Pattern-reversal visual-evoked potential in patients with occult macular dystrophy

Gen Hanazono^1,2, Hisao Ohde^2,3, Kei Shinoda^1,4, Kazushige Tsunoda^1,2, Kazuo Tsubota², Yozo Miyake^1,5
1Department of Ophthalmology, National Institute of Sensory Organs, Tokyo, Japan; ²Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan; ³Kamoshita Eye Clinic, Tokyo, Japan; ⁴Department of Ophthalmology, Teikyo University School of Medicine, Tokyo, Japan; ⁵Aichi Medical School, Aichi, Japan

Purpose: Occult macular dystrophy (OMD) is a hereditary retinal disease characterized by a normal fundus, normal full-field electroretinograms (ERGs), progressive decrease of visual acuity, and abnormal focal macular ERGs. The purpose of this study was to report pattern-reversal visual-evoked potential (pVEPs) findings in OMD patients.
Patients and method: The pVEPs recorded from four patients with OMD (aged 42–61 years; 2 men and 2 women) were reviewed. The visual acuities ranged from 20/200 to 20/30. The amplitudes of the N-75 and P-100 (P2 amplitude) and the latency of the N-75 components (N1 latency) were analyzed.
Results: The mean (±SD) P2 amplitude was 2.7 ± 1.9 µV for the 5´, 4.8 ± 2.9 µV for the 10´, 3.2 ± 2.1 µV for the 20´, and 4.4 ± 3.5 µV for the 40´ checkerboard stimuli. The N1 latency was 122.2 ± 6.4 ms for the 5´, 105.0 ± 11.5 ms for the 10´, 97.7 ± 10.0 ms for the 20´, and 91.0 ± 13.7 ms for the 40´ checkerboard stimuli. The mean P2 amplitude was reduced and the N1 latency was delayed in comparison with the laboratory standard for the Keio University Hospital.
Conclusions: The delayed latency and reduced amplitude suggest a major contribution of the central cone pathway to the pVEPs.

Keywords: occult macular dystrophy, visual-evoked potential, electroretinogram