Eye is the Window to the Brain Pathology.

In many neurological diseases, retina is affected leading to partial or complete vision loss, which further depends upon the severity of the disease. For example, majority of the stroke victims suffer vision loss due to stroke-induced retinal damage [1,2]. Similarly, there is an aggregation of toxic huntingtin protein [3], intra retinal amyloid deposition [4], and loss of retinal dopaminergic neurons [5] in mouse model of Huntington, Alzheimer and Parkinson’s disease respectively. These studies strongly suggest the association between brain and the eye. However, questions remain how important is the pathophysiological responses of the retina of the eye in understanding these neurological diseases? This has not been well investigated. Moreover, why eye is the mirror/ window to the brain pathology? Part of the reason is the retina being a structure of the brain, which projects out of the diencephalon, similar embryonic origin as brain, shares similar brain vasculature, blood barriers as well as pathophysiology. Moreover, earlier changes necessary to understand the pathophysiology of specific neurological diseases is easily demonstrated in the retina of the eye as described above.