The effects of refractive status and central corneal thickness on applanation tonometry measurements

Objective To investigate the effect of the refractive status and central cornea thickness (CCT) on Goldmann applanation tonometry (GAT). Methods A total of 119 cases of normal subjects (195 eyes) and 74 cases of myopia (148 eyes) were included in this study. The CCT was measured by Pentacam and intraocular pressure (IOP) by using GAT. SPSS17.0 was used to process the data. Results The average CCT of the normal group was (525.07±38.58)μm. The mean IOP was (12.96±2.64)mmHg. The difference on both IOP and the mean CCT between low myopia group and normal group had statistically significant. The difference in IOP between high myopia group and normal group had statistically significant. The IOP of myopia group was negatively correlated with diopter (r=-0.396, P <0.001). IOP increased 1mmHg with per -3.86D increase. IOP of normal and myopic groups correction formulas were 1mmHg/45.55μm, 1mmHg/34.46μm, respectively. Conclusions CCT and refractive state can influence IOP. Key words: Refractive status; Central corneal thickness; Goldmann applanation tonometry; Pentacam; IOP correction