Characterization of macular edema from various etiologies by optical coherence tomography

Purpose: To use optical coherence tomography (OCT) to characterize the intraretinal changes associated with macular edema (ME) according to its etiology. Design: Observational case series. Methods: Seventy-eight eyes of 78 patients with ME were examined retrospectively by OCT, using the Humphrey 2000 OCT system (Humphrey Co., San Leandro, California). ME etiologies were diabetic retinopathy (27 cases), central retinal vein occlusion (18 cases), pseudophakia (15 cases), posterior uveitis (10 cases), and retinitis pigmentosa (eight cases). Macular thickness was measured using OCT mapping software. It was correlated with logarithmic visual acuity. Results: In 72 of 78 cases (92%), ME was located in the outer retinal layers. Serous retinal detachment was present in 29 of 78 cases (37%). It was most frequent in central retinal vein occlusion (10 of 18 cases, 56%). There were no significant differences in visual acuity (P=.26) or macular thickness (P=.95) whether or not serous retinal detachment was combined with ME. The posterior hyaloid was partially detached in 17 of 78 cases (22%) of overall cases. Serous retinal detachment did not correlate with partial posterior hyaloid detachment (P=.6). Mean macular thickness ranged from 506 mu m in central retinal vein occlusion to 373 mu m in retinitis pigmentosa. Visual acuity correlated with macular thickness in diabetic retinopathy (R=0.55; P=.0027) and pseudophakia cases (R=0.66; P=.016). Conclusions: OCT characterized the retinal morphologic changes associated with ME, especially the vitreomacular relationship and sub-clinical serous macular detachment. This detachment did not correlate with poor visual acuity. Macular thickening only correlated with visual loss in diabetic retinopathy and pseudophakia.