All normal subjects displayed a significant PIPR for a 10-second, 470-nm light stimulus, but not a 623-nm stimulus, which is consistent with the proposed melanopsin-mediated response. In most normal individuals, the amplitude of the PIPR was substantial. This test has the potential to be used as a tool in evaluating subjects with inner retinal dysfunction or melanopsin-related disorders.

This study demonstrates that there is a significant decrease in the ipRGC-mediated PIPR in glaucomatous patients when compared to age-matched controls. As the severity of the glaucomatous neuropathy increases, there is a correlated decrease in the PIPR. Therefore, this test has the potential for use as a clinical tool in evaluating patients with glaucoma.

Circadian rhythms generated by the suprachiasmatic nucleus (SCN) are entrained to the environmental light/dark cycle via intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin and the neuropeptide PACAP. The ipRGCs regulate other non-image-forming visual functions such as the pupillary light reflex, masking behaviour and light induced melatonin suppression. To evaluate whether PACAP immunoreactive retinal projections are useful as a marker for central projection of ipRGCs in the monkey brain, we characterized the occurrence of PACAP in melanopsin expressing ipRGCs and in the retinal target areas in the brain visualized by the anterograde tracer Cholera Toxin subunit B (CtB) in combination with PACAP staining. In the retina, PACAP and melanopsin were found to be co-stored in 99% of melanopsin expressing cells characterized as inner and outer stratifying melanopsin RGCs. Two macaque monkeys were anesthetized and received a unilateral intravitreal injection of CtB. Bilateral retinal projections containing co-localized CtB and PACAP immunostaining were identified in the SCN, the lateral geniculate complex (LGN) including the pregeniculate nucleus (PrGC), the pretectal olivary nucleus (PON), the nucleus of the optic tract (NOT), the brachium of the superior colliculus (BSC), and the superior colliculus (SC). In conclusion, PACAP immunoreactive projections with co-localized CtB represent retinal projections of ipRGCs in the macaque monkey, and support previous retrograde tracer studies demonstrating that melanopsin containing retinal projections reach areas in the primate brain involved in both image and non-image-forming visual processing.

Circadian rhythms generated by the suprachiasmatic nucleus (SCN) are entrained to the environmental light/dark cycle via intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin and the neuropeptide PACAP. The ipRGCs regulate other non-image-forming visual functions such as the pupillary light reflex, masking behaviour and light induced melatonin suppression. To evaluate whether PACAP immunoreactive retinal projections are useful as a marker for central projection of ipRGCs in the monkey brain, we characterized the occurrence of PACAP in melanopsin expressing ipRGCs and in the retinal target areas in the brain visualized by the anterograde tracer Cholera Toxin subunit B (CtB) in combination with PACAP staining. In the retina, PACAP and melanopsin were found to be costored in 99% of melanopsin expressing cells characterized as inner and outer stratifying melanopsin RGCs. Two macaque monkeys were anesthetized and received a unilateral intravitreal injection of CtB. Bilateral retinal projections containing co-localized CtB and PACAP immunostaining were identified in the SCN, the lateral geniculate complex (LGN) including the pregeniculate nucleus (PrGC), the pretectal olivary nucleus (PON), the nucleus of the optic tract (NOT), the brachium of the superior colliculus (BSC), and the superior colliculus (SC). In NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript conclusion, PACAP immunoreactive projections with co-localized CtB represent retinal projections of ipRGCs in the macaque monkey, and support previous retrograde tracer studies demonstrating that melanopsin containing retinal projections reach areas in the primate brain involved in both image and non-image-forming visual processing.

is believed to start in the optic nerve head, the lamina cribrosa in particular, hence there is critical need for approach to imaging this region of the eye in-vivo.• Understanding the complex interplay of intraocular pressure changes and lamina cribrosa is vital to our understanding of the disease progression.