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: | Ibrahim Seven, Marcony R. Santhiago, Glauco R. Mello, William J. Dupps, Crislaine C. Serpe |
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| Rok vydání: | 2021 |
| Předmět: |
medicine.medical_specialty
Keratoconus Visual acuity Corneal Stroma Riboflavin medicine.medical_treatment Finite Element Analysis Scheimpflug principle Refraction Ocular law.invention Prosthesis Implantation 03 medical and health sciences 0302 clinical medicine law Ophthalmology Humans Medicine Prospective Studies Retrospective Studies Coma Photosensitizing Agents Keratometer Intrastromal corneal ring segment business.industry Biomechanics Corneal Topography Corneal asymmetry medicine.disease eye diseases Sensory Systems Cross-Linking Reagents 030221 ophthalmology & optometry Surgery Collagen sense organs medicine.symptom business 030217 neurology & neurosurgery |
| Zdroj: | Journal of Cataract and Refractive Surgery. 47:916-926 |
| ISSN: | 1873-4502 0886-3350 |
| DOI: | 10.1097/j.jcrs.0000000000000533 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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