Comparison of Corneal Biomechanical Properties Betweeen Physiological Macrodiscs and Glaucomatous Macrodiscs

INTRODUCTION: This study was designed to compare optic nerve head (ONH) parameters and corneal biomechanical properties of healthy and glaucomatous macrodiscs.
METHODS: This cross-sectional study included total of 234 eyes, of which 92 served as normal controls, 92 had healthy macrodiscs, and 50 had glaucomatous macrodiscs. Measurement of ONH parameters in all p¬atients was performed using optic coherence tomography (OCT). Corneal hysteresis (CH) was measured in each patient using Ocular Response Analyzer (ORA; Reichert, Inc., Depew, NY, USA). Central corneal thickness (CCT) was determined by ultrasonic pachymetry. All OCT and ORA parameters of healthy and glaucomatous macrodiscs were compared.
RESULTS: Optic disc area of healthy macrodiscs and glaucomatous macrodiscs was similar, and larger than observed in control group (p=0.70, p=0.0001, respectively). Rim area was significantly thinner in glaucoma group than healthy macrodisc group or control group. (p=0.0001, p=0.022, respectively) Mean cup area of glaucomatous discs was larger than healthy macrodiscs (p=0.001). Cup/disc (C/D) area ratio, and horizontal and vertical C/D ratios were higher in glaucoma group than healthy macrodisc group (p=0.002, p=0.002, p=0.018, respectively) ORA analyses revealed that CH of glaucoma patients was lower than that of healthy macrodisc or control group (p=0.048, p=0.035, respectively), whereas, mean CH of macrodisc group was similar to that of control group (p=0.988). Mean CCT of macrodisc group was higher than that observed in control or glaucoma patients (p=0.015, p=0.045).
DISCUSSION AND CONCLUSION: It was concluded that OCT analyses can help differentiate healthy macrodiscs from glaucomatous discs. CH and corneal thickness measurements of healthy macrodiscs are greater than those of glaucomatous optic discs.