In cases of pediatric glaucoma, long-term home monitoring is possible, according to Derek Bitner, MD, Wolfe Eye Clinic, Des Moines, Iowa. What’s more, such patients often experienced large pressure spikes during the period they were monitored, investigators reported in the Journal of the American Association for Pediatric Ophthalmology and Strabismus.1 While clinicians do their best to keep tabs on pediatric patients’ pressures in the office, these investigators wanted to look at how IOP behaves during other times of the day. “Just like in adult glaucoma, IOP is not stagnant—it changes and we don’t always catch it,” Dr. Bitner said. “We don’t see the patients frequently enough to catch all of these changes in pressure.” The investigation’s goal was to determine if there was an easy way to monitor patients at home that could offer more data points on pressure rather than just getting one point in the office, he explained.
Checking for changes
Investigators trained families on how to use a rebound tonometer (Icare, Vantaa, Finland). During the study period, parents of the seven children included were called on to monitor both eyes. “We loaned them a device and asked them to check the pressure throughout the day—at least 3 times a day—but they didn’t always do that,” Dr. Bitner said, adding that investigators ended up with very real-world data, which they examined for trends. The study yielded several important findings. “One of the key findings was that pressures do change throughout the day in children with glaucoma,” Dr. Bitner said, adding that investigators wanted to show that home monitoring could be done. In addition, they wanted to know if families could be easily trained on how to do it and if they could get reliable information. “I think that was verified with the study,” Dr. Bitner said. Investigators also wanted to know how many readings would be necessary to catch large pressure fluctuations. “Because we were only getting two to three readings a day in most families, we wanted to know how many days in a row they would have to check the pressure in order to catch the spike, which we defined as 20% over the mean,” he explained. Within 2 weeks of monitoring, more than 90% of the eyes being monitored experienced one of those spikes. Dr. Bitner views this as an important parameter for future studies. In addition, investigators considered the efficacy of different kinds of glaucoma surgery to determine what this did to patients’ pressures. After intervention, patients showed a significant decrease in the mean pressure as well as the mean daily fluctuation.
Somewhat surprising was the amount of fluctuation in IOP initially seen in some cases. “There was one patient whose pressures at home ranged anywhere from the mid 20s to the low 50s. We weren’t expecting to see that much fluctuation, but we were impressed by how well that patient responded to treatment,” Dr. Bitner said.
In Dr. Bitner’s view, home monitoring is promising from a clinical perspective. “[Physicians who] treat glaucoma have the option to consider something similar because IOP varies greatly over a 24-hour period, especially in people with glaucoma,” Dr. Bitner said. “With the advent of these rebound tonometers, you don’t need topical anesthetic so more patients can do it.” He thinks this will benefit not only pediatric glaucoma patients with parents who want to monitor their progression, but could be applied to selected adult glaucoma patients as well. The technology proved easy to use. “One of our patients was a 10-year-old and she was doing it on her own,” he said. The Icare device is a specific type of tonometer that uses rebound technology, he explained, adding that it’s a lightweight probe that bounces back to determine what the pressure is. “The patients don’t feel it. That’s why we can use it on babies without them crying, and their parents are able to do it with relative ease,” he said. Currently, the one limitation is the cost of the device itself, which is a few thousand dollars, Dr. Bitner notes. “The technology is there and it’s just a matter of finding the best way to utilize it,” he said. Dr. Bitner hopes practitioners come away from the study with the message that long-term home monitoring of IOP is possible, even in children. “In our patients, the most common kind of surgery is angle surgery, which is trabeculotomy or goniotomy, and the data show that the surgery works well in decreasing the fluctuation of IOP as well as the average pressure,” he said.
1. Bitner DP, et. al. Long-term home monitoring of intraocular pressure in pediatric glaucoma. J AAPOS. 2016 Oct 1. [Epub ahead of print]