Association of Retinal Thickness at Month 1 Post-Treatment with Later Thickness and Visual Acuity in Central Vein Occlusion

Purpose : To investigate the association of retinal thickness 1 month post-randomization (1 month after first study injection with aflibercept or bevacizumab) with later retinal thickness, visual acuity, and number of treatments in eyes with central or hemiretinal vein occlusion enrolled in the SCORE2 trial. Design Cohort study using data from a randomized multicenter clinical trial. Methods Analysis included 350 SCORE2 participants through 2 years of follow-up. Main outcome measures are central subfield thickness (CST) on spectral domain optical coherence tomography, best-corrected visual acuity letter score (VALS), and number of treatments for macular edema. CST was classified as thin (≤216µm), medium (>216µm and ≤300µm), or thick (>300µm). Results At Month 1, 15% (51/350) of study eyes were in the thin CST class, 57% (199/350) in the medium CST class, and 29% (100/350) in the thick CST class. Of eyes with thin CST at Month 1, 89-96% were also thin during Months 2-12. Over all visits studied, the VALS of eyes in the medium Month 1 CST class was significantly greater than the Month 1 thin class. During Months 6-12 (p<0.001) and 12-24 (p <0.001), but not during Months 0-6 (p=0.36) when monthly treatment was protocol-specified, the mean number of treatments for macular edema per study eye was highest in the thick CST class and lowest in the thin CST class. The thin CST class is significantly more likely to have disorganization of the retinal inner layers inside the central subfield, more paracentral acute middle maculopathy at Month 1, and a history of anti-VEGF treatment prior to trial enrollment. Conclusions Eyes with a thin CST at Month 1 were more likely to be in their Month 1 CST class during Months 2-12 than eyes in the thick or medium Month 1 CST classes. Eyes in the medium CST class had the best VALS, with fewest treatments in the thin class after Month 6. These findings suggest that having a post-treatment thin CST can be as detrimental to visual acuity as having a post-treatment thick CST.