Simple Eye Test Can Predict Success of Laser Surgery for Age-Related Vision Loss

A simple test using standard eye-testing equipment can accurately predict whether laser blended vision — a surgery for presbyopia, the age-related loss of near vision that develops in people 40 and older — will work for a given patient, according to research presented at the 44th Congress of the European Society of Cataract and Refractive Surgeons (ESCRS).

Laser blended vision corrects one eye for distance and the other for near vision, relying on the brain's ability to blend the two views into clear vision at all ranges — something most, but not all, people can do. The research was presented by Brendan Cummings, a consultant ophthalmologist at the Wellington Eye Clinic in Dublin, Ireland.

Cummings and colleagues used a phoropter — the standard machine used in eye tests to switch between lenses — to first find the lenses that maximize a patient's distance vision, then asked patients to mentally benchmark that as 100%. They then defocused one eye at a time, making it short-sighted, and asked patients how their vision compared. If patients reported at least 80% as good with one eye defocused, they were considered likely to successfully blend the two views and suitable for the surgery. The test also identifies which eye is dominant, so it can be treated for distance vision while the other is treated for near vision.

The study included 1,341 patients with a range of vision problems. Using the test before laser surgery identified 30 people, or 1.66%, as unsuitable for the treatment. Among those who went ahead with the surgery, 96.9% successfully adapted to their laser blended vision.