Abstract
Abstract: :
Purpose: To determine whether the multifocal ERG (mfERG) responses of retinal areas without any lesions correlate with the severity of diabetic retinopathy of the whole retina in patients with non–proliferataive diabetic retinopathy (NPDR). Methods: MfERG was recorded using the RETIscan system (Roland consult, Brandenbrug, Germany) in 40 eyes of 20 non–diabetic controls, 32 eyes of 16 diabetic patients without retinopathy, and 96 eyes of 48 diabetic patients with NPDR (16 mild, 18 moderate, and 14 severe NPDR). Patients with previous ocular treatment or systemic complications except diabetes were excluded. Fundus photography and fluorescein angiography were used to detect retinal lesions and compared with corresponding mfERG responses from 103 stimulus locations. The differences between the values obtained from patients and controls were computed at each location, and only the values from the areas without any retinal lesions were analyzed and correlated with retinopathy grading (ETDRS classification) of the whole retina. Results: Implicit time delays were significantly different among the groups and correlated with diabetic retinopathy grading of the whole retina (p < 0.05). Local ERG responses were decreased in amplitudes in diabetic patients with or without diabetic retinopathy (p < 0.05), but the amount of decrease did not correlate with the retinopathy grading. Conclusions: MfERG responses of the clinically normal retinal areas are abnormal and correlate with the severity of diabetic retinopathy of the whole retina. This suggests that the function of retinal neural cells in eyes with diabetic retinopathy deteriorates even in the areas without any retinal lesions.
Keywords: diabetic retinopathy • electroretinography: clinical • electrophysiology: clinical