To Study the Correlation Between the Pressure to Cornea Index and Both Structural and Functional Measures of Glaucoma

Abstract

Introduction In an attempt to integrate IOP and CCT into a unified risk factor, rather than simply attempting to correct for IOP measurement inaccuracy, Iliev et al. have proposed a new glaucoma index, the PRESSURE TO CORNEA INDEX (PCI). The authors believed that PCI could better reflect the individual susceptibility to glaucomatous damage than either IOP alone or CCT by itself. We in our study tried to explore possible use of PCI as a parameter for disease severity. In an attempt to do so, we compared PCI to the structural (C/D ratio) and functional (MD and PSD) measures of glaucoma. Methods In this cross-sectional study, Pressure-to-cornea index was calculated for 100 eyes of 53 patients (ocular hypertension, primary open angle glaucoma, normal tension glaucoma and controls). Cup-to-disc (C/D) ratio, mean deviation (MD) and pattern standard deviation (PSD) as recorded by Humphrey automated perimetry (SITA 24-2) were correlated with PCI. Results The difference in the value of PCI among different groups was statistically significant. (p = 0.000) There was positive correlation between PCI and C/D (P = 0.000); negative correlation between PCI and MD (P = 0.000); and positive correlation between PCI and PSD (P = 0.106). XI Conclusion: We conclude that PCI can be used as a unified risk factor. Also we have found statistical significant correlation between structural and functional measures of glaucoma to Pressure to cornea index (PCI) and hence, we conclude that it can be used in glaucoma severity as well.