Interdigitation and ellipsoid zones disruption correlate with visual outcomes among treatment naive patients with diabetic macular edema.

INTRODUCTION We have recently shown that defects in interdigitation and ellipsoid zones (IZ and EZ) can predict response to anti-VEGF therapy in a small group of treatment-naive diabetic macular edema (DME) patients. The aim of the current study is to further evaluate this association in a larger study group of patients over a longer follow-up time. METHODS Thirty eyes of 30 treatment-naive DME patients were analyzed in this retrospective study. The integrity of foveal IZ and EZ was evaluated using OCT at the diagnosis of DME and following anti-VEGF injections. The defect size was correlated with best-corrected visual acuity (BCVA) and central macular thickness (CMT). RESULTS The mean patients' age at baseline was 63.0±10.0 years. Patients underwent 3.9±2.9 anti-VEGF injections for a mean of 9.1±4.8 months. Following treatment, the mean Snellen visual acuity improved from 20/52 to 20/44 (p=0.05), CMT decreased from 432.5±141.4 m to 375.2±121.4 µm (p=0.05) and IZ/EZ defect size decreased from 259.83±375.94 µm to 65.34±143.97 µm (p=0.001). In patients with no IZ/EZ defects at baseline the mean Snellen visual acuity was better when compared to those with IZ/EZ defects (20/36 vs. 20/70, p=0.031). The number of eyes with IZ/EZ defects decreased from 17 (57%) at baseline to 6 (20%) at end of follow-up (p<0.01). BCVA gain correlated with IZ/EZ defect size reduction (r=0.41, p=0.02) but not with improvement in CMT (r=0.28, p=0.121). CONCLUSIONS IZ/EZ defect size correlated not only with baseline BCVA, but also predicted the change in BCVA after anti-VEGF treatment. Possible future automatic measurement of IZ/EZ defect size might prove helpful for evaluation of treatment response.