Correlation between Central Corneal Thickness and Visual Field Defect, Cup to Disc Ratio and Retinal Nerve Fiber Layer Thickness in Primary Open-Angle Glaucoma Patients
Boonchai Wangsupadilok MD*, Lachaya Orapiriyakul MD*
Affiliation : * Department of Ophthalmology, Songklanagarind Hospital, Prince of Songkla University, Songkhla, Thailand
Objective : To assess the correlation between central corneal thickness (CCT) and visual field parameters, cup-to-disc ratio
and retinal nerve fiber layer (RNFL) thickness in primary open-angle glaucoma (POAG) patients in Songklanagarind
Hospital.
Material and Method: A Retrospective analytical study of the medical records of primary open-angle glaucoma patients,
between January 2006 and April 2008, were reviewed. All subjects underwent a complete eye examination. The CCT
measurement was performed by ultrasonic pachymeter. Mean deviation (MD), pattern standard deviation (PSD), cup-to-disc
ratio, and the RNFL thickness of each patient were collected. The correlation coefficient between CCT and MD, PSD,
cup-to-disc ratio and RNFL thickness was analyzed.
Results : Twenty-six POAG patients (47 eyes) were eligible for the study. Mean age was 60.967.44 years. Average CCT
was 511.1529.66 μm. Mean MD and PSD were -10.01 8.20 and 7.524.43 decibel respectively. Mean cup-to-disc ratio
was 0.710.17. Mean RNFL thickness of superior, inferior, temporal, nasal quadrants and all quadrants were 101.6028.68,
87.1532.56, 60.6414.14, 61.8313.96 and 77.8017.58 μm, respectively. There were significant correlations between
CCT and MD (r = 0.532, p<0.001), PSD (r = -0.288, p = 0.05), cup-to-disc ratio (r = -0.478, p = 0.001), and average
RNFL thickness (r = 0.487, p = 0.001).
Conclusion : There were significant correlations between CCT and visual field parameters, cup-to-disc ratio, and RNFL
thickness.
Keywords : Central corneal thickness, Mean deviation, Pattern standard deviation, Retinal nerve fiber layer thickness, Optical coherence tomography
