Corneal properties and glaucoma: a review of the literature and meta-analysis

Purpose: Studies have suggested that corneal biomechanical properties influence intraocular pressure (IOP) measurements, namely central corneal thickness (CCT) and corneal hysteresis (CH). The present study aimed to investigate the associations of CH and CCT with glaucoma development. Methods: We performed a review of the literature and meta-analysis of observational studies (2006-2016) that included both adult glaucoma patients and controls and reported CCT and CH as outcomes. Nineteen studies were considered eligible, and the mean difference (MD) between groups (patient and control) for both variables was used for statistical analyses. Results: A total of 1,213 glaucoma and 1,055 healthy eyes were studied. Quantitative analysis suggested that CH was significantly lower in the glaucoma group than in the control group (MD=-1.54 mmHg, 95% CI [-1.68, -1.41], P< 0.0001). Additionally, CCT was significantly lower in the glaucoma group than in the control group (MD=-8.49 mu m, 95% CI [-11.36, -5.62], P< 0.001). Conclusion: Corneal properties appear to differ between glaucoma patients and healthy controls. Our results emphasize the importance of corneal biomechanical properties in IOP interpretation and should support further studies on the influence of CH and CCT in glaucoma screening and diagnosis.