The Impact of Central Corneal Thickness on Intraocular Pressure Measured by Non-Contact Tonometry
Boonchai Wangsupadilok MD*, Orasa Horatanaruang MD*
Affiliation : * Department of Ophthalmology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
Objective : To investigate the impact of central corneal thickness (CCT) on the intraocular pressure (IOP) measurement by
non-contact tonometry (NCT).
Material and Method: Eye examination data of normal volunteers aged between 18-96 years and intraocular pressure less
than 22 mmHg were retrospectively reviewed. Subjects with possible conditions that affected the results of CCT and IOP
measurement by NCT were excluded. The data of CCT and IOP measurements by NCT were obtained. Linear and multiple
regression analysis were used to evaluate the influence of CCT and age on IOP measurement by NCT.
Results : Four hundred and thirty seven eyes of 437 subjects were enrolled. The mean age was 49.05 + 18.84 years. The
average CCT was 524.56 + 32.40 microns and the mean IOP measurement by NCT was 13.85 + 2.81 mmHg. Linear
regression model showed a significant negative correlation between CCT and subject age (p < 0.001), but had a positive
correlation between CCT and IOP measurement by NCT (p = 0.006).
Conclusion : CCT has a significant impact on IOP measurement by NCT. The finding suggests that CCT is an important
parameter for interpretation of IOP measurement by NCT.
Keywords : Central corneal thickness, Non-contact tonometry, Intraocular pressure
