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M. J. Silva, V. P. Costa, A. P. C. Lupinacci, J. S. Paula; Effect of Central Corneal Thickness on Tonometry as Measured by Dynamic Contour Tonometry and Goldmann Tonometry in Primary Congenital Glaucoma. Invest. Ophthalmol. Vis. Sci. 2009;50(13):2865.
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© ARVO (1962-2015); The Authors (2016-present)
To analyze the agreement, and the influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurements obtained with dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in primary congenital glaucoma (PCG) patients.
Eighteen (31 eyes) PCG patients (25.7 ± 7.2 years old) were examined. PCG was defined by history of elevated IOP, enlarged corneal diameter (buphthalmos), Haab’s striae and abnormal findings at gonioscopy. GAT (Haag Streit R900, Switzerland), DCT (SMT Swiss Micro Technology, Switzerland), and CCT (Sonomed Micropach 200P+, USA) measurements were obtained, in this order, by three examiners (one examiner per instrument). The mean of 5 CCT measurements was used for analysis. DCT measurements were accepted only when quality scores indicated good quality (1 or 2). Linear regression analysis was performed to test the correlation between CCT, DCT and GAT measurements. Bland Altmann analysis was performd to evaluate the agreement between DCT and GAT measurements.
Mean CCT was 534 ± 72.3 µm (range: 430 to 610). Mean IOP measurements were 15.1 ± 4.2 mmHg (range: 7 to 34) for DCT and 14.5 ± 5.6 mmHg (range: 5,5 to 22,7) for GAT (P=0.514, paired t test). Spearman correlation tests showed IOP measured by GAT and DCT to have poor correlation with CCT (r = 0.006, P=0.38 and r = 0.035, P=0.82, respectively). IOP measurements by GAT displayed a strong correlation with those obtained with DCT (r = 0.462, P=0.0089). Bland-Altmann analysis revealed poor agreement between DCT and GAT readings, with 95% confidence intervals of ± 5,31 mmHg.
Although GAT and DCT measurements did not differ significantly in these PCG patients, there was a poor agreement between the measurements obtained with each instrument. Neither DCT nor GAT was influenced by CCT in this series of PCG patients.
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