An article in JAMA Ophthalmology reported a study of a large group of women who had cataracts. Slightly more than half had cataract surgery. The total group was followed for about 20 years. Interestingly the surgery group had a 60 per cent lower mortality.
I do not understand this study even though the researchers controlled many factors including demographics, initial health and weight. The take away lesson is that even a carefully controlled study reported in a peer reviewed journal may be difficult to understand.
I certainly would not encourage a patient to have cataract surgery because he or she might live longer if the cataract was removed.