positive predictive value is estimated to be over 90%. From this, the average cost to screen and inform an Alaskan preschooler is about $10.50. The cost to detect by photoscreening an Alaskan with amblyogenic risk factors is about $225. Compared to AAP 1995 guidelines, implementing photoscreening adds 9% while mandating complete pre-Kindergarten exam adds 49% to overall eye care.
In some of the least accessible parts of America, MTI™ photoscreening with experienced physician interpretation achieved high community penetrance and high positive predictive value for latent hyperopia and other amblyogenic factors. The costs must be weighed against societal health goals. When the follow-up costs are considered, adding photoscreening to current AAP guidelines may add $112 per child over ten years, but probably would also assist in the reduction of amblyopia. We suspect that penetrance of urban photoscreening will remain low unless pediatric vision screening guidelines and reimbursement are revised.

Arnold, R. W., A. W. Arnold, et al. (2004). "Amblyopia detection by camera (ADBC): Gateway to portable, inexpensive, vision screening." Alaska Med 46(3): 63-72.

Arnold, R. W., G. R. Beauchamp, et al. (2005). "Compared value of amblyopia detection (letter)." Ophthalmology: (submitted) never published.

Arnold, R. W., L. Coon, et al. (1995). "Collaborative visual rehabilitation: High astigmatism, esotropia and elevator palsy." Alaska Med 37(3): 88-90.

Arnold, R. W. and S. P. Donahue (2006). "Compared value of amblyopia detection." Binocul Vis Strabismus Q 21(2): 78.

Arnold, R. W. and S. P. Donahue (2006). "The yield and challenges of charitable state-wide photoscreening." Binocul Vis Strabismus Q 21(2): 93-100.
INTRODUCTION: State-wide cooperative programs for pediatric vision screening utilizing the MTI photoscreener and centralized interpretation were established in Alaska (The Alaska Blind Child Discovery, ABCD) and in Tennessee (Tennessee Lions Outreach). METHODS: Details of setup, implementation and interpretation of the state-wide MTI photoscreening programs are compared through 2002. The absolute numbers of children screened and the breakdown in interpretation categories are presented. RESULTS: ABCD screened 14,000 children while Tennessee Lions screened 100,800. Similarities between ABCD and Tennessee programs were funded by Lions Clubs and other charitable and public health organizations, community screening and each had coordinated centralized image interpretation and notification. The programs differed by clinic focus (Tennessee Lions organized pre-schools while ABCD used village and community health fairs and schools), parent notification (Tennessee Lions communicated through pre- schools and ABCD mailed directly to parents), and image interpretation (Tennessee used VOIC age-based and pupil-size crescents while ABCD used "delta-center crescent"). Predictive value positive was 73% for Tennessee and 89% for ABCD. Tennessee achieved better followup on referrals after a specific coordinator was employed. Image interpretation breakdown for ABCD: Tennessee Lions Outreach were anisometropia (29%:34%), high hyperopia (33%:16%), astigmatism (18%:30%), strabismus (7%:15%), myopia (5%:2%), cataract (0.7%:0.2%). Two state-wide programs detected 3216 amblyopic children at a charity borne-cost of $1.5 million. If the parents persisted with appropriate amblyopia therapy, the expected societal value was estimated at $17 million. Lacking societal mandate and funding, these concerted charitable efforts only achieved a community penetration rate of 10% to 14%. CONCLUSION: National adoption of preschool vision screening by a method with similar or even better validity and cost effectiveness as MTI photoscreening, ideally in the pediatric medical home, is warranted.
Arnold, R. W. and K. F. Fierstein (2000). "Are vision screening devices accurate and reliable for use in pediatricians' offices to test children younger than 4 years old?: Con." Pediatric News: submitted.

Arnold, R. W., E. Gionet, et al. (2000). "The Alaska Blind Child Discovery project: Rationale, Methods and Results of 4000 screenings." Alaska Med 42: 58-72.
BACKGROUND: Photoscreening allows lay persons to adapt the Enhanced Bruckner Test to preschoolers in an attempt to identify refractive amblyopia. The Alaska Blind Child Discovery (ABCD) project is charitably funded and administered. METHODS: MTI photoscreening was offered to children in rural and urban communities in southern Alaska from 1996 through June 1999. Parents answered questions concerning the child's health, family ocular history and whether the child had any eye "Warning Signs." The MTI images were interpreted by two eye doctors using a modification in MTI published guidelines. RESULTS: Out of 4000 screenings performed on 3930 children, there was an overall "not normal" interpretation of 9% and an inconclusive rate of 1%. The mean S.D. age was 3.9 2 years. Only 6% had had a prior eye exam. The average number of Polaroid pictures per screening was 1.16. Follow-up data on "not normal" results was obtained on just over 50%. The positive predictive value during the first two years was 77% but improved to 92% from 1998-1999. Affirmative answers to the questions concerning previous eye exam, child's health, siblings eye health and positive "Warning Signs" were significantly associated with "not normal" interpretations but affirmative answers about eye health of mother, father and relatives were not. Community penetrance of photoscreening to the target age-group ranged from only 5% for Anchorage to almost 100% for the Bristol Bay public health nurses. Five percent of parents of "positive" results surveyed would not have recommended screening for their friends. Equipment functioned dependably even in remote Alaska. CONCLUSION: Charitable volunteer Polaroid photoscreening detected amblyopia and significant pediatric eye disease in over 300 children during the first 3.5 years of ABCD.
Arnold, R. W., E. G. Gionet, et al. (2003). "Duration and effect of single-dose atropine: paralysis of accommodation in penalization treatment of functional amblyopia." Binoc Vis and Strabismus Quart 19(2): 81-86.
BACKGROUND AND PURPOSE: Atropine dilates the pupil and paralyzes the ciliary muscle accommodation, blurring vision, and therefore is an effective penalization of the sound eye in the treatment of functional amblyopia of the other eye. The degree of blur induced is a function of the amount of the patient's uncorrected hyperopia and the distance from the eye of the viewed material or object. Another factor determining effectiveness of atropine penalization is the duration of the effect of the atropine. It is the purpose of this study to investigate these factors. METHODS: Six normal children underwent complete eye exam with cycloplegic refraction several days before deliberate instillation of atropine 1% in the sound, or right eye. Distance and near acuity was then tested after 30 minutes, and on subsequent days. Additional data points were derived by placing known minus lenses in front of the tested eye. In addition, we also studied one successfully treated amblyopic patient when he terminated chronic daily atropine in his normal, sound eye. RESULTS: Atropine initially produced a linear reduction in logMAR acuity (blur) at distance of about 0.2 logMAR lines per diopters of uncorrected hyperopia. The magnitude of the blur was greater for near, but the effect of increased hyperopia was slightly greater for distance measurements. This blurring of acuity lasted just less than 48 hours for normal subjects, and just over 48 hours following prompt cessation of chronic daily atropine in that one subject. Regression formulae were derived relating uncorrected hyperopia and time interval following atropine cessation on distance and near acuity in children of amblyopic age range. CONCLUSION: The degree of penalization is highly dependent on the uncorrected hyperopic refractive error. A significant penalization effect is present only for one day or so. Daily atropine is therefore indicated for penalization. To better tailor penalization therapy to target sound eye acuity blur, these formulae and graphs can be used, specifically, in addition, to determine the amount of deliberate spectacle hyperopic undercorrection to maximize the penalization effect.
Arnold, R. W., K. Kesler, et al. (1994). "Susceptibility to ROP in Alaskan Natives." J Pediatr Ophthalmol Strabismus 31: 192-194.

Arnold, R. W., J. B. Ruben, et al. (2005). "Korean kindergarten vision screen programme (letter)." Br J Ophthalmol 89(3): 392-393.

Arnold, R. W. and G. Sitenga (2000). "The detection of congenital glaucoma by photoscreen interpretation." Alaska Med 42(3): 73-77.
Photoscreening is designed to detect abnormalities in children's eye, particularly abnormal refractive errors, which can lead to amblyopia. An Alaska Bind Child Discovery MTI Polaroid photoscreen in one girl resulted in diagnosis and treatment of congenital glaucoma. Patients with known pediatric eye disease underwent photoscreening. Subtle non- refractive changes in photoscreen images may reveal eye disease even more serious than amblyopia. We suggest that human or computer interpretation of photoscreening images, particularly when retained, be done conscientiously with respect to the refractive state and alignment of the eyes, but also regarding other potentially serious ocular pathology.
Arnold, R. W., C. A. Stange, et al. (2006). "The compared predictive value of Bruckner, acuity and strabismus from pediatric referrals." Am Orthopt J 56(1): 15-21.
Although pediatric vision screening now passes evidence-based scrutiny, and has recent AAP guidelines, routine acuity testing in pediatric offices may still perform poorly.
From 6/2002 through 8/2005, all children aged 0-6 directly referred by pediatric care givers to one pediatric ophthalmologist were compared as to referral indication; failed acuity, strabismus and positive Bruckner test. AAPOS gold standard exam criteria was applied and compared to community photoscreening.
By referral indication, the following are numbers and predictive values: acuity (n=80, PPV 51%), Brückner (n=74, PPV = 89%), Strabismus (n=432, PPV = 81%). Community photoscreening referred n=392 with PPV = 91%. The objective tests and strabismus queries were not age-dependent.
The pediatric home best conforms to WHO guidelines due to case-continuous finding and assistance with treatment compliance particularly for strabismus. Objective tests outperform acuity testing in referral for refractive amblyopia including Brückner test in experienced hands. Observation and history best refers strabismus.

