Rebound tonometry shows better precision, reproducibility
In three consecutive studies, rebound tonometry with iCare technology showed greater precision than standard Goldmann tonometry.
Rebound tonometry (RT) with iCare technology also had lower within-subject variance and better intraoperator reproducibility than standard Goldmann.
According to the study authors, iCare RT is designed to overcome the limitations of Goldmann applanation tonometry, which is currently the clinical standard for the measurement of IOP. The standard ic100 device (iCare USA) is hand-held and requires no anesthesia or dye, and the probe tip — the only part that touches the eye — is disposable. An upgraded model, the ic200, can be used in the sitting or upright position, and a third HOME model can be used by patients at home.
In all three studies, a similar number of participants with and without glaucoma were enrolled. In the first analysis, 28 subjects underwent five ic100 RT tonometry measurements in one eye and five Goldmann tonometry measurements in the fellow eye. The within-subject variance in RT measurements was 70% lower as compared with Goldmann tonometry, indicating better intraoperator reproducibility, the authors wrote. In the second study, three operators each performed three ic100 RT measurements in both eyes of 19 subjects, and in the third analysis a single operator collected three measurements with three ic100 tonometers in both eyes of 25 subjects. Agreement of IOP measurements among the three operators and the three devices was good approaching excellent.
Goldmann applanation tonometry has sources of error that affect measurements at different visits and no inherent means to identify whether intervisit changes in IOP may be true changes or artifacts, the authors said.
“The ic100 tonometer’s lower measurement variability suggests that it can characterize IOP changes over time more robustly than Goldmann tonometry, aiding clinicians in assessing the effectiveness of therapy and the consistency of IOP control in patients with glaucoma,” the authors wrote.
Integration of the HOME device with the ic100 or ic200 in the clinic will introduce a new dimension in glaucoma management, allowing detection of after-hours IOP elevations and IOP monitoring after surgical procedures.