Panretinal Photocoagulation Adjunctive to Intravitreal Ranibizumab for Macular Edema Secondary to Central Retinal Vein Occlusion

Abstract

Purpose: : To report our initial experience with panretinal photocoagulation (PRP) administered as an adjuvant therapy following intravitreal ranibizumab in patients with macular edema due to central retinal vein occlusion.

Methods: : Twenty patients with macular edema secondary to perfused CRVO were enrolled in an ongoing prospective, open-label study. All patients were treated monthly with IVT ranibizumab for 3 months followed by quarterly PRN (cohort 1, n=10) or monthly PRN (cohort 2, n=10) injections for the first year. Beginning in the second year, all patients were treated on a monthly PRN basis and patients receiving repeat ranibizumab injections for recurrent macular edema were eligible to receive argon PRP. Of the 20 patients enrolled in this study, 10 patients were treated with PRP using the following parameters: spot size of 400µm for duration of 0.05 to 0.1 seconds and up to 1200 total burns. One patient recieved PRP for reasons other than persistent or recurrent edema and was not included in this analysis. Central retinal thickness (CRT), best corrected visual acuity (BCVA), fundus photographs and fluorescein angiograms were evaluated, as well as the incidence and severity of adverse events. Patients continued to receive IVT ranibizumab as needed after PRP treatment.

Results: : PRP was administered at an average of 25.5 months (range 15-35) post day 0 and an average of 1125.1 burns (range 872-1795) was given over a single sitting. Mean CRT and VA prior to PRP administration (same day) were 506±78µm and 43±23 letters respectively. Three months following PRP average CRT and VA were 421±163µm and 49±22 letters. Average drug-free interval was 1.8±0.6 months prior to PRP treatments and 2.7±2.8 months post PRP treatment. Though there was a trend towards improvement in CRT, BCVA and injection intervals following PRP, these were not statistically significant changes. No patients experienced ocular or systemic adverse events related to the PRP treatment; however 4 of 10 patients reported some minimal to mild changes in vision following PRP.

Conclusions: : In this short-term small subgroup analysis, PRP treatment may have trended towards improvement in CRT, BCVA, and time between injections; however this was not statistically significant and some patients may experience visual symptoms following PRP. Further examination of larger patient populations with longer follow-up is warranted to determine if PRP adjunctive to continued ranibizumab therapy could be beneficial in patients with CRVO.

Clinical Trial: : www.clinicaltrials.gov NCT00406796

Keywords: vascular occlusion/vascular occlusive disease • laser • retina