Electrophysiology in Acute Anterior Ischaemic Optic Neuropathy

Abstract

In a retrospective study of 18 patients, in which 19 eyes were involved, we found in general during the acute phase of an anterior ischaemic optic neuropathy, i.e., within 4 weeks, markedly delayed and reduced pattern-evoked potentials, normal electroretinograms, and decreased electro-oculograms following light stimulation with normal standing potentials. Apart from some sclerosis of the vessels, no other abnormalities of the retinal circulation could be established in our patients. The explanation for the lowered light rise might be the partial and temporary disturbance of the choroidal circulation, which is not extensive enough to influence also the more variable standing potential. In long-standing cases the pattern-evoked potentials seem to remain abnormal, whereas the decreased electro-oculogram following light stimulation recovers.

Clinical electrophysiology of the optic nerve and retinal ganglion cells

“…Some of this may arise around the heterogeneous cohorts recruited within these early studies or consideration for the timing of PR-VEPs after the acute event. For example, it has since been noted that within the acute phase of ION that latency can be more affected [ 196 ]. Furthermore, it is unknown whether PR-VEP morphology changes or field defects were accounted for, as a central scotoma or altitudinal field defects can reduce the macular derived P100 and enhance the paramacular components of the VEP (i.e.…”

Electro-oculography in bilateral optic neuropathy

“…First, Brudet-Wickel and van Lith reported evidence of partial, temporary disturbance of the choroidal circulation in anterior ischemic optic neuropathy that may cause for the abnormalities of light rise in EOG. Since the choroid is the principal vascular structure nourishing the outer retinal layers and the RPE, disturbance of choroidal circulation could have caused hypoxia of the retinal tissues [6]. This in turn can cause abnormalities in photoreceptors and RPE which is reflected in EOG as a reduction in LP:DT ratio in patients of our study.…”

“…The ratio of the potential between light and dark adaptation, known as the LP:DT ratio (light peak:dark trough ratio), is an essential diagnostic test in retinal disorders [4,5]. A study done in patients with ischemic optic neuropathy showed a decrease in the EOG potentials presumably due to ischemia in the RPE [6]. The EOG in other forms of optic neuropathy has not been reported.…”