Preop low-light pupil diameter shows no relationship with visual outcome

ATLANTA — From an evidence-based medical perspective, there is "clearly" little justification for measuring pupil diameter under low light conditions prior to performing LASIK, a surgeon said here.

"An analysis of peer-reviewed literature shows that there's a wide range of sample sizes, a wide range of periods of follow-up of these patients and of methods to measure postoperative quality of vision," Peter J. McDonnell, MD, said at Refractive Surgery Subspecialty Day preceding the American Academy of Ophthalmology meeting. "Most studies, in fact, demonstrate no relationship between pupil diameter measured preoperatively with symptoms measured postoperatively."

Dr. McDonnell reviewed the literature to determine whether a relationship exists between pupil diameter and the ability to predict postoperative difficulties, but in large and small studies with long and short follow-up, there was no consensus. Most studies demonstrated no relationship of pupil diameter to symptoms, Dr. McDonnell said.

One study that did find a relationship showed this relationship only in the first month; thereafter the relationship was no longer notable.

Dr. McDonnell’s paper presented at the AAO/ISRS Refractive Surgery Subspecialty day was a comprehensive review of the peer literature on the importance of measuring the low light pupil diameter before laser vision correction. In this sentinel analysis, he found that there is no compelling reason to measure it. Most studies did not find any relationship between the low light pupil and visual symptoms after surgery. This has the potential to change common practice patterns because many LASIK surgeons today assess the pupil diameter before the procedure.

Steven C. Schallhorn, MD
San Diego, California