{"title":"Changes in Corneal Biomechanical Properties after Laser-Assisted <em>in situ</em> Keratomileusis and Photorefractive Keratectomy in Myopia.","authors":"Sadia Humayun, Yumna Waheed Bangash, Mazhar Ishaq, Habiba Yasmeen","doi":"10.29271/jcpsp.2023.09.1023","DOIUrl":null,"url":null,"abstract":"<p><strong>Objective: </strong>To compare changes in corneal biomechanical properties after laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in low and moderate myopia by Ocular Response Analyzer.</p><p><strong>Study design: </strong>Quasi-experimental study. Place and Duration of the Study: Armed Forces Institute of Ophthalmology (AFIO), Rawalpindi, Pakistan, between September 2020 and April 2022.</p><p><strong>Methodology: </strong>Myopic correction was done in forty-six eyes of twenty-three patients by PRK, and forty-seven eyes of twenty-four patients by LASIK. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using Ocular Response Analyzer (ORA), pre-operatively, and then 1, 3, and 6 months, postoperatively. The relationship between the amount of myopia treated and biomechanical properties was also studied.</p><p><strong>Results: </strong>CRF and CH were decreased significantly after LASIK and PRK. A significantly larger decrease in CRF was observed after LASIK as compared to PRK at 6 months (Mann-Whitney U test: CRF, p = 0.02); however, decrease in CH was not statistically significant between LASIK and PRK at 6 months period (Mann-Whitney U test: CH, p = 0.388). A significant correlation was observed between the changes in biomechanical properties and extent of myopic correction after LASIK and PRK.</p><p><strong>Conclusion: </strong>Biomechanical strength of the cornea was significantly reduced by PRK and LASIK, which was also dependent on the spherical equivalent (SEQ) of myopic correction. A significantly larger change in CRF was observed after LASIK as compared to post PRK.</p><p><strong>Key words: </strong>Myopia, Laser in situ keratomileusis, Photorefractive keratectomy, Cornea, Biomechanics.</p>","PeriodicalId":54905,"journal":{"name":"Jcpsp-Journal of the College of Physicians and Surgeons Pakistan","volume":null,"pages":null},"PeriodicalIF":0.7000,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Jcpsp-Journal of the College of Physicians and Surgeons Pakistan","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.29271/jcpsp.2023.09.1023","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MEDICINE, GENERAL & INTERNAL","Score":null,"Total":0}
引用次数: 0
Abstract
Objective: To compare changes in corneal biomechanical properties after laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in low and moderate myopia by Ocular Response Analyzer.
Study design: Quasi-experimental study. Place and Duration of the Study: Armed Forces Institute of Ophthalmology (AFIO), Rawalpindi, Pakistan, between September 2020 and April 2022.
Methodology: Myopic correction was done in forty-six eyes of twenty-three patients by PRK, and forty-seven eyes of twenty-four patients by LASIK. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using Ocular Response Analyzer (ORA), pre-operatively, and then 1, 3, and 6 months, postoperatively. The relationship between the amount of myopia treated and biomechanical properties was also studied.
Results: CRF and CH were decreased significantly after LASIK and PRK. A significantly larger decrease in CRF was observed after LASIK as compared to PRK at 6 months (Mann-Whitney U test: CRF, p = 0.02); however, decrease in CH was not statistically significant between LASIK and PRK at 6 months period (Mann-Whitney U test: CH, p = 0.388). A significant correlation was observed between the changes in biomechanical properties and extent of myopic correction after LASIK and PRK.
Conclusion: Biomechanical strength of the cornea was significantly reduced by PRK and LASIK, which was also dependent on the spherical equivalent (SEQ) of myopic correction. A significantly larger change in CRF was observed after LASIK as compared to post PRK.
目的:用眼反应分析仪比较低、中度近视患者激光原位角膜磨除术(LASIK)与光屈光性角膜切除术(PRK)术后角膜生物力学特性的变化。研究设计:准实验研究。研究地点和时间:2020年9月至2022年4月，巴基斯坦拉瓦尔品第武装部队眼科研究所(AFIO)。方法:23例患者46眼PRK矫正近视，24例患者47眼LASIK矫正近视。术前、术后1、3、6个月分别用眼反应分析仪(ORA)测定角膜迟滞(CH)和角膜阻力因子(CRF)。研究了近视度数与生物力学性能的关系。结果:LASIK和PRK术后CRF和CH均明显降低。6个月时，与PRK相比，LASIK术后CRF的下降幅度更大(Mann-Whitney U检验:CRF, p = 0.02);而6个月时，LASIK与PRK的CH降低无统计学意义(Mann-Whitney U检验:CH, p = 0.388)。观察到LASIK和PRK术后生物力学性能的变化与近视矫正程度有显著的相关性。结论:PRK和LASIK均显著降低了角膜的生物力学强度，并依赖于近视矫正的球形当量(SEQ)。与PRK后相比，LASIK术后观察到的CRF变化明显更大。关键词:近视，激光原位角膜磨镶术，光屈光性角膜切除术，角膜，生物力学
期刊介绍：
Journal of College of Physicians and Surgeons Pakistan (JCPSP), is the prestigious, peer reviewed monthly biomedical journal of the country published regularly since 1991.
Established with the primary aim of promotion and dissemination of medical research and contributed by scholars of biomedical sciences from Pakistan and abroad, it carries original research papers, , case reports, review articles, articles on medical education, commentaries, short communication, new technology, editorials and letters to the editor. It covers the core biomedical health science subjects, basic medical sciences and emerging community problems, prepared in accordance with the “Uniform requirements for submission to bio-medical journals” laid down by International Committee of Medical Journals Editors (ICMJE). All publications of JCPSP are peer reviewed by subject specialists from Pakistan and locally and abroad.
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