The Comparison of Retinal Blood Flow and Foveal Avascular Zone between the Eyes with Panretinal Photocoagulation and the Eyes without PRP using Scanning Laser Ophthalmoscope[SLO] in Diabetic Retinopathy

Lee, J H; Kwak, H W; Kim, J M

Abstract

Panretinal photocoagulation[PRP] has become the most widely used treatment for preproliferative or proliferative diabetic retinopathy. Although it has been proven effective in reducing the occurrence of severe visual loss and in regressing of neovascularization in eyes with proliferative diabetic retinopathy, very little is known about how it works. To compare the retinal blood flow of the eyes with PRP to the eyes without PRP, we measured arteriovenous passage time[AvPT] and the size of foveal avascular zones[FAZ] using Scanning Laser Ophthalmoscope[SLO] system. Sixteen patients with severe nonproliferative or proliferative DR who had undergone PRP on only one eye were included in this study. In 16 patients, 14 patients[87.5%] showed a delay in arteriovenous passage time in treated eyes, and the difference between the treated group and the untreated group was statistically significant[p<0.05]. Ten patients[62.5%] showed a decrease in the size of foveal avascular zone in treated eyes, but there is no significant difference in the mean foveal avascular area between the treated group and the control group[p>0.07]. This result suggests that the panretinal photocoagulation may induce the improvement in the partial pressure of the retinal vascular oxygen and the increase in macular blood flow, but further investigation and analysis will be necessary.