Arnold, R. W., L. Stark, et al. (2006). "Tent photoscreening and patched acuity by school nurses: Validation of ASD-ABCD." J AAPOS In press.

Donahue, S., R. Arnold, et al. (2003). "Preschool vision screening: What should we be detecting and how should we report it? Uniform guidelines for reporting results from studies of preschool vision screening." J AAPOS 7(5): 314-316.

Donahue, S. P., R. W. Arnold, et al. (2004). "Pediatric Photoscreening: Eye to Eye." J Pediatr Ophthalmol Strabismus 41(2): 72-6.

Kerr, N. and R. Arnold (2004). "Vision screening for children: current trends, technology and legislative issues." Curr Opin Ophthalmol 15: 454-459.

Kovtoun, T. A. and R. W. Arnold (2004). "Calibration of photoscreeners for threshold contact- induced hyperopic anisometropia: Introduction of the JVC photoscreeners." JPOS 41(3): 150-158.

Lang, D., J. Blackledge, et al. (2005). "Is Pacific Race a retinopathy of prematurity risk factor?" Arch Pediatr Adolesc Med 159(8): 771-773.
Background: Black race affords some protection from retinopathy of prematurity (ROP), but more ROP was previously found in another darkly pigmented race, the Alaskan natives.
Design: From fall 1989 through summer 2003, all Alaskan infants with a birth weight of 1500 g or less were examined, documenting mother’s stated race, prenatal care, and neonatal intensive care unit course.
Results: Retinopathy of prematurity was classified as to predefined threshold for peripheral ablative treatment (region of avascular retina and fibrovascular ridge and vessel tortuosity) in 873 infants. Threshold ROP was more prevalent in Alaskan natives (24.9%) and Asians (15.9%) (10% overall), with no significant difference between Alaskan natives and Asians (P=.24). Alaskan native males had more threshold ROP (69%) compared with non–Alaskan native males (51%). Compared with threshold nonnatives, Alaskan native threshold infants had greater birth weights (829±222 vs 704±186 g), required less time on ventilation (46±22 vs 70±75 days), and progressed to treatment at a younger age (35.5±2.2 vs 36.2±2.6 weeks’ gestational age) (data are given as mean±SD).
Conclusions: In this limited study, we find increased risk of threshold ROP in 2 northern Pacific races. Threshold Alaskan natives had similar or better prenatal and neonatal intensive care unit variables than did threshold nonnatives; however, Alaskan native males were still at a greater risk.

Lang, D. M., A. W. Arnold, et al. (2006). "Photoscreening, remote autorefraction and patched acuity testing in the Koyukon region of Alaska." Alaska Med 48: In Press.
Photoscreening and remote autorefraction showed promise in the urban “Vision in Preschoolers Study.” We transported a comparative screening with confirmation program to a remote part of interior Alaska.
80 children from villages in the Koyukon region received on-site three-pronged vision screening followed by gold-standard confirmatory exams. Each had patched HOTV acuity, photoscreening and Suresight remote autorefraction.
There was a high prevalence of amblyopia and vision disorders in these villages. Acuity testing was moderately valid but not useful for children less than 4 years old. Suresight has specificity over 90% with sensitivity of 60%. Photoscreening had specificity over 95% and sensitivity of 70% and was better than Suresight for children under age 4.
The Welch Allyn Suresight had similar high validity in the Koyukon as in VIPS and provides immediate, on-site results. We recommend that Welch Allyn adopt more specific VIPS referral guidelines. Photoscreening, particularly with commercial digital flash cameras and specific interpretation, is a cost effective screening tool particularly for younger children.

Leman, R. E., M. D. Armitage, et al. (2005). "The receiver-operator curve for flip-card surround HOTV in younger school children." Am Orthopt J 55(1): 128-135.
The AAP vision screening guidelines are not uniformly delivered. Moderate amblyopia can be successfully treated in children 7 year of age and older. The ideal method and threshold of vision and/or acuity testing in school is not known.
1700 students from first grade, Kindergarten and pre-K were screened with a flip-card, surround HOTV protocol with other eye patched combined with photoscreening. 234 had “Gold Standard” confirmatory exams from which AAPOS standards were validated.
Receiver Operator Curves were constructed by adjusting referral criteria by grade. A cut-off of 20/25 yielded fairly good (50%) sensitivity and 90% specificity for First and Kindergarten but many of the pre-K were unable to complete the testing.
Patched surround HOTV flip card acuity is useful in starting school children and a cut-off of 20/25 passing acuity suggested. Pre-K are not well acuity screened due to high inconclusive rate
Leman, R. E., M. M. Clausen, et al. (2006). "A comparison of patched HOTV visual acuity and photoscreening." J Sch Nurs 22(4): 237-243.
Early detection of significant vision problems in children is a high priority for pediatricians and school nurses. Routine vision screening is a necessary part of that detection and has traditionally involved acuity charts. However, photoscreening in which "red eye" is elicited to show whether each eye is focusing may outperform routine acuity testing in pediatric offices and schools. This study compares portable acuity testing with photoscreening of preschoolers, kindergarteners, and 1st-graders in 21 elementary schools. School nurses performed enhanced patched acuity testing and two types of photoscreening in a portable tent. Nearly 1,700 children were screened during spring semester 2004, and 14% had confirmatory exams by community eye care professionals. The results indicate that one form of photoscreening using a Gateway DV-S20 digital camera is significantly more sensitive to children with significant vision problems, as well as being the most cost effective (85% specificity and only $0.11 per child). This suggests that the adaptation of photoscreening into a routine vision screening protocol would be beneficial for efficiently detecting vision problems that could lead to amblyopia

Kirk VG, Clausen MM, Armitage MD, Arnold RW. Preverbal photoscreening for amblyogenic factors and outcomes in amblyopia treatment: early objective screening and visual acuities. Arch Ophthalmol 2008;125:489-492. BACKGROUND: Previous studies have suggested that infant photoscreening yields better results than visual acuity screening in preschool-aged children. With conventional vision screening, the patient must be able to provide monocular visual acuity cooperation, whereas objective screening for amblyogenic factors can be done at much younger ages. METHODS: From February 1996 through February 2006, Alaska Blind Child Discovery photoscreened 21 367 rural and urban Alaskan children through grade 2, with an 82% positive predictive value (ie, true number of those referred); 6.9% were referred for a complete eye examination and treatment. All "referred" interpreted images for children younger than 48 months who were then followed up and treated for more than 2 years were reviewed to determine whether treatment was successful. RESULTS: Of 411 "positive" screening photos from children younger than 4 years, 94 patients had more than 2 years follow-up. The 36 children photoscreened before age 2 years had a mean treated visual acuity of 0.17 logarithm of the minimum angle of resolution (logMAR), which was significantly better than that of 58 children screened between ages 25 and 48 months (mean, 0.26 logMAR). Despite similar levels of amblyogenic risk factors, the proportion of children failing to reach a visual acuity of 20/40 was significantly less among those screened before age 2 years (5%) than in those screened from ages older than 2.0 years and younger than 4.0 years (17%). CONCLUSION: Very early photoscreening yields better visual outcomes in amblyopia treatment compared with later photoscreening in preschool-aged children.


Arnold RW, Armitage MD, Limstrom SA. Sutured protective occluder for severe amblyopia. Arch Ophthalmol 2008;126:891-895. OBJECTIVE: To investigate the feasibility, acceptability, efficacy, and cost of a newly developed translucent shield that can be fixed by sutures to the orbital rim for a month of amblyopia therapy. METHODS: In an institutional review board-approved protocol for patients with amblyopia who do not adhere to the use of conventional patching, shield occluders were fashioned from heat-moldable sturdy black or translucent (20/4000) plastic with holes drilled for attachment. Under brief general anesthesia, patients aged 5 to 10 years had a thorough examination before the shield occluder was sewn to the brow and cheek of the nonamblyopic eye with 3-0 monofilament polypropylene sutures. RESULTS: Ten children completed this protocol from December 1999 through January 2002. All tolerated the occluder for 12 to 36 days. The resultant skin scars were acceptable to parents, patients, and investigators. The amblyopic eyes improved from a mean (SD) of 0.77 (0.30) logMAR (Snellen equivalent, 20/119) to 0.45 (0.29) logMAR (Snellen equivalent, 20/57), a change of 0.32 (0.16) logMAR lines. There was no damage to the sound (occluded) eye. CONCLUSION: Sew-on occluder shields are an alternative when adherence to the use of other types of patching (often referred to as compliance with patching) is not satisfactory.


