Study finds majority of patients instill glaucoma drops improperly

Issue: September 10, 2012

An important factor contributing to unintentional noncompliance with glaucoma eye drop therapy is simply that patients do not instill eye drops correctly, according to a study.

Study participants were prone to a number of issues, including squeezing out too much solution from a bottle during instillation, eye drops falling on the eyelids or cheek, and touching the tip of the bottle to the globe or periocular tissue.

The cross-sectional observational study, published in the Journal of Glaucoma, found that less than 10% of the 70 study participants instilled eye drops correctly. Success was defined as squeezing out one drop and placing it into the conjunctival sac without any contact with the bottle tip.

Improper drop instillation is a major issue for noncompliance to medical therapy,” study co-author Tanuj Dada, MD, said. “Not only does noncompliance increase the cost of therapy, but it also leads to increased ocular and systemic side effects and a decrease in quality of life.

Tanuj Dada

Study design, results

All study patients (mean age: 51.1 years) had either primary open-angle or primary angle-closure glaucoma and had been self-administering topical anti-glaucoma medications for at least 6 months.

Patients were instructed to instill a single drop of a tear substitute (0.5% sodium carboxymethyl cellulose) in one eye. A single observer recorded all instillations from a comfortable viewing distance and viewing angle.

The mean time to instill the drop was 14.8 seconds, and the mean number of drops squeezed from the bottle was 1.8 per instillation (range: 1 to 8 drops). Only 50% of patients squeezed out a single drop.

In 31.4% of patients, the drops fell either on the eyelids or cheek, and 11.4% misdirected two or more eye drops. Only 68.6% of patients instilled the tear substitute in the eye. The mean number of drops that reached the conjunctival sac was 1.3. Furthermore, 75.7% of patients touched the tip of the bottle to the globe or periocular tissue.

In sum, only 8.5% of patients succeeded as instructed, instilling a single eye drop into the conjunctival sac without contact with the bottle tip.

Patient education

The study was prompted in part by patients reporting that they were consuming eye drop bottles in a much shorter time than expected, Dada said.

Eye drop instillation is as routine as consuming tablets or capsules, yet we found nearly a 90% noncompliance rate for technique,” he said.

Only 18.5% of patients in the study recalled receiving instruction from their clinician on how to instill the eye drops.

Dada recommended that all patients beginning medical therapy for glaucoma, as well as the relatives who live with them, should receive a demonstration of how to instill eye drops before a prescription is provided. During follow-up, the patients should provide a return demonstration, and family members should instill the drops for older patients with tremor or musculoskeletal disorders, Dada suggested.

Because many patients are unable to instill eye drops properly, despite having the necessary knowledge, laser or surgical therapy may be alternatives, rather than continuing them on lifelong therapy, he said.

Dada et al are conducting a follow-up study to assess the impact of teaching and demonstrating the correct technique of eye drop instillation for patients.

We expect to see an improvement in their performance,” he said. – by Bob Kronemyer

Reference:

Gupta R, Patil B, Shah BM, Bali SJ, Mishra SK, Dada T. Evaluating eye drop instillation technique in glaucoma patients. J Glaucoma. 2012;21(3):189-192.

For more information:

Tanuj Dada, MD, can be reached at Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 110029, India; email: tanujdada@gmail.com.
Disclosure: Dada has no relevant financial disclosures.