(PDF 151 KB) In recent years, scientists working at the
intersection of two historically well-developed fields, retinal
physiology and circadian biology, upended the conventional view
of retinal organization with the confirmation of a nonvisual
ocular photoreceptor system. The fact that the eye has functions
beyond image perception holds the potential to explain why a
significant proportion of patients with progressive degenerative
ocular disease suffer from sleep disturbances. An understanding
of these non-rod/non-cone photoreceptors might also explain
seasonal affective disorder (SAD), jet lag and depression in the
blind. It has the potential to influence intraocular lens
selection for cataract patients. “The shocker is, you don’t need
rods and cones to synchronize your circadian clock to the local
light-dark cycle,” said Russell N. Van Gelder, MD, PhD. “There’s
this whole other photoreceptive system lurking in the retina
entraining your circadian system.” Dr. Van Gelder is professor
and chairman of ophthal