Arch Ophthalmol. 2009 Dec;127(12):1591-5.
Comparison between the plusoptiX and MTI Photoscreeners.
Matta NS, Arnold RW, Singman EL, Silbert DI. CO, CRC, COT, Family Eye Group, 2110 Harrisburg Pike, Ste 215, Lancaster, PA 17601, USA.
OBJECTIVE: Both the Medical Technology and Innovations (MTI) and plusoptiX photoscreeners are used to objectively screen for amblyogenic risk factors in children. The MTI has been extensively studied, but the limited availability of film may render it obsolete. We compared the MTI with the plusoptiX, a newer digital photoscreener, for the ability to detect amblyogenic factors when compared with a comprehensive pediatric ophthalmic examination. We believe our results will help to guide community-based vision screening programs. METHODS: One hundred fifty-one children were examined consecutively in our office. Each patient was screened with the MTI and plusoptiX devices on the same day as part of a comprehensive pediatric ophthalmic examination. Results via MTI were evaluated by an expert masked examiner (R.W.A.), and the plusoptiX results were interpreted by the incorporated software. RESULTS: Sixty-five percent of patients were found to have amblyopia or amblyogenic risk factors during the pediatric ophthalmic examination conducted via the American Association of Pediatric Ophthalmology and Strabismus referral criteria. We found the MTI photoscreener to have a sensitivity of 83.6%, specificity of 90.5%, false- positive rate of 9.4%, false-negative rate of 16.3%, and positive predictive value of 94.2%. The plusoptiX demonstrated a sensitivity of 98.9%, specificity of 96.1%, false- positive rate of 3.7%, false-negative rate of 1.0%, and positive predictive value of 97.9%. CONCLUSION: The MTI and plusoptiX photoscreeners proved to be effective when compared with a comprehensive cycloplegic pediatric ophthalmic examination. The plusoptiX, however, was found to have a higher sensitivity and specificity than the MTI.

Clausen MM, Armitage MD, Arnold RW. Overcoming barriers to pediatric visual acuity screening through education plus provision of materials. J AAPOS 2009;13:151-4. PURPOSE: The American Academy of Pediatrics (AAP) recommends that LEA and HOTV optotypes be used for vision screening and that adhesive tape be used to occlude one eye during testing. We have developed an educational program designed to improve the quality and efficiency of vision screening. The purpose of this study was to ascertain the effectiveness of this program. METHODS: All 672 pediatric doctors and nurses in the state of Alaska were surveyed by mail to assess their screening protocol and the number of patients cared for annually. Respondents received educational material, including an instructional video, eye patches for visual acuity testing, and a critical line HOTV test box. Subjects were resurveyed 3 months later to determine whether the instructional intervention altered their established protocol. RESULTS: Of the 672 practitioners contacted for the survey, 239 (35.6%) responded, representing 31,000 patients, or 62% of all preschool children in Alaska. Use of recommended optotypes was rare (Lea, 3%, HOTV, 7%) compared with the use of nonrecommended optotypes (including use of the E test by 40% of respondents). The postintervention survey was answered by 107 (16%) practitioners. Of these, 24 (23%) reported that they had begun using an adhesive patch for visual acuity testing, whereas 19 (18%) had begun using AAP-recommended testing optotypes. CONCLUSIONS: In-office video education and provided adhesive eye patches increased the use of patches in primary care preschool vision screening. Mail delivery was less effective than anticipated.

Matta NS, Arnold RW, Singman EL, Silbert DI: Can a photoscreener help us remotely evaluate and manage amblyopia? Am Orthopt J 2011, 61:124-127. INTRODUCTION AND PURPOSE: To determine whether the plusoptiX(R) S04 photo-screener can assist in remotely managing amblyopia. METHODS: A retrospective chart review was performed on 103 children with amblyopia. All patients had a plusoptiX(R) screening performed while wearing their optical correction during a comprehensive pediatric ophthalmology examination. RESULTS: Children were classified as being fully treated in their glasses or needing further intervention to treat their amblyopia and / or strabismus. Further treatment was indicated if children were found to have abnormal alignment and / or best corrected visual acuity of 20 / 40 or worse in either eye with correction. Photoscreening results for these children demonstrated a sensitivity, specificity, false negative rate and false positive rate of 69%, 84%, 31%, and 16%, respectively. When visual acuity and photoscreening were combined for children who initially passed the plusoptiX(R) screen, these metrics improved to 97%, 89%, 2.7%, and 11%, respectively. CONCLUSION: Photoscreening combined with simple measurements of visual acuity may be a viable option for following efficacy of treatment in amblyopes. In some parts of the United States and in many areas of the world where telemedicine plays an increasingly important role, the plusoptiX(R) photoscreener could enhance vision care and may enhance telemedicine and the treatment of amblyopia


Arnold RW, Arnold AW, Eby E, Aleshire J: Lay Person Slit Lamp Detection of Iritis in Absence of an Eye MD: Test of a Portable Model of Cells and Flare. Binocular vision & strabology quarterly, Simms-Romano's 2012, 27(2):129-134. BACKGROUND: Asymptomatic - or minimally so, eye conditions like uveitis, iritis, and glaucoma are silent stealthily blinding diseases, especially when present in children. The iritis that accompanies Juvenile Idiopathic or Rheumatoid Arthritis (JIA or JRA) is characteristically asymptomatic. Children with these must be examined regularly and routinely(see Reference 1 and Table) on an opthalmologic biomicroscopic slit lamp for the microscopic cells (and aqueous flare) which occurr in the anterior chamber of the eye, signaling the presence of iritis, and an immediate need for anti-inflammatory agents. Such an exam is also indicated when the so afflicted develop most any symptoms of a new or recurrent eye problem. Slit lamp iritis determination remains challenging. It virtually requires a major, not portable, table mounted and expensive biomicroscope. And the examiner designated in schedules (1) is a trained ophthalmolgist,, an "Eye M.D.". Both. There are times and places throughout the world where and when a slit lamp may be available but there is no Eye MD (or qualified ophthalmic technician or assistant) available in a timely manner to timely examine for iritis when such is needed as noted. However, there are theoretical advantages if a parent could detect iritis in their J I A child if a slit lamp were available, if they had been trained to use it and recognize iritis cells and flare. METHODS: A portable model of varying iritis severity was developed. Parents of JIA patients were instructed on slit lamp use and then attempted to match unknown models of iritis severity with known training models of varying concentrations of cells and flare. RESULTS: Twelve parents ranked the 5 unknowns with an average summed deviation from expected of 2.2 +/-2 grade levels (out of 12). This was a good and useful degree of training. CONCLUSION: We were able to teach lay adults to match a model of iritis severity on a slit lamp. We would suggest that where needed, they could provide urgent and more convenient and faster diagnosis and treatment of recurrent iritis and also augment recommended scheduled Eye MD screening for iritis in JIA patients providing an effectively higher level of care, quality of life, and reduction in loss of vision for JIA victims at lower cost and greater facility for the patients, their caregivers and society as a whole.


Arnold RW, Tulip D, McArthur E, Shen J, Tappel J, Arnold LE, Winkle E, Armitage MD: Predictive value from pediatrician Plusoptix screening: Impact of refraction and binocular alignment. Binoc Vis and Strabismus Quart 2012, 27(4):227-232. ABSTRACT: Background: The positive predictive value (PPV) of conventional preschool acuity screening is about 50% whereas previous Polaroid photoscreening with experienced

interpretation can achieve PPV greater than 85%. The Plusoptix photoscreener has immediate

computer interpretation and a CPT code available to pediatricians.

Methods: Two Plusoptix S09 were used in two pediatric group practices with previously

validated refractive criteria and new manufacturer’s binocular alignment criteria. CPT billing

was monitored. Referred patients had prior gold-standard AAPOS examinations.

Results: 12% of 675 photoscreened preschoolers were referred. Of the 39 with AAPOS

gold-standard exams, the PPV from strabismus referrals was 17%, while 26 of 27 refractive

referrals had true amblyopia risk factors (PPV 96%). Screening CPT code 99174 reimbursement

rose from zero to half of insurers in 15 months.

Conclusion: Plusoptix photoscreening is valid after adjusting the binocular alignment

criteria. Such photoscreening should be employed by pediatric practices to detect and ultimately

to reduce amblyopia vision impairment in children.


Silbert DI, Matta NS, Arnold RW: Comparing The Iscreen To The Mti Photoscreener In Pediatric Vision Screening. IOVS 2012. Purpose: The iScreen digital photoscreener and the MTI photoscreener are both used to objectively screen for amblyopia risk factors in children. The MTI photoscreener is an analog model placing images on instant film and has been extensively tested, but limited availability of film may render it obsolete. The newly introduced iScreen digital photoscreener is a similar hand-held device, taking two rapid digital images, which are electronically transmitted for interpretation. In this study we compare the iScreen photoscreener with MTI for the ability to detect amblyopia risk factors compared to an ophthalmology exam and cycloplegic refraction in one cohort of children. We believe our results will help guide community-based screening programs in their selection of vision screening devices.

