Alzheimer’s disease, described as an age-associated neurodegenerative condition, is one of the most prevalent disorders under the umbrella term neurodegenerative diseases. One of the most prevalent conditions observed in the elderly population, it claims nearly 2.5 million lives on an annual basis. According to a 2023 survey, with 500,000 new cases reported in the US every year, the 6.7 million diagnoses of Alzheimer’s disease account for over 10% of the country’s population. This implies that for every 9 Americans over the age of 65, 1 will display symptoms of Alzheimer’s. Besides its prevalence, the disease has begun to gain a reputation for being associated with several separate or secondary conditions. Among the several disorders speculated to be linked with Alzheimer’s, glaucoma gained public interest after a recent study.
In a recent review published in the journal the International Journal of Molecular Sciences, magnetic resonance imaging (MRI) technology-dependent analysis showed a significant association between Alzheimer’s disease and glaucoma. Glaucoma is a group of disorders characterized by the progressive deterioration of vision. Affecting over 78 million people worldwide, this condition progresses due to multifactorial degenerative optic neuropathy. In simpler terms, neuronal cells associated with vision, also known as retinal ganglion cells, undergo degradation due to several factors, resulting in a gradual loss of sight.
The probability of developing Alzheimer’s and related symptoms in this population is estimated to be 12%. The significant overlap in the two conditions was further analyzed. Diagnostically, the appearance of plaque-like structures on the brain scans characterizes Alzheimer’s disease. On a molecular level, the plaques observed are amyloid beta buildups formed with the aid of tau proteins. Studies of patients presenting both conditions showed the presence of amyloid beta proteins in the vicinity of affected retinal ganglion cells.
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The pathologies of Alzheimer’s disease and glaucoma are similar in several ways. Glaucoma is associated with brain regions other than those that are the core of central vision. These regions superimpose on the areas related to Alzheimer’s disease. Brain scans and several studies show that the two conditions are fundamentally interlinked. The posterior cortical atrophy (PCA) score is used to grade the severity of Alzheimer’s in an individual based on atrophies in the posterior region of the brain. When used to evaluate glaucoma patients, they showed a score in close range to that of the former disease. Another interesting observation was the genetic convergence of the two conditions. Chromosome 17, which is related to a variety of congenital anomalies, had a role in both Alzheimer’s disease and glaucoma.
The gene responsible for coding the tau protein is located on the NFT region of chromosome 17. This microtubule-related protein is a recognized risk factor locus for Alzheimer’s disease. The optic nerve degeneration in glaucoma is also found to be related to this region. A phenotypic similarity was observed at 19 sites of the brain with 11 loci depicting significant local connections. This increases the probability of having similar genetic causes for various neurodegenerative diseases.
Carae Wagner specializes in reporting on the healthcare sector, with a specific emphasis on digital health, gene therapy, viral vectors, and public policy. She holds degrees in English and Psychology from the University of Virginia. Her writing has been featured in publications such as Forbes, Slate, C-Ville Weekly, and various others. She maintains a focus on anxiety disorders and depression and aims to explore other areas of mental health including dissociative disorders such as maladaptive daydreaming.