Abstract
Purpose: :
To evaluate the increment of photopic b–wave amplitude recorded during light adaptation in patients with diabetes mellitus (DM).
Methods: :
Photopic electroretinogram (ERG) was recorded on 21 eyes with DM (age 61.6±9.1 y.o.) and 8 normal eyes (age 65.3±5.8 y.o.). Eyes with DM were divided into 4 groups according to the degree of diabetic retinopathy (DR): (1) NDR group (8 eyes, age 61.5±9.7 y.o.): no DR was seen. (2) SDR group (4 eyes, age 60.5±3.1 y.o.): simple DR. (3) PPDR group (4 eyes, age 65.8±10.2 y.o.): pre–proliferative DR. (4) PDR group (5 eyes, age 59.4±11.7 y.o.): proliferative DR. Subjects were given 30 minutes before examination for dark adaptation. Subsequently at 5 various points, namely, 0, 5, 10, 15 and 20 minutes after starting light adaptation, photopic ERG was recorded with background light of 24 cd/m2. Amplitude of photopic b–wave was then assessed.
Results: :
The ratio of b–wave amplitude at 0–minute to 20–minute light adaptation was 2.30±0.50 in normal subjects. In diabetic patients, it was 2.03±0.52 in NDR group, 1.85±0.31 in SDR group, 1.92±0.41 in PPDR group, and 1.70±0.30 in PDR group. The amplitude increment was found smaller in diabetic patients than in normal subjects.
Conclusions: :
These results suggested disturbance of light adaptation in diabetic patients.
Keywords: diabetes • electroretinography: clinical