Visual Function and Cognitive Dysfunction in Older Adults

Background: Studies have shown a correlation between visual impairment and increased risk of Alzheimer's disease (AD). Therefore, it is important to understand the relationship between visual function and cognitive dysfunction in order to improve care and health-related quality of life. This study assesses the relationship between self-reported visual function and cognitive dysfunction through the use of two questionnaires, the Mini-Mental Status Exam (MMSE) and the 25 item National Eye Institute Vision Function Questionnaire (NEI VFQ-25). Methods: 131 participants from the Alzheimer's Disease in Primary Care (ADPC) study were recruited to complete the NEI VFQ-25. This questionnaire takes into account multiple domains of health and measures the impact of ocular dysfunction on each of the domains. Before completing the questionnaire, as part of the ADPC study, the subjects underwent neuroimaging and a battery of neuropsychological testing, including the MMSE. Based on clinical dementia rating scale (CDR), MMSE scores and additional cognitive testing, participants were classified into three groups of cognitive impairment. These were: normal control with no cognitive impairment (CDR sum of box score equaling 0), mild cognitive impairment (CDR sum of box score between 0.5 to 2) and Alzheimer's dementia (CDR sum of box score over 2.5). To examine the relationship between cognition and self-reported visual function, we performed a Kruskal Wallis test to assess vision specific role difficulties in the three diagnostic categories. Results: The Kruskal Wallis test revealed a significant difference in role difficulties related to vision among the three diagnostic groups (p = 0.04). This means that as the MMSE score decreased due to cognitive impairments, participants reported greater difficulties in their activities of daily living and completion of tasks due to deteriorating eyesight. Conclusions: An important component during the ophthalmic and neuropsychological evaluation of a patient is the consideration of visual function as it relates to quality of life. The need for the NEI-VFQ questionnaire arises because vision tests cannot comprehensively represent the emotional well-being or social function of a patient, formally known as the health-related quality of life. Identifying and addressing reduced visual function could play a role in improving the health-related quality of life for patients who are at an increased risk of cognitive dysfunction.