Correlation between Central Corneal Thickness, Intraocular Pressure and Retinal Nerve Fiber Layer Thickness in Glaucoma Suspects, ZEINAB S. EL-SANABARY, KARIM A. RAAFAT, MOHAMED A. HASSABALLAH and NANCY Y. KHAIRAT
Abstract
Background: The measurement of Central Corneal Thick-ness (CCT) by pachymetry has been an essential part of the contemporary glaucoma work-up. Corneal thickness (along with other hysterics) may hold significant influence on accurate measurement of Intraocular Pressure (IOP). However, the Ocular Hypertension Treatment Study (OHTS), a large-scale longitudinal study, clearly demonstrated a thin CCT value as a substantial and independent risk factor for the development of Primary Open-Angle Glaucoma (POAG). The FD-OCT offers comprehensive glaucoma evaluation by providing assessment of RNFL thickness and optic disc morphology. In this study, we studied the correlation between central corneal thickness, IOP and RNFL thickness in glaucoma suspects.
Methods: 31 eyes of glaucoma suspects were included in the study. Glaucoma suspects were classified as those with: IOP >21mmHg or ONH changes, such as an optic rim notch, vertical cup/disc diameter ratio asymmetry and reliable Humphrey SITA central 24-2 standard visual field that is normal or showing changes not fulfilling the minimal criteria for glaucoma diagnosis. All subjects underwent complete ophthalmic examination, gonioscopy, Goldmann applanation tonometry, OCT corneal pachymetry, Visual field examination using standard automated perimetry performed with a Hum-phrey Field Analyzer using the Swedish Interactive Threshold Algorithm (SITA) standard strategy, program central 24-2 and imaging using FD-OCT; the RTVue-100 glaucoma protocol.
Results: The study showed significant correlation between CCT and IOP. However the correlation between average RNFL thickness and CCT and between average RNFL thickness and IOP was not statistically significant.
Conclusions: CCT is a significant glaucoma predictor in glaucoma suspects.