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Alaska Blind Child Discovery

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

Validation- 2 Criteria?

    Validation Flowchart for Photoscreening    
ABCD History
Kids Eye Disorders
    VIMEO ABCD intro to Validation    
Vision Screening
    AAPOS 2021 Uniform Guidelines    
    Instrument Referral Criteria for 2021    
ABCD Clinics

Validation of vision screening actually involves two criteria.
Similar to target shooting. One on the target- the other on the gun-sight.

The target is a concentric circle and you score when you hit the bulls eye. That resembles the AAPOS 2003 GSE amblyopia risk factor cut offs.Your gun has an adjustable sight; that is like how far you let the crescent progress in the pupil. In a Plusoptix, a Welch Allyn Suresight, a Retinomax and a SPOT- it may be an output level that is reported as a refractive error. This can be confusing since the terminology is the same as the concentric rings on the target- or the bulls eye.Our TRUE and FALSE are dependent on the AAPOS 2003 GSE. large intermittent strabismus is a potentially variable True or False. Other cases are partial media opacity or eyelashes over the pupil.
The refer or pass relate to the specific referral criteria for a given screener. Inconclusive might mean aiming at a still child, but getting no output from the screener, or too small a pupil, but it can also mean an autistic kid crying who won't even look at the screener.

A different analogy might be an unmarked thermometer and trying to determine whether a child has an infection. Infections usually cause fever- and pediatricians agree this is above 101°F or 38C- these are similar to the 2003 AAPOS GSE criteria. Markings on your glass vaccuum tube with mercury- these are like the referal criteria for your screening instrument.

Therefore, in validation, there are two types of criteria: 1) a criteria specific to your screening instrument that allows you to determine "refer" or "pass," and 2) the outcome criteria from confirmatory, cycloplegic examination of what levels of refractive error, or ocular alignment constitute a "TRUE" or "FALSE" amblyopia risk factor.

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    Visionscreen Validation Grid (Excel)    


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