Methods: We performed a retrospective medical record review of patients who underwent iScreen and MTI photoscreening. 47 consecutive children were examined in our office. Each child was screened with both the iScreen as well as the MTI photoscreener in our office on the same day as part of a comprehensive pediatric ophthalmology examination. iScreen images were analyzed by the company and MTI images were analyzed by an expert masked examiner. Referral by either device was compared to the presence of amblyopia risk factors as determined by a cycloplegic examination as per the AAPOS referral criteria.

Results: 47 children were analyzed in total. 70% of children were found to have amblyopia risk factors. The iScreen was found to have a sensitivity of 81% and specificity of 79%. The MTI was found to have a sensitivity of 79% and specificity of 100%.

Conclusions: The iScreen and MTI performed similarly on this cohort of patients when compared to a comprehensive pediatric ophthalmology examination. Screening programs should feel comfortable substituting the iScreen photoscreener for the MTI.


Arnold RW: Amblyopia risk factor prevalence. J Pediatr Ophthalmol Strabismus 2013, 50(4):213-217. PURPOSE: In 2003, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) published a set of risk factors for amblyopia. The intent was to promote uniformity of reporting and development in screening. Because this prevalence is not yet known, this meta-analysis is an attempt to estimate it. METHODS: Major community preschool eye examination studies were reviewed and AAPOS cut-offs estimated. RESULTS: The approximate prevalence of anisometropia is 1.2%, hyperopia is 6%, astigmatism is 15%, myopia is 0.6%, strabismus is 2.5%, and visual acuity less than 20/40 is 6%. The mean combined prevalence is 21% +/- 2% compared to a prevalence of amblyopia 20/40 and worse of 2.5%. CONCLUSIONS: Knowing risk factor prevalence simplifies validation efforts. Amblyopia screening with a risk factor sensitivity less than 100% is expected and desirable. [J Pediatr Ophthalmol Strabismus 2013;50(4):213-217.].


Arnold RW, Arnold AW, Armitage MD, Shen JM, Hepler TE, Woodard TL: Pediatric photoscreeners in high risk patients 2012: A comparison study of Plusoptix, iScreen and SPOT. Binoc Vis and Strabismus Quart 2013, 28(1):20-28. Background: New photoscreening models promise to detect amblyopia risk

factors early in hopes of reducing permanent pediatric monocular and binocular vision

impairment. The 3 commercially available interpreted photoscreeners had not yet been


Methods: This is a prospective, observational screening study following AAPOS

guidelines on pediatric patients with and without developmental delays. 270 patients in a

pediatric eye practice aged 4.7 +/- 4 years with 7% special needs. From December 2011 through

March 2012, the Plusoptix, the iScreen, and the Pediavision SPOT were applied before

confirmatory exam in a clinical pediatric eye practice.

Results: The inconclusive rate ranged from 1-4% (iScreen) to 12% (Plusoptix).

Sensitivity ranged from 72% (iScreen) to 84% (Plusoptix) and specificity ranged from 68%

(SPOT) to 94% (Plusoptix). The iScreen can provide results in 99% of high risk patients..

Conclusions: In this cohort with high pre-screening prevalence, the 2011 photoscreeners

had favorable validation that is expected to improve with further clinical study. Pediatricians

have practical technology with a recognized procedure code to assist in amblyopia reduction.


Arnold RW, Davis B, Arnold LE, Rowe KS, Davis JM: Calibration and validation of nine objective vision screeners with contact lens-induced anisometropia. J Pediatr Ophthalmol Strabismus 2013, 50(3):184-190. PURPOSE: New objective photoscreeners are emerging with encouraging national guidelines and pediatric providers can be reimbursed for photoscreening. METHODS: Nine objective screeners were applied to two emmetropic subjects with or without known power contact lenses to induce spherical and cylindrical anisometropia close to American Association for Pediatric Ophthalmology and Strabismus (AAPOS) thresholds. RESULTS: The screeners produced near linear pupil crescents and estimated refractions for induced anisometropia. Most performed well with AAPOS 2003 validation; however, the iPhone (Apple, Cupertino, CA) was too sensitive, whereas the remote autorefractors using Vision in Preschoolers Study criteria were less sensitive. CONCLUSIONS: The new, interpreted objective screeners appear valid for detection of anismetropia.


Donahue SP, Arthur B, Neely DE, Arnold RW, Silbert D, Ruben JB: Guidelines for automated preschool vision screening: A 10-year, evidence-based update. J AAPOS 2013, 17(1):4-8.SUMMARY: In 2003 the American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee proposed criteria for automated preschool vision screening. Recent literature from epidemiologic and natural history studies, randomized controlled trials of amblyopia treatment, and field studies of screening technologies have been reviewed for the purpose of updating these criteria. The prevalence of amblyopia risk factors (ARF) is greater than previously suspected; many young children with low-magnitude ARFs do not develop amblyopia, and those who do often respond to spectacles alone. High-magnitude ARFs increase the likelihood of amblyopia. Although depth increases with age, amblyopia remains treatable until 60 months, with decline in treatment effectiveness after age 5. US Preventive Services Task Force Preventative Services Task Force guidelines allow photoscreening for children older than 36 months of age. Some technologies directly detect amblyopia rather than ARFs. Age-based criteria for ARF detection using photoscreening is prudent: referral criteria for such instruments should produce high specificity for ARF detection in young children and high sensitivity to detect amblyopia in older children. Refractive screening for ARFs for children aged 12-30 months should detect astigmatism >2.0 D, hyperopia >4.5 D, and anisometropia >2.5 D; for children aged 31-48 months, astigmatism >2.0 D, hyperopia > 4.0 D, and anisometropia >2.0 D. For children >49 months of age original criteria should be used: astigmatism >1.5 D, anisometropia>1.5 D, and hyperopia >3.5 D. Visually significant media opacities and manifest (not intermittent) strabismus should be detected at all ages. Instruments that detect amblyopia should report results using amblyopia presence as the gold standard. These new American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee guidelines will improve reporting of results and comparison of technologies.


Silbert DI, Arnold RW, Matta NS: Comparison of the iScreen and the MTI photoscreeners for the detection of amblyopia risk factors in children. J AAPOS 2013, 17(1):34-37. BACKGROUND: The iScreen and Medical Technology and Innovations, Inc, (MTI) photoscreeners objectively screen for amblyopia risk factors in children. The MTI photoscreener has been extensively validated as a device that objectively screens for amblyopia risk factors in children, but limited availability of the instant film it uses may soon render it obsolete. More recently the iScreen photoscreener has been introduced. This device captures images digitally and transmits them electronically to be interpreted. We compared the newer iScreen's ability to detect amblyopia risk factors in children with the established MTI photoscreener. METHODS: The medical records of consecutive subjects screened by both the iScreen and MTI photoscreeners on the same day were retrospectively reviewed. The iScreen images were analyzed by the device's central interpretation center; MTI images were analyzed by an expert masked examiner using the delta crescent method. Referrals by both instruments were compared to the results of cycloplegic examination as per the American Association for Pediatric Ophthalmology and Strabismus 2003 referral criteria. RESULTS: A total of 169 children were included in the study. Of these, 107 (63%) were found to have amblyopia risk factors. The iScreen was found to have an accuracy rate of 81%, sensitivity of 87%, and specificity of 76%. The MTI was found to have an accuracy rate of 81%, sensitivity of 81%, and specificity of 81%. CONCLUSIONS: The iScreen and MTI performed similarly in detecting amblyopia risk factors when compared to a comprehensive pediatric ophthalmology examination.

Arnold RW, Armitage MD: Performance of four new photoscreeners on pediatric patients with high risk amblyopia. J Pediatr Ophthalmol Strabismus 2014, 51(1):46-52.  PURPOSE: A new study by the American Academy of Pediatrics touts the benefits of photoscreening, especially in preverbal children who cannot yet perform monocular acuity screening. Emerging devices have not been compared in young and developmentally challenged children. METHODS: Consecutive patients in a pediatric eye practice had a comprehensive eye examination and four photoscreens: PlusoptiX (PlusoptiX, Nuremburg, Germany), SPOT (PediaVision, Lake Mary, FL), iScreen (iScreen, Memphis, TN), and the GoCheckKids application (Gobiquity, Aliso Viejo, CA) for the iPhone 4s (Apple, Cupertino, CA) with Delta Center Crescent interpretation. They were validated according to the 2003 American Association for Pediatric Ophthalmology and Strabismus uniform guidelines. RESULTS: One hundred eight children aged 1 to 12 years participated, with 56% having amblyopia risk factors and 10% having autism. For the four devices, sensitivity, specificity, and inconclusive results were as follows: PlusoptiX (83%, 86%, 23%), SPOT (80%, 85%, 4%), iScreen (75%, 88%, 13%) and iScreen (with Delta Center Crescent) (92%, 88%, 0%), and GoCheckKids (with Delta Center Crescent) (81%, 91%, 3%). CONCLUSIONS: Even in high risk and young children, current instrument-based screeners can reliably screen for refractive and strabismic risk factors that lead to amblyopia. Some devices can reduce the proportion of inclusive results in challenging cases.


