Reliable home monitoring of IOP now possible

According to Dr Sanjay Asrani (Duke University Eye Center, Durham, North Carolina, USA), the ability of patients monitoring their own intraocular pressure (IOP) at home in between visits to their ophthalmologist will enable a better diagnosis and disease management. "Through patient selfmonitoring we will be able to get many more IOP measurements allowing us to diagnose if the patient has glaucoma or not, as well as the type of glaucoma they have, and it will allow us to monitor progression," he said.

Measuring IOP without anaesthetic

"I started believing it when I saw it being used in the laboratory in animal eyes without a reaction from the animals during the measurement. Once the FDA approved instrument was available, I tried it on myself at home and found that I could measure my own pressure," he said. "I then asked my wife to measure her eye pressure, and though she is not in the eye field, she was able to get her IOP without much training. This led me to believe that the technology had great potential for home monitoring of IOP."

However, it was necessary to be sure that the measurements achieved with by the patients themselves would be reliable so Dr Asrani and colleagues planned and conducted a study to evaluate the potential for home use of the device.¹

Comparative study

To examine the reliability and repeatability of the IOP measurements made by patients at home, Dr Asrani and colleagues made a comparative assessment of measurements taken by patients and trained technicians with the ICare tonometer. Additionally, they compared all the measurements to Goldmann applanation tonometry measurements that were taken by a trained technician.

"We wanted to ensure that the ICare measurements would be done before an anaesthetic was instilled in the eye and thus we planned the study in which the Goldmann measurement was the last in the sequence of measurements," added Dr Asrani.

The study group comprised 100 glaucoma patients. "We wanted to take a good variety of patients from the clinic (those who were used to contact lenses or not and those used to instilling eye drops in their own eyes or not) to give us an idea of the broader applicability of the use of this device because patient who use contact lenses or eye drops are more comfortable getting close to their eyes with their fingers," he said.

To ensure the study was fair two different trained technicians were employed to perform the ICare and then Goldmann applanation tonometry measurements. After the first measurements were taken using the ICare device and noted, the technician trained the patients to take their own IOP measurements. Then the second technician, who was masked to the previous readings, performed the Goldmann applanation tonometry readings. "This reduced the chances of bias in the measurements," said Dr Asrani.