title: Unilateral anterior ischemic optic neuropathy: chromatic pupillometry in affected, fellow non-affected and healthy control eyes.
abstract: The intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin, which is sensitive to blue light. Previous chromatic pupillometry studies have shown that the post-illumination response is considered an indicator of the melanopsin activation. The aim of this study was to investigate the ipRGC mediated pupil response in patients with a unilateral non-arteritic anterior ischemic optic neuropathy (NAION). Consensual pupil responses during and after exposure to continuous 20 s blue (470 nm) or red (660 nm) light of high intensity (300 cd/m(2)) were recorded in each eye for 10 patients. Comparisons were performed both intra-individually (affected versus non-affected eyes) and inter-individually (compared with healthy controls). The pupil response was calculated both during the illumination and during the post-illumination phase. The pupil responses to blue and red colors were significantly reduced in the NAION-affected eyes, compared with the fellow non-affected eyes. When comparing the affected eyes with the healthy control eyes, the post-illumination responses were not significantly different. In addition, the post-illumination pupil responses after blue light exposure were increased in the fellow non-affected patients' eyes, compared with the healthy controls. However, significance was only reached for the late post-illumination response. In conclusion, chromatic pupillometry disclosed reduced post-illumination pupil responses in the NAION-affected eyes, compared with the non-affected fellow eyes, suggesting dysfunction of the ipRGCs. Compared with the responses of the healthy controls, the blue light post-illumination pupil responses were similar in the affected eyes and increased in the fellow non-affected eyes. This suggests a possible adaptive phenomenon, involving the ipRGCs of both eyes after unilateral NAION.
authors.affiliation: Department of Ophthalmology, Glostrup Hospital Copenhagen, Denmark.
authors.forename: Kristina
authors.initials: K
authors.lastname: Herbst
authors.forename: Birgit
authors.initials: B
authors.lastname: Sander
authors.forename: Henrik
authors.initials: H
authors.lastname: Lund-Andersen
authors.forename: Marianne
authors.initials: M
authors.lastname: Wegener
authors.forename: Jens
authors.initials: J
authors.lastname: Hannibal
authors.forename: Dan
authors.initials: D
authors.lastname: Milea
keywords: intrinsically photosensitive ganglion cells; ischemic optic neuropathy; melanopsin; pupil light response; pupillometry