Rebound tonometry device readings correlate with GAT, with limitations
IOP readings from the iCare HOME rebound tonometer “correlate well” with those obtained with Goldmann applanation tonometry, with some limitations, according to a study.
The unmasked prospective study randomized 101 subjects with glaucoma and 53 without to undergo IOP estimation by a physician using either the iCare HOME or the iCare ONE device first. Patients then estimated their own IOP using the same device. In a second round of measurements, IOP was estimated by the physician using the iCare device that was not used in the first round, and patients again estimated their IOP using the second device. Finally, IOP was physician-estimated using Goldmann applanation tonometry (GAT).
Results showed a high correlation between all tools, independent of who managed the tool. Mean IOPs for right eye measurements only were 15.9 mm Hg for the ONE device measured by an ophthalmologist, 15.8 mm Hg for the ONE device measured by the patient, 15 mm Hg for the HOME device measured by the ophthalmologist, 14.9 mm Hg for the HOME device measured by the patient and 15.8 mm Hg for GAT as measured by the ophthalmologist.
“Nevertheless, on Bland-Altman analysis, the [physician measured HOME rebound tonometer] showed a mean tendency to underestimate IOP in comparison to a GAT reading of 0.8 mm Hg,” the researchers wrote. Furthermore, compared with GAT at higher IOP levels, both the HOME device and the ONE device increasingly overestimated IOP, and at lower IOP levels, the device underestimated IOP, regardless of who obtained the measurements. – by Kate Sherrer
Disclosure: The study authors report no relevant financial disclosures.