Comparisons of intraocular pressure measurements: Goldmann applanation tonometry, noncontact tonometry, Tono-Pen tonometry, and dynamic contour tonometry

Aims To compare intraocular pressure (IOP) readings between Tono-Pen tonometry and GAT, between noncontact tonometry (NCT) and GAT, and between dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT). The correlation between IOP reading and possible confounder was identified. Methods This observational cross-sectional study enrolled sixty-two healthy subjects. All IOP and ocular pulse amplitude (OPA) measurements were taken by a single ophthalmologist; mean keratometric power (MK), central corneal thickness (CCT), and lens thickness (LT) were measured by a single experienced technician. Results Stepwise multiple regression analysis indicated that GAT (P=0.017) and DCT (P=0.002) readings correlated positively with MK; GAT, NCT, and Tono-Pen readings correlated positively with CCT (P<0.05); NCT (P=0.035), and DCT (P=0.016) readings correlated negatively with LT; GAT (P=0.006) and Tono-Pen (P=0.009) readings correlated positively with OPA. Conclusions The K, CCT, LT, and OPA are confounders in tonometry readings. Eye (2009) 23, 1582-1588; doi:10.1038/eye.2009.77; published online 1 May 2009