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Ophthalmology. 2015 Sep;122(9):1777-85. doi: 10.1016/j.ophtha.2015.06.002.

Pupillary Responses to High-Irradiance Blue Light Correlate with Glaucoma Severity.

Author information

1
Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore Graduate Medical School, Singapore, Republic of Singapore.
2
Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore Graduate Medical School, Singapore, Republic of Singapore; Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Republic of Singapore.
3
Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Republic of Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore.
4
Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Republic of Singapore.
5
Program in Neuroscience and Behavioral Disorders, Duke-National University of Singapore Graduate Medical School, Singapore, Republic of Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore. Electronic address: joshua.gooley@duke-nus.edu.sg.

Abstract

PURPOSE:

To evaluate whether a chromatic pupillometry test can be used to detect impaired function of intrinsically photosensitive retinal ganglion cells (ipRGCs) in patients with primary open-angle glaucoma (POAG) and to determine if pupillary responses correlate with optic nerve damage and visual loss.

DESIGN:

Cross-sectional study.

PARTICIPANTS:

One hundred sixty-one healthy controls recruited from a community polyclinic (55 men; 151 ethnic Chinese) and 40 POAG patients recruited from a glaucoma clinic (22 men; 35 ethnic Chinese) 50 years of age or older.

METHODS:

Subjects underwent monocular exposure to narrowband blue light (469 nm) or red light (631 nm) using a modified Ganzfeld dome. Each light stimulus was increased gradually over 2 minutes to activate sequentially the rods, cones, and ipRGCs that mediate the pupillary light reflex. Pupil diameter was recorded using an infrared pupillography system.

MAIN OUTCOME MEASURES:

Pupillary responses to blue light and red light were compared between control subjects and those with POAG by constructing dose-response curves across a wide range of corneal irradiances (7-14 log photons/cm(2) per second). In patients with POAG, pupillary responses were evaluated relative to standard automated perimetry testing (Humphrey Visual Field [HVF]; Carl Zeiss Meditec, Dublin, CA) and scanning laser ophthalmoscopy parameters (Heidelberg Retinal Tomography [HRT]; Heidelberg Engineering, Heidelberg, Germany).

RESULTS:

The pupillary light reflex was reduced in patients with POAG only at higher irradiance levels, corresponding to the range of activation of ipRGCs. Pupillary responses to high-irradiance blue light associated more strongly with disease severity compared with responses to red light, with a significant linear correlation observed between pupil diameter and HVF mean deviation (r = -0.44; P = 0.005) as well as HRT linear cup-to-disc ratio (r = 0.61; P < 0.001) and several other optic nerve head parameters.

CONCLUSIONS:

In glaucomatous eyes, reduced pupillary responses to high-irradiance blue light were associated with greater visual field loss and optic disc cupping. In POAG, a short chromatic pupillometry test that evaluates the function of ipRGCs can be used to estimate the degree of damage to retinal ganglion cells that mediate image-forming vision. This approach could prove useful in detecting glaucoma.

PMID:
26299721
DOI:
10.1016/j.ophtha.2015.06.002
[Indexed for MEDLINE]
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