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Drift during suction can contribute to flap decentration in LASIK
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BOSTON — Microkeratomes can "drift" during suction, resulting in a decrease in pupil-to-hinge distance that can affect flap centration during LASIK, a study found.
Images copied from video recordings of 121 LASIK surgeries using two Bausch & Lomb microkeratomes, the Hansatome and the Automated Corneal Shaper (ACS), were analyzed by Dimitri Azar, MD, and colleagues here at the Massachusetts Eye and Ear Infirmary. They measured the distance from pupil center to corneal flap hinge (pupil-to-hinge distance), hinge size, distance from the center of the pupil to the margins of the flap and the positions of the suction ring before and after vacuum.
The mean drift of eyes during suction with the Hansatome was 0.27 mm and with the ACS 0.12 mm. The Hansatome induced, on average, more biased drift (temporal vs. random) than did the ACS. The mean final displacement of the center of the flap from the center of the pupil was of equal magnitude for the two microkeratomes.
The study is published in the November issue of American Journal of Ophthalmology.