Purpose: Senile cataract and cognitive dysfunction (senile dementia, cognitive impairment and Alzheimer disease) are commonly coexisting. Some ophthalmologists believe that cataract surgery not only can restore health to a patient’s eyes, but also can improve the degenerative state of mind. Since their relationship is not fully understood, this study aims to prospectively investigate the association between cataract surgery and long-term incidence of cognitive dysfunction among older people with senile cataract.
Methods: Retrospective Cohort study design. We used the National Health Insurance Research Database of Taiwan to investigate the relationship between cataract surgery and incidence of cognitive dysfunction in patients with cataract between January 2000 and December 2010. A total of 31401 cataract patients were included. There were 11385 patients receiving cataract surgery and 20016 age-, sex-, and cataract-diagnosis-timing matched controls who were linked to the claim data to identify the first occurrence of a primary or secondary diagnosis of cognitive dysfunction (including cognitive impairment,
senile dementia, and Alzheimer disease). We used the Kaplan-Meier method to estimate the survival curves of cognitive dysfunction. Cox proportional hazards regression modeling was used to determine the association between patients with cataract who received surgery or not and risk for cognitive dysfunction, adjusting for comorbidities, such as hypertension, diabetic mellitus, hyperlipidemia, dysrhythmia, and coronary artery disease.
Results : Over nearly 10 years of follow-up, a total of 505 cataract subjects who received surgery developed cognitive dysfunction, representing a cumulative incidence rate of 4.44% (n = 727; 3.63% in controls). Cataract patients who received surgery had a similar risk of cognitive dysfunction as patients who did not receive surgery (Hazard Ratio (HR): 1.08, 95% Confidence Interval (CI) 0.97-1.21). In the age-stratified analysis, cataract surgery was associated with increased risk of cognitive dysfunction among patients between 65-74 years of age (HR 1.20, 95% CI 1.04-1.39), and the association was null in patients over 75 years (75 84 years, HR 0.948, 95% CI 0.78-1.16; ≧85 years, HR 0.727, CI 0.41-1.28).
Conclusion: Overall, cataract patients (>65 years) undergoing surgery had a similar risk of cognitive dysfunction (HR 1.08, 95% Confidence Interval (CI) 0.97 1.21). Among cataract patients who were 65-74 years of age, the long-term risk for cognitive dysfunction seemed to increase in those who received cataract surgery compared to those who did not. The risk of surgery was not observed in the older age groups (≧75 years old). The surgery for cataract led to better vision for patients, but there was no conclusive evidence for improvement in cognitive function. On the other hand, “the necessity for cataract surgery” could be an indicator for aging change, especially for “younger” aged people (<75 years). The ophthalmologists should be aware of the patients with the potential need for
cataract surgery, which could be a sign of cognitive dysfunction. The multiple lines of communication between ophthalmology, neurology and geriatriology are very
important.