Corneal haze after photorefractive keratectomy using different epithelial removal techniques1: Mechanical debridement versus laser scrape☆,
Section snippets
Patients
Twenty eyes of 10 patients (seven women, three men; age, 31.5 ± 7 years; range, 22–41 years) were enrolled in this study, and mean spherical equivalent was −4.75 ± 0.94 diopters (D; range, −2.75 to −6.00 D). The surgical candidates were given consent forms regarding excimer laser PRK and the different methods of epithelial removal. In all patients, one eye was treated with mechanical epithelial debridement and the fellow eye was treated using the laser-scrape technique. The research protocol
Morphologic characteristics of anterior stromal wound healing
Differences in anterior stromal wound healing morphologic characteristics were assessed in the same patient before and after PRK performed after laser-scrape epithelial debridement (Fig 1). Anterior stromal images were obtained from the CMTF peak of the anterior keratocyte layer or anterior stromal haze, which were located within 60 μm of the stromal surface. In the preoperative cornea, normal quiescent keratocytes with low-reflecting nuclei were observed (Fig 1A). At 3 weeks after PRK,
Discussion
Mechanical debridement was the first method used for epithelial removal before PRK surgery. Although this technique is quite effective, several problems may occur. The time required for the debridement can be longer than the laser-scrape technique, especially for inexperienced surgeons. This may cause stromal dehydration secondary to evaporation and could affect refractive predictability. Also, Bowman’s layer defects, irregular anterior stromal surface, and retained islands of residual
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Cited by (44)
Comparison of mechanical debridement and trans-epithelial myopic photorefractive keratectomy: A contralateral eye study
2019, Journal of Current OphthalmologyCitation Excerpt :In our study, re-epithelialization was completed maximally up to 7 days in all eyes in both groups except one m-PRK eye that had complete re-epithelialization on day 10, postoperatively. Lee et al.9 evaluated corneal healing after PRK using mechanical and laser scrap techniques and reported that there is no significant difference in the corneal wound healing response between these two techniques. In another study by Lee et al.,22 epithelial healing and clinical outcomes in PRK following mechanical and trans-epithelial techniques were evaluated using Visx Star S3.
Techniques, indications and complications of corneal debridement
2014, Survey of OphthalmologyCitation Excerpt :This process has limited precision, as the excimer laser must be programmed for a predetermined epithelial thickness.123 Advantages of laser epithelial removal, however, include a short surgical time, less technical demand, and minimal damage to surrounding tissues.48,83 Potential side effects of excimer laser use can be subdivided into thermal, mechanical, or actinic.121
Loss of corneal transparency
2010, Ocular Disease: Mechanisms and Management Expert ConsultLoss of corneal transparency
2010, Ocular Disease: Mechanisms and ManagementComparison of Epi-LASIK and Off-Flap Epi-LASIK for the Treatment of Low and Moderate Myopia
2008, OphthalmologyCitation Excerpt :No significant difference was noted in third- and fourth-order root mean square and, more particularly, in spherical aberration and coma between the 2 groups of eyes at any postoperative interval. Among others, a rotating brush, a blunt blade (beaver), alcohol application, and transepithelial laser or laser-scrape technique have been used for epithelial removal before PRK.8–10 In many cases, the mechanical removal was found to result in defects in the Bowman layer, an irregular anterior stromal surface, and retained islands of residual epithelium.11,12
Laser in situ keratomileusis versus surface ablation: Visual outcomes and complications
2007, Journal of Cataract and Refractive Surgery
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Supported in part by National Eye Institute (grant no.: EY07348 [JVJ] Bethesda, Maryland; and Senior Scientist Awards [JVJ and HDC]) an Olga Keith Weiss Scholar Award [WMP] and an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York.
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The authors have no proprietary interest in any of the equipment mentioned in this article.