Kirk S, Armitage MD, Dunn S, Arnold RW: Calibration and Validation of the 2WIN Photoscreener Compared to the PlusoptiX S12 and the SPOT. J Pediatr Ophthalmol Strabismus 2014, 51(5):1-4.  PURPOSE: Pediatricians are interested in the amblyopia detection ability of photoscreeners, whereas ophthalmologists ponder their value as autorefractors. The 2WIN (Adaptica, Padova, Italy) is a new device capable of estimating refractive error and ocular alignment by infrared photoscreening. METHODS: Sequential pediatric eye patients with a high (56% to 60%) prescreening prevalence of amblyopia risk factors were screened with the PlusoptiX S12 (PlusoptiX, Inc., Atlanta, GA), SPOT (PediaVision, Lake Mary, FL), and 2WIN photoscreeners before confirmatory examination adhering to American Association for Pediatric Ophthalmology and Strabismus guidelines and Alaska Blind Child Discovery institutional review board protocol. Instrument referral guidelines determined through phase 1 comparison was then applied on additional patients for validation in phase 2. RESULTS: Sixty-two children (age: 1 to 10 years, mean: 5.2) were screened with all three devices before cycloplegic examination. Refractive results were inconclusive due to pupil size, cooperation, and out-of-range values. Values for sensitivity (91% and 78%), specificity (71% and 59%) and inconclusive rate (10% and 13%) were found for PlusoptiX and SPOT. The 2WIN was calibrated for this age range (phase 1), yielding 71% sensitivity, 67% specificity, and a 5% inconclusive rate. Regression compared to examination for the PlusoptiX, SPOT, and 2WIN, respectively, were sphere (r2: 0.76, 0.87, and 0.58), cylinder power (r2: 0.67, 0.56, and 0.50), and cylinder axis (r2: 0.71, 0.41, and 0.40). A preferred 2WIN instrument criteria set was determined from the receiver operating characteristic curve. In phase 2, with 117 patients comparing 2WIN to PlusoptiX A-09, sensitivity was 73% and 85%, specificity was 76% and 73%, and inconclusive rate was 8% and 12%. The three instant-interpreting photorefractors performed well on amblyopic children, with the 2WIN having low inconclusive results. The PlusoptiX outperformed the SPOT and 2WIN as an autorefractor, particularly with respect to astigmatism power and axis. CONCLUSIONS: The new 2WIN is a promising addition to portable photoscreeners for amblyopia detection and estimating refractive error.


Silbert DI, Arnold RW: Do we need to directly detect astigmatism when photoscreening for amblyopia risk factors (ARFs) IOVS 244 2015, 19(4):e61. Introduction: The cost of smart phone platforms makes them highly desirable for use as vision-screening devices. Traditional vision screening uses two off-axis flashes in sequential photographs. We hypothesize that the vast majority of astigmatic eyes could be appropriately detected with a single flash and only one photograph simplifying image acquisition.

Methods: A total of 174 patients at 2 sites were enrolled prospectively. Children aged 12-72 months of age were consented and tested. The GoCheck Kids (Gobiquity Mobile Health Inc) smartphone photo- refraction measurements were compared to cycloplegic (gold standard) refraction using AAPOS ARF guidelines. Two photographs were taken on each patient at 90  and 180 . Analyses were performed for single-axis and double-axis photorefraction and compared. Results: A total of 55/348 eyes of 30 patients with a cycloplegic astigmatism component above AAPOS ARF guidelines were identified; 14 of 30 patients were referred for cylinder only, with the remaining 16 with refractive anomalies. Overall, single-axis sensitivity/specificity for AAPOS ARFs were 59% and 83%, respectively, while dual axis was 74%/82% respectively.

Discussion: A single flash photoscreening system is effective for the detection of hypermetropia, myopia, and anisometropia. Although it will not directly detect astigmatism, astigmatism is indirectly detected and referred due to its association to other refractive anomalies. Elimination of need for a second photograph simplifies the use of a smartphone to detect ARFs.

Conclusions: A single flash photoscreening system such as the Gobiquity mobile photoscreening device can be substituted for traditional two flash systems without sacrificing much sensitivity and specificity in astigmatism detection.


Tsao Wu M, Armitage MD, Trujillo C, Trujillo A, Arnold LE, Tsao Wu L, Arnold RW: Portable acuity screening for any school: validation of patched HOTV with amblyopic patients and Bangerter normals. BMC Ophthalmol 2017, 17(1):232.  BACKGROUND: We needed to validate and calibrate our portable acuity screening tools so amblyopia could be detected quickly and effectively at school entry. METHODS: Spiral-bound flip cards and download pdf surround HOTV acuity test box with critical lines were combined with a matching card. Amblyopic patients performed critical line, then threshold acuity which was then compared to patched E-ETDRS acuity. 5 normal subjects wore Bangerter foil goggles to simulate blur for comparative validation. RESULTS: The 31 treated amblyopic eyes showed: logMAR HOTV = 0.97(logMAR E-ETDRS)-0.04 r2 = 0.88. All but two (6%) fell less than 2 lines difference. The five showed logMAR HOTV = 1.09 ((logMAR E-ETDRS) + .15 r2 = 0.63. The critical-line, test box was 98% efficient at screening within one line of 20/40. CONCLUSION: These tools reliably detected acuity in treated amblyopic patients and Bangerter blurred normal subjects. These free and affordable tools provide sensitive screening for amblyopia in children from public, private and home schools. Changing "pass" criteria to 4 out of 5 would improve sensitivity with somewhat slower testing for all students.


Arnold RW, Arnold AW, Hunt-Smith TT, Grendahl RL, Winkle RK: The Positive Predictive Value of Smartphone Photoscreening in Pediatric Practices. J Pediatr Ophthalmol Strabismus 2018:1-4. PURPOSE: To compare smartphone photoscreening with other commercial objective screeners for amblyopia screening for young children. METHODS: Ten pediatricians in four practices employed Nokia 1020 smartphones (Espoo, Finland) with single-axis Gobiquity software (Scottsdale, AZ) during well-child visits. Outcomes of confirmatory pediatric ophthalmology examinations were prospectively compared using American Association for Pediatric Ophthalmology and Strabismus uniform standards. RESULTS: Five percent of 6,310 in-office screenings were referred: 25% for high anisometropia, 31% for hyperopia, and 15% for myopia. The positive predictive value (PPV) in 217 follow-up examinations was 68% (95% confidence interval: 62% to 74%) by 2013 age-stratified standards and 77% (confidence interval: 71% to 83%) by 2003 American Association for Pediatric Ophthalmology and Strabismus standards. The follow-up rate was 65%. CONCLUSIONS: Smartphone photoscreening had PPV comparable with other commercial objective screeners. Simple, valid photoscreeners should help pediatricians achieve widespread compliance with screening guidelines to reduce the burden of pediatric amblyopia vision impairment.


Arnold RW, O'Neil JW, Cooper KL, Silbert DI, Donahue SP: Evaluation of a smartphone photoscreener app to detect refractive amblyopia risk factors in children 1-6 years. Clin Ophthalmol 2018, 12:1-5.  Purpose: To determine the specificity and sensitivity of a smartphone app (GoCheckKids [GCK] used as a photoscreening tool on the iPhone 7 to detect refractive amblyopia risk factors in children aged 1–6 years.

Participants and methods: A prospective, multicenter, 10-month evaluation of children aged 1–6 years old who underwent photoscreening with the GCK app to detect amblyopia risk factors. The first acceptable quality photograph of each study subject was evaluated by trained technicians using GCK’s proprietary automated image processing algorithm to analyze for amblyopia risk factors. Trained graders, masked to the cycloplegic clinical data, remotely reviewed photographs taken with the app and compared results to the gold standard pediatric ophthalmology examinations using the 2013 American Association for Pediatric Ophthalmology & Strabismus amblyopia risk factor guidelines. Primary outcome was the ability of the GCK app to identify amblyopia risk factors compared to the cycloplegic refraction. Results: There were 287 patient images analyzed. The overall sensitivity and specificity in detecting amblyopia risk factors were 76% and 85%, respectively using manual grading. The overall automated grading results had a sensitivity and sensitivity in detecting amblyopia risk factors of 65% and 83%, respectively.

Conclusion: The GCK smartphone app is a viable photoscreening device for the detection of amblyopia risk factors in children aged 1–6 years.


