Ocular response analyzer in pre‐perimetric glaucoma

Abstract

AbstractPurpose To compare corneal biomechanical parameters measured by Ocular Response Analyzer (ORA) in pre‐perimetric glaucoma eyes (PPG), versus intra‐ocular hypertension (OHT), open angle glaucoma (OAG) and normal subjects (NS).Methods Comparative study including 317 eyes: 165 normal (NS), 64 OHT, 46 OAG and 42 PPG. PPG criteria: intra‐ocular pressure (IOP) > 21 mm Hg, glaucomatous alterations of the optic disc and no visual field defect. Measured parameters: corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated IOP (IOPg), corneal compensated IOP (IOPcc), IOP by Goldmann aplanation tonometry (GAT) and central corneal thickness (CCT). Statistical analysis used non parametric tests and significant p value < 0,05.Results Whatever the parameter, there is no significant difference between PPG and OAG groups. GPP mean CH value (9,5 ± 1,5) was statistically different compared with NS (10,2 ±1,5), but no difference was found with OHT (9,6 ± 2) or with OAG (9,2 ± 1,8). No significant difference was found between PPG mean CRF value (10,2 ± 1,6) and those measured in NS ( 10,1 ±1,6), OHT ( 10,9 ± 2,1), and OAG (9,9 ± 1,5). PPG mean CCT (533 ± 39 µm) value was different only from OHT (552 ± 46 µm). For IOP parameters (IOPg, IOPcc, TAG), PPG eyes presented no difference with OAG eyes, but there was difference with OHT and with NS. Whatever the parameter, there was a great overlap of values between groups. Previous reports have demonstrated that CH is lower in OAG, and CRF higher in OHT. This study found that PPG eyes have the same corneal biomechanical parameters as OAG, and that PPG presents difference with OHT (CCT) and with normal eyes (CH).Conclusion ORA seems to be useful for early diagnosis of pre‐perimetric glaucoma.