Nonlinear Relationship of Retinal Thickness and Visual Acuity in Central Retinal and Hemiretinal Vein Occlusion

Purpose: To investigate whether a nonlinear association between central subfield thickness (CST) on spectral-domain OCT and concurrent visual acuity letter score (VALS) exists in eyes treated initially with afli-bercept or bevacizumab for macular edema associated with central retinal vein occlusion (CRVO) or hemiretinal vein occlusion (HRVO) in the Study of Comparative Treatments for Retinal Vein Occlusion 2 (SCORE2). Design: Long-term follow-up after a randomized clinical trial from 64 centers in the United States.Participants: Participants were followed up to 60 months and treated at investigator discretion after completing the 12-month treatment protocol.Methods: Two-segment linear regression models were compared with simple linear regression models of VALS on CST. Pearson correlation coefficients were calculated to assess strength of CST and VALS associations.Main Outcome Measures: Central subfield thickness was measured by OCT and VALS by the electronic Early Treatment Diabetic Retinopathy Study methodology. Results: Estimated inflection points, reflecting turning points at which the CST and VALS association changes from positive to negative, calculated at 7 postbaseline visits, range from 217 to 256 mm. A strongly positive cor-relation exists to the left of each estimated inflection point, ranging from 0.29 (P < 0.01 at month 60) to 0.50 (P < 0.01 at month 12), and a strongly negative correlation exists to the right of each estimated inflection point, ranging from-0.43 (P < 0.01 at month 1) to-0.74 (P < 0.01 at month 24). Randomization statistical tests showed that 2-segment models are favored over 1-segment models for all postbaseline months (P < 0.001 for all tests performed).Conclusions: The relationship between CST and VALS in eyes with CRVO or HRVO after treatment with anti-vascular endothelial growth factor (VEGF) therapy is not simply linear. The usually modest correlations between OCT-measured CST and visual acuity belie strong left and right correlations present in 2-segment models. Post-treatment CST close to the estimated inflection points showed the best expected VALS. The SCORE2 participants with a post-treatment CST after treatment close to the estimated inflection points of 217 to 256 mm showed the best VALS. In patients treated with anti-VEGF for macular edema associated with CRVO or HRVO, a thinner retina is not always associated with better VALS. Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclo-sures at the end of this article. Ophthalmology 2023;130:1066-1072 (c) 2023 by the American Academy of Ophthalmology