Abstract
Purpose: :
To evaluate retinal function after panretinal photocoagulation (PRP) compared to PRP plus intravitreal injection of ranibizumab (IVR) in patients with high-risk proliferative diabetic retinopathy (PDR) by means of electroretinography (ERG).
Methods: :
In a prospective study, patients with high-risk PDR and no prior laser treatment were randomly assigned to receive PRP (PRP group; n=9) or PRP plus IVR (PRPplus group; n=11).PRP was administered in two sessions (weeks 0 and 2), and IVR was administered at the end of the first laser session in the PRPplus group. Standardized ophthalmic evaluations including (ETDRS) best-corrected visual acuity (BCVA), and fluorescein angiographyto measure area of fluorescein leakage (FLA), were performed at baseline and at weeks 16 (±2), 32 (±2) and 48 (±2). ERG was measured according to ISCEV standard at baseline and at week 48 (±2).
Results: :
After 48 weeks, 2400 to 3000 laser spots were made in eyes from PRP group, while only 1400 to 1800 spots were necessary in PRPplus.There was a statistically significant (p<0.05) FLA reduction at all study visitsin both groups, with the reduction observed in the PRPplus group significantlylarger than that in the PRP group at week 48. ROD b-wave amplitude was significantly reduced to 46 ± 5 %(P<0.05) of baseline in the PRP group; and to 64 ± 6 %(P<0.05) in PRPplus. This reduction was significantly higher in PRP than in PRPplus (P=0.024; t-Test). The same was observed for SF amplitude: PRP: 45 ± 4 % and PRPplus: 62 ± 5 %; also showing higher reduction in PRP than in PRPplus (P=0.0094). SF a-wave, OP, CONE and 30 Hz showed statistically significant within group reductions, but no differences in between group analyses.
Conclusions: :
These results suggest that treating high risk PDR with PRP plus IVR is effective for proliferative retinopathy control, and allow the use of less extensive PRP, which induces less retinal functional loss, in particular for rod-driven post-receptoral responses, than treatment with PRP alone.
Clinical Trial: :
http://www.clinicaltrials.gov NCT00993525
Keywords: electroretinography: clinical • retina • diabetic retinopathy