Journal article
Clinical Implications of New Aspects of the Pupil Light Reflex Mediated by Melanopsin Containing Retinal Ganglion Cells
Neuro-Ophthalmology Japan, Vol.25(2), pp.216-232
2008
Abstract
[Abstract][Objective]:To understand which stimulus conditions and dynamics of the pupil light reflex help to localize the site of damage in the visual pathway to the outer photoreceptor layer using comparing red and blue light stimuli as a function of light intensity. [Background]:New information about the physiology of melanopsin expressing retinal ganglion cells mediating the pupil light reflex and their projections to the brain may provide a basis for localizing the site of damage to the retina in patients with photoreceptor degeneration vs. optic nerve disease. [Methods]:Subjects with visual field loss localized to either the photoreceptor layer of the retina or optic nerve were evaluated by recording the pupil light reflex to various types of visual stimuli and comparing them to normal eyes. [Results]:Pupil waveform shape, duration, and differential response to low vs. high stimulus intensity and red vs. blue color were useful in localizing the site of damage. Normal eyes showed more sustained pupil response to blue light compared to luminance-matched red stimuli at brighter light intensities. Outer retinal disease showed reduced transient pupil responses, but intact sustained pupil contraction to bright blue stimuli. Optic nerve disease reduced both transient and sustained pupil contractions. [Conclusion]:Photoreceptor mediated and intrinsic activation of the melanopsin retinal ganglion cell has both a transient and a sustained pupil response to red and blue light, which is intensity dependent. Eyes with severe photoreceptor loss can still maintain a pupil contraction to bright blue light, which appears to be mediated by the intrinsic light activation of the melanopsin retinal ganglion cells. Knowledge of response properties and projections of these neurons mediating the pupil light reflex should facilitate localization of damage to either outer photoreceptors or optic nerve.
Details
- Title: Subtitle
- Clinical Implications of New Aspects of the Pupil Light Reflex Mediated by Melanopsin Containing Retinal Ganglion Cells
- Creators
- Randy H. KardonAki Kawasaki
- Resource Type
- Journal article
- Publication Details
- Neuro-Ophthalmology Japan, Vol.25(2), pp.216-232
- Publisher
- The Japanese Neuro-Ophthalmology Society
- ISSN
- 0289-7024
- Language
- Japanese
- Date published
- 2008
- Academic Unit
- Iowa Neuroscience Institute; Ophthalmology and Visual Sciences
- Record Identifier
- 9984071704902771
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