Arnold RW, Damarjian AG, Molina A, Smith KA: Calibrated measurement of acuity, color and stereopsis on a Nintendo 3DS game console. Clin Optometry 2019, 11:47-55. Background: We developed dynamic, forced-multiple choice games to measure monocular near acuity, color vision and stereopsis on the autostereoscopic barrier screen of the Nintendo 3DS gaming system.
Methods: In an IRB study, normal pediatric and adult subjects and patients performed routine patched near visual acuity, Ishahara’s color test and Stereo Fly. Then each performed a two-phase orientation and testing game “PDI Check” on a Nintendo 3DS
Results: 45 patients aged 5-60 completed the routine and Nintendo near tests resulting in reliable, discriminatory functions. Thresholds were determined to separate poor from fair-to-normal monocular acuity with sensitivity 83% and specificity 100%, stereoacuity with sensitivity 80% and specificity 97% and color with sensitivity 83% and specificity 97%.
Conclusion: The Nintendo 3DS game “PDI Check” can provide reliable near vision testing via a dynamic, randomized method that does not require goggles for stereo, and does not require patching to assure monocular testing.


Arnold SL, Arnold AW, Sprano JH, Arnold RW: Performance of the 2WIN photoscreener with “CR” strabismus estimation in high risk patients. Am J Ophthalmol. 2019;207:195-203. Background: Accurate estimation of refractive error and ocular alignment is critical for identifying amblyopia risk factors. The 2WIN photoscreener (Adaptica, Italy) uses a novel infrared-transmitting occluder to quickly estimate intermittent deviations.
Methods: 2WIN refraction was compared to dry and cycloplegic retinoscopy and Retinomax. 2WIN “CR” function with wand was compared to cover test.
Results: 371 patients, 0.6-63 years, median age 6 years had refraction and 2WIN yielding high degrees of correlation (Pearson Product Moment) on linear regression for spherical equivalent (0.73-0.79), Cylinder power (0.78-0.79), J) vector (0.79-0.83) and J45 vector (0.64-0.67) . Similar proportions of 2WIN and Retinomax were inside target refraction values for spherical equivalent (70% vs 69%), cylinder power (94% vs 90%) and cylinder axis (69% vs 71%). 2WIN CR above 10 PD correlated with cover test for constant and intermittent deviations (Pearson 0.64-0.71). 2WIN + CR screened for 2003 AAPOS amblyopia risk factors with 68% sensitivity and 84% specificity in preschool children with 56% prescreening probability and 31% developmental delays.
Conclusion: The 2WIN correlated well with exam and Retinomax. The CR function reliably estimated constant and intermittent strabismus over 10 PD.


Smith KA, Arnold AW, Sprano JH, Arnold SL, Arnold RW: Performance of a quick screening version of Nintendo 3DS “PDI Check” game on patients with ocular suppression. JPOS 2019, 56(4):234-237. Background: Testing of monocular acuity and stereo can be a challenging and time-consuming process for certain patients. PDI Check is a vision screening game that utlizes the autostereoscopic parallax barrier screen of the Nintendo 3DS. Version 0.2.5 of the game presents Landholt C enlarging optotypes with ocular rivalry so suppression can be assessed.
Methods: Children and adults were consented to perform the PDI Check Quick Screening game following conventional near testing of patched Rosenbaum acuity, Titmus Fly stereo, Worth 4 dot and Ishihara color. Time to complete each and preferred method were recorded.
Results: 77 patients, aged 5-63 attempted all tests. There was a positive correlation between PDI check and conventional tests for all visual tasks. Using previously determined instrument referral criteria, sensitivity/specificity was determined for right acuity 67%/91%, left acuity 55%/94%, stereopsis 87%/95%, red-green color 80%/99% and ocular suppression 58%/98%. Screening time was 202±96 seconds versus 99±42 seconds for PDI Check; the game was preferred by 87%.
Conclusion: PDI check provided valid assessment of near vision in less than half the time of conventional testing without patches or goggles. This Quick version may help eye technicians and doctors with time efficiency in the frequent task of near screening.

Smith KA, Damarjian AG, Molina A, Arnold RW. (2019). "Calibrated measurement of acuity, color and stereopsis on a Nintendo 3DS game console." Clin Optom (Auckl) 11: 47-55.
Background We developed dynamic, forced-multiple choice games to measure monocular near acuity, color vision and stereopsis on the autostereoscopic barrier screen of the Nintendo 3DS gaming system.
Methods In an IRB study, normal pediatric and adult subjects and patients performed routine patched near visual acuity, Ishahara’s color test and Stereo Fly.  Then each performed a two-phase orientation and testing game “PDI Check” on a Nintendo 3DS
Results 45 patients aged 5-60 completed the routine and Nintendo near tests resulting in reliable, discriminatory functions.  Thresholds were determined to separate poor from fair-to-normal monocular acuity with sensitivity 83% and specificity 100%, stereoacuity with sensitivity 80% and specificity 97% and color with sensitivity 83% and specificity 97%.
Conclusion The Nintendo 3DS game “PDI Check” can provide reliable near vision testing via a dynamic, randomized method that does not require goggles for stereo, and does not require patching to assure monocular testing. 

Arnold, R. W. (2020). "Comparative AAPOS validation of the blinq birefringent amblyopia screener with isolated small-angle strabismus." Clin Ophthalmol 14: 325-329.
Background The Rebion blinq binocular birefringent ocular alignment screener was recently commercially released, but it did not yet have validation by American Association for Pediatric Ophthalmology and Strabismus (AAPOS) uniform guidelines.
Methods Children and adults from a high-risk eye practice had screening by blinq and the Adaptica 2WIN with CR corneal reflex strabismus estimation1 and then were validated by AAPOS 2003 guidelines plus additional efforts to identify patients with diminished binocularity.
Results Both blinq and 2WIN were completed by 87 patients median age 6.5 years.  Sensitivity, specificity and positive predictive value (PPV) to detect amblyopia risk factors for blinq were 75%, 68% and 81% whereas 2WIN had 91%, 68% and 84%. The blinq referred two young patients with isolated, small-angle strabismic amblyopia that 2WIN refractive function passed.  2WIN CR function correctly identified the small deviations.
Conclusion Despite its non-refractive design to identify binocular foveation, blinq performed well with refractive and strabismic uniform risk factors and a PPV greater than 80%.


Levitt AH, Martin SJ, Arnold RW. (2020). "Performance of glow-fixation GCK and 2WIN photoscreeners and Retinomax to uncover hyperopia." Clin Ophthalmol 14: 2237-2244.
Background A low-detail, glowing fixation device was added to GoCheck Kids (GCK) photoscreener in hopes of unmasking hyperopia and amblyopia risk factors (ARF).
Methods Pediatric eye patients were screened by GCK and 2WIN photoscreeners, and Retinomax autorefractor before being compared to AAPOS ARFs.
Results Screening was attempted by 131 children who then had school bus accommodation-relaxing skascopy (SBA-RS) before cycloplegic examination.  By 2013 AAPOS uniform guidelines, sensitivity/specificity for GCK was 87%/68%, for 2WIN was 87%/71% and for Retinomax 79%/68%.  Detection of amblyopia had sensitivity/specificity by GCK of 78%/63%, for 2WIN 79%/65% and for Retinomax 77%/68%.  Inconclusive screens were 7 for GCK, 6 for 2WIN and 13 for Retinomax.  Mean hyperopia for GCK (+2.49±0.74 D) was similar to cycloplegic refraction (+2.93±0.72D) and SBA-RS (+2.80±0.82 D) while GCK was slightly more than Retinomax (+1.59±0.93 D, p=0.13) but significantly more than 2WIN (+1.02±0.49 D, p<0.01).
Conclusion GCK, 2WIN and Retinomax had similar validity detecting uniform amblyopia risk factors and amblyopia itself.  The non-detailed glow fixation device allowed GCK to uncover substantial hyperopia while the detailed flashing fixation devices on 2WIN and Retinomax seemed to stimulate accommodation in some hyperopic children.

Martin SJ, Htoo HE, Hser N, Arnold RW. (2020). "Performance of two photoscreeners enhanced by protective containers." Clin Ophthalmol 14: 1427-1435.
Photoscreeners provide valid, cost-effective early detection of amblyopia risk factors, however they require proper illlumination, flash intensity, pupil dilation and patient cooperation.
Background Adaptica (Padova, Italy) developed the Kaleidos case for their 2WIN infrared photoscreener.  GoCheck Kids (GCK, Scottsdale, Arizona) developed a flash concentrating case for the iPhone 7+ smart-phone (Cupertino, California).
Methods In remote Burma and urban Alaskan clinics, Kaleidos and GCK were used before confirmatory eye exam using AAPOS 2003 and 2013 Uniform Guideline validation.  2WIN spherocylinder refraction was compared to Retinomax (Righton, ) and cycloplegic exam using J0 and J45 vector transformation.
Results The average age of the 48 Burma patients and 114 Alaskan patients was 8±6 with 50 young enough for the 2013 Guidelines.  Kaleidos closely matched refraction with Intraclass correlation (ICC) for J0 vector 0.47 (0.38-0.55) and for J45 vector 0.57 (0.49-0.64).  Estimates of sphere, anisometropia and cylinder for GCK had ICC 0.66, 0.62 and 0.64 whereas Kaleidos had 0.82, 0.80 and 0.83.  By 2003 guidelines Kaleidos screened sensitivity:specificity:PPV of 87%:84%:84% but 13 inconclusive from Burma reduced that to 88%:70%:70%.  GCK with only 6 inconclusives had validity 79%:83%:79% improved to 85%:73%:82% with central expert interpretation.  Using 2013 Guidelines, Kaleidos was 70%:96%:93% while GCK was 53%:90%:77%.
Conclusion Both devices detected amblyopia risk factors well.  GCK had less inconclusive results even in Asian pupils while Kaleidos matched sphere and cylinder refraction.  Specialized housing enhanced performance of 2WIN and GCK photoscreeners improving speed and reliability for amblyopia screening and refraction even in populous and luminous locations.

