Abstract
Purpose :
Management of glaucoma depends significantly on intraocular pressure (IOP) measurement. There are a variety instruments that are used to measure IOP in a clinical setting. We performed a clinical prospective study of IOP measurements to test the accuracy and reliability of a novel automatic, handheld, rebound tonometer (RBT), the Tono-Vera, compared with Goldmann applanation tonometer (GAT), iCare RBT, and air-puff Ocular Response Analyzer (ORA).
Methods :
We performed measurements on 200 eyes of 104 patients ages 19-86 years old (mean age 64.3 years), with 99/104 having a diagnosed form of glaucoma. Eyes with recent laser procedure or surgery were excluded from the study. IOP was measured using Tono-Vera, GAT, iCare, and ORA’s central cornea IOP. The Autorefractor Kerameter (ARK) was used to measure sphere, cylinder, and axis. Pachymetry central corneal thickness (CCT) was recorded. Bland-Altman analysis was used to compare the Tono-Vera IOPs with each device. Primary consideration in analysis was focused on the standard of care method, GAT. There are no adjustments for CCT in this analysis.
Results :
The Tono-Vera overestimates IOP compared with the GAT in 91% of cases. The Tono-Vera overestimates IOP compared with iCare in 94.5% of cases and with ORA in 52.5% of cases. The mean IOP ± SD measurements were 17.54 ± 4.87 mmHg, 14.58 ± 3.99 mmHg, 14.87 ± 5.07mmHg, and 17.33 ± 5.68 mmHg in Tono-Vera, GAT, iCare, and ORA, respectively. The Tono-Vera overestimates IOP (p<0.05) by +3.048 ± 3.013 mmHg [2.596, 3.431] compared with GAT, +2.674 ± 1.693 mmHg [1.459, 1.928] compared with iCare, and +0.080 ± 4.000 mmHg [3.449, 4.558] compared with ORA.
Conclusions :
The novel RBT, Tono-Vera, overestimates measurements of IOP compared to GAT and iCare in glaucomatous eyes, yet provides an agreeable IOP compared to the ORA. Previous studies of RBT measurements compared with GAT disagree on the reliability of RBT readings depending on CCT and the sample population. However, the handheld Tono-Vera provides ample accessibility to IOP measurements compared with GAT and ORA. Despite the Tono-Vera consistently overestimating IOP compared to GAT, the mean difference in IOP is in a reasonable range.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.