Assessment of corneal biomechanics in young myopic individuals using ocular response analyzer

Abstract

Objective The aim of this study was to assess corneal biomechanical properties using the ocular response analyzer (ORA) in myopic young individuals with normal topography. Background The development in corneal refractive surgeries raises the necessity of studying corneal properties in detail. Corneal viscoelasticity, in terms of corneal biomechanics, is measured by ORA through the analysis of the corneal dynamic behavior when it is deformed by an air puff. The important parameters measured are corneal resistance factor (CRF) and corneal hysteresis (CH). Patients and methods This study included 116 myopic eyes, which were assessed by clinical examination, best corrected visual acuity examination, and corneal pentacam topography. CH and CRF were measured using ORA. Results The mean age in our study participants was 23.6 ± 2.9 years, and the mean of the spherical equivalent was −4.56 ± 2.4 (moderate myopia). The mean CRF was 9.7 ± 1.4 mmHg, while the mean CH was 10.0 ± 1.3 mmHg. As regards corneal topography, normal participants were recruited with the following measurements: Kmax (maximum keratometry) 44.3 ± 1.4 and the mean central corneal thickness (CCT) was 529.5 ± 12.7 μm. Correlation of CRF and CH values in this moderate myopic group were negatively correlated with the spherical equivalent. Both CH and CRF had positive linear correlation with CCT and Kmax, and negative correlation with age. Conclusion The ORA is used to measure CH and CRF by which the biomechanical changes of the cornea in different degrees of myopia can be detected. It was found that it is important when evaluating the corneal biomechanical properties to take CCT and myopic status into consideration.