User:Eg2619/Alzheimer's disease

Dementia is a progressively debilitating disease. In addition to age, dementia creates greater risk for visual impairments. These impairments can lead to significant negative impacts on dementia patients with visual impairments and their caregivers, such as a higher risk of inpatient admission and hospice use. There are multiple screening assessments that can be useful for diagnosing visual impairment such as the Pupil Reflex, Confrontation fields, and the Snellen chart. Visual impairments can manifest as alterations such as visual acuity, contrast sensitivity, and color vision.

Caregiver Impact

Visual impairments can lead to significant negative impacts on dementia patients with visual impairments and their caregivers, including inpatient admission and hospice use. However, studies have found no significant difference in annual health costs and annual medical fee-for-service costs between those living with dementia with and without visual impairment. Additionally, vision impairments are associated with greater incidence of loneliness, anxiety, depression, and lower quality of life. Caregivers report conflict due to safety concerns, physical exhaustion from dependency, less time dedicated to activities such as visiting friends, and significant time taking care of loved ones. However, in one journal article, the caregivers that spent significantly more time caregiving were compared to those who were caregiving for those without dementia or visual impairments.

Screening Assessments used for Visual Impairments

Screening for visual impairments in dementia patients is crucial for potential treatments and reducing the impacts on caregivers. Dementia patients in long-term care are under-diagnosed. There are factors for screening for sensory impairments, such as speaking clearly, using concise instructions, and limiting time required to complete the test. One review of screening tests included those over 65 with neurodegenerative impairment and only included visual assessments. This review used certain criteria to which assessments would be most suitable for screening visual impairments. These tests involved measures for visual acuity, visual field, color vision, and anatomy. The screening tests that were suggested to be most promising were the Pupil Reflex, Neuro-ophthalmic Assessment, Counting Fingers, Hand Motion, Acuity card (letters), Snellen chart, Feinbloom, Confrontation fields, Ishihara plates, among others.

The Pupil Reflex measures anatomical changes by seeing if the pupils constrict equally and examines cranial nerve II. The Neuro-opthalmic Assessment examines ocular movements, ductions, and pupils, as well as cranial nerve III, IV, VI. The Counting Fingers and Hand Motion measure near visual acuity through cranial nerve II and macular function. The Acuity card with letters also assesses near vision, but preferable with habitual refraction with glasses on and no-glare. The Snellen chart and Feinbloom examines visual acuity for distance with habitual refraction under good lighting and no glare conditions. Confrontation fields measures visual field face to face using objects as well as hands. Ishihara plates measures color vision with the presence of congenital (binocular testing) or acquired (monocular testing) color impairments.

Types of Visual Impairments

Contrast Sensitivity

In Alzheimer's disease, the sensory system is affected negatively. The olfactory, vision, and auditory system can become impaired over time. The visual impairments in those with dementia can manifest in numerous ways. Contrast sensitivity can be impaired in Alzheimer's disease, mild cognitive impairment, and those with cognitive issues without performance issues. It may also be associated with tau tangles and amyloid plaque deposition according to florbetapir and flortaucipir PET scans.

Abnormal Pupillary Responses

Those with Alzheimer's disease can have abnormal pupillary responses. Those with mild cognitive impairment show changes in pupillary response compared to healthy controls. There was also a study completed which suggested those with amnestic mild cognitive impairment had greater differences in pupil dilation than those with non-amnestic mild cognitive impairment and healthy individuals.

Retinal Thinning

There are many studies which have also reported retinal thinning in Alzheimer's disease. Retinal thinning has been found to be observed in mild cognitive impairment and found to be related to memory issues in amnestic mild cognitive impairment. One study reported greater retinal thinning in the peripapillary retinal nerve fibre layer compared with controls. However, another study found that there was no significant difference in the thickness of inner retinal layers between those with mild cognitive impairment and those with early to moderate Alzheimer's disease. Given the mixed results, retinal thinning needs to be further investigated.