Comparison of Dynamic Contour, Rebound and Standard Goldmann Applanation Tonometry

Abstract

Abstract: : Purpose: to compare the intraocular pressure (IOP) in thin, normal and thick corneas with three different tonometers Methods: a total of 50 eyes of 50 patients were tested with the three tonometers. For Goldmann tonometer (GAT), the mean of three consecutive tests was used, for ICare tonometer (rebound tonometry, Tiolat Oy, Helsinki, Finland) both the IOP and the number of times needed to obtain a valuable measure were noted, and for Pascal dynamic contour tonometer (PDCT, SMT Swiss Microtechnology AG, Port, Switzerland), the IOP, the quality of the result and the ocular pulse difference were jotted). Patients were divided in three groups according to their corneal thickness (pachymetries<520µ, between 520 and 580µ and >580µ) Results: 11 patients had thin corneas (mean pachymetry 496.27 ± 20.27) 22 had normal corneas (mean pachymetry 552.09 ± 14.09µ) and 17 had thick corneas (mean pachymetry 607.94 ± 19.47µ). Reliability analysis showed an inter–test correlation of 0.90 (0.75; 0.97) for the group with thin corneas, of 0.87 (0.76; 0.94) for the group with normal corneas, and of 0.69 (0.45; 0.86) for the group with thick corneas. Results for the last group were even worse when comparing PDCT with ICare or GAT, and improved to 0.77 (0.48; 0.91) when comparing Icare with GAT (p<0.001) Conclusions: results obtained were good with high and significant correlations (p<0,01), but PDCT showed the least correlation with the two other tonometers in the group of thick corneas, what could verify the fact that it is the only one which is not influenced by corneal thickness

Keywords: anterior segment