Determining the accuracy of an eye tracking system for laser refractive surgery

PURPOSE: Patient eye and head movements during laser refractive surgery may result in errors between the surgical beam position and the desired locati on for optimum correction. This, in turn, may lead to reduced postoperative vision, including increased higher order aberrations of the eye. Active ey e tracking systems are often incorporated into laser delivery systems, whic h aim to reduce the effect of patient eye movement. METHODS: In this study, the accuracy of an eye tracking system designed for laser refractive surgery was determined. An enucleated porcine eye was att ached to a scanning device and the movement measured using the eye tracking system. The recorded position is compared to the preprogrammed position of the scanning device. RESULTS: The system demonstrated an accuracy of 0.06 m for an. intact corne a and 0.1 mm for a cornea with a thin flap removed. This compares to an ave rage decentration of ablation of 0.4 mm for patients relying on passive fix ation, as measured by previous clinical trials. CONCLUSION: implementation of this eye tracker would lead to improved align ment between the laser and eye during laser refractive surgery.