Instrument Referral Criteria for PlusoptiX, SPOT and 2WIN Targeting 2021 AAPOS Guidelines

Abstract

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 IRC via receiver operating characteristic (ROC) curves. The refractions of the devices were also compared.

Results: This study defines three sets of refractive 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) was 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 were: <4y: 1.5, 1.75, 3.25, 3.5 and ≥4y: 1.5, 1.75, 2.25, 2.0; 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 (better) versus PlusoptiX: 1.9±1.6 and 2WIN: 2.2±1.4 (p<0.001).

Conclusion: The 2021 AAPOS exam guidelines foster 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.

Keywords: amblyopia; amblyopia risk factors; infrared autorefractor; refraction; vision screening; visually significant refractive errors.

Figure 1

Refractive Amblyopia Risk Factors (ARFs) “diamond graph” AAPOS diopter cut-offs with prevalence scale under each orange axis with thickness approximating each ARF’s severity. Upper graph: 2003 AAPOS preschool guidelines indicated by red diamond. 2013 age-stratified diamond levels indicated by green (toddlers), purple (preschool) and red (Kindergarten). The lower diamonds show 2021 AAPOS ARF preK cut-offs in blue and school-aged in red attempting to reduce false positives and referral rate, while striving to detect the more severe ARFs early for which the patient cannot easily compensate with accommodation. The prevalence of risk factors is related to the area of each diamond.

Figure 2

The three leading infrared multiradial photoscreening autorefractors; Adaptica 2WIN (left), PlusoptiX A12 (center) and the Welch Allyn SPOT (right).

Figure 3

Alternative definitions of anisometropia for sphero-cylinder refractions. An advantage of spherical equivalent is identical value whether plus or minus cylinder notation. The values (A) through (F) all could be utilized to calculate “anisometropia” for a sphero-cylinder refraction. Spherical equivalent anisometropia is the absolute value of (B – E); the meridional anisometropia from the more-minus is the absolute value of (A – D).

Figure 4

Cohort exam details and ages. Compared non-parametric and means for age and refractive components for PlusoptiX, SPOT and 2WIN photorefractors.

Figure 5

ROC curves for three photoscreeners. Infrared multi-radial computerized autorefractors Plusoptix A12, Welch Allyn SPOT and Adaptica 2WIN performance screening for 2021 AAPOS Uniform Guidelines. Arrows point to selected “medium” instrument referral criteria refractive sub-components. In the right column, the autorefractor with the largest number of subjects (2WIN) has 2003 ROC compared with that from the 2021 AAPOS Uniform Guidelines for Amblyopia Risk Factors (Anisometropia, hyperopia and high astigmatism) and also Visually Significant Refractive Errors (moderate symmetric astigmatism and myopia).

Figure 6

Medium Instrument Referral Criteria targeting their AAPOS 2021 refractive Amblyopia Risk Factors for younger and older than 4 years of age.

Figure 7

Receiver operating characteristic (ROC) curves for separate cohorts using three autorefractive devices targeting AAPOS 2021 Uniform Guidelines Amblyopia Risk Factors and Visually Significant Refractive Errors. Regions representing “excellent”, “good”, and “fair” accuracy are delineated by blue, green, and yellow “northwest’ regions on the ROC curve.

Figure 8

Refractive comparison of three photorefractors. Plusoptix A12, the Welch Allyn SPOT and the Adaptica 2WIN infrared autorefractors are compared with cycloplegic examination in children analyzed by Bland Altmann analysis of Spherical Equivalent (M), J0 and J45 vector transformation and also the ABCD Ellipsoid unitary variable shown in Box and Whisker Plot and Column demonstrating GRADE match.

Figure 9

Ellipsoid comparison of refractive component from three infrared autorefractive devices compared to refined retinoscopy. Left shows ellipsoid composite metric (0 = perfect spectacle match, 1.0 is 1 line blue, 2.0 is 3 line defocus nd 3.0 corresponds to a 6 line defocus).