Abstract
Purpose:
To compare the difference in intraocular pressure measurements between the Pascal Dynamic Contour Tonometer intraocular pressure (IOP) and Goldmann Applanation Tonometry IOP in normal patients and patients with open angle glaucoma.
Methods:
Intraocular pressures were measured with both a Pascal Dynamic Contour Tonometer and a Goldmann Applanation Tonometer on 174 consecutive patients seen in a glaucoma clinic at the Reading Health Center. The difference between the two IOP measurements and the percentage of eyes with a greater than 3 mm Hg IOP difference was determined for each group.
Results:
In normal eyes (n=22), the average Goldmann IOP was 13.31 +/- 2.14 mm Hg and the average Pascal IOP was 16.53 +/- 2.32 mm Hg. The average difference between Pascal IOP and Goldmann IOP (delta IOP) was 3.22 +/-1.67 mm Hg. In open angle glaucoma eyes (n=152), the average Goldmann IOP was 15.38 +/- 3.98 mm Hg and average Pascal IOP was 19.94 +/- 4.79 mm Hg. The average delta IOP was 4.56 mmHg +/- 2.67. Based on the average delta IOP of 3.2 mm Hg for normal eyes, the percentage of eyes with a greater than 3 mm Hg delta IOP was determined to be 52.4% of normal eyes versus 79.1% of open angle glaucoma eyes. The difference between the number of eyes, with a delta IOP greater than 3 mm Hg, was statistically significant between the two groups (p=0.0071).
Conclusions:
The pressures measured by Pascal versus Goldmann Tonometry show a larger difference in glaucoma eyes than normal eyes. Patients with glaucoma are more likely to have a greater than 3 mm Hg IOP difference between Pascal Dynamic Tonometry and Goldmann Tonometry. If the Pascal measurement of IOP is independent of corneal and other factors which affect the Goldmann IOP, the larger variation between the Pascal and Goldmann IOP's in eyes with glaucoma may have clinical implications.
Keywords: 465 clinical (human) or epidemiologic studies: systems/equipment/techniques