Longitudinal Evaluation of Accommodation During Treatment for Unilateral Amblyopia

PURPOSE: Retinal image quality is dependent on accommodative performance. This longitudinal observational study of children with unilateral amblyopia evaluated the accommodative performance of the amblyopic eye during treatment. METHODS: Twenty-six participants with unilateral amblyopia and 10 participants with typical vision aged 3 to 10 years participated. Accommodative response was measured using modified Nott retinoscopy in monocular and binocular viewing conditions for target distances of 50, 33, and 25 cm, at enrollment and each follow-up visit. RESULTS: Participants with amblyopia accommodated less accurately when viewing with their amblyopic eye in monocular than in binocular conditions. Over the course of amblyopia treatment, accommodative performance improved with amblyopic eye visual acuity (VA) improvement, although this was not consistent across individual participants. A linear mixed model showed that accommodative error worsened with increasing depth of amblyopia for monocular viewing with the amblyopic eye (0.14 diopter [D] per line of acuity loss, P = 0.001), with an interaction between VA and stimulus demand (0.09 D of additional lag per diopter of stimulus, per line of acuity loss, P < 0.001). Participant age, patching duration, length of time in the study, history of strabismus, and stereoacuity were not significant predictors of accommodative performance. CONCLUSIONS: Overall, poor monocular accommodative performance of the amblyopic eye was associated with worse amblyopia and improved simultaneously with VA improvement, although there was variability across the study cohort. Further research is needed to determine the causal relationship between amblyopic eye VA and accommodation and its impact on amblyopia treatment.