Keffalos MA, Martin SJ, Arnold RW. (2021). "Drive-By Photoscreening: plusoptiX, 2WIN and blinq Amblyopia Detection during the COVID-19 pandemic." Clin Ophthalmol 15: 775-782.
Background Community photoscreening for amblyopia had successfully been adopted by many communities, however many clinics curtailed screening as a result of the COVID-19 pandemic.  We modified three conventional devices and tested them for outdoor, drive-by socially-distanced photoscreening.
Methods External frames that provide luminance control and focus distance were fashioned for plusoptiX S12 (Nuremberg, Germany), Adaptica 2WIN in Kaleidos case (Padova, Italy) and the Rebion blinq (Boston, USA).  Children were screened by each device and then Retinomax (Righton, Japan) before AAPOS guideline validation.
Results Eighty-eight children average age 8±7 years had precise refraction and alignment from which 69% AAPOS 2003 risk factors were determined.  The sensitivity/specificity/inconclusive rate for plusoptiX were 85%/96%/16%, for 2WIN 79%/89%/5% and for blinq 43%/74%/8%.  Blinq improved to 54%/70% when screening for amblyopia ± strabismus.  Bland Altman analysis of spherical equivalent showed plusoptiX and 2WIN with less over-minus than Retinomax and J0 and J45 vectors highly reliable for astigmatism determination.
Conclusion The infrared photorefractors in modified cases reliably screened amblyopia risk factors and refraction.  The birefringent scanner provided drive-by results but less reliably with wire-frame opaque case than without the case in a dimly lit room. Modified drive-by photoscreeners could help reduce amblyopia and provide socially-distanced refraction during an extended pandemic.

Brown SP, Rue CM, Smith KA, Arnold RW (2021). Extraordinary dynamic near vision in champion shotgun shooters; PDI Check evaluation of stereo and color without floor effect. Clinical Ophthalmology. 2021;15:575—81. Background Conventional near and stereo tests have a “floor effect;” inability to discriminate normal from super-normal. Shotgun champions require unique performance in binocularity and rapid color discrimination. Methods Twenty-nine champion clay-target shooters, 14 normal ARMY and 12 color-normal subjects were tested with conventional near vision tests and on PDI-Check, a series of dynamic, near vision tests on the autostereoscopic Nintendo console. Results
Conventional tested shotgunners had all perfect Ishihara and 75% best 40 sec Stereo fly while Army had 92%perfect Ishihara and 69% best stereo fly. On PDI-Check,experienced shotgunners with median stereo of 17 (IQR 12-41) arc sec were better than Army volunteers 59 (IQR 30 to 487) arc seconds (Mann- Whitney U=62, p=0.04). Median PDI-Check for shotgun compared to Army was 88% compared to 84% for blue cone, 90% compared to 84% for green and 77% compared to 72% (red, Mann-Whitney p=0.05). Adding dark cherry filter shooting glasses improved the red and green color detection (p<0.01). This study lacked power to detect eye dominance using PDI Check color or stereo. Conclusion
Many champion shotgun shooters had outstanding dynamic near stereo and better-than-average color vision which could be optimized with dark filter spectacles for red and green hues. PDI Check not only helps identify abnormal binocularity and color vision, but it can clarify supranormal vision as well.

Arnold AW, Smith KA, Molina A, Damarjian AG, Arnold RW. (2021). "Trichromatic enhanced dynamic color screening on the PDI Check Nintendo 3DS game." Clin Optom 13: 137-141.
Introduction: Classification of color deficiency has required substantial time and expense with the static Farnsworth-Munsell and Innova Rabin tests.  Therefore, dynamic color tests were developed for the Nintendo 3DS.
METHODS Fifteen color deficient patients and 17 age-matched normals performed Rabin color test in addition to PDI Check dynamic color games resembling Farnsworth-Munsell presentation (version 0.2.8) and 3-color iso-luminance gray (version 0.2.13).
RESULTS Tests of red, green and blue cone-deficient with the v0.2.8 had sensitivity/specificity/PPV of 92%/86%/92% protanopes, 78%/90%/88% deutanopes and 87%/50%/93% tritanopes.  Version 0.2.13 had sens/spec/PPV of 78%/83%/78% red-cone, 100%/85%/80% green cone and 67%/78%/33% blue cone.   Corresponding IntraClass Correlation (ICC) utilizing v0.2.8 were red-cone 0.22(-0.02-0.60), green-cone 0.34(-0.10-0.67) and blue-cone 0.38(0.12-0.75).  ICC for v0.2.13 were higher with protanope 0.62(-0.07-0.87), deuteranope 0.64(-0.09-0.88) and tritanope (0.31(-0.07-0.70).  The PDI Check color game took 65 seconds compared to 97 seconds for Innova Rabin. CONCLUSION
The PDI Check color game identifies patients with inherited color deficiencies.


Arnold RW, Beveridge JS, Martin SJ, Beveridge NR, Metzger EJ, Smith KA (2021). Grading Sphero-Cylinder Spectacle Similarity. Clin Optom (Auckl). 2021;13:23-32. Background: Portable autorefractors can estimate refractive error in remote locations, but sphero-cylinder comparison and donated-spectacle dispensing are not yet simple. Methods: Normal astigmats determined best corrected acuity, then degraded 1 logMAR (Grade A), 3 logMAR (Grade B), and 6 logMAR (Grade C) to determine limits of astigmatism axis and power at these levels. The cylindrical refraction was vector transformed with J0 on the abscissa and J45 on the ordinate. Results: Ten subjects produced multiple refractions at the interfaces of Grades A, B, and C representing ovals on the J0 and J45 coordinates. When rotated, the vertical axis represented 45 degrees or 135 degrees , the horizontal long axis was 1.6x the short axis. The size of the ovals positively correlated with cylinder power. Given a target refraction, the comparability of a candidate lens was demonstrated on our interactive database yielding a simple A, B, C, or worse grade for cylinder, spherical equivalent, and pupillary diameter. Conclusions/Relevance: Inputting a remote autorefraction, pupillary diameter and age as target and a donated spectacle as the candidate with a "B" grade similarity would be expected to attain 20/40 acuity (3 logMAR degrade) if best corrected visual acuity was 20/20. This practical Excel database could facilitate widespread remote lay dispensing of the cylinder as well as spherical spectacles. The grade similarity can also compare refracting tools such as photoscreeners and hand-held autorefractors. Clinical Trials Registry: NCT04297969.


Arnold R, Martin SJ, Beveridge JR, Arnold AW, Arnold SL, Beveridge NR, et al (2021). Ellipsoid Spectacle Comparison of PlusoptiX, Retinomax and 2WIN Autorefractors. Clin Ophthalmol. 2021;15:3637-48. Background: Handheld devices can automatically give an estimate of refraction. The established method for refraction comparison using spherical equivalent (M) and J0, J45 vector transformations by Bland–Altman analysis is too complex for non-eye doctors involved with vision screening and remote vision clinics. Therefore, a simpler comparison technique was developed.
Methods: Based on the spectacle limit to resolve grade A 1 logMAR, B 3 logMAR and C 6 logMAR blur, J0, J45, and M are combined into the Alaska Blind Child Discovery (ABCD) composite ellipsoid GRADE system. Pediatric eye patients had confirmatory examination after dry refraction with three portable autorefractors: Plusoptix, 2WIN and Retinomax. The refractions were then compared using both Bland–Altman and ABCD composite. Performance to detect AAPOS amblyopia risk factors was also assessed.
Results: A total of 202 children, mean age seven years, 28% high spectacle need and 43% AAPOS 2013 amblyopia risk factors showed high correlation with cycloplegic refraction (intraclass correlation 0.49 to 0.90) for sphere, J0 and J45 spectacle components. Plusoptix had more (10%) inconclusives due to patients out-of-range. The Retinomax was unable to screen some younger children and was less reliable for sphere but gave more precise astigmatism estimates. The proportion of autorefractions expected to give GRADE A/B high- need patients acuity improvement to 20/40 would be 41% for Plusoptix, 39% for 2WIN and 65% for Retinomax. Sensitivity/specificity for amblyopia risk factor detection was 80%/83% for Plusoptix, 72%/88% for 2WIN and 84%/73% for Retinomax.
Conclusion: The simplified spectacle comparison resembled Bland–Altman and could assist lay vision screeners and non-eye doctors attempting remote spectacle donation worldwide.


