Neurodegenerative diseases and color vision impairment: a literature review

Background. Early detection and diagnosis of dementia are of key importance in treatment, slowing disease progression or suppressing symptoms. Color vision impairment may be observed in some cases in patients with Alzheimer's disease, and its potential role in early diagnosis of neurodegenerative diseases is questioned. Objectives. The aim of this review is to provide up-to-date information on color vision impairment in various neurodegenerative diseases. Material and methods. A literature search was conducted using the electronic databases PubMed, Scopus and Web of Science, and the term "dementia" was searched with keyword combinations related to color vision. Results. A total of 785 records were identified through database searching, and 25 articles were ultimately included in the analysis. Multiple studies have shown that patients with neurodegenerative diseases and dementia have impaired color vision, and the possible role of color vision changes are considered as potential biomarkers for early detection in several cases. The results show that color vision impairment is being investigated not only in patients with Alzheimer's disease but also in other neurodegenerative diseases. Conclusions. In individuals with cognitive impairment or neurodegenerative diseases, color vision changes have repeatedly been reported. In some cases, the use of color vision changes for differential diagnosis between certain neurodegenerative diseases has proved useful. Several authors have agreed that color vision tests could be a possible simple method for early diagnosis of dementia.