Aberrations induced in wavefront-guided laser refractive surgery due to shifts between natural and dilated pupil center locations
Accepted 11 July 2005.
Purpose
To determine the aberrations induced in wavefront-guided laser refractive surgery due to shifts in pupil center location from when aberrations are measured preoperatively (over a dilated pupil) to when they are corrected surgically (over a natural pupil).
Setting
Center for Visual Science and Department of Ophthalmology, University of Rochester, Rochester, New York, USA.
Methods
Shifts in pupil center were measured between dilated phenylephrine hydrochloride (Neo-Synephrine [2.5%]) and nonpharmacological mesopic conditions in 65 myopic eyes treated with wavefront-guided laser in situ keratomileusis (Technolas 217z, Bausch & Lomb). Each patient's preoperative and 6-month postoperative wave aberrations were measured over the dilated pupil. Aberrations theoretically induced by decentration of a wavefront-guided ablation were calculated and compared with those measured 6 months postoperatively (6.0 mm pupil).
Results
The mean magnitude of pupil center shift was 0.29 mm ± 0.141 (SD) and usually occurred in the inferonasal direction as the pupil dilated. Depending on the magnitude of shift, the fraction of the higher-order postoperative root-mean-square wavefront error that could be due theoretically to pupil center decentrations was highly variable (mean 0.26 ± 0.20 mm). There was little correlation between the calculated and 6-month postoperative wavefronts, most likely because pupil center decentrations are only 1 of several potential sources of postoperative aberrations.
Conclusions
Measuring aberrations over a Neo-Synephrine-dilated pupil and treating them over an undilated pupil typically resulted in a shift of the wavefront-guided ablation in the superotemporal direction and an induction of higher-order aberrations. Methods referencing the aberration measurement and treatment with respect to a fixed feature on the eye will reduce the potential for inducing aberrations due to shifts in pupil center.
From the Center for Visual Science (Porter, Williams), Department of Ophthalmology (Yoon, MacRae), The Institute of Optics (Wolfing), University of Rochester, Rochester, New York, San Diego State University (Lozano), San Diego, California, Physiological Optics (Tumbar), Schepens Eye Research Institute, Boston, Massachusetts, Bausch & Lomb (Cox), Rochester, New York, USA
Reprint requests to Jason Porter, PhD, Center for Visual Science, University of Rochester, Rochester, New York 14627, USA.
Supported by National Institutes of Health grants EY01319, EY07125, and EY04367 and a research grant from Bausch & Lomb and by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST-9876783.
Drs. Porter, Yoon, MacRae, and Williams have served as consultants to Bausch & Lomb. The University of Rochester has licensed intellectual property to Bausch & Lomb and has a research contract with them. No other author has a financial interest in any product mentioned.
Gary Gagarinas, Brenda Houtenbrink, Gina Crowley, Joseph Stamm, and Steven Schneider provided technical assistance.
ABSTRACT