Novel imaging device helps physicians understand patient eye drop regimen

Take-Home Message: A novel imaging device is being tested for monitoring patients’ eye drop instillation techniques at home and in clinic.

By Lynda Charters; Reviewed by

Fort Myers, FL-For patients with glaucoma, “it is well known that compliance with instillation of eye drops is problematic, especially among patients who are visually impaired,” said Alexander M. Eaton, MD.

For that reason, Dr. Eaton and colleagues are developing and evaluating use of a novel imaging device that confirms the misuse of eye drop regimens of patients in both clinic and at-home settings. In addition, the system’s video imaging may serve as a teaching device for patients in the correct instillation of eye drops, said Dr. Eaton, who is in private practice in Fort Myers and Naples, FL.

“We believe that the system offers the opportunity to understand drop delivery better in patients so as to enable physicians to better manage their disease,” he said.

Features of the system include a video camera, light source, and recording device that can be clipped onto eye drop bottles.

“The device is simple to use, provides date- and time-stamped information, and can be used by patients at home to evaluate the efficiency of their eye drop use,” Dr. Eaton said.

The new technology differs from other available devices and standard eye drop aids in that these devices/aids have not determine whether drops actually landed in the desired location or provided video images by which patients could be re-trained in instillation, Dr. Eaton explained.

Testing in pilot study

To test the ease of use and effectiveness of the device, patients from a general ophthalmology practice and from a retina practice for whom eye drops had been prescribed were included in a pilot study. Some patients used the device in a clinic setting and others used it at home. In the former group of 17 men and eight women, the average age was 78 years and in the latter group of 11 men and six women, 70 years. The majority of patients had glaucoma.

In the clinic phase, 37 patients were enrolled and data from 25 patients were analyzed. In the home phase, 38 patients were enrolled and data from 17 were analyzed; among the 21 who were excluded, 10 filled out the data log incorrectly and three did not attempt drop instillation.

“The data only reflect patients who attempted drop instillation,” he said.

In many cases, the video became a learning experience for physicians in re-training patients. One patient did not remove the bottle cap, whereas another patient had such a poor instillation technique-with head not tilted back and eyes closed-that it became clear why the drops were not controlling IOP. In contrast, some patients were observed using too many drops.

Many patients exhibited good technique when using the device, in that they had a steady hand, head tilted back, dropper in a vertical position, one drop was dispensed, and the eye was mostly open. Others had a reasonable technique, but tended to contaminate the bottle tip by touching the eye with each application.

In-clinic testing

In this phase of the study, investigators evaluated the number of drops dispensed and the number that reached the eye. Patients were asked to instill 10 drops each to the left and right eyes. The investigators compared the data reported by the patients with the reading center assessment of the video and the prescribed regimen.

Thought patients believed they had delivered the correct number of drops, they actually instilled an average of 25 drops instead of the instructed 20 drops.

“Importantly, the patients were unaware of the amount of drug that they were wasting,” he Dr. Eaton said.

Significant differences (p = 0.003 and p = 0.005, respectively) were observed between the patient and the reading center results and the reading center and the prescribed regimen, he noted.

When investigators evaluated the number of drops delivered into the eye, there was greater variability. Patients realized they delivered less than the 20 drops requested. The reading center data showed the actual number of drops delivered was even less than what patients thought they had delivered. The investigators found a significant (p < 0.001) difference between the reading center results and the prescribed regimen.

Home testing

Patients were instructed to use the device for 1 week at home. As with the in-clinic phase, patient data were compared with the reading center data and the prescribed regimen. Investigators found greater variability in the number of drops the patients used.

“The average number of drops to be dispensed was about 31, and patients realized they instilled more,” Dr. Eaton said. “However, the reading center analysis determined they put in even more.”

The difference between the reading center and the prescribed regimen was significant (P < 0.001).

Regarding the number of drops actually delivered to the eye, patients were about 10% off from what they were supposed to instill, he explained.

Importantly, less than 5% of patients instilled the drops properly by not touching their eye with the bottle tip and instilling only one drop. In the clinic, 60% of patients instilled more than one drop and in the home study about 30%. About 30% and 20%, respectively, touched the bottle tip to their eyes.

Based on these data, investigators found that 28% and 35%, respectively, of patients ran out of drops before the end of the month.

“Our initial data are consistent with previous reports in the literature and demonstrated that many patients are not receiving the prescribed regimen,” Dr. Eaton said. “We are currently using the system to evaluate the effect of the bottle shape and design on drop delivery and [whether] patients can be re-trained on proper dose delivery based on their results.”

Alexander M. Eaton, MD

E: ame@retinahealthcenter.com

This article was adapted from Dr. Eaton’s presentation at the 2014 meeting of the American Academy of Ophthalmology. Dr. Eaton has a financial interest in this technology. The EDIT system is an investigational device and is being used with IRB approval.