Predicted and Measured Changes in Posterior Corneal Astigmatism after Uncomplicated Femtosecond Assisted LASIK (FsLASIK) and Microkeratome LASIK Correction for Myopia and Low Astigmatism
| Autor: | Sudi Patel, Maja Bohac, Ivan Gabric, Violeta Shijakova, Alma Biscevic, Kresimir Gabric |
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| Rok vydání: | 2021 |
| Předmět: |
medicine.medical_specialty
genetic structures medicine.medical_treatment Corneal Stroma Keratomileusis Laser In Situ Visual Acuity Astigmatism Refraction Ocular Cornea Microkeratome Ophthalmology medicine Myopia Humans LASIK FsLASIK astigmatism vector analysis Corneal surface skin and connective tissue diseases business.industry Corneal Topography General Medicine medicine.disease humanities eye diseases Femtosecond Lasers Excimer sense organs business Corneal astigmatism |
| Zdroj: | Seminars in ophthalmology. 36(8) |
| ISSN: | 1744-5205 |
| Popis: | Purpose: To compare predicted and measured changes in astigmatism at the posterior corneal surface (PCS) after FsLASIK or LASIK. Methods: Astigmatism was measured at both corneal surfaces (PentacamTM) before and 3 months after unremarkable FFsLASIK (roup 1, n = 100) or LLASIK (roup 2, n = 100) for myopia (−7.25DS to −0.75DS) and low astigmatism (≤1.00DC). Photoablation was achieved using Schwind Amaris750STM laser (Aberration Free profile, centered on corneal vertex). Pre-and postop astigmatic data, according to subjective refraction and estimates for the corneal surfaces (over the central 3.2 mm zone), were subjected to vector analysis to calculate surgically induced astigmatism (SIA) by refraction (SIAR), at the anterior (SIAFact) and posterior corneal surfaces (SIABact). The difference vector between SIAR and SIAFact was regarded as the predicted SIA at the PCS (SIABest). Results: Reporting key findings. Mean(±sd, 95%CI) SIABest and SIABact powers in group 1 were −0.52DC(±0.35, -0.56 to −0.45) and −0.11DC(±0.08, -0.13 to −0.10) in group 1, −0.35DC(0.20, -0.39 to −0.32) and −0.08DC(0.07, -0.09 to −0.06) in group 2. Differences between SIABest and SIABact were significant for powers but not axes. Significant correlations(p < .01) were revealed between (I) SIAR and SIAFact powers [Group 1, SIAR = 0.370.SIAFact-0.292, r = 0.299. Group 2, SIAR = 0.484.SIAFact-0.394, r = 0.519] but not the axes and (II) ΔC (difference between pre-[x1] and postop measured PCS astigmatic powers) and x1 [Group 1, ΔC = 0.384x1 + 0.119, r = 0.423. Group 2, ΔC = 0.135x1 + 0.047, r = 0.229, p = .022]. There was no correlation between SIABest and SIABact powers or axes. Conclusion: The changes in posterior corneal astigmatic powers according to Pentacam measurements are small and do not account for the deficit between SIAR and SIAFact after FsLASIK or LASIK. |
| Databáze: | OpenAIRE |
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