Photorefractive Keratectomy Using Solid State Laser 213 nm and Excimer Laser 193 nm: A Randomized, Contralateral, Comparative, Experimental Study

• Published in: Investigative ophthalmology & visual science 2008-04, Vol.49 (4), p.1415-1420
• Main Authors: Tsiklis, Nikolaos S, Kymionis, George D, Kounis, George A, Naoumidi, Irini I, Pallikaris, Ioannis G
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cornea - surgery; Cornea - ultrastructure; Corneal Stroma - ultrastructure; Disease Models, Animal; Epithelium, Corneal - ultrastructure; Eye and associated structures. Visual pathways and centers. Vision; Female; Fundamental and applied biological sciences. Psychology; Lasers, Excimer; Lasers, Solid-State; Male; Medical sciences; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Myopia - pathology; Myopia - surgery; Ophthalmology; Photorefractive Keratectomy - methods; Rabbits; Random Allocation; Vertebrates: nervous system and sense organs
• ISSN: 0146-0404; 1552-5783; 1552-5783
• DOI: 10.1167/iovs.07-1280

To compare histopathologic changes after photorefractive keratectomy (PRK) for myopia using either a solid state laser (SSL) at 213 nm or an excimer laser (EL) at 193 nm in an experimental model. Forty pigmented rabbits (80 eyes) underwent myopic PRK for the correction of 6 D. Photoablation was randomly assigned, with a solid state laser used in one eye and an EL in the fellow eye. Rabbits were killed immediately after ablation (n = 10) or at 7 days (n = 10), 1 month (n = 8), 3 months (n = 6), or 12 months (n = 6) after surgery. Corneal tissue was preserved for light microscopy and transmission electron microscopy at all postoperative intervals. All eyes reepithelialized in 1 week with no early or late postoperative complication. Immediately after ablation, light, scanning, and transmission electron microscopy revealed relatively smooth ablation surfaces in both groups. Seven days after surgery, epithelium in the SSL specimens appeared thinner than in the EL specimens. Activated keratocytes were observed adjacent to the epithelium in both groups, whereas endothelial cells demonstrated normal morphology. At 1, 3, and 12 months after surgery, tissue appearance of all corneal layers was similar in both groups. PRK in rabbits using ultraviolet SSL and EL revealed similar histopathologic findings up to 1 year after surgery.