Neuropathies of the optic nerve and visual evoked potentials with special reference to color vision and differential light threshold measured with the computer perimeter OCTOPUS

Abstract

The contrast evoked potentials (VEPs) to different check sizes were recorded in about 200 cases of discrete optic neuropathies (ON) of different origin. Differential light threshold (DLT) was tested with the computer perimeter OCTOPUS. Saturated and desaturated tests were applied to evaluate the degree of acquired color vision deficiency. Delayed VEP responses are not confined to optic neuritis (RBN) alone and the different latency times obtained from other ON are confluent. The delay may be due to demyelination, to an increasing dominance of paramacular VEP subcomponents or to an increasing dominance of the upper half-field responses. Recording with smaller check sizes has the advantage that discrete dysfunctions in the visual field (VF) center are more easily detected: a correlation between amplitudes and visual acuity is best in strabismic amblyopias, is less expressed in maculopathies of the retina and weak in ON. The absence or reduction of amplitudes to smaller check sizes, however, is an important indication of a disorder in the VF center of ON in an early or recovered stage. Acquired color vision defects of the tritan-like type are more confined to discrete ON, whereas the red/green type is reserved to more severe ON. The DLT of the VF center is reduced in a different, significant and non significant extent in discrete optic neuropathies and the correlation between DLT and visual acuity is weak. A careful numerical analysis is needed in types of discrete ON where the central DLT lies within normal statistical limits: a side difference of the DLT between the affected and the normal fellow eye is always present. Evaluation of visual fatigue effects and of the relative sensitivity loss of VF center and VF periphery may provide further diagnostic information.

Clinical electrophysiology of the optic nerve and retinal ganglion cells

“…producing a bifid or ‘p-n-p’ waveform). This can mistakenly be construed as an atypically early or delayed P100 as demonstrated by Thompson [ 197 ], therefore half-field PR-VEPs are essential to elaborate on the origins of the components observed, as are PR-VEPs to a range of check widths [ 198 ]. Overall, a fair conclusion now is that ION predominantly affects PR-VEP amplitude, but latency can in some circumstances be affected, but is typically less marked than that observed in optic neuritis [ 194 , 197 – 202 ].…”

Comparison of automated perimetry and pattern visually evoked cortical potentials in optic neuritis

“…No relation between programs 33 and 34 and pattern VECP in MS was found by Meienberg, Flammer, and Ludin [7]; a moderate correlation between program 11 and VECP was found by Younge [8]. Wildberger [9] reported a reduced sensitivity in the central nine points of program 31 in association with a disturbed VECP in most cases of optic neuropathy. But he found delayed latency even in most cases with normal central nine points of program 31, where we found few abnormal VECPs.…”

Konzentrische Gesichtsfeldeinschränkungen ungeklärter Genese

“…Bei allen Patienten mit ungeklarter GF-Einschrankung (= VFcon-Patienten) wurden die visuell evozierten Potentiale (VEP) auf Schachbrettmusterumkehr abgeleitet (Methodik s. Wildberger, 1984). Die Ableitbarkeit von VEP-Antworten guter Qualitat diente uns u.a.…”