Poor agreement between Goldmann and Pascal tonometry in eyes with extreme pachymetry

Abstract

Aim To compare the intraocular pressure (IOP) measurements obtained using the Pascal dynamic contour tonometer (PDCT) with the standard Goldmann applanation tonometry (GAT) and to correlate them with the central corneal thickness (CCT) in a nonglaucomatous population. Methods We prospectively measured IOP using PDCT and GAT in random order in 100 normal eyes. CCT was analysed with an ultrasonic pachymeter in each case. Statistical analysis of baseline and stratified data included intraclass correlation coefficient (ICC), Lin correlation, and Bland-Altman analysis to evaluate the agreement between both techniques. Results GAT was used first in 51 eyes and PDCT in 48 cases. Mean IOP was 14.8 mm Hg with GAT and 20.3 mm Hg with PDCT. Mean pachymetry was 553.23 micrometres (lm) (SD: 4.7 lm). Global agreement of IOP between GAT and PDCT was 0.09 by ICC and 0.170 by Lin correlation. When CCT values ranged between 540 and 545 lm, the agreement between both tonometers was optimal (ICC 0.54 and Lin 0.61). Outside these pachymetry values, agreement between both tonometers diminished dramatically. Conclusion Statistically significant agreement between both devices was reached only at intermediate pachymetry readings in contrast with other studies that show excellent global agreement between GAT and PDCT.

Surveillance for ocular hypertension: an evidence synthesis and economic evaluation.

“…217 One additional study was reported as a multicentre study, taking place in Italy and Spain. 218 After contacting authors to clarify the age of study participants, eight authors from nine studies 135,140,141,148,189,190,192,201,212 confirmed eligibility for inclusion. One study included only participants who were aged ≥ 50 years but did not give the age range.…”

“…Six studies 134,142,161,189,192,210 provided information on the recordability of the DCT. The data are shown in Appendix 5.…”

“…In total, 642 reports were identified from the electronic searches as being possibly relevant. [189][190][191][192] three in each of Saudi Arabia, [193][194][195] India, [196][197][198] Portugal 106,199,200 and Greece [201][202][203] and two in Taiwan, 125,204 Israel, 205,206 the Netherlands, 207,208 Sweden 209,210 and Turkey. 211,212 One study took place in each of Austria, 126 Brazil, 213 France, 123 Ireland, 214 New Zealand, 215 Norway 216 and Denmark.…”

Goldmann applanation tonometry and dynamic contour tonometry in eyes with elevated intraocular pressure (IOP): comparison in the same eyes after subsequent medical normalization of IOP

“…A number of studies have demonstrated an excellent agreement between GAT and DCT, although DCT readings tended to be generally higher in healthy eyes [13,20] and glaucomatous eyes [15,21,22], with the difference ranging from 0.4 mmHg to 4.4 mmHg. Recently, Milla et al reported that the IOP readings obtained by DCT were 5.5 mmHg higher on average than those by GAT, and that the differences became even higher with increasing IOP values [23]. However, Barleon et al described that DCT measurements tended to be lower than GAT measurements for higher IOP values (>25 mmHg), whereas the situation was reversed for smaller IOP values (8 to 20 mmHg) [24].…”

Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

“…71,72 Most of the studies agree that DCT tends to overestimate GAT by about 2.3 -3.4 mmHg, depending on the IOP level, CCT and other corneal properties. 15,16,30,73 Milla et al 73 found an optimal agreement between DCT and GAT when the CCT was between 540 and 545 μm. As the CCT and the IOP increase, the difference between both tonometers also increases.…”