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Lucy I Mudie, Sophie LaBarre, Sezen Karakus, Beatriz E Munoz, David S Friedman; Performance of the Icare Home (TA022) self-tonometer.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):6438. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Intraocular pressure (IOP) is a significant risk factor for glaucoma, and all current therapies for glaucoma are aimed at lowering IOP. Despite this, most patients only have their IOP measured once every six months or more. A rebound tonometer to use at home has been developed and this study aimed to determine the agreement between the Icare Home and Goldmann tonometry (GAT).
We recruited 173 adults from the Wilmer Eye Institute, Baltimore, MD between 2014 and 2015. Subjects with glaucoma were given standardized training and had to show independence in use of the Icare Home. The final criterion for certification in use of the device was the ability to obtain measurements within 5mmHg of GAT. Three consecutive measures were obtained with the Icare Home. Reference tonometry was obtained using the Icare TA01i and GAT. Grading of corneal staining using the Oxford Scheme was performed at baseline and after each attempt to measure IOP. The agreement between the tonometers was used to assess precision, and intraclass correlation coefficient (ICC) was used to assess within-patient reliability for the Icare Home.
44/171 failed to complete the study; 7 stopped due to time, 10/171 (6%) stopped because of difficulty using the device, and 27/171 (16%) failed to be certified due to difference in IOP during training. 127 patients completed the study and were included in the final analysis. The ICC for the Icare Home was 0.91 (95% CI: 0.89 - 0.94). The Home and GAT agreed within 5mmHg in 116/127 subjects (91.3%), 2 subjects (1.6%) had a difference that was greater than 7mmHg during final testing. The mean difference between the Icare Home and GAT was -0.33 mmHg (SD 3.11). Corneal staining became worse after using the Icare Home in 5/127 (3.9%) subjects, while it improved in 6 subjects, and remained the same in 116 patients. No corneal abrasions or adverse events were observed after using the Icare Home.
Not all subjects could learn how to use the Icare Home, but for those who could, the majority were able to obtain measurements within the limits of agreement. The Icare Home is safe and reliable for self-tonometry. It has the potential to address an unmet need by providing more frequent IOP measurements, and therefore more information to ophthalmologists about a patient’s risk of glaucoma progression and response to therapy.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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