Efficacy of Anti-VEGF therapy for different OCT Patterns in diabetic macular edema and the correlation between ellipsoid zone integrity and visual acuity

To observe the efficacy of Anti-VEGF therapy for different patterns of optical coherence tomography of diabetic macular edema, and to explore the relationship between the integrity of the ellipsoid zone (EZ) and visual acuity outcomes. A total of 90 affected eyes with DME who received anti-VEGF therapy were enrolled in this study. The examination of BCVA was according to Early Treatment Diabetic Retinopathy Study, and the results were recorded as logarithm of the minimum angle of resolution (logMAR). Spectral-domain OCT was used to measure central macular thickness (CMT) and assess the integrity of the ellipsoid zone.All eyes were classified into three groups based on OCT patterns: diffuse retinal thickening (DRT group, 29 eyes), cystoid macular edema (CME group, 30 eyes), and serous retinal detachment (SRD group, 31 eyes). All patients received an intravitreal injection of 0.05 ml (2.5 mg) conbercept.Changes in BCVA and CMT among the three groups were compared and analyzed at baseline and at 3, 6, and 12 months after treatment. The length of the EZ defect was measured. Based on the extent of EZ disruption, eyes were classified into three grades (0, 1, and 2) to analyze the correlation between EZ integrity and visual acuity. In addition, factors influencing post-treatment visual acuity were analyzed. Compared with the central macular thickness (CMT) before treatment, the CMT of the affected eyes was significantly decreased in the diabetic retinal thickening (DRT) group (t = 6.506, 4.134, 7.782, P < 0.05), cystoid macular edema (CME) group (t = 15.407, 20.746, 24.749, P < 0.05) and serous retinal detachment (SRD) group (t = 9.580, 14.823, 16.931, P < 0.05), with statistically significant differences. Compared with the baseline, the best-corrected visual acuity (BCVA) of the affected eyes was significantly improved at 3, 6 and 12 months after treatment in the DRT group (t = 8.667, 17.050, 9.114, P < 0.05), CME group (t = 12.104, 11.583, 9.204, P < 0.05) and SRD group (t = 7.726, 9.310, 11.757, P < 0.05), with statistically significant differences. There were statistically significant differences in the LogMAR BCVA among the DRT, CME and SRD groups before treatment and at each time point after treatment (F = 11.379, 11.461, 15.282, 7.782, P < 0.05). A statistically significant difference was observed in the ellipsoid zone grading among the DRT, CME and SRD groups (χ²=21.179, P < 0.005). Compared with the baseline, the visual acuity was significantly improved at 3, 6 and 12 months after treatment in patients with ellipsoid zone grade 0 (t = 10.178, 12.375, 8.881, P < 0.05), grade 1 (t = 12.353, 13.914, 12.175, P < 0.05) and grade 2 (t = 5.154, 8.192, 8.712, P < 0.05) of LogMAR BCVA ellipsoid zone grading, respectively. Among the three ellipsoid zone groups, patients with ellipsoid zone grade 0 had the best visual acuity, while those with grade 2 had the worst visual acuity; statistically significant differences were found among the three groups before treatment and at 3, 6 and 12 months after treatment. The visual acuity at 12 months after treatment was significantly correlated with diabetic macular edema (DME) classification, ellipsoid zone defect grading, BCVA before treatment and CMT before treatment (r = 0.372, 0.547, 0.745, 0.309, all P < 0.05), while no significant correlations were found with age, duration of diabetes, glycosylated hemoglobin A1c (HbA1c), diabetic retinopathy (DR) stage and CMT at 12 months after treatment (r=-0.103, -0.035, 0.173, -0.026, 0.084, all P > 0.05). Anti-VEGF therapy could significantly improve the visual acuity of different patterns of DME, reduced the CMT, and had the best efficacy in the DRT group. There was relationship between the integrity of ellipsoid zone and the visual acuity outcomes.