EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/387844
89 EW GLAUCOMA October 2014 moves toward reality in that first month was 20/70, i - proving to 20/25. Using Goldmann applanation tonometry as the com- parator, the WIT was fairly close to the Goldmann readings until week 31 onward, where the differences between the 2 readings ranged from 2.4 mmHg to 6.5 mmHg. Dr. Melki said those differenc- es were "a concern," but believes a recalibration to avoid the mea- surement drifts noted in the early studies will rectify the issue. Recalibration is simply a matter of taking a Goldmann measure- ment and comparing it to the WIT. Patients in the European studies re- quired the device to be recalibrated "about once over a 2-year period." Because the group has been unable to duplicate the drift in the lab, they are convinced it is related to exter- nal forces in the human eye. "The newer version of the device has protrusions on the side so there is no direct contact with the wall of the eye," Dr. Melki said. Fixing the drift issue is imperative, as patients with keratoprostheses are one of the target groups for the device. Dr. Melki's group does not want to pursue combining the technology into an IOL, as they believe keeping them separate will make the device available to more potential patients. IOP fluctuation Both groups of researchers acknowl- edge a big advantage of continual monitoring will be the information about evening/night IOP fluctu - tions that are difficult to obtain. "It remains to be seen whether this new information that we will gather is going to affect how we treat glaucoma," Dr. Melki said. "It could very well be that IOP fluctu - tion has no effect on overall glau- coma progression and won't be a factor in how we treat patients. Or it might be that fluctuation has a lot more to do with visual field progression than spikes in pressure." What both groups do believe is that obtaining that knowledge is in reach within the next few years. EW References 1. Varel C, Shih Y-C, Otis BP, Shen TS, Böhringer KF. A wireless intraocular pressure monitoring device with a solder-filled micr - channel antenna. J Micromech Microeng. 2014; doi:10.1088/0960-1317/24/4/045012. Contact information Böhringer: karl@ee.washington.edu Melki: melki@bostoneyegroup.com Shen: ttshen@uw.edu 2. Melki S, Todani A, Cherfan G. An implantable intraocular pressure transducer: Initial safety outcomes. JAMA Ophthalmol. 2014;doi:10.1001/ jamaophthalmol.2014.1739. Editors' note: The sources have no financial interests related to their comments.