‘Cataract surgery might lower the risk of dementia’ was a headline widely reported in the media. It was based on a rigorous study, but what the study can tell us is often misunderstood.
What the study shows
An American team followed more than 3 000 adults aged 65 and over, without dementia at the start, who had been diagnosed with cataract. Among them, 46% were operated on. Result published in JAMA Internal Medicine: the risk of developing dementia was approximately 30% lower in operated persons (risk ratio of approximately 0.71), after taking into account several factors such as level of education, smoking or the APOE gene. This difference persisted for at least a decade.
The comparison group is particularly informative. Glaucoma surgery, which does not restore lost sight, was not associated with a lower risk.
What the study does not prove
- This is an observational study: it shows an association, not a cause-and-effect relationship. Operated persons may also be in better health or more medically monitored.
- The mechanism is a hypothesis: better vision would promote social contacts, physical activity and intellectual stimulation, and reduce isolation.
- Surgery should not be seen as a preventive treatment for dementia.
Why cataract surgery is still useful
The cataract is the opacification of the lens, common with age. It hinders reading, night driving, increases the risk of falls and isolates. Restoring good vision improves autonomy and quality of life, independently of any effect on memory. The procedure, performed on an outpatient basis in a few minutes, is one of the most commonly performed and safest (cataract surgery).
When should I seek advice?
Blurred or veiled vision, dazzling, dull colours, frequent changes of glasses: an examination makes it possible to know if the operation is indicated and to choose the suitable implant (implants and lens surgery).
Sources
- University of Washington – Study: cataract surgery linked to lessened dementia risk
- Pourquoi Docteur – L’opération de la cataracte réduirait le risque de démence chez les personnes âgées
- Le Quotidien du Médecin – L’opération de la cataracte permettrait de réduire le risque de démence
Your ophthalmologist answers your questions during the consultation. For a sudden symptom or sudden loss of vision, seek advice promptly: see the eye emergencies page.