This review discusses the relationship between retinal degeneration and neurodegenerative diseases, particularly Alzheimer's disease (AD) and Parkinson's disease (PD). The retina, as an extension of the central nervous system (CNS), shares structural and functional similarities with the brain, making it a potential window into early signs of neurodegenerative diseases. Retinal alterations, such as changes in visual acuity, contrast sensitivity, and retinal thickness, can serve as noninvasive markers for the early diagnosis of AD and PD. In AD, retinal degeneration is associated with the accumulation of amyloid β (Aβ) plaques and neurofibrillary tangles, which are also found in the brain. Similarly, in PD, α-synuclein deposition in the retina and dopaminergic neurons can alter visual functions. Electrophysiological tests like electroretinography (ERG) and visual evoked potentials (VEPs) are useful tools for assessing retinal function and detecting early signs of these diseases. The review highlights the potential of retinal analysis as a cost-effective method for early diagnosis, overcoming the limitations of traditional brain imaging techniques.This review discusses the relationship between retinal degeneration and neurodegenerative diseases, particularly Alzheimer's disease (AD) and Parkinson's disease (PD). The retina, as an extension of the central nervous system (CNS), shares structural and functional similarities with the brain, making it a potential window into early signs of neurodegenerative diseases. Retinal alterations, such as changes in visual acuity, contrast sensitivity, and retinal thickness, can serve as noninvasive markers for the early diagnosis of AD and PD. In AD, retinal degeneration is associated with the accumulation of amyloid β (Aβ) plaques and neurofibrillary tangles, which are also found in the brain. Similarly, in PD, α-synuclein deposition in the retina and dopaminergic neurons can alter visual functions. Electrophysiological tests like electroretinography (ERG) and visual evoked potentials (VEPs) are useful tools for assessing retinal function and detecting early signs of these diseases. The review highlights the potential of retinal analysis as a cost-effective method for early diagnosis, overcoming the limitations of traditional brain imaging techniques.