Abstract
Purpose::
To evaluate in ex vivo porcine eyes the corneal hysteresis (CH) and the corneal resistant factor (CRF) obtained with the Ocular Response Analyzer (ORA) and test the efficacy of this methods to measure the biomechanical properties of the cornea.
Methods::
Forty-five porcine globes were used within a period of six hours after death. Eyes were divided in two groups: Group A (corneal weakening) in which one and two flaps were created with an automated microkeratome, and group B (stiffening) in which eyes were exposed to formalin, UV light, and photoactivated riboflavin to induce crosslinking. CH and corneal resistance factor (CRF) were assessed before and after the procedure using the ORA.
Results::
There was a non-significant difference between pre and post-procedure CH in the one flap and UV light subgroups (p=0.052, and 0.227 respectively). Significant reduction in CH was seen in the 2 flaps subgroup (P<0.001). Significant Elevation in CH was seen in the formaldehyde and UV light + riboflavin subgroups (P<0.001). Finally, pre and post-procedure CRF was significantly different in all groups (P<0.001) except in the one exposed to UV light alone (P=0.899).
Conclusions::
The measure of CH and CRF with the ORA resulted in good predictor factors of the biomechanics properties of the cornea in this model.
Keywords: cornea: clinical science • imaging/image analysis: clinical • intraocular pressure