Nomogram-Based Intraocular Lens Power Adjustment after Myopic Photorefractive Keratectomy and LASIK: A New Approach
Received 2 September 2004; accepted 2 March 2005.
Purpose
(1) To evaluate the accuracy of nomogram-based adjustment of intraocular lens (IOL) power to achieve a desired refractive target after cataract surgery in postmyopic LASIK and photorefractive keratectomy (PRK) eyes and (2) to compare the accuracy of the nomogram-based method with the clinical history method.
Design
Multicenter, retrospective, interventional, noncomparative case series.
Subjects
Fourteen patients (19 eyes) after myopic LASIK or PRK with visually significant cataracts.
Intervention
All eyes underwent cataract extraction and posterior chamber intraocular lens implantation. In each case, IOL power was determined with standard keratometry and biometry. Power adjustment was made by use of a theoretical nomogram followed by implantation.
Main Outcome Measures
(1) Final refraction and spherical equivalent after cataract surgery and (2) deviation of the final spherical equivalent from the refractive target.
Results
After cataract extraction, by use of nomogram adjustment, 63.2% of eyes were within 0.5 D of the intended spherical equivalent, 84.2% were within 1.0 diopter of the intended spherical equivalent, and 100% were within 1.5 D of the intended spherical equivalent. The clinical history method was accurate in predicting the correct IOL power in 37.5% of cases, regardless of whether spectacle or corneal plane refraction was used.
Conclusions
(1) Given the change in spherical equivalent induced by myopic LASIK/PRK, IOL power can be adjusted accurately to avoid undercorrection without the need for the prerefractive surgery corneal power. (2) The nomogram-based method was more accurate than the clinical history method.
1Department of Ophthalmology, University of California, Davis Medical Center, Sacramento, California.
2John A. Moran Eye Center Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah.
Correspondence and reprint requests to Vahid Feiz, MD, Department of Ophthalmology, UC Davis Medical Center, 4860 Y Street, Suite 2400, Sacramento, CA 95817.
Manuscript no. 2004-76.
Supported, in part, by a grant to the Department of Ophthalmology at University of California, Davis, from Research to Prevent Blindness, Inc., New York, New York.
The authors have no financial interest in any of the products or procedures listed in the article.
ABSTRACT