Effect of surface photorefractive keratectomy and laser in situ keratomileusis on the corneal endothelium

• Published in: Journal of cataract and refractive surgery Vol. 23; no. 3; pp. 386 - 397
• Main Authors: Kent, David G., Solomon, Kerry D., Peng, Qun, Whiteside, Stephen B., Brown, Sandra J., Apple, David J.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.04.1997; Elsevier Science
• Subjects: Aged; Biological and medical sciences; Cadaver; Cell Count; Cell Death; Coloring Agents; Cornea - pathology; Cornea - surgery; Corneal Transplantation - methods; Endothelium, Corneal - pathology; Humans; Laser Therapy; Lasers, Excimer; Medical sciences; Microscopy, Fluorescence; Myopia - surgery; Organ Culture Techniques; Photorefractive Keratectomy - methods; Refraction, Ocular; Safety; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the eye and orbit; Treatment Outcome; Human; Cornea; Keratomileusis; Substance loss; Surgery; In situ; Laser; Endothelium; Photorefractive keratectomy
• ISSN: 0886-3350; 1873-4502
• DOI: 10.1016/S0886-3350(97)80183-6

Purpose: To investigate endothelial cell loss in pairs of fresh human autopsy globes following high-diopter myopic photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK). Setting: Center for Research on Ocular Therapeutics and Biodevices and Magill Laser Center for Vision Correction, Storm Eye Institute, Charleston, South Carolina, USA. Methods: In the first part of the study, 12 globes had either -10 diopter (D) multizone surface PRK or -10 D single-zone LASIK. In the second part, three groups of 5 globes each had -15 D, -20 D, or -25 D multizone-blend LASIK procedures. Fellow globes in both groups were used as untreated controls. Comeoscleral buttons were excised from all globes. Following 7 days in corneal organ culture, the endothelial surface was stained with two vital dyes: calcein-AM and ethidium homodimer. Fluorescence microscopy was used to obtain endothelial cell counts. Results: The mean dead cells per square millimeter (cells/mm2) were 0.94 in the -10 D PRK treated corneas compared with 0.91 in the fellow untreated eyes (P = 0.06). The mean dead cells/mm2 in the -10 D single-zone LASIK-treated corneas and in the fellow untreated eyes were 0.61 (P = 0.88). The mean dead cells/mm2 in the -15 D, -20 D, and -25 D multizone-blend LASIK-treated corneas were 3.08, 2.33, and 5.55, respectively, compared with 3.49, 1.92, and 5.01 in the fellow untreated eyes (P = 0.276, P = 0.339, and P = 0.427, respectively). Dead cell counts for treated and control paired corneas were highly correlated in all treatment groups. Conclusions: No significant endothelial cell loss occurred after -10 D PRK or LASIK corrections up to -25 D. Although this study has limitations that prevent direct extrapolation to the clinical situation, it does afford a comparable clinical correlate for endothelial cell toxicity following typical excimer laser ablations.