Accurate centration during the excimer laser procedure is important in optimizing the visual results. Centration is even more crucial for hyperopic than myopic treatments. A decentered ablation may occur if the patient’s eye slowly begins to drift and loses fixation, if the surgeon initially positions the patient’s head improperly, or if the patient’s eye is not perpendicular to the laser treatment (Fig 6-3). The incidence of decentration increases with surgeon inexperience, hyperopic ablations, and higher refractive correction, due to longer ablation times. Decentration may be reduced by ensuring that the patient’s head remains in the correct plane throughout the treatment—that is, perpendicular to the laser (parallel to the ground)—and that there is no head tilt. Treatment of decentration with topography-guided technology, and/or with the use of masking agents may be effective.
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.