The main purpose of this study was to investigate the short-term effect of anti-glaucoma medications on the blue light elicited PIPR in healthy individuals. Dorzolamide, a carbonic anhydrase inhibitor used in glaucoma, did not affect the pupillary light reflex ( 13, 14). Pindolol, a non-selective beta-blocker used as an anti-glaucoma agent, reduced resting pupil size and contraction amplitude of pupillary light reflex in healthy adults ( 12). found that latanoprost decreases constriction latency and pupil size in glaucomatous human eyes ( 11). These prostaglandin receptors cause contraction in cat and bovine iris sphincter muscle ( 6, 9, 10). However, the pupillary light response is affected by various physiological and environmental factors – importantly, topical anti-glaucoma drugs may alter this response.Īnimal studies have shown that latanoprost and other ocular hypotensive prostaglandin analogs such as travoprost, prostaglandin F2α, and bimatoprost have different affinities to FP-, E2-, and D2-prostaglandin receptor subtypes ( 6– 10). Thus, pupillometry may be applied as a quick, non-invasive, and objective method to evaluate glaucoma progression. Three studies, using chromatic pupillometry, have shown decreased pupillary response and in particular reduced PIPR in glaucoma patients, indicating functional impairment of the ipRGCs ( 3– 5). The melanopsin elicited sustained pupillary response after light offset is termed post-illumination pupillary response (PIPR) ( 2). The outer retina photoreceptors (rod and cones) exhibit fast temporal kinetics and cause a brisk pupillary constriction in response to light, while the inner retinal melanopsin containing intrinsic photosensitive retinal ganglion cells (ipRGCs) exhibit slower temporal kinetics and elicit a sustained pupillary constriction to light stimuli, persisting after light cessation ( 1). Dorzolamide reduced pupil size, while timolol reduced both pupil size and maximal contraction to red light, but the effect was minute and not of clinical importance.Ĭhromatic pupillometry is a relatively novel research tool for the evaluation of outer and inner retina function. Intraocular pressure was significantly reduced by all three drugs after 3.5 h ( p < 0.01), while it remained unchanged during the control day ( p = 0.3).Ĭonclusion: Anti-glaucoma medications did not interfere with the blue light elicited PIPR. Timolol also reduced the maximal contraction amplitude significantly during red light ( p = 0.02). Pupillary size decreased slightly with timolol (0.1 mm, p = 0.03) and dorzolamide (0.2 mm, p < 0.001), but not with latanoprost. During the control day, the only significant variation over time was observed for the red light PIPR 0–10s ( p = 0.02). Results: We found no drug effect on the blue light PIPR 10–30s or any other blue light pupil parameters. ![]() Intraocular pressure (IOP) was measured before and 3.5 h after drug instillation. Additionally, pupil size, maximal contraction, and the early post-illumination pupillary response (PIPR 0–10s ) to blue and red light were investigated. Main outcome was the PIPR 10–30s to blue light. Stimulus was blue (463 nm) and red light (633 nm) of 2 log (lux). Methods: In this randomized, double-masked, crossover trial, pupillometry was performed before and after topical administration of latanoprost, dorzolamide, and timolol in 20 healthy subjects. Since animal studies have indicated that common anti-glaucomatous agents affect the iris muscle, we investigated the short-term effect of the anti-glaucoma drugs on the pupillary light reflex and in particular on the PIPR 10–30s. Purpose: The late post-illumination pupillary response (PIPR 10–30s ) to blue light is reduced in glaucoma, suggesting that pupillometry can be used in clinical glaucoma evaluation. 2Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. ![]()
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