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Late-Onset Corneal Haze and Myopic Regression After Photorefractive Keratectomy (PRK)

Kuo, Irene C MD; Lee, Salena M MD; Hwang, David G MD, FACS

Clinical Sciences

Objective: To report the incidence and clinical course of a series of patients who developed both delayed-onset, clinically significant progressive haze and myopic regression after photorefractive keratectomy (PRK).

Methods: In this retrospective case series, the charts of 542 consecutive patients who had undergone PRK with the VISX Star Excimer or Nidek EC-5000 laser between July 1996 and October 1998 and who had a minimum of 6 months of follow-up were reviewed. Ten eyes of 8 patients developed progressive haze to greater than 1+ and myopic regression equal to or more than −1 D 3 months or more after PRK. The historical and clinical features were reviewed.

Results: The incidence of combined progressive haze and myopic regression was 1.8%. The average age was 40.5 years. Three of the 8 patients were female. The median spherical equivalent (SE) attempted correction was −6.69 D (range −4.00 to −12.25 D). Five patients who underwent bilateral PRK had unilateral involvement. The mean SE regression was −2.01 ± 0.79 D (range −1.00 to −3.00 D). Regression plateaued at a mean of 9.8 months. Haze ranging up to 4+ peaked at a mean of 7.4 months. Topical steroid treatment and/or epithelial scraping was attempted in 3 eyes but was ineffective.

Conclusions: Combined delayed-onset progressive haze and myopic regression can occur after PRK. In such cases, the amount of haze appears to correlate with the magnitude of attempted initial correction (r = 0.639, P = 0.046) although not with the magnitude of subsequent regression. Patients may need at least 10 months of follow-up to achieve a stable refraction and level of haze. These observations suggest a need for improved understanding of corneal wound healing following PRK and of biologic factors that may contribute to variability in outcomes.

From the Cornea and Refractive Surgery Service of the Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143.

Received for publication June 3, 2003; accepted November 21, 2003.

Supported in part by an unrestricted grant from Research to Prevent Blindness, Inc, New York, NY.

Presented as a poster at the Association for Research in Vision and Ophthalmology Annual Meeting, Fort Lauderdale, FL, 2002.

The authors of this manuscript have no commercial interest in any of the products, drugs, or instruments discussed in the manuscript.

Reprints: Irene C. Kuo, MD, Wilmer Eye Institute, 4924 Campbell Blvd. # 100, Baltimore, MD 21236 (e-mail:; David G. Hwang, MD, FACS, Co-Director, Cornea and Refractive Surgery Service, Department of Ophthalmology, University of California, San Francisco, 10 Kirkham Street, San Francisco, CA 94143-0730 (e-mail:

© 2004 Lippincott Williams & Wilkins, Inc.