Abstract
Abstract: :
Purpose: To investigate electroretinographic changes of oscillatory potentials (OP) during dark adaptation (DA) in diabetes mellitus(DM) patients with different clinical types of diabetic retinopathy (DMR). Method: Electroretinograms (ERGs) from 42 DMs were recorded. Of the DMs, 11 had no visible diabetic retinopathy( NDR), 19 simple diabetic retinopathy(SDR), 6 had pre-proliferative diabetic retinopathy(PPDR), and 6 had proliferative diabetic retinopathy(PDR). After 15 minutes of light adaptation, ERGs was recorded every 30 seconds during dark adaptation using a 560-nm monochromatic, rectangular, 3.3-Hz light stimulation lasting 15 msec. Recordings were continued for 15 minutes' from onset of DA. Results: OP1 and OP2 did not show definite changes in peak times or amplitudes. OP3, which was observed early after the onset of DA, converted to OP4 with the appearance of a new OP (OP3') between OP2 and OP3. In the different groups the first appearance of OP3' was: in NDR, 15.0 ± 6.6 (mean±SD), in SDR, 20.3 ± 5.7 sec, in PPDR 48.6±24.1 sec, and in PDR 276.0± 70.1 sec, after DA. The amplitudes of the first OP3' were reduced in all clinical types and their peak times were NDR 44.9± 18.1msec,SDR 44.7± 1.8 msec, PPDR 44.3± 1.5 msec, PDR 45.3± 0.5 msec. The differences in times of the first appearance of OP3' between groups were statistically significant, however those in amplitudes and peak times of OP3' were not (One way factorial ANOVA). Conclusion: We deduced that these delays in the appearance of OP3' correlated with the progress of DM retinopathy. From the early stages, patients with DM have rod dysfunction. However, as the behavior of OP3 (OP3') has rod-like characteristics, we hypothesized that OP3 reflects the specific site of retinal damage in DM changes.
Keywords: diabetic retinopathy • electroretinography: clinical • dark/light adaptation