The extent and visual acuity outcome in disorganization of the inner retinal layers following resolution of macular edema under different treatment modalities

Abstract

Purpose :
Disorganization of the inner retinal layers (DRIL) has been shown to correlate with visual acuity in previous studies ¹²³ The purpose of our study is to determine the amount of DRIL and visual acuity in patients with central retinal vein occlusion across various treatment modalities (CRVO) in 6 months after the resolution of macular edema.

Methods :
This is a prospective randomized single-masked clinical trial evaluating 20 patients with CRVO that were divided into 3 treatment groups, ranbizumab, dexamethasone implant and combination therapy of both. Each patient was diagnosed with macular edema secondary to CRVO for the first time. All patients had resolution of their macular edema at 6 months. VA and CRT were measured monthly for each patient. For each patient the OCT at the screening visit and the OCT at the 6 month visit when the macular edema had resolved was evaluated. The central 1000 micron region was measured by 2 independent masked graders for the horizontal extent of DRIL.

Results : DRIL was present in 19 out of 20 patients. 7 out of 8 patients in the ranibzubam group, 5 out of 5 in the Dexamethasone group and 4 out of 4 in the combination group were identified with DRIL by both graders. Intergrader agreement was very high with a cohens kappa value of 0.90 for qualitative assessment of whether DRIL was present or not. Spearman reliability coefficient R was 0.64 with statistical significance of P=0.008 for quantitative measurement of DRIL in microns. At 6 months the extent of DRIL was found not to be statistical significance between Ranbizumab and Dexamethasone implant (326 microns vs 484 microns, P value = 0.33). Change in VA and CRT were equivalent between the ranibizumab and dexamethasone group ( 19 letters vs 14.5 letters p= 0.83) (-397.57 vs -522.2, p=0.52).

Conclusions :
On average there was less DRIL identified after 6 months with the resolution of macular edema in the ranibizumab group. The amount of DRIL and visual acuity was found not be the statistically significant in comparison to the Dexamethasone implant, this is likely due to the small sample size of both groups. Further investigation into the ability of anti-VEGF therapy in preventing the disorganization of inner retinal layers with a larger sample size is warranted.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.