Age-Related Variations of Rabbit Corneal Geometrical and Clinical Biomechanical Parameters

Abstract

Purpose To study the variations in corneal clinical biomechanical parameters (CCBP) and corneal geometrical parameters of rabbit in relation to age. Methods Rabbits aged 3, 7, 12, 18, and 24 months were enrolled. Each eye of the rabbits was tested with Ocular Response Analyzer (ORA), Optical Coherence Tomography (OCT), and Pachymeter to obtain the intraocular pressure (IOP): Goldmann-correlated IOP (IOPg) and Corneal Compensated Intraocular Pressure (IOPcc); CCBP: Corneal Hysteresis (CH) and Corneal Resistance Factor (CRF); corneal geometric parameters: corneal curvature radius (CCR) and central corneal thickness (CCT). Results The IOP of the rabbits changes slightly from 3 to 7 months of age, while it significantly decreases from 7 to 18 months of age and increases from 18 to 24 months of age; CH and CRF decrease with the increase of age; CCT increases from 7 to 18 months and decreases from 3 to 7 months of age and from 18 to 24 months of age; CCR presents an upward trend from 3 to 18 months and a significant decrease between 18 and 24 months of age. Conclusion CH and CRF are negatively correlated with age. CCT and CCR are positively correlated with age.

Corneal Biomechanical Properties after FS-LASIK with Residual Bed Thickness Less Than 50% of the Original Corneal Thickness

“…In Table 1 , preoperative corneal thickness (CCT, MCT, and PCT) and postoperative CCT were shown. According to our previous research [ 28 ], there was no significant difference between CCT measured by a pachymeter and OCT images, and in this study, we also got no significant difference in results shown in Table 1 . Moreover, CCT measured from OCT images was more accurate in post-LASIK eyes than that measured from other measurements [ 29 ].…”

The Mechanical Interpretation of Ocular Response Analyzer Parameters

“…In this study, corneal strip tensile and stress relaxation experiments were carried out on rabbits with different ages to obtain corneal biomechanical properties. The results of the relationship between ORA parameters and age based on the same rabbits were reported in our last research [23]. Combining these results, we can recognize the mechanical interpretation of ORA parameters preliminarily.…”

“…All rabbits were anesthetized with 3% pentobarbital sodium (Merck, Germany) at a dose of 1ml/kg and measured with ORA in vivo for 4 times. The details of the methods for ORA measurements on rabbits have been reported in our previous study [23]. The screening condition was “WS>3.5.” After ORA measurements in vivo, corneal strips tensile experiments were performed on Care-IBTC-50 (In-situ Bi-directional Tension & Compression) Testing System (CARE Measurement & Control Corp., Tianjin, China) under room temperature and 9% saline bath environment.…”

“…In our previous paper, we had compared corneal biomechanical properties of 3-month rabbits and 7-month rabbits preliminarily, and the results showed difference between the two groups both in corneal elastic modulus and viscoelastic property [22]. So, in our last study, we proposed a possible way to study the relationship between corneal clinical biomechanical parameters and corneal traditional biomechanical parameters by the correlation analysis of rabbit corneal biomechanical parameters with different ages [23].…”

Time Course Changes of the Mechanical Properties of the Iris Pigment Epithelium in a Rat Chronic Ocular Hypertension Model

“…The rats in this research are in the young age, so the basically unchanged IPE stiffness of blank-control eyes during 8-week period fits our expectations. There also have been many researches about the age-related changes in the stiffness of ocular tissues such as cornea [ 37 – 39 ], sclera [ 40 , 41 ], and lens [ 42 , 43 ]. We will be able to perform indentation experiments on IPE of rats from youth to old age.…”