Laser blended vision test reported to screen surgery candidates
A conference report describes an 80% perception cutoff, but key data needed to validate the test are not yet available.
By Priya Raghavan · Science Reporter
3 min read
A laser blended vision test using routine eye-exam equipment was reported to help screen people for a procedure intended to reduce age-related difficulty with close vision. The result matters because the procedure depends on a patient’s ability to adjust to each eye being focused differently, yet the findings have been presented only at a conference and lack several details needed to establish predictive accuracy.
The research was presented at the 44th Congress of the European Society of Cataract and Refractive Surgeons by Brendan Cummings, a consultant ophthalmologist at the Wellington Eye Clinic in Dublin, according to an ESCRS-provided report published by Medical Xpress.
What is the laser blended vision test?
Laser blended vision is aimed at presbyopia, the age-related loss of clear near vision that commonly emerges after 40. In the approach described by ESCRS, one eye is treated for distance viewing and the other for near viewing, leaving the brain to combine the two inputs across different distances.
The proposed screen uses a phoropter, the device clinicians use during standard refraction exams to change lenses. After setting the best distance correction, clinicians ask the patient to rate that vision as 100%; they then blur one eye to make it short-sighted and ask the patient to compare the result. The same assessment is repeated with the other eye, ESCRS said.
In the reported study, a patient who rated vision with one eye blurred at 80% or more of the starting level was considered likely to tolerate blended vision. The assessment was also used to identify the eye intended for distance correction.
What did the study report?
ESCRS said the study involved 1,341 people who were short-sighted, long-sighted or had neither condition. It said 30 participants, or 1.66%, were judged unsuitable before surgery, and that 96.9% of those who went on to treatment adapted successfully.
Those results describe outcomes after a selected group was screened, rather than independently proving that the test predicts success. The society’s account does not provide a peer-reviewed paper, a definition of successful adaptation, follow-up length, patient demographics, adverse-event results, or a comparison group. It also does not report sensitivity, specificity or predictive-value calculations for the 80% cutoff.
Patients considering the procedure would therefore need an individual clinical assessment rather than treating the threshold as established guidance. The conference findings concern laser blended vision and should not be applied to other eye procedures without separate evidence.
What should patients discuss before LASIK?
Mayo Clinic says LASIK can cause dry eyes and temporary visual effects such as glare, halos or double vision. It also says some health conditions and recent changes in vision can increase risk or make results less predictable; those considerations are separate from the conference-reported screening method.
This story draws on original reporting from Medical Xpress.