Goldmann applanation tonometry-correcting equations: comparison with dynamic contour tonometry

Session Details

Session Title: Advanced Tools for Outcome Assessment

Session Date/Time: Tuesday 17/09/2019 | 08:30-10:30

Paper Time: 10:10

Venue: Free Paper Forum: Podium 4

First Author: : I.De Pascale ITALY

Co Author(s): :    M. De Bernardo   L. Vitiello   G. Cembalo   D. Biondino   C. Casaburi   N. Rosa              

Abstract Details

Purpose:

Goldmann applanation tonometry (GAT) is considered to be the gold standard for the intraocular pressure (IOP) measurement but corneal characteristics are known to make these measurements less reliable and several correcting factors have been described to overcome this problem. Dynamic Contour tonometry (DCT) should not be influenced by corneal characteristics. The purpose of the study is to investigate the reliability of a large number of correcting GAT formulas comparing the results to those obtained with DCT.

Setting:

University Eye Clinic, Department of Medicine, Surgery and Dentistry, “Scuola Medica Salernitana”, University of Salerno.

Methods:

The study included 56 right eyes of 56 healthy subjects aged from 21 to 74 years, ( mean = 41.57 ±13.93 years) whose eyes underwent IOP measurement with both DCT and GAT. GAT measurements were corrected with corneal correcting factor obtained by 10 different formulas. The obtained values were compared with those obtained with DCT.

Results:

Mean IOP measured with DCT was 18.9 ±3.14 mmHg and 15.91 ±2.60 mmHg measured with GAT. The mean difference between DCT and GAT measurements was 2.18 ±2.37mmHg. Among the correcting formulas, only the one described by Chihara reduced the mean absolute difference. The one described by Srodka did not provide significant changes, whereas the other eight formulas increased the difference between GAT and DCT.

Conclusions:

Chihara equation seems to be the most reliable, reducing the difference between the two IOP measurement methods to -0,27 ± 0,76 mmHg. Other equations don’t provide a valid improvement of the agreement between the two methods or they provide a worsening of the agreement.

Financial Disclosure:

None