Corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery
Purpose: A percentage tissue altered (PTA) score of ≥40% has been advocated as an independent indicator of post-operative ectasia risk following laser in-situ keratomileusis (LASIK). This study was performed to test the hypothesis that refractive procedures, such as laser-assisted subepithelial kera...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2020
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| Online Access: | https://hdl.handle.net/10356/142168 |
| _version_ | 1826121641629843456 |
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| author | Ong, Hon Shing Mohamed Farook Tan, Benjamin Boon Chuan Williams, Geraint P. Santhiago, Marcony Rodrigues Mehta, Jodhbir Singh |
| author2 | School of Materials Science and Engineering |
| author_facet | School of Materials Science and Engineering Ong, Hon Shing Mohamed Farook Tan, Benjamin Boon Chuan Williams, Geraint P. Santhiago, Marcony Rodrigues Mehta, Jodhbir Singh |
| author_sort | Ong, Hon Shing |
| collection | NTU |
| description | Purpose: A percentage tissue altered (PTA) score of ≥40% has been advocated as an independent indicator of post-operative ectasia risk following laser in-situ keratomileusis (LASIK). This study was performed to test the hypothesis that refractive procedures, such as laser-assisted subepithelial keratectomy (LASEK) or small incision lenticule extraction (SMILE), may alter the range of PTA, within which refractive corneal surgery can be safely performed. Setting: Refractive department, tertiary ophthalmic hospital. Design: Retrospective observational study. Methods: Review of case notes was performed for patients who presented for refractive surgeries, other than LASIK. To determine the risk of corneal ectasia for each patient prior to refractive surgery, we estimated what each patient’s PTA would have been if they had undergone LASIK. The Randleman Ectasia Risk Score System (ERSS) was also calculated. Results: 114 eyes (66 patients) were included. 94 eyes underwent SMILE. 20 eyes underwent LASEK. A significant proportion of eyes had PTA ≥40% – SMILE eyes: up to 31.9%, LASEK eyes: up to 60.0% (at presumed LASIK flap of 120 μm). The maximum calculated PTAwas up to 47.9% in the SMILE group and up to 51.5% in the LASEK group. Using ERSS, 12.8–16% of SMILE eyes and 15.0–80.0% of LASEK eyes would have been considered to have moderate-tohigh ectasia risk. No post-surgical ectasia was observed at 3 years. Conclusion: SMILE and LASEK alter the range of PTA, within which corneal refractive surgery may be performed with a lower risk of developing post-operative corneal ectasia; a safe PTA threshold needs to be determined for these procedures before recommendations for clinical practice can be made. |
| first_indexed | 2024-10-01T05:35:51Z |
| format | Journal Article |
| id | ntu-10356/142168 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T05:35:51Z |
| publishDate | 2020 |
| record_format | dspace |
| spelling | ntu-10356/1421682023-07-14T15:56:12Z Corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery Ong, Hon Shing Mohamed Farook Tan, Benjamin Boon Chuan Williams, Geraint P. Santhiago, Marcony Rodrigues Mehta, Jodhbir Singh School of Materials Science and Engineering Engineering::Materials Percentage Tissue Altered Ectasia Purpose: A percentage tissue altered (PTA) score of ≥40% has been advocated as an independent indicator of post-operative ectasia risk following laser in-situ keratomileusis (LASIK). This study was performed to test the hypothesis that refractive procedures, such as laser-assisted subepithelial keratectomy (LASEK) or small incision lenticule extraction (SMILE), may alter the range of PTA, within which refractive corneal surgery can be safely performed. Setting: Refractive department, tertiary ophthalmic hospital. Design: Retrospective observational study. Methods: Review of case notes was performed for patients who presented for refractive surgeries, other than LASIK. To determine the risk of corneal ectasia for each patient prior to refractive surgery, we estimated what each patient’s PTA would have been if they had undergone LASIK. The Randleman Ectasia Risk Score System (ERSS) was also calculated. Results: 114 eyes (66 patients) were included. 94 eyes underwent SMILE. 20 eyes underwent LASEK. A significant proportion of eyes had PTA ≥40% – SMILE eyes: up to 31.9%, LASEK eyes: up to 60.0% (at presumed LASIK flap of 120 μm). The maximum calculated PTAwas up to 47.9% in the SMILE group and up to 51.5% in the LASEK group. Using ERSS, 12.8–16% of SMILE eyes and 15.0–80.0% of LASEK eyes would have been considered to have moderate-tohigh ectasia risk. No post-surgical ectasia was observed at 3 years. Conclusion: SMILE and LASEK alter the range of PTA, within which corneal refractive surgery may be performed with a lower risk of developing post-operative corneal ectasia; a safe PTA threshold needs to be determined for these procedures before recommendations for clinical practice can be made. Published version 2020-06-16T09:06:39Z 2020-06-16T09:06:39Z 2019 Journal Article Ong, H. S., Mohamed Farook, Tan, B. B. C., Williams, G. P., Santhiago, M. R., & Mehta, J. S. (2019). Corneal Ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery. Clinical Ophthalmology, 13, 2003-2015. doi:10.2147/opth.s215144 1177-5467 https://hdl.handle.net/10356/142168 10.2147/OPTH.S215144 31686775 2-s2.0-85073743922 13 2003 2015 en Clinical Ophthalmology © 2019 Ong et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). application/pdf |
| spellingShingle | Engineering::Materials Percentage Tissue Altered Ectasia Ong, Hon Shing Mohamed Farook Tan, Benjamin Boon Chuan Williams, Geraint P. Santhiago, Marcony Rodrigues Mehta, Jodhbir Singh Corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery |
| title | Corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery |
| title_full | Corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery |
| title_fullStr | Corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery |
| title_full_unstemmed | Corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery |
| title_short | Corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery |
| title_sort | corneal ectasia risk and percentage tissue altered in myopic patients presenting for refractive surgery |
| topic | Engineering::Materials Percentage Tissue Altered Ectasia |
| url | https://hdl.handle.net/10356/142168 |
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