Logo image
Toward a clinical protocol for assessing rod, cone, and melanopsin contributions to the human pupil response
Journal article   Open access   Peer reviewed

Toward a clinical protocol for assessing rod, cone, and melanopsin contributions to the human pupil response

Jason C Park, Ana L Moura, Ali S Raza, David W Rhee, Randy H Kardon and Donald C Hood
Investigative ophthalmology & visual science, Vol.52(9), pp.6624-6635
08/22/2011
DOI: 10.1167/iovs.11-7586
PMCID: PMC3175993
PMID: 21743008
url
https://doi.org/10.1167/iovs.11-7586View
Published (Version of record) Open Access

Abstract

PURPOSE. To better understand the relative contributions of rod, cone, and melanopsin to the human pupillary light reflex (PLR) and to determine the optimal conditions for assessing the health of the rod, cone, and melanopsin pathways with a relatively brief clinical protocol. METHODS. PLR was measured with an eye tracker, and stimuli were controlled with a Ganzfeld system. In experiment 1, 2.5 log cd/m(2) red (640 ± 10 nm) and blue (467 ± 17 nm) stimuli of various durations were presented after dark adaptation. In experiments 2 and 3, 1-second red and blue stimuli were presented at different intensity levels in the dark (experiment 2) or on a 0.78 log cd/m(2) blue background (experiment 3). Based on the results of experiments 1 to 3, a clinical protocol was designed and tested on healthy control subjects and patients with retinitis pigmentosa and Leber's congenital amaurosis. RESULTS. The duration for producing the optimal melanopsin-driven sustained pupil response after termination of an intense blue stimulus was 1 second. PLR rod- and melanopsin-driven components are best studied with low- and high-intensity flashes, respectively, presented in the dark (experiment 2). A blue background suppressed rod and melanopsin responses, making it easy to assess the cone contribution with a red flash (experiment 3). With the clinical protocol, robust melanopsin responses could be seen in patients with few or no contributions from the rods and cones. CONCLUSIONS. It is possible to assess the rod, cone, and melanopsin contributions to the PLR with blue flashes at two or three intensity levels in the dark and one red flash on a blue background.
Leber Congenital Amaurosis - physiopathology Humans Middle Aged Clinical Protocols Retinal Cone Photoreceptor Cells - physiology Rod Opsins - physiology Male Dark Adaptation Reflex, Pupillary - physiology Young Adult Pupil - radiation effects Light Retinal Rod Photoreceptor Cells - physiology Adult Female Aged Retinitis Pigmentosa - physiopathology

Details

Metrics

Logo image