Central corneal pachymetry in patients undergoing laser in situ keratomileusis1
Historical image
Received 26 May 1998; accepted 7 July 1999.
Abstract
Objective
To report the preoperative ultrasonic central pachymetric measurements on a large group of eyes undergoing laser-assisted in situ keratomileusis (LASIK) surgery for myopia and myopic astigmatism, to determine whether central corneal thickness is correlated with other geometric features of the eye or is correlated with age or gender, and to discuss the resulting limitations on possible ablation depths.
Design
Prospective, multisite, cross-sectional study.
Participants
Eight hundred ninety-six eyes in 450 patients from 21 to 66 years of age.
Main outcome measures
Central corneal thickness and its correlation to intraocular pressure, corneal curvature, axial length, horizontal corneal diameter, refraction, age, and gender.
Results
The mean central corneal thickness was 550 μm with a standard deviation of 33 and a range of 472 to 651 μm. The lower 25th quantile was 528 μm. The central corneal pachymetry correlated with the mean manual keratometric measurement (P = 0.0001), simulated keratometry (Sim K) (P = 0.0001), and intraocular pressure (P = 0.0001). Central corneal thickness did not correlate with axial length, age, gender, horizontal corneal diameter, and refraction.
Conclusion
This clinical study shows there is a substantial range of central corneal thickness in normal myopic eyes. With LASIK, there is a general concern that one should not thin the cornea further than a given amount. Because this study shows wide variability in central corneal thickness, it is prudent to measure pachymetry before surgery and gear treatment plans accordingly. Possible treatment limits relative to corneal thickness are discussed.
Manuscript no. 98266.
1Price-Whitson Center for Refractive Surgery, Indianapolis, Indiana USA
2Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana USA
Reprint requests to Francis W. Price, Jr., MD, 9002 North Meridian Street, Suite 100, Indianapolis, IN 46260 USA
1 The authors have no proprietary or financial interest in any product mentioned in this article.
ABSTRACT