Comparison of Central Corneal Thickness and Endothelial Cell Density in Patients with Various Types of Glaucoma and Patients without Glaucoma: A Case-control Study

Introduction: Corneal affection in glaucoma patients is very high due to various risk factors that may lead to unforeseen and unplanned deleterious effects on the cornea leading to vision loss. Accurate intraocular pressure determination requires corneal thickness measurement and uncontrolled intraocular pressures, use of long term medication, intra ocular surgeries including cataract and glaucoma shunt surgeries may cause significant endothelial loss. Therefore, adequate planning and management and follow-up in these patients is required weighing all the long term consequences and emphasis the need for implementing adequate precautions. Aim: To evaluate and compare the Central Corneal Thickness (CCT) and corneal Endothelial Cell Density (ECD) in patients with glaucoma and without glaucoma by specular microscopy. Materials and Methods: A case-control study conducted in a Super Speciality Eye Hospital, Bengaluru, Karnataka, India, was conducted from August 2016 till April 2018. All participants underwent a detailed ophthalmological examination including slit lamp bio microscopy, Intraocular Pressure (IOP) measurement, and CCT and ECD measurement by Tomey EM 3000 non-contactspecular microscopy. The Statistical analysis was completes using Statistical Package For the Social Sciences ( SPSS) 18.0 and R environment version 3.2.2 software's. Results: The CCT of the glaucoma patients and the controls showed no significant difference (p-value=0.250). The CCT was comparatively thicker in Ocular Hypertension (OHTN) patients and thinner in Normal Tension Glaucoma (NTG) however statistical significance was not established (p-value=0.250). The mean ECD of controls was 2509.05 +/- 298.48 (cells/mm3) and that of cases was 2465.68 +/- 392.91 ( cells/mm3) (p-value=0.404). The difference in the ECD amongst the glaucoma subgroups was not statistically significant (p-value=0.669). However, a lower ECD were seen in Pseudoexfoliation Glaucoma (PXG) and Angle Closure Glaucoma (ACG) subgroups. Conclusion: No significant difference was found in CCT and endothelial cell in cornea of patients with and without glaucoma. Normal Tension Glaucoma (NTG) patients have comparatively thinner corneas and OHTN patients had thicker corneas. There was no significant correlation established between ECD of Normal corneal vs. Glaucoma and its subgroups.