Purpose: To analyze a multiflash multifocal electroretinogram in 20 patients with open-angle glaucoma (OAG). Methods: The stimulation sequence consisted of a binary m-sequence (Lmax 200 cd/m2, Lmin <1 cd/m2). Each m-sequence stimulus was followed by three global flashes (luminance: 400 cd/m2) at an interval of 26 ms. Results: The presence of a response to the three global flashes indicated an adaptive effect of the response to the preceding m-sequence stimulus. In the nasal retinal response average the relative amplitude contribution of the response to the second global flash in relation to the other two global flash responses was outside the range of normal (10th–90th percentile) in 10 of 20 OAG patients. Conclusions: The changes in the relative contribution of the response to the second global flash seem indicative of impaired adaptive effects presumably due to inner retinal damage.
Subclinical retinal involvement characteristic of MAR appears to be more common than previously suspected in patients with cutaneous malignant melanoma. Our findings in this small cohort seem to indicate that the percentage of patients with symptoms suggestive of MAR is higher in advanced stages of disease. Further clinical studies are required to evaluate if the presence of subclinical symptoms suggestive of MAR is correlated with a worse prognosis and a shortened progression-free and overall survival.
To study the influence of cataract on the multifocal electroretinogram (mfERG), 18 patients underwent mfERG recordings prior to and following cataract surgery. The central 50 degrees of the retina were stimulated by 103 hexagons alternating independently between white and black according to a binary m-sequence. The frame rate was 75 Hz. The maximum luminance was 200 cd/m2, the minimum luminance < 1 cd/m2 with a mean luminance of 100 cd/m2. For each retinal location, the latencies of the first negative peak (N1), the first positive peak (P1) and the second negative peak (N2) as well as the amplitude from N1 to P1 and the amplitude from P1 to N2 of the first order response were obtained. Concentric ring averages around the foveal response were analyzed. Following cataract surgery, the mean amplitude of the response in the central four degrees increased from 37.83 to 42.37 for N1P1 (p = 0.019) and from 39.44 to 47.20 for P1N2 (p = 0.001). To reduce the influence of retest variability, each response average was divided by the recording's overall amplitude. For the central 4 degrees this ratio increased by 0.18 (p = 0.002) for N1P1 and by 0.27 (p < 0.001) for P1N2. Clouding of the optic media such as produced by cataracts has a slight but significant influence on the multifocal ERG.
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