Biomechanical characteristics changes with ocular response analyzer in keratoconic eyes after intrastromal corneal ring segment (keraring) implantation

Abstract

Background: Keratoconus is a progressive and non-inflammatory cornea ectasia in central and paracentral of cornea, developed by progressive thinning and protrusion and cone formation. Despite use of spectacles and contact lens for improvement of vision, these methods were impracticability and unsatisfactory. Our aim in this study was to assess effect of Intrastromal corneal ring segment (keraring) implantation on corneal biomechanical parameters. Methods: In clinical trial study, 21 keratoconic eyes with inclusion criteria were selected and placed ICRS (keraring) and biomechanical characteristics were assessed preoperation and 1 and 6 months after surgery with ocular response analyzer. Result: Mean CRF and CH and difference CH-CRF measures were not significant in this study at 1 and 6 months after surgery. Mean difference of k1, k2 at 1 and 6 months after surgery were significant comparing to pre-operation results (p=0.02). IOPg and IOPcc were not significant in post operation than preoperation. Waveform score measures were significant in post operation than preoperation. Change of CH-CRF with waveform score change measures were significantly difference (p=0.02, R=0.31). CCT were not significant in post operation than pre operation. Changes of CCT measures had significant relation with change of IOPcc (p=0.02, R=0.40). Change of CCT measures had significant relation with change of CH-CRF (p=0.02, R=0.11) Conclusion: Keraring made change of corneal shape but did not changed biomechanical properties.