TOPOGRAPHY OF DIABETIC MACULAR EDEMA WITH OPTICAL COHERENCE TOMOGRAPHY

Objective: This study aimed to develop a protocol to screen and monito r patients with diabetic macular thickening using optical coherence to mography (OCT), a technique for high-resolution cross-sectional imagin g of the retina. Design: A cross-sectional pilot study was conducted. Participants: A total of 182 eyes of 107 patients with diabetic retino pathy, 55 eyes from 31 patients with diabetes but no ophthalmoscopic e vidence of retinopathy, and 73 eyes from 41 healthy volunteers were st udied. Intervention: Six optical coherence tomograms were obtained in a radial spoke pattern centered on the fovea. Retinal thickness was co mputed automatically from each tomogram at a total of 600 locations th roughout the macula. Macular thickness was displayed geographically as a false-color topographic map and was reported numerically as average s in each of nine regions. Main Outcome Measures: Correlation of OCT w ith slit-lamp biomicroscopy, fluorescein angiography, and visual acuit y was measured. Results: Optical coherence tomography was able to quan tify the development and resolution of both foveal and extrafoveal mac ular thickening. The mean +/- standard deviation foveal thickness was 174 +/- 18 mu m in normal eyes, 179 +/- 17 mu m in diabetic eyes witho ut retinopathy, and 256 +/- 114 mu m in eyes with nonproliferative dia betic retinopathy. Foveal thickness was highly correlated among left a nd right eyes of normal eyes (mean +/- standard deviation difference o f 6 +/- 9 mu m). Foveal thickness measured by OCT correlated with visu al acuity (r(2) = 0.79). A single diabetic eye with no slit-lamp evide nce of retinopathy showed abnormal foveal thickening on OCT. Conclusio ns: Optical coherence tomography was a useful technique for quantifyin g macular thickness in patients with diabetic macular edema. The topog raphic mapping protocol provided geographic information on macular thi ckness that was intuitive and objective.