Assessment of Preoperative Risk Factors for Post-LASIK Ectasia Development

Abstract

To evaluate preoperative risk factors (mainly those related to corneal topography/tomography) for post-LASIK ectasia development. Methods: A retrospective case review for post-LASIK ectasia for myopia or myopic astigmatism. The evaluated data included preoperative subjective refraction, method of flap creation, and topometric/tomographic parameters from Oculus Pentacam, including subjective curvature pattern, topometric, elevation, and pachymetric indices from the Belin Ambrosio display "BAD", and the Pentacam Random Forest Index (PRFI). Moreover, preoperative ectasia detection indices were calculated (including Percentage of Tissue Altered "PTA" index, Randleman Ectasia Risk Score System "ERSS", and Navarro Index for Corneal Ectasia "NICE"). Results: Twenty-four eyes of 15 patients were enrolled. Concerning the risk factors, age was lower than 25 in 19 eyes (79%); flaps were created using a microkeratome in 17 eyes (70.8%); thinnest pachymetry was lower than 510μm in eight eyes (33%); total deviation from BAD was higher than 1.6 in 50%; Ambrósio's relational thickness (ART) max was lower than 340 in 45.83%; PTA index was higher than 40% in 16%; ERSS was more than 3 points in 62.5%; NICE was higher than 8 points in three eyes (12.5%); PRFI index was more than 0.125 in 87.5%; two eyes (8%) had no identifiable risk factors. Conclusion: Current ectasia risk assessment criteria were insufficient for detecting a relatively large number of cases. There is an unequivocal need for more information, which may be derived from biomechanical assessment and epithelial thickness mapping. Novel corneal tomography indices derived from artificial intelligence may increase accuracy in characterizing ectasia susceptibility.

Assessment of Preoperative Risk Factors for Post-LASIK Ectasia Development [Response to Letter]

“…First, we thank Dr. Navarro-Naranjo and his colleagues for their collaboration and interest in our ectasia study. 1 In their letter, they mentioned some inaccuracies reported in our study related to the calculation of the NICE. We must respectfully disagree as we present Table 1, which includes the clinical data from the parameters considered in the NICE index.…”

“…Clinical Ophthalmology 2024:18 1045-1047 score higher than 5. 1 Based on their criteria, these scores would contraindicate for LASIK. 2 Interestingly, the remaining nine eyes had a score of 4.…”

Assessment of Preoperative Risk Factors for Post-LASIK Ectasia Development [Letter]

“…We read with enthusiasm the article "Assessment of Preoperative Risk Factors for Post-Lasik Ectasia Development" by El-Naggar MT et al 1 The authors retrospectively analyzed a cohort of patients who underwent LASIK surgery for the correction of myopia and/or astigmatism whom developed secondary corneal ectasia (n=24). 2 In order to identify the performance as preoperative diagnostic tests, the authors applied known combined screening diagnostic tests to identify eyes that were not in a suitable condition to have undergone surgery.…”