Abstract
Purpose The biomechanical properties of ecstatic cornea undergo changes. This study evaluates the biomechanical changes of ecstatic cornea after implantation of two types of intracorneal stromal ring (ICR). Methods For doing this prospective cross-sectional study, 32 patients with keratoconus (KCN) were randomly divided into two 16-member groups (group I: MyoRing, group II: KeraRing). The main inclusion criteria were transparent cornea with no scar in the central part, corneal thickness >450 µ in the incision region, keratometry within 48–52 diopters, and progressive course of corneal thinning. Biomechanics of the cornea was evaluated by “ORA” and “Corvis” devices. All of the data were recorded and analyzed before implantation of the rings and 6 months thereafter. Results The mean ages of patients of groups I and II were 26 ± 6.55 and 33.86 ± 8.5, respectively. The postoperative change of sphere refraction was significant in both groups. However, reduction in the astigmatism was significant only in group I. In addition, the change of flat meridian keratometry (Kf) was significant before and after ring implantation in group I, unlike group II. The changes in CH and CRF parameters (ORA) were not significant in either group before and after the operation. Besides, only HRC parameter (Corvis) decreased significantly in both groups before and after the operation. Conclusion Both MyoRing and KeraRings have positive effects on the biomechanics of cornea at least during the first year after implantation. Comparison of these two types of ICR did not show significant differences in Corvis and ORA parameters.
Highlights
Keratoconus (KCN) is a corneal disorder causing a progressive noninflammatory status and, eventually, gradual thinning of the cornea along with progression of myopia and astigmatism [1, 2]
Patient information was collected in the Ophthalmology Clinic of Mashhad University of Medical Sciences (MUMS). is research project was approved by the Ethics Committee of MUMS, and all patients granted informed consent for participation prior to inclusion, based on the Helsinki declaration
Among the patients with definite KCN, inclusion criteria for ICRS implantation were intolerance to spectacles or rigid gas permeable contact lenses (RGP), a transparent cornea with no scarring in the central part, corneal thickness greater than 450 microns in the incision region, keratometry between 48 and 52 diopters (D), and no therapeutic option other than corneal transplantation to improve their functional vision. e contraindications of ICRS implantation in KCN patients were keratometry over 70 D, central corneal opacity, existence of an irregular scar in the cornea, patients with atopic and chronic itching, consumption of immunomodulatory drugs, ocular infections, rheumatologic diseases, and corneal dystrophia [9]
Summary
Keratoconus (KCN) is a corneal disorder causing a progressive noninflammatory status and, eventually, gradual thinning of the cornea along with progression of myopia and astigmatism [1, 2] In such cases, implantation of an intracorneal stromal ring (ICR) is a relatively safe and reversible method for improving vision, through which no tissue is excised from the cornea, and the center of it is not manipulated [3, 4]. E CST method is a quantitative and qualitative method for measuring the biomechanical properties of the cornea as well as a noncontact tonometry which tests the dynamic response of the cornea to air impulse It measures the extent of changes in the corneal height inwards after applying the air impulse [7]. CST measures difference variables, including corneal thickness, range of corneal changes, applanation length, corneal deformity changes, and anterior corneal curvature [7, 8]. e aims of the current study were to investigate the biomechanical changes of corneas among KCN patients after ICRS implantation and to compare the results of KeraRing and MyoRing implantation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
