Surgeon offsets and dynamic eye movements in laser refractive surgery
Accepted 27 January 2005.
Refers to erratum:
Erratum
Journal of Cataract & Refractive Surgery
March 2006 (Vol. 32, Issue 3, Page 378) Full Text |
Full-Text PDF (38 KB)
Purpose
To determine the amount of static and dynamic pupil decentrations that occur during laser refractive surgery.
Setting
The Center of Visual Science and the Department of Ophthalmology, University of Rochester, Rochester, New York, USA.
Methods
The surgeon's accuracy in aligning the pupil center with the laser center axis was measured when engaging the eye-tracker in 17 eyes receiving conventional laser in situ keratomileusis (LASIK) procedures (Technolas 217z; Bausch & Lomb). Eye movements were measured subsequently during the treatment in 10 eyes using a pupil camera operating at 50 Hz. Temporal power spectra were calculated from the eye movement measurements.
Results
The mean pupil misalignment by the surgeon at the beginning of the procedure was 206.1 μm ± 80.99 (SD) (with respect to the laser center). The laser center was typically misaligned below (inferiorly) and to the left (nasally and temporally in left and right eyes, respectively) of the laser center. Small amounts of cyclotorsion were observed during the ablation (<2 degrees). The mean magnitude of dynamic pupil decentration from the laser center during treatment was 227.0 ± 44.07 μm. The mean standard deviation of eye movements was 65.7 ± 25.64 μm. Temporal power spectra calculated from the horizontal and vertical changes in eye position during the ablation were similar. Ninety-five percent of the total power of the eye movements was contained in temporal frequencies up to 1 Hz, on average, in both directions.
Conclusions
Most eye movements during LASIK are slow drifts in fixation. An eye-tracker with a 1.4 Hz closed-loop bandwidth could compensate for most eye movements in conventional or customized ablations.
From the Center for Visual Science (Porter, Pan, Twietmeyer, Williams), University of Rochester, the Department of Ophthalmology (Yoon, MacRae), University of Rochester, and Bausch & Lomb (Cox), Rochester, New York, USA
Reprint requests to Jason Porter, PhD, the Center for Visual Science, University of Rochester, Rochester, New York 14627.
Supported by National Institutes of Health grants EY014999, EY01319, EY07125, and EY04367, and research grants from Bausch & Lomb and Research to Prevent Blindness. Also supported in part 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. In addition, the University of Rochester has licensed intellectual property to Bausch & Lomb and has a research contract with them.
Gary Gagarinas, Brenda Houtenbrink, Gina Crowley, Michele Comery, and Joseph Stamm gave technical assistance for the article.
ABSTRACT