Results of intrastromal corneal ring segment implanted alone or combined with same-day corneal crosslinking and their correlation with preoperative corneal biomechanical strain from finite element analysis.

Autor:	Serpe CC; From the Department of Ophthalmology (Serpe, Santhiago), University of Sao Paulo, Brazil ; Department of Ophthalmology (Serpe, Mello), Federal University of Paraná, Curitiba, Brazil; Cole Eye Institute (Serpe, Dupps), Cleveland Clinic, Ohio; Department of Ophthalmology (Seven, Dupps), Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Ohio; Department of Biomedical Engineering (Dupps), Lerner Research Institute, Ohio; Department of Biomedical Engineering (Dupps), Case Western Reserve University, Ohio; Department of Ophthalmology (Santhiago), University of Southern California, California., Mello GR, Seven I, Dupps WJ Jr, Santhiago MR
Jazyk:	angličtina
Zdroj:	Journal of cataract and refractive surgery [J Cataract Refract Surg] 2021 Jul 01; Vol. 47 (7), pp. 916-926.
DOI:	10.1097/j.jcrs.0000000000000533
Abstrakt:	Purpose: To compare the results of intrastromal corneal ring segment (ICRS) alone or combined with same-day corneal crosslinking (CXL) and investigate the relationship of preoperative corneal biomechanics data on the outcomes. Setting: Department of Ophthalmology of Federal University of Parana. Design: Prospective nonrandomized interventional comparative study. Methods: Forty-nine eyes of 44 keratoconus patients underwent ICRS only (n = 27, Group 1) or same day ICRS+CXL (n = 22, Group 2) and were followed up for at least 24 months. Visual acuity and preoperative and postoperative tomographic variables were compared between groups. Tomographic data were obtained with a dual Scheimpflug analyzer, and eye-specific finite-element models were used to derive 3 variables related to preoperative biomechanical strain (maximum principal strain [MPS]): mean MPS (mMPS), highest local MPS (hMPS), and position of the hMPS (hMPSx and hMPSy). The relationship between preoperative strain data and the change (∆, difference between postoperative and preoperative data) in tomographic parameters was also investigated. Results: Steepest (K2) and maximum keratometry (Kmax), inferior-superior (I-S) index, coma, and cone location magnitude index (CLMI) significantly improved in both groups. Corrected distance visual acuity was significantly better after ICRS alone (P = .03), whereas corneal asymmetry measured through the I-S index was better after CXL+ICRS (P = .04). In Group 1, hMPSy significantly correlated with K2, tomographical cylinder, mean keratometry, and ∆spherical aberration, whereas mMPS significantly correlated with ∆eccentricity. In Group 2, hMPS significantly correlated with K2, Kmax, I-S index, and ∆coma, and hMPSy significantly correlated with I-S index and ∆coma. The mMPS significantly correlated with ∆CLMI. Conclusions: ICRS alone seems to be the most suitable option to improve visual acuity, whereas combined ICRS+CXL provided better corneal regularizing results. Preoperative peak strain (hMPS) was predictive of the extent of regularization and flattening after ICRS+CXL. (Copyright © 2020 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)
Databáze:	MEDLINE
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