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.