Two year electrophysiology follow‐up in quinine amblyopia

Abstract

A 19-year-old girl presenting with quinine amblyopia had serial electrophysiology studies over a 2 year period. Visually evoked responses and the electro-oculogram were abolished early. By 2 months the VER and visual acuity had returned to normal. The electroretinogram, initially mildly subnormal, became virtually abolished by 2 months. No recovery in cone function took place. Of the rods 50% regained function with normal latency by 1 year, but receptor sensitivity did not return to normal until 2 years after ingestion. The electro-oculogram also recovered slowly over a 2 year period. This pattern suggest that quinine exerts a direct toxic effect on the cells of the outer retina and pigment epithelium, as well as on the ganglion cells.

Quinine toxicity

“…Ischaemia has also been suggested as a cause of visual symptoms but the retinal vessel calibre is normal when symptoms are maximal and vasodilators have proven ineffective. Blindness is usually temporary although permanent scotomata have been reported 1,15–17 . Improvement in vision may continue to occur for several months.…”

Vi-2 : Apport De l'ÉLECTROPHYSIOLOGIE Chez l'ADULTE : Exemples

“…On observe un certain degré de récupération du système scotopique [Moloney et al, 1987], alors que le dysfonctionnement du système photopique semble durable [Canning, Hague, 1988]. L'atteinte du P-ERG suggère aussi une atteinte des cellules ganglionnaires [Canning, Hague, 1988].…”