Corneal Endothelial Cell insult by Chronically Elevated Intraocular Pressure in Primary Open Angle Glaucoma: A Cross-sectional Study

Abstract PURPOSE: To evaluate specular microscopic changes of corneal endothelial cell (CEC) count and morphology in correlation to retinal nerve fiber layer RNFL changes detected by OCT in early and advanced primary open-angle glaucoma (POAG).METHODS: A cross-sectional study was conducted on patients with POAG versus non-glaucomatous patients of the same age group. Specular microscopy, VF test, OCT scans of RNFL, and macular ganglion cell complex (GCC) were performed. Glaucoma group was further subdivided into early and advanced stages.RESULTS: The study included 130 eyes of 130 subjects, 70 were eyes with POAG (early glaucoma 40 eyes, advanced glaucoma 30 eyes), 60 were healthy eyes (control group). Both groups were comparable regarding mean age and sex.In the early glaucoma group, a significant negative correlation was found between the coefficient of variation (CV%) and superior RNFL thickness (r=-0.5, p-value=0.018). A significant negative correlation was also found between percentage of cellular hexagonality (HEX%) and vertical cup/disc (C/D) ratio (r=-0.43, p-value= 0.035). A significant positive correlation was found between HEX% and (superior, inferior) RNFL thickness (r=0.53, 0.5 and p-value= 0.008, 0.015) respectively.Mean CEC count was significantly lower in the advanced glaucoma group than in the control group (2958.7±371.2 vs 3085±172.5, p value=0.043). CONCLUSIONS: CEC is affected by chronic intraocular pressure (IOP) elevation just like the RNFL and macular GCC. CEC morphology is insulted in the early stages of POAG while the count can withstand chronic IOP elevation till advanced stages where both are affected.