MAR 04, 2011
This article provides an enlightening review of published medical studies and developing knowledge about how the symptoms of cataract and visual impairment may overlap with the symptoms of cognitive impairment. Since ophthalmologists see large numbers of older patients, they will likely encounter patients with cognitive impairment and dementia, some of whom have yet to be diagnosed.
The authors explain that visual symptoms due to either cataract or dementia can be difficult to distinguish. Cataract surgery may improve cognitive performance in some patients with early cognitive impairment but its benefits in patients with established dementia are less clear. The authors recommend a multidisciplinary approach to managing patients with visual symptoms, ophthalmic pathology and cognitive impairment, with good lines of communication between ophthalmology, neurology and psychiatry departments.
The major causes of dementia with prominent visual symptoms at the outset include dementia with Lewy bodies, Parkinson disease dementia, posterior cortical atrophy and sporadic Creutzfeldt-Jakob disease.
The authors say that patients diagnosed with dementia or cognitive impairment may achieve poorer outcomes than other patients and should be counseled about this before surgery. There is also a risk that without thorough preoperative clinical assessment, inappropriate cataract surgery could be performed on patients with cognitive impairment.
In patients with visual symptoms due to both cataract and cognitive impairment, a lack of awareness of the cognitive component of the symptomatology could lead to unrealistic expectations of the improvement in symptoms after cataract surgery. Persistent visual symptoms after cataract surgery may be incorrectly attributed to other pathology, such as cystoid macula edema or age-related macular degeneration, leading to inappropriate management.
Nevertheless, it is important to acknowledge that family members and caregivers of patients with dementia and cataract are often reluctant to consent to cataract surgery because of the perception that the patient's limited activities of daily living will not benefit from improved vision. However, patients with dementia frequently do exhibit meaningful cognitive improvement after cataract surgery.