Purpose:
Diabetic macular edema has been associated with increased intravitreal levels of VEGF. Therefore, ischemia is probably part of the physiopathology. The purpose of this study is to evaluate ischemia through the rarefaction of peripheral capillaries.
Methods:
A retrospective analysis of large field angiographic images with a scanning laser ophthalmoscope (OPTOS, Edinburgh, Scotland) conducted between early April and late June 2011 was performed. After excluding patients with previous panretinal laser photocoagulation and those with peripheral non-analyzable images, the peripheral area on early phase images in 58 patients was evaluated. 17 had a diabetic maculopathy and 41 had retinal diseases other than diabetes (non diabetic group).The rarefaction of the peripheral capillary network was graded from 0 to 4 (0: normal, 1: minimal, 2: moderate, 3: large, 4: severe) a sixth group represents patients with other peripheral abnormalities without rarefaction of the network.
Results:
In the diabetic maculopathy group, 5 patients were excluded, 12% were graded stage 0, 29.5% stage 1, 23.5% stage 2, 17.5% stage 3 and none stage 4. No other abnormalities were found. In the nondiabetic group, 7% were graded stage 0, 21.5% stage 1, 12% stage 2, 19% stage 3, 9.5% stage 4, 19% with other kind of peripheral lesions and 12% (5 patients) were excluded. No significant difference was found between the two groups.
Conclusions:
The peripheral capillary rarefaction is difficult to analyze on conventional angiography (peripheral images are usually obtained in the late phase). This angiographic finding is probably not encountered more often in diabetic maculopathy than other retinal diseases. It remains to be demonstrated in which cases peripheral capillary rarefaction should be considered as significant and whether targeted laser treatment as a part of diabetic macular edema therapy should be discussed.
Keywords: diabetic retinopathy • imaging/image analysis: clinical • clinical (human) or epidemiologic studies: prevalence/incidence