EYE DROP INSTILLATION

Consistently getting one – and only one – eye drop onto the eye remains a significant challenge in treating glaucoma. Greater awareness of the obstacles patients face in effectively instilling eye drops, and better patient education, may help improve medication adherence and effectiveness, Alan L Robin MD, Baltimore, US, told Glaucoma Day at the 2014 American Academy of Ophthalmology annual meeting in Chicago.

The problem is underappreciated, even among patients themselves, Dr Robin said. In a study he conducted, 92 per cent of patients said they never missed their eyes with eye drops, but observations showed 35 per cent missed at least sometimes and more than a quarter missed regularly.

“The first thing is that you have to ask the patient if they are having problems. The second is perhaps you shouldn’t believe them, especially if they say they are having none. It’s not all that easy,” Dr Robin said. Squeezing out no drops or multiple drops, not washing hands before instilling drops, and contaminating the bottle tip are also common problems.

Dr Robin’s research also suggests that ophthalmologists often do not offer much instruction on using eye drops, let alone assess whether patients are actually able to successfully instill them. To raise awareness, he outlined several obstacles patients face to successful eye drop use.

Bottle design – Bottles can be difficult to open initially, prompting patients to use their teeth or a knife, risking contamination or even injury. Some bottle tips must be punctured by reversing the cap, but patients may find this difficult and simply cut off the tip, making drop control impossible, Dr Robin noted. Variation in the colour and size of bottles also has been shown to affect patient compliance. “We prescribe without thinking about the bottle,” he said.

Hand strength – The pressure required to squeeze out drops varies widely by bottle type, and often exceeds what many patients can comfortably apply (Drew & Wolffsohn. ARVO 2014). “In the era of generics there is tremendous variability; try it yourself and you will see some are harder and some are easier. It can make a big difference in adherence,” Dr Robin said.

Drop size – The size of drop extracted with each squeeze can vary significantly between branded and generic drugs. As a result, patients who have not previously run out of drops may run out when substitutions are made, Dr Robin said.

Contamination – Some patients apply drops by putting the bottle directly on the eye surface, which can lead to infection. And while there is no one correct technique, instruction can help, Dr Robin said. He suggested an online video by Robert Ritch MD (https://www.youtube.com/watch?v=FhkRAaIbIuE).

However, many ophthalmologists do little or no eye drop patient education. In a study involving 275 patients seen by 17 doctors at an initial or three-month visit only 30.9 per cent received verbal instructions, and only 9.8 per cent a technique demonstration. Written instructions were given only once at the patient’s request. “We really have to do a better job,” Dr Robin said.

Alan L Robin: arobin@glaucomaexpert.com