Arnold R(2021)W. Digital values for alpha acuities. JPOS. 2021;58(2):132-5. Background: The lack of consistent data formatting for visual acuity in electronic health records has led to inefficient data extraction and analysis.
Methods: Prior acuity efforts were reviewed and analyzed relative to alpha-designated visual acuity. Prominent elecrtonic medical record formatting was reviewed.
Results: A table was generated facilitating the asignment of digital values to alpha acuities for metric and USA designation.
Discussion: Consistent and usable visual acuity data should lead to better research and improve physician burn-out.


Mahlen T, Arnold R(2021). Pediatric non-refractive vision screening with EyeSwift, PDI Check and blinq. Clin Ophthalmol. 2021;16:375-84. Background
The purpose of this paper is to validate three recent non-refractive devices that target sensory and/or strabismus risk factors for amblyopia. The EyeSwift with eye tracking (NovaSight, Israel) and PDI Check on autostereoscopic Nintendo 3DS (Anchorage) are video games that estimate acuity, binocularity and color. The Rebion blinq (Boston) assesses foveation by birefringence.
Methods Students were consented to be screened by each device before confirmatory examination with optimized, refined refraction. Results were compared with correlation and Bland Altman plots while screening ability was compared with 2021 AAPOS Guidelines and the strabismus-amblyopia rubric proposed by David Hunter.
Results 77 ethnically diverse students, aged 11±4 (4-19) years had a 77% prevalence of 2021 risk factors. Near visual acuity, inter-eye difference and stereopsis correlated significantly (p<0.01) for the EyeSwift (r2 .14, .06 and .45) and PDI Check (r2 .23, .22 and .32). The sensitivity/specificity to target 2021-AAPOS : Hunter-rubric for EyeSwift was 82%/56% : 74%/62%, for PDI Check was 75/64% :69%/69% and for blinq 75/48% : 82%/39%. Sensitivity/specificity for the 7 color-deficient students was 86%/84% for EyeSwift and 100%/81% for PDI Check. Screening time was 96±19 seconds for PDI Check and 375±102 seconds for EyeSwift but less than 25 seconds for blinq.
Conclusion Reliable near visual acuity, stereo and color testing was obtained from the two binocular, touch screen devices often with minimal coaching of the student. The blinq rapidly gives an estimate of whether both eyes are steadily fixing, and the ProVersion predicted 100% which eye is deviated or amblyopic. Non-refractive validation metrics were beneficial.


Arnold R, Angi M (2022). Multifaceted amblyopia screening with blinq, 2WIN and PDI Check. Clin Ophthalmol. 2022;16:411-21. Background Novel devices target different facets of the amblyopia risk factors (ARFs). Rebion blinq through birefringence assesses binocular foveation. The Adaptica 2WIN is a multi-radial infrared photorefractor that also estimates ocular alignment. PDI Check is a forced-choice, dynamic near vision game for the autostereoscopic Nintendo 3DS.
Methods New and return patients to a pediatric ophthalmology clinic had concomitant confirmatory exam after all three vision screens validated with ROC curves, Bland Altman plots and ABCD ellipsoid. Exam outcomes were classified by ARFs visual acuity, strabismus, binocularity and refractive errors featuring the 2021 AAPOS Guidelines and Bosque-Hunter rubric for blinq.
Results 202 ethnically diverse students aged 10±4 (4-19years), 33% treatment-näive, had high 58% prevalence 2021 AAPOS ARFs. Linear logMAR visual acuity, inter-eye difference, stereo and 3-cone color correlated well between PDI Check and exam. 2WIN matched sphero-cylinder exam with ellipsoid scoring 2.1±1.5. For AAPOS 2021 refractive plus strabismus, sensitivity/specificity for PDI Check was 68%/59%, 2WIN 72%/95% and blinq 87%/32%. For the amblyopia or strabismus rubric, PDI Check was 79%/68%, 2WIN 56%/65% and blinq 94%/37%.
Conclusion Each device had advantages and disadvantages screening this cohort of older, high prevalence students many of whom had already been treated. Validation methods should cover more than just refraction as the new 2021 AAPOS Guidelines do. Clinical Ophthalmology


Arnold RW, Silbert DI, Modjesky H (2022). Instrument referral criteria for Plusoptix, SPOT and 2WIN targeting 2021 AAPOS guidelines. Clin Ophthalmol. 2022;16. Background The American Association for Pediatric Ophthalmology and Strabismus (AAPOS) issued a 2021 update of Uniform Validation Guidelines for instrument-based pediatric vision screeners. With each update it is important for each manufacturer to update the Instrument Referral Criteria (IRC) programed into their devices in order to optimize sensitivity and specificity to detect AAPOS criteria.
Methods De-identified data comparing photoscreening with simultaneous confirmatory examinations constituted separate cohorts for the development of Instrument referral criteria via receiver operating characteristic (ROC) curves. The refractions of the devices were also compared.
Results This study defines three sets of IRC (Sensitive, Medium and Specific) for three leading infrared photoscreening devices, PlusoptiX A12, Welch-Allyn SPOT and Adaptica 2WIN for children < 4 and >= 4 years in order to better target the 2021 AAPOS guidelines. The cohorts were similar but the SPOT group (n=755, mean age 9) was older with more astigmatism and the 2WIN (n=1362, mean age 7) were younger with more hyperopia and anisometropia compared to the cohort for PlusoptiX A12 (n=616, mean age 8). The age-based, medium magnitude IRC for anisometropia, hyperopia, astigmatism and myopia for SPOT (<4y:1.5,1.75,3.25,2.0) and (≥4y:1.5,1.75,2.25,3.5), for PlusoptiX (<4y:1.75,3.0,3.5,3.5) and (≥4y:1.75,3.0,2.5,2.5) and for 2WIN (<4y:1.75,2.5,3.5,3.5) and (≥4y:1.5,2.0,2.5,2.0). The mean ABCD ellipsoid spectacle matches differed; SPOT 1.8±1.3 (best) versus PlusoptiX 1.9±1.6 and 2WIN 2.2±1.4 (p<0.001).
Conclusion The 2021 AAPOS exam guidelines fosters early, specificity before age 4 and sensitivity after age 4. These evidence-based IRC for current SPOT, PlusoptiX and 2WIN photoscreeners should allow device manufacturers the data necessary to adjust their device IRC to maximize specificity, sensitivity or a medium between the two. This paper provides practical suggestions for better validation. Improved early screening combined with thorough treatment should reduce life-long vision impairment due to amblyopia.


Arnold RW, Donahue SP, Silbert DI, Longmuir SQ, Bradford GE, O’Neil J, et al(2022). Uniform guidelines for pediatric vision screen validation 2021. J AAPOS. 2022;26. Background As instrument based pediatric vision screening technology has evolved, AAPOS has worked to develop uniform guidelines, initially in 2003 and later updated in 2013, to assist manufacturers and researchers on the levels of amblyopia risk factors (ARFs) and visually significant refractive errors each given device’s instrument referral criteria should target. Since then, clinical experience has revealed an apparent high level of over-referral for non-amblyopic, symmetric astigmatism. This manuscript further refines the examination failure levels for ARFs and visually significant refractive errors in an effort to limit over-referrals while still capturing children in need of timely, comprehensive eye care.
New ARF and Refractive Error Failure Levels In this report, the threshold for symmetric astigmatism identified by cycloplegic refraction is raised compared to the 2013 guidelines. While astigmatism has a high prevalence in many screening populations, effective treatment can be initiated at a later age without resulting in a significant risk for impairment. The threshold for anisometropia has been decreased, making it more sensitive (ie lower threshold for referral). Though anisometropia has a lower prevalence, the potential for amblyopia is higher. In studies of automated screening devices, AAPOS now recommends that the gold-standard confirmatory comprehensive examination failure levels include anisometropia as >1.25D and hyperopia as >4.0 D. Astigmatism >3.0D in any meridian and myopia more than 3 diopters should be detected in children <48 months, whereas astigmatism >1.75 D and myopia 2 diopters or more should be detected after 48 months. Any media opacity >1mm and manifest strabismus of more than 8 PD should also be identified.
Conclusion Researchers can now adjust and publish instrument referral criteria adjusting their targeted sensitivity and specificity to detect new AAPOS defined confirmatory complete cycloplegic eye examination failure levels for amblyopia risk factors and visually significant refractive errors. The levels target ARFs and higher amounts of symmetric astigmatism and myopia for children under 4 years of age when conventional visual acuity can be less reliable. After age 4 years and in preparation for school, lower magnitudes of symmetric astigmatism and myopia are also targeted. While these levels of refractive error have low risk of amblyopia, they can influence school performance and allow myopia prevention therapy to be initiated. Methods that improve comparability of validation including receiver operating characteristic (ROC) curves and Bland Altman analysis are suggested. In addition to ARF detection, the ability of screening instruments to identify the presence or absence of amblyopia identified on confirmatory exams should be reported whenever possible.






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