Retinal function in eyes with proliferative diabetic retinopathy treated with intravitreal ranibizumab and multispot laser panretinal photocoagulation.

PURPOSE

To compare retinal function changes in eyes with proliferative diabetic retinopathy (PDR) after intravitreal ranibizumab (IVR), combined or not with conventional (ETDRS) or multispot laser panretinal (PASCAL) photocoagulation (PRP).

METHODS

This study included laser-naive PDR patients that required PRP. Eyes were randomly and prospectively assigned to receive IVR or IVR combined with PASCAL or EDTRS. PRP was performed at baseline in 1 (PASCAL) or 2 (ETDRS) sessions. In eyes with macular edema, macular short pulse grid laser was associated with IVR at baseline and IVR was repeated monthly or quarterly if neovascularization was detected on angiography. Comprehensive ophthalmological evaluations, including SD-OCT, were performed at baseline and every 4 weeks after treatment. Full-field electroretinography (ERG: extended ISCEV standard) was performed at baseline and at 12, 24 and 48 weeks.

RESULTS

IVR = 13, PASCAL = 15 and ETDRS = 15 eyes finished 48-week follow-up. There was a statistically significant BCVA improvement of 0.1-0.3 logMAR in all groups, and fluorescein angiography leakage area (FLA) reduced in 56%, 73%, and 73% from baseline for ETDRS, IVR and PASCAL, respectively, up to 48 weeks without significant differences between groups (p > 0.05). A significant a- and b-wave amplitudes reduction was observed for dark- and light-adapted ERG for ETDRS and PASCAL, but only minor dark-adapted b-wave reduction was found for IVR, up to 48 weeks. As an example, at week 48, combined response b-wave amplitude reduced in 181.5 ± 31.4 µV, 128.0 ± 27.9 µV and 82.4 ± 15.2 µV for ETDRS, PASCAL and IVR (p < 0.05 each group), respectively. No significant difference was observed between ETDRS and PASCAL for any ERG parameter.

CONCLUSIONS

IVR combined with single or multiple spot PRP causes similar retinal function impairment during 48 weeks of observation, while IVR alone seems to be similarly effective controlling FLA without changing retinal function.