Abstract:

Objective To characterize the clinical features of the hard exudates within the macular area in nonproliferative diabetic retinopathy. Methods A retrospective hospital-based cross-section study was conducted. 261 patients(440 eyes) who were diagnosed as nonproliferative diabetic retinopathy in one or both eyes by fundus fluorescein angiography(FFA) were enrolled in this study. The extension and severity of hard exudate within the macular area were graded from the fundus photograph and collected. The relationship between hard exudates and visual acuity were also analyzed. Results There were 440 eyes diagnosed as background diabetic retinopathy(BDR) Ⅱ and Ⅲ. Among them, 152 eyes(34.6%) had no macular involvement by hard exudates, but 272 eyes(61.8%) had hard exudates involving macular area. sixteen eyes(3.6%) could not be graded because of media haze. Hard exudates were mainly situated in the temporal side of the macula and often involved one or two quadrants of macular area. Eyes without hard exudates involving 500 μm of the center of the macula were 63.9% out of 440 and 50.6% had visual acuity beyond 0.5. Eye with mild macular involvment were 27.6% out of 440 and 42.6% had visual acuity beyond 0.5. Eyes with heavily involved macula were 4% out of 440 and 22.9% had visual acuity beyond 0.5(P=0.02). 88% patients had severe hard exudates in one eye and mild hard exudates in the other. There was significant difference in severity of hard exudates between two eyes(P<0.0001). Conclusion Retinal hard exudate is a common retinal lesion of the nonproliferative diabetic retinopathy. The hard exudates is often located at the temporal side of macula. The extention asymmetry of hard exudates is common while severe hard exudates is rare. The location and severity of retinal hard exudates are directly related to the decrease of visual acuity.

Key words: retinal hard exudates, nonproliferative diabetic retinopathy, macular