Abstract
Purpose: :
To examine and to find the correlation between the electrophysiological symptoms, the structure and the thickness of macular retina in patients with different kinds of macular diabetic edema.
Methods: :
14 patients (22 eyes) aged 40-70 with 2 diabetes type were investigated. (visual acuity < 0.5 with correction). There were 8 eyes with diffuse macular edema (DME), 7 eyes with focal macular edema (FME) and 7 eyes with cystoids macular edema (CME). The control group was composed by 9 volunteers without any pathology. To elucidate the correlation between structure changes of foveal zone and its bioelectrical activity the thickness of retinal layers in central sector of optical coherent tomography (OCT) and the average multifocal electroretinography indices (mfERG): the index of retinal density (IRD), the latencies of P1 and N1, the amplitudes of P1 and N1 in first and second rings were analyzed.
Results: :
The analysis of our results showed that the fovea thickness increased accordingly to the increasing of macular edema _ from FME to CME (without statistic significant difference with control group). It was determined that the IRD and the P1 amplitude were lower than in the control group in patients with DME (IRD: 33.9+_10.01, P1 amplitude: 0.51+_0.13) and with CME (IRD: 41.6+_9.83, P1 amplitude: 0.63+_0.21), p<0.05. The IRD in control group was 83.1+_12.4 (SD) and P1 amplitude was 1.25+_0.12 (SD).
Conclusions: :
The level of depression of bioelectrical activity of macula according mfERG indices in patients with macular diabetic edema depends on the retinal thickness and kind of macular edema. It is suggested that the mfERG impulses are generated in photoreceptors and in the interneuron as well. This question needs the future investigation and analysis.
Keywords: diabetic retinopathy • electroretinography: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)