Correlations between Corneal Biomechanics and Glaucoma Severity in Patients with Primary Open Angle Glaucoma

To investigate the relationship between corneal biomechanical changes and glaucoma severity in primary open angle glaucoma patients.

Correlation study.

Our study included 70 glaucomatous eyes; they were divided in groups using Glaucoma Staging System Based on Humphrey Visual Field. Ocular Response Analyzer (ORA) was used in order to determine corneal hysteresis (CH) and corneal resistance factor (CRF); ultrasonic pachimetry (Ocuscan) to measure central corneal thickness (CCT) and Humphrey Visual Analyser to determine mean deviation (MD), pattern standard deviation (PSD) and visual field index (VFI). For statistical analysis we used descriptive analysis and linear regression using IBM SPSS Statistics Standard.

Out of the 70 eyes with primary open angle glaucoma examined that had visual acuity 0,7 or better, 35 were included in stage 1 (MD 0.01dB -> -6dB), 21 in stage 2 (MD -6.01dB -> -12dB) and 14 in stage 3 (MD -12.01dB -> -20dB). A considerable statistic correlation was found between CH and VFI both in the entire group of primary open angle glaucoma patients( r=0.44, p<0.001), and in stages 1 (r=0.44, p<0.009), 2 (r=0.51, p<0.01) and 3 (r=0.52, p<0.05).

The study shows a moderate correlation, statistically significant, between corneal hysteresis and visual field index in glaucoma patients. Ocular response analyzer can be considered an useful instrument in evaluation of primary open angle glaucoma patients.