Multifaceted Amblyopia Screening with blinq, 2WIN, and PDI Check

Abstract

Background: Novel devices target different facets of amblyopia risk factors (ARFs). Through birefringence, the Rebion blinq assesses binocular foveation. The Adaptica 2WIN is a multiradial 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 returning patients to a pediatric ophthalmology clinic had concomitant confirmatory exams after all three vision screens had been validated with ROC curves, Bland-Altman plots, and Alaska Blind Child Discovery ellipsoid grades. Exam outcomes were classified by ARF visual acuity, strabismus, binocularity, and refractive errors following the 2021 AAPOS guidelines and Bosque-Hunter rubric for the blinq.

Results: A total of 202 ethnically diverse students aged 10±4 (4-19) years, 33% treatment-naïve, had a high (58%) prevalence of ARFs. Linear logMAR visual acuity, intereye differences, stereo and three-cone color correlated well between PDI Check and exams. Mean score on the 2WIN matched sphero-cylinder exam with ellipsoid scoring was 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 in 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.

Keywords: amblyopia; strabismus; validation; vision screening.

Figure 1

Three vision-screening devices: Rebion blinq birefringent binocular foveation scanner (upper left), Adaptica 2WIN infrared multiradial autorefractor (upper right), and PDI Check dynamic forced-choice vision-screening game on the Nintendo 3DS (bottom).

Figure 2

ROC curves for amblyopia screening. Rebion blinq (gray), Adaptica 2WIN (teal blue), and PDI Check Nintendo 3DS game (orange) performance on detecting high prevalence of amblyopia risk factors and actual amblyopia and strabismus. Of the various exam outcomes, AAPOS 2021 outlined in green on the left and Bosque–Hunter rubric outlined in purple at lower right. Commonly referenced AAPOS 2003 (older triad of 2013) and aspects of manifest strabismus (cover test >8 prism diopters and “any” cases with prior strabismus surgery or chemodenervation) and diminished binocularity are also included.

Figure 3

Refractive comparison between Adaptica 2WIN and optimal refraction. Bland–Altman plots with intraclass correlation (ICC) for vector-transformed astigmatism (J0 and J45) and spherical equivalent (left). ABCD ellipsoid spectacle comparison (right) for anisometropia, astigmatism, spherical equivalent (SphEq), and overall combined ellipsoid. Means ± SD given. The bar chart shows the proportion and number of patient/eyes for which 2WIN scored an A match (blur <1 logMAR), B match (blur 1–3 logMAR), C match (blur 4–6 logMAR), and poor match (7 logMAR and worse) and inconclusive photorefraction results.

Figure 4

PDI Check near results compared to examination. Linear correlations far left, Bland–Altman plots center for stereo (top row; log arc seconds), logMAR visual acuity, and intereye difference (bottom row, logMAR). On the right, PDI Check mean, monocular trichromatic isoluminance gray cone is compared to exam results from Ishihara orange–pink vs gray “35” and “96” plates.