Abstract
Abstract: :
Purpose:To compare the Intraocular Pressure (IOP) measurements obtained with the Pascal Dynamic Contour Tonometer (DCT) and the Goldman Applanation Tonometer (GAT), and its association with Central Corneal Thickness (CCT) in a population–based sample of adult Latinos. Methods: The Los Angeles Latino Eye Study is a population–based study of Latinos (primarily Mexican–Americans) aged 40 and older. Participants underwent a complete ophthalmic examination including measurement of IOP with the DCT (Ziemer Ophthalmic Systems AG, Switzerland) and the GAT (Haag–Streit, Bern, Switzerland), in a randomly assigned order. The DCT IOP was compared to the GAT IOP in the same eye. The CCT was measured with the ultrasonic pachymeter (DGH Technology, Exton, PA). A random eye from each participant was selected for this analysis. A paired t–test was used to compare the DCT IOP with GAT IOP. Results: 806 participants with a mean (SD) age of 60.2 years (±10.6) were included in this study. The mean (SD) GAT IOP was 14.0 mmHg (±3.3) the mean (SD) DCT IOP was 14.8 mmHg (±3.8) the mean (SD) CCT was 548 µm (±35.1). When the data were stratified by CCT < 500µm, 501 – 550µm, 551 – 600µm and >600 µm, the mean difference (GAT IOP – DCT IOP)between the GAT IOP and DCT IOP decreased from 1.1 mmHg to 0.4 mmHg. For eyes with CCTs <500µm the mean difference (GAT IOP – DCT IOP) was –2mmHg regardless of the IOP level. However, for eyes with CCT > 500µm the mean difference was greater with higher IOP levels. Conclusions: On average, the GAT IOP is higher than the DCT IOP. However, there is an interaction between the difference in IOP measurements and CCT. In eyes with thin CCTs, the DCT IOP measurements are higher than the GAT IOP measurements, whereas for thick CCTs, the opposite relationship is observed. From a clinical perspective, these data suggest that in eyes with thin CCT, the DCT may provide more accurate estimates of the IOP.
Keywords: intraocular pressure • clinical (human) or epidemiologic studies: systems/equipment/techniques • clinical (human) or epidemiologic studies: risk factor assessment