1. Vector Analysis of Femtosecond Laser-Assisted Arcuate Keratotomy for Post-Keratoplasty Astigmatic Correction
- Author
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Mahmoud Gamal, Ihab S. Osman, Ali A A Elzarga, Amr Osman, and Mohamed M Khafagy
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,genetic structures ,Visual Acuity ,Uncorrected visual acuity ,Astigmatism ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Postoperative Complications ,0302 clinical medicine ,Ophthalmology ,medicine ,Humans ,Prospective Studies ,Child ,Keratotomy, Radial ,Best corrected visual acuity ,Analysis of Variance ,Irregular astigmatism ,business.industry ,Arcuate keratotomy ,General Medicine ,Middle Aged ,Nomogram ,Laser assisted ,medicine.disease ,Sensory Systems ,030221 ophthalmology & optometry ,Female ,Surgically induced astigmatism ,Laser Therapy ,business ,Keratoplasty, Penetrating ,030217 neurology & neurosurgery - Abstract
Purpose: To study the astigmatic correction of high post-keratoplasty astigmatism using Femtosecond laser (FSL)-assisted Arcuate Keratotomy (FS-AK). Methods: A prospective interventional cohort study. We enrolled 17 eyes with high degree of irregular astigmatism, scheduled for FS-AK. FSL was used to perform paired arcuate incisions 1.00 mm inside the graft. Patients’ uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and astigmatic change were recorded and followed up to 1 year after surgery. Vector analysis using Alpins’ method was done to analyze the astigmatic correction. Results: FS-AK reduced the refractive astigmatism at final follow-up visit at 12 months (p = 0.0008, repeated-measures analysis of variance [ANOVA]). The procedure improved the UCVA over the follow-up period (p = 0.007, repeated-measures ANOVA), with a similar effect on the BCVA (p = 0.046, repeated-measures ANOVA). There was a mild correlation between the target-induced astigmatism and the surgically induced astigmatism (R2 = 0.245) with a tendency to overcorrect more than under correct the astigmatism. A constant rotational error in the counterclockwise direction was also detected. Conclusions: FS-AK improves the visual outcome and reduces the refractive cylinder in post-penetrating keratoplasty astigmatism. The predictability of astigmatism correction was variable in reducing post-keratoplasty astigmatism. Refinement of the treatment nomogram for such cases is highly recommended.
- Published
- 2019