Abstract
Purpose :
To compare intraocular pressure (IOP) measurements by Goldmann applanation tonometer (GAT), disposable Goldmann applanation tonometer(dGAT), ICare ic100 tonometer, and Tono-pen XL in glaucomatous, ocular hypertensive, post-corneal transplantation, and normal eyes.
Methods :
Intraocular pressure was measured by four different tonometers: GAT, dGAT, Icare, and Tono-pen XL and central corneal thickness was measured using ultrasound pachymetry for thirty-nine patients. Whether the patient had corneal pathology such as keratoconus, previous corneal transplant, had glaucoma, ocular hypertension, or were normal was recorded.
Results :
There was a good correlation between IOP measurements by GAT and that by disposable GAT (r=0.816, p<.001), that by Tonopen (r=0.945, p<.001), and that by ICare (r=0.916, p<.001). The intraclass correlation coefficients of disposable GAT, Tonopen XL, and ICare when compared to GAT were 0.79, 0.94, and 0.90, respectively. The IOP mean differences between GAT and disposable GAT were mean: 0.04mm Hg; SD:4.68 mm Hg; 95% limits of agreement: -9.14 to 9.22 mm Hg. The IOP mean differences between GAT and Tonopen were mean: 1.53 mm Hg; SD: 2.64 mm Hg; 95% limits of agreement: -3.64 to 6.70 mm Hg.The IOP mean differences between GAT and ICare were mean: 0.08 mm Hg; SD: 3.45 mm Hg; 95% limits of agreement: -6.69 to 6.84 mm Hg. For post corneal transplant patients the mean difference between GAT and Tonopen was the smallest (0.5 mm Hg).
Conclusions :
In terms of IOP measurement, the modality that was reliable and showed a good correlation with GAT was the Tonopen XL, with ICare having the second best correlation and the disposable GAT having the least correlation with GAT. Tonopen XL also was most reliable post corneal transplantation. Despite these differences, we observed good interdevice agreement between GAT and the disposable GAT, Tonopen XL and ICare. This suggests that single-use applications of disposable Goldmann tonometry and iCare may be good alternatives for general patients with and without glaucoma.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.