Most visually-impaired glaucoma patients administer eye drops incorrectly

The authors used video analysis to evaluate the ability of visually-disabled glaucoma patients to successfully administer a single drop onto their eye. This is believed to be the first study to do this. Only 71 percent of subjects were able to get a drop onto the eye, with just 39 percent doing so without touching the ocular surface. The authors conclude that the study's results highlight the need to develop better instructional methods, devices and techniques to improve the delivery of IOP-lowering medications and prevent problems, such as wasting drops and potential infection.

Subjects in this prospective, observational study were 204 glaucoma patients with visual acuity of 20/60 or worse or moderate or severe visual field damage in at least one eye. Ninety-four percent had used drops for more than six months. Subjects completed a survey about eye drop use and were video-recorded instilling one drop into their worst-seeing eye in their usual fashion using a 5-ml bottle.

Twenty-four percent of the 142 subjects who denied touching the bottle to the ocular surface were observed touching the bottle to the eye. Those who were able to instill a drop without touching the ocular surface used a mean of 1.4 ± 1.0 drops using 1.2 ± 0.6 attempts. The only factor that the authors found predicted unsuccessful eye drop instillation was age of 70 years and older.

The authors say the results suggest that glaucoma patients with visual impairment may perform more poorly at eye drop installation. They say that patients with visual impairment due to glaucoma are the most in need of perfect adherence yet may progress due to factors that seem out of their control, such as poor instillation technique. They conclude that the ability to self-administer eye drops and cost considerations of wasted drops must be thought out before institution of glaucoma therapy.

If clinicians notice glaucoma progression, they should investigate basic issues. This includes watching patients administer their drops and offering better instruction. We may even consider asking a patient's family member or friend to help with drop instillation.