Author's reply.

Dear Sir,

We thank the authors for their interest to our article.[1] In our study we have demonstrated that exfoliative glaucoma (EXG) patients have lower corneal hysteresis (CH) levels and at this point we have hypothesized that this lower CH levels may be a reason for rapid progression in visual deterioration in EXG patients.

The authors asked for correlations between visual field test (mean deviation [MD]) and corneal biomechanical properties. We did not correlate visual field parameters with corneal biochemical properties in our study. As we have stated, our study is cross-sectional observational study. We thought that simply comparison of MD value of the visual field with corneal biomechanical properties may not be relevant. Because visual field test is a dynamic test and may be affected by several factors.[2] MD could be affected by refraction errors, small pupils and hazy media.[345] We know that patients with EXG have smaller pupil diameter and a higher incidence of lenticular opasification.[6] In order to find and observe a correlation between visual field parameters and corneal biochemical parameters, researchers should start a prospective study and should actively observe changes in visual field parameters in patients with lower CH and show correlation between CH and visual field deterioration. As we have stated in our study, there is a need for longitudinal prospective studies to show changes in visual field defects relative to baseline levels in patients with different corneal biomechanical properties to prove that lower CH is associated with a more rapid progression of optic neuropathy in eyes with EXG.

Authors asked for whether any adjustment performed for multiple comparisons. There are many factors affecting CH, apart from our study findings, such as axial length, age, corneal curvature, corneal disease, etc.[78] In our study, age was significantly different between groups. As we have stated in the discussion section of the manuscript, this factor may be a limitation for our study. But comparison of parameters adjusting only for age, intraocular pressure or any ocular response analyzer measure would not be enough because CH is affected by many ocular and systemic factors. We did not made any adjustments for multiple comparison of corneal biomechanical properties in statistical analysis of this study.

We appreciate the opportunity given to us by the editor and authors and we hope these replies will help the understanding of corneal biomechanical properties in EXG eyes or other types of glaucoma and encourage researchers for longitudinal prospective studies with larger study groups.