Biomechanics of Corneal Ring Implants
نویسنده
چکیده
PURPOSE To evaluate the biomechanics of corneal ring implants by providing a related mathematical theory and biomechanical model for the treatment of myopia and keratoconus. METHODS The spherical dome model considers the inhomogeneity of the tunica of the eye, dimensions of the cornea, lamellar structure of the corneal stroma, and asphericity of the cornea. It is used in this study for calculating a strengthening factor sf for the characterization of different ring-shaped corneal implant designs. The strengthening factor is a measure of the amount of strengthening of the cornea induced by the implant. RESULTS For ring segments and incomplete rings, sf = 1.0, which indicates that these implants are not able to strengthen the cornea. The intracorneal continuous complete ring (MyoRing) has a strengthening factor of up to sf = 3.2. The MyoRing is, therefore, able to strengthen the cornea significantly. CONCLUSIONS The result of the presented biomechanical analysis of different ring-shaped corneal implant designs can explain the different postoperative clinical results of different implant types in myopia and keratoconus.
منابع مشابه
Prediction of Corneal Condition After Corneal Ring Implantation in Keratoconus Patients
Background: Keratoconus is a common complication among corneal defects. As a result of expeditious and extensive progress of medical science in recent decades, corneal ring implantation has turned into a successful surgical procedure to correct the vision of Keratoconus patients; however, selecting the right patient is essential in the success of the operation. The prediction of corneal conditi...
متن کاملClinical outcomes after complete ring implantation in corneal ectasia using the femtosecond technology: a pilot study.
PURPOSE To evaluate the clinical outcomes after implantation of the MyoRing (DIOPTEX GmBH, Linz, Austria) by means of femtosecond laser technology in eyes with corneal ectasia. DESIGN Retrospective, consecutive, nonrandomized, case series. PARTICIPANTS A total of 12 eyes of 11 patients with ages ranging from 17 to 50 years were included. All cases were diagnosed with corneal ectasia accordi...
متن کاملCorneal Hydrops Secondary to Intrastromal Corneal Ring Intrusion into the Anterior Chamber 7 Years after Implantation: A Case Report
INTRODUCTION This report describes the first known case of late-onset intrusion of an intrastromal ring segment into the anterior chamber due to posterior migration of a ring segment. To our knowledge, intrastromal ring segment penetration has only been shown to occur in the intraoperative or immediate postoperative period. We postulate that the perforation in this case is due to progressive th...
متن کامل[Asymmetric intrastromal corneal ring for the treatment of keratoconus].
PURPOSE To analyze corneal curvature and visual acuity after asymmetric intrastromal corneal rings implantation, not following the nomogram proposed by the manufacturer. METHODS Seven eyes of seven keratoconus patients which had asymmetric corneal rings implanted in their corneal stroma were studied. RESULTS A flattening of the average corneal keratometry was noted in all patients, as well ...
متن کاملPost intrastromal corneal ring segments insertion complicated by Candida parapsilosis keratitis
This case report describes the clinical and histopathologic features, including molecular confirmation, of fungal keratitis after intrastromal corneal ring segments placement for keratoconus. A 52-year-old woman underwent insertion of Intacs(®) corneal implants for treatment of keratoconus. Extrusion of the implants was noted 5 months post insertion and replaced. Three months later, monocular i...
متن کامل