Electro-oculography in bilateral optic neuropathy

Abstract

Objective: Effect of bilateral, optic neuropathy on the function of retinal pigment epithelium has not been investigated extensively to date. This study aimed to determine the effect of bilateral, optic neuropathy on light peak:dark trough ratio, light peak and dark trough values of electro-oculography. Thirty-seven patients with a clinical diagnosis of bilateral optic neuropathy and 40 control subjects were recruited in this observational, cross-sectional study, carried out at the Neurophysiology unit, Teaching Hospital, Peradeniya, Sri Lanka. Pattern reversal visual evoked potentials, pattern electroretinography and electro-oculography were recorded in all of them. Results: Twenty-four patients (64.9%) had reduced light peak:dark trough ratio values. The median light peak:dark trough ratio ± inter quartile range of the patient group (1.50 ± 0.4) was significantly lower than that of the controls (1.80 ± 0.2), (p < 0.001). Median dark trough value was significantly higher in patients compared to the control value. These changes may be due to higher conductance of ion channels in the retinal pigment epithelium, sub retinal space creation, changes in choroidal circulation or secondary to photoreceptor abnormalities in the macular region. These results indicate that retinal pigment epithelium might be affected in bilateral optic neuropathy.

Integrating visual electrophysiology into clinical practice: Role of advanced visual electrophysiological tests to diagnose retinal and optic nerve disorders

“…In the individual analysis, reduced Arden ratio in EOG was found in 55 out of 90 (61.1%) patients. This shows that RPE exhibits abnormal function in the majority of patients with optic neuritis which is considered to be a novel finding even in the international research field [3,4]. EOG abnormalities observed in our study could be due to a derangement in the chloride conductance which could have occurred as a result of acute episode of optic neuritis.…”