Abstract
Abstract: :
Purpose: To determine, in a pilot study, whether eyes with clinically significant diabetic macular edema have substantial concomitant peripheral retinal vascular abnormalities which can be detected on ultra wide (200°) fluorescein angiography (Optos P200A). Methods: Eleven consecutive patients with clinically significant macular edema (CSME) were sent for fluorescein angiography using an Optos Panoramic P200 ultra wide angle angiographic unit. Eyes which had undergone previous panretinal photocoagulation were excluded from study, even if CSME was present. The remaining eyes with edema had no apparent clinical evidence of proliferative diabetic retinopathy, but some had undergone previous panretinal photocoagulation in their fellow eye. The Optos angiogram was centered at the fovea, and was obtained without changing fixation, using a single sodium fluorescein injection. The best arteriovenous phase frame was selected for each eye, and was evaluated specifically for the presence of capillary drop out and areas of neovascularization located outside of the macular arcades. This was facilitated by first inserting a digital grid of 12 concentric circles (divided into 45° sectors) into each digital image. The radii of the circles ranged from 1 to 12 optic disc diameters (DD), and each grid was adjusted to properly reflect the disc diameter for each eye. Results: Of the 17 eyes of 11 patients, the percent of extramacular sectors showing ischemia ranged from 36% to 88%, with a mean of 71% + 12%. When only one eye of each patient was used in the calculations (randomly selecting one of the eyes who were bilaterally eligible), the mean percent of sectors showing ischemia was 75% + 7%. We then excluded the four patients who had undergone panretinal photocoagulation in either eye. The mean percent of ischemic sectors seen in eyes of patients with CSME and no previous history of retinal neovascularization was 74% + 7%. No peripheral ischemia was found in only two eyes with CSME. The mean radius of each image field across all eligible eyes was 8.9 + 1.3 disc diameters. Conclusions: Clinically significant diabetic macular edema appears to be associated with measurable retinal capillary drop out located outside of the arcades in a high percentage of patients. Such an association has important treatment implications.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • diabetic retinopathy • macula/fovea