Light-Induced Pupillary Responses in Alzheimer's Disease

Light-Induced Pupillary Responses in Alzheimer's Disease Pratik S. Chougule1, Raymond P. Najjar1,2, Maxwell T. Finkelstein1, Nagaendran Kandiah3,4 and Dan Milea1,2,5* 1Department of Visual Neurosciences, Singapore Eye Research Institute, Singapore, Singapore 2The Ophthalmology & Visual Sciences ACP, Duke-National University of Singapore (NUS) Medical School, Singapore, Singapore 3Department of Neurology, National Neuroscience Institute, Singapore, Singapore 4Duke-National University of Singapore (NUS), Singapore, Singapore 5Singapore National Eye Centre, Singapore, Singapore The impact of Alzheimer's disease (AD) on the pupillary light response (PLR) is controversial, being dependent on the stage of the disease and on the experimental pupillometric protocols. The main hypothesis driving pupillometry research in AD is based on the concept that the AD-related neurodegeneration affects both the parasympathetic and the sympathetic arms of the PLR (cholinergic and noradrenergic theory), combined with additional alterations of the afferent limb, involving the melanopsin expressing retinal ganglion cells (mRGCs), subserving the PLR. Only a few studies have evaluated the value of pupillometry as a potential biomarker in AD, providing various results compatible with parasympathetic dysfunction, displaying increased latency of pupillary constriction to light, decreased constriction amplitude, faster redilation after light offset, decreased maximum v...
Source: Frontiers in Neurology - Category: Neurology Source Type: research