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 and refraction.
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 was 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.
Keywords: amblyopia, photorefraction, ROC curve, Bland Altman, birefringent screen