Purchase this article with an account.
R.D. Johnson, Jr., C.J. Roberts, A.M. Mahmoud, P.A. Weber; A Comparison of Dynamic Contour Tonometry, Goldmann Applanation Tonometry and Central Corneal Thickness in Glaucomatous and Ocular Hypertensive Eyes . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4437.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To compare dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in glaucomatous and hypertensive (OHT) subjects.
35 eyes of 19 POAG patients and 22 eyes of 11 OHT patients were prospectively enrolled in the study from the office of a glaucoma specialist. Intraocular pressure (IOP) was measured with Goldmann applanation tonometry (GAT), and Pascal Dynamic Contour Tonometer (DCT). Central Corneal Thickness (CCT) was measured with an Orbscan topographer (Bausch & Lomb). Visual fields were measured using the Humphrey 24–2 threshold program and an AGIS score was calculated and recorded. Statistical analysis using a student t–test and regression analysis was completed with a significance level set to a p–value <0.05.
The average GAT minus DCT difference in the POAG group was –2.99+3.3 mm Hg. The average GAT minus DCT difference in the OHT population was –1.32+2.5 mm Hg. The GAT–DCT difference was statistically significantly distinct between the two groups (p<0.04). The OHT subjects had significantly thicker corneas at 582.8+86 microns compared to the POAG subjects at 548.1+43 microns (p<0.05). CCT was significantly positively correlated with GAT (p<0.02, R2 =0.27) and DCT (p<0.05, R2 =0.20) in the OHT group. However, there was no relationship between CCT and any measure of IOP in the POAG group. CCT was significantly negatively correlated with AGIS score in the POAG group (p<0.03, R2 =0.13). The difference between GAT and DCT was not significantly correlated with AGIS score. Ocular Pulse Amplitude (OPA) was significantly positively correlated with GAT (p<0.01) and DCT (p<0.01) in both the OHT and POAG groups.
A significant difference was found between glaucomatous and OHT subjects in the relationship between CCT and IOP, as well as the difference between GAT and DCT measurements of IOP. The glaucomatous eyes had a greater magnitude of difference between GAT and DCT, and yet had significantly lower CCT’s. This implies that thickness alone is not sufficient to correct for IOP as measured by GAT in the POAG population.
This PDF is available to Subscribers Only