New methodologies promise accurate objective measurement of night vision after LASIK

Paris—Because complaints about night vision are common after LASIK, there is a need to develop methods to accurately and reproducibly measure patient complaints, said Pedro Faria, MD, at the European Society of Cataract and Refractive Surgeons meeting.

Dr. Faria, of the University Hospital Coimbra, Coimbra, Portugal, described a study in which he and his colleagues evaluated contrast sensitivity using mesopic high-resolution perimetry and the optics using the optical quality analysis system, a double-pass technique, in 20 patients who had undergone LASIK. These patients underwent contrast sensitivity testing preoperatively and 3 and 12 months postoperatively.

The preliminary results showed an improvement in the thresholds in the contrast sensitivity test. Compared with a population of patients with normal vision, the preoperative results were quite different in the 21 patients. The investigators also found a "striking improvement in the central zone compared with the peripheral zone that reached significance," according to Dr. Faria.

The results of optical testing showed an improvement in the point-spread function. All patients had uncorrected visual acuities of 20/20 and there were no complaints of visual disturbances. Modulation test function also improved after LASIK.

"We believe that these seem to be good methods to evaluate the quality of vision," Dr. Faria stated. He and his colleagues expect to present more definitive results within the year.