Abstract
Purpose: :
To evaluate the repeatability of the biomechanical waveforms indices measured with the Ocular Response Analyzer device in Normal and post refractive surgery eyes.
Methods: :
Prospective noninterventionnal study including 200 eyes of 100 patients: Normal, n=120, post Lasik, n=40 and post PRK, n =40. Ten consecutive measurements were taken for each eye and the repeatability of the 37 waveforms parameters in addition to the Corneal Hysteresis (CH), Corneal Resistance Factor (CRF), IOPg and IOPcc was evaluated with the Intraclass Correlation Coefficient (ICC).
Results: :
The mean of the goldmann correlated IOP value (IOPg), corneal compensated IOP value (IOPcc), corneal hysteresis (CH) and corneal resistance factor (CRF) were respectively: 14.36+/- 1.34 mmHg; 15.67 +/- 1.67 mmHg; 9.76 +/-0.95 mmHg and 9.52+/-0.79 mmHg. The ICC was superior to 0.6 for all these biomechanical parameters (respectively 0.850; 0.727; 0.855 and 0.759.). Only five of the waveform parameters had an ICC superior to 0.6: "P1area" which is the area of peak 1 (ICC= 0.823), "P2area" which is the area of peak 2 (ICC=0.646), "h1" which is the height of peak 1 (ICC= 0.702), "P1area1" which is the area of peak 1, derived from the upper 50% of the applanation peak (ICC=0.772) and "h11" which is the height of peak1, derived from the upper 50% of the applanation peak 1 (ICC= 0.697).
Conclusions: :
Signal curves analysis and scoring system combining multiple signal curves parameters should rely on the most repeatable parameters. More studies are necessary to evaluate the repeatability of the ORA unit in different pathologies
Keywords: cornea: clinical science • clinical (human) or epidemiologic studies: systems/equipment/techniques • refractive surgery: other technologies