Inter-instrumental agreement between goldman applanation tonometer (GAT) and non-contact tonometer (NCT) in relation to central corneal thickness (CCT) - an entity revisited

Background: To compare the level of intra ocular pressure measured by two different tonometers in relation to central corneal thickness (CCT). Material and Methods: Intraocular pressure (IOP) was measured in 118 consecutive patients first by Goldman applanation Tonometer (GAT) followed by Non-contact tonometer (NCT). Central corneal thickness was measured in each case by non-contact method. The values of IOP thus obtained by both the methods were compared in relation to the CCT values. Results: Out of total 118 patients, maximum subjects belonged to 31-40 year age-group (n=44). The mean age was 46.5 years. 66 male and 52 female participated in this study. The mean CCT was 517.68μm with standard deviation 26.77. 95 IOP readings were normal with NCT and 14 readings were graded as ocular hypertension (IOP measuring more than 21mm Hg) giving a specificity rate of 95.95% and sensitivity rate of 73.68%. Conclusion: In patients with normal range of CCT, GAT remains the method of choice.