Intrinsically photosensitive melanopsin retinal ganglion cell contributions to the pupillary light reflex and circadian rhythm

  title={Intrinsically photosensitive melanopsin retinal ganglion cell contributions to the pupillary light reflex and circadian rhythm},
  author={Emma L. Markwell and Beatrix Feigl and Andrew J. Zele},
  journal={Clinical and Experimental Optometry},
Recently discovered intrinsically photosensitive melanopsin retinal ganglion cells contribute to the maintenance of pupil diameter, recovery and post‐illumination components of the pupillary light reflex and provide the primary environmental light input to the suprachiasmatic nucleus for photoentrainment of the circadian rhythm. This review summarises recent progress in understanding intrinsically photosensitive ganglion cell histology and physiological properties in the context of their… 

The Circadian Response of Intrinsically Photosensitive Retinal Ganglion Cells

Out Outer retinal photoreceptor contributions to the inner retinal ipRGC driven post-illumination pupil response also show circadian variation whereas direct outer retinal cone inputs to the pupil light reflex do not, indicating that intrinsically photosensitive retinal ganglion cells mediate this circadian variation.

Melanopsin-Expressing Intrinsically Photosensitive Retinal Ganglion Cells in Retinal Disease

  • B. FeiglA. Zele
  • Biology, Medicine
    Optometry and vision science : official publication of the American Academy of Optometry
  • 2014
A paradigm for differentiating inner and outer retinal inputs to the pupillary control pathway in retinal disease is introduced and applied to patients with age-related macular degeneration (AMD).

Melanopsin Retinal Ganglion Cells and Pupil: Clinical Implications for Neuro-Ophthalmology

The most relevant findings of pupillometric studies in glaucoma, hereditary optic neuropathies, ischemic optic neuro Pathies, idiopathic intracranial hypertension, multiple sclerosis, Parkinson's disease, and mood disorders are presented.

Temporal characteristics of melanopsin inputs to the human pupil light reflex

Melanopsin and Rod–Cone Photoreceptors Play Different Roles in Mediating Pupillary Light Responses during Exposure to Continuous Light in Humans

It is shown that visual photoreceptors are required for normal pupillary responses to continuous light exposure at low irradiance levels, and for sustained pupillary constriction during exposure to light in the long-wavelength portion of the visual spectrum, and that it might be possible to enhance nonvisual light responses to low-irradiance exposures by using intermittent light to activate cone photoreception repeatedly in humans.

Melanopsin-mediated post-illumination pupil response in the peripheral retina.

It is shown that the pupil constriction amplitude was similar at both eccentricities and the time to minimum diameter increased as melanopsin excitation increased, and the eccentricity-dependent change in PIPR amplitude may be analogous to the hill of vision observed in visual perimetry.

Intrinsically photosensitive (melanopsin) retinal ganglion cell function in glaucoma.

Intrinsically photosensitive retinal ganglion cell function measured directly with the PIPR may become a clinical indicator of progressive changes in glaucoma.

Intrinsically photosensitive retinal ganglion cell function in relation to age: A pupillometric study in humans with special reference to the age-related optic properties of the lens

Age did not reduce, but rather enhance pupil responses mediated by ipRGC, but there must be other age related factors such as lens scatter and/or adaptive processes influencing the ipR GC mediated pupil response enhancement observed with advancing age.



Melanopsin and rod–cone photoreceptive systems account for all major accessory visual functions in mice

The rod–cone and melanopsin systems together seem to provide all of the photic input for these accessory visual functions such as pupillary light reflex and circadian photo-entrainment.

Melanopsin-Containing Retinal Ganglion Cells: Architecture, Projections, and Intrinsic Photosensitivity

It is shown that melanopsin is present in cell bodies, dendrites, and proximal axonal segments of a subset of rat RGCs, most likely the visual pigment of phototransducing R GCs that set the circadian clock and initiate other non–image-forming visual functions.

Phototransduction by Retinal Ganglion Cells That Set the Circadian Clock

It is shown that retinal ganglion cells innervating the SCN are intrinsically photosensitive, and depolarized in response to light even when all synaptic input from rods and cones was blocked.

Photon capture and signalling by melanopsin retinal ganglion cells

Fundamental parameters governing intrinsic light responses and associated spike generation of retinal ganglion cells are reported, finding that a flash causing a few hundred isomerized melanopsin molecules in a retina is sufficient for reaching threshold for the pupillary light reflex.

Melanopsin Is Required for Non-Image-Forming Photic Responses in Blind Mice

It is observed that mice with both outer-retinal degeneration and a deficiency in melanopsin exhibited complete loss of photoentrainment of the circadian oscillator, pupillary light responses, photic suppression of arylalkylamine-N-acetyltransferase transcript, and acute suppression of locomotor activity by light, indicating the importance of both nonvisual and classical visual photoreceptor systems for nonvisual photic responses in mammals.

Intrinsically photosensitive retinal ganglion cells detect light with a vitamin A-based photopigment, melanopsin.

  • Yingbin FuH. Zhong K. Yau
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 2005
Study of mice lacking RPE65, a protein essential for the regeneration of rod and cone pigments, and exogenous all-trans-retinal was also able to rescue the low sensitivity of rpe65-/- ipRGCs suggest melanopsin could be a bistable pigment.

Strange vision: ganglion cells as circadian photoreceptors