Seeing Is Remembering

Landmark paper: A Maharani et al., “Cataract surgery and age-related cognitive decline: A 13-year follow-up of the English Longitudinal Study of Ageing”, PLOS ONE, 13 (2018). DOI: e0208045.

Most cataract surgeons would agree that the improved vision patients experience after cataract surgery has a positive impact on those patients’ lives. This is felt to be particularly so in patients who have concurrent cognitive impairment, such as dementia. Unfortunately, most of the studies to date looking at the depth of dementia after cataract surgery have failed to show an improvement, probably because of the structure of the dementia assessments used before and after surgery. A paper in PLOS ONE has shown, however, that the cognitive decline associated with normal ageing was slowed by cataract surgery.

The English Longitudinal Study of Ageing (ELSA) forms part of the SENSE-Cog multi-phase research program, which is funded by the European Union Horizon 2020 program. The researchers looked at cognitive function before and after cataract surgery in the respondents and compared it with a control group. Cognitive function was measured using episodic memory scores as part of a wider panel of questions looking at ageing in general. In the memory test, the interviewers read a list of 10 simple nouns once. The respondents were asked to repeat those nouns twice: immediately after the words were read out (immediate recall) and at the end of the cognitive function module (delayed recall). This test was performed at least three times over a 13-year timeframe. Cataract surgery respondents had at least one cataract removal after the first test and then two after over the observation period. There were 2,068 patients in the surgery group and 3,636 in the control group.

Cataract surgery was positively associated with a lower rate of cognitive decline among older adults in England, independent of risk factors for cognitive impairment including those related to age, gender, education, wealth, chronic diseases, depressive symptoms, and physical inactivity.

Vision loss and cognitive decline, particularly in dementia, is an increasing part of the workload in our clinics. My choice of landmark paper shows us the benefit of visual rehabilitation on cognition and by extension the potential deficit caused by visual loss on patients ageing. The topic will be discussed further at the RCOphth Congress in Glasgow, May 20-23 2019.