Assessment of Macular Function by Multifocal Electroretinography and Optical Coherence Tomography before and after Panretinal Photocoagulation in Diabetic Retinopathy

We evaluated macular function before and after panretinal photocoagulation (PRP) in diabetic retinopathy using a multifocal electroretinogram (mfERG) and optical coherence tomogram (OCT). In mfERGs, the 1st positive wave (P1) minus the 1st negative wave (N1) amplitude (P1 ? N1 amplitude), the P1 peak latency and the response density were measured in 7, 19, 37 and 103 hexagonal areas or elements (Areas 1, 2, 3 and 4) within a central radius of 5, 7, 10 and 20 degrees, respectively. The mean retinal thickness was estimated from 9 calculation points at the foveal region within 5 degrees; the central and each of the other 4 points at a distance of 250 ?m and 500 ?m from the central por tion on horizontal and vertical sections on OCT. The P1 peak latencies from the 4 areas were remarkably prolonged in 14 eyes of 9 patients with preproliferative or early proliferative diabetic retinopathy showing no clinically significant macular edema before PRP as compared with those in 15 normal control eyes, without a tendency of recovery throughout the course after PRP except for area 1. The P1-N1 amplitudes and the mean response density levels from the 4 areas were remarkably decreased in the diabetic eyes before PRP as compared with those in the control eyes, followed by a maximum decrease in both parameters at 3 months after PRP. However, remarkable recoveries were detected in both decreased parameters from the 4 areas at 6 months after PRP. The mean foveal retinal thickness on OCT was remarkably increased in the diabetic eyes before PRP as compared with the thickness in 16 normal control eyes. Most remarkably, a transient increase in thickness was detected in diabetic eyes 1 month after PRP, followed by a tendency of recovery 3 to 6 months after PRP. These results indicate that mfERG and OCT examinations are useful in the assessment of macular function before and after PRP in diabetic retinopathy, especially within 5 degrees of the central portion, and that the effects of PRP on macular function in this entity seem to be reversible at the foveal region, although we need to do further investigation in relation to the outcome of visual acuity

Effects of Metoclopramide Hydrochloride, a D2-Selective Dopamine Receptor Antagonist, on the Fast Oscillation of the Electrooculogram

Fast oscillation (FO) of an electrooculogram (EOG) was recorded in both eyes of 10 healthy volunteers before and after administration of metoclopramide hydrochloride (MTCL), a D2-selective dopamine receptor antagonist, paying particular attention to sex concerning sensitivity to dopamine in young subjects. Healthy volunteers were divided into male and female groups; 5 males (10 eyes) aged 21 to 23 years (average, 21.8 years) and 5 females (10 eyes) aged 19 to 25 years (average, 21.8 years). As an FO parameter, the dfFO (the averaged difference in ?V between maximum amplitude in the dark period and minimum amplitude in the light period during FO measurement) was evaluated. The mean level of dfFO significantly increased between phase A (the initial 10 min before intravenous injection of 10 mg of MTCL) and phase B (10 min after the injection) in the male and female groups (P < 0.01 and P < 0.025) and between phase A and phase C (the additional 10 min after the injection) in both groups (P < 0.01 and P < 0.05). The mean level of dfFO in the female group was significantly higher than that of the male group in phase B (P < 0.05). As a control, the experimental procedure was performed with physiological saline administration, and no changes were observed. The data suggest that there exists some difference between young males and females generation concerning sensitivity to dopamine and that young females may show a higher-than-male sensitivity to dopamine in the occurrence of FO potential