This year Marco Pellegrini et al in the journal Clinical and Experimental Ophthalmology (2020;48:593-601) published an analysis of 16 studies, 14 of which addressed depression and 9 cognitive function before and after cataract surgery in the elderly.
Their meta-analysis of these studies provided evidence that cataract surgery does reduce depressive symptoms and improve cognitive function in the elderly, just as we long suspected.
Previous studies had showed the worse the patient's vision, the more likely to be depressed they are. It was therefore not surprising that the worse the vision prior to cataract surgery, the more the patient’s depressive symptoms improved after cataract surgery,’
In one study assessed, this result was found to continue for over 13 years.