The Complementary Roles of Photoscreening and Clinical Referrals for Amblyopia Risk Factor Detection

Abstract

INTRODUCTION: Many major health organizations recommend vision screening at least once between 3 and 5 years of age. In Portugal, in addition to clinical screening, the “Rastreio de Saúde Visual Infantil” (RSVI) program provides photoscreening at ages 2 and 4. We aimed to compare the demographic and clinical characteristics of children (aged 2-5 years) referred to a tertiary ophthalmology service by the RSVI screening program versus standard clinical referrals, and to evaluate the diagnostic performance of different models for detecting amblyopia and its risk factors.

METHODS: This observational, cross-sectional study analyzed records of 541 children, categorized into a Screening Referral Group (SRG, n=338), referred by RSVI, and a Standard Referral Group (STG, n=203), referred by pediatricians or family medicine physicians. Demographic, clinical, and refractive data were compared. The performance of screening models combining photoscreening (RSVI and AAPOS 2021 criteria), uncorrected visual acuity (UCVA), and stereopsis assessment was assessed using ROC analysis.

RESULTS: The SRG was younger (p<0.001) and had a higher prevalence of hypermetropic refractive errors (85.5% vs 54.2%), greater spherical equivalent, and greater anisometropia (p<0.001). Conversely, the STG had a higher prevalence of strabismus (19.2% vs 1.8%, p<0.001). The overall rate of amblyopia was similar (6.5% vs 6.7%), but it was primarily refractive in the SRG and strabismic/mixed in the STG. A model combining AAPOS photoscreening criteria with UCVA and stereoaucity had the highest diagnostic accuracy for amblyopia (AUC 0.932). A model combining RSVI criteria, UCVA, and stereoaucity was superior to RSVI alone for detecting amblyopia, strabismus, or the need for glasses (AUC 0.913 vs 0.760).

CONCLUSION: Photoscreening and standard clinical referrals are highly complementary pathways that identify significantly different patient populations. Photoscreening is effective at detecting presymptomatic amblyogenic refractive errors in younger children, while clinical suspicion remains crucial for identifying strabismus. Multi-modal screening strategies may lead to a more effective screening program.