Due to the nature of the medications optometrists use and the typical age of glaucoma patients, these patients have the potential to become dry eye patients. Given that the data regarding the incidence of dry eye in the overall population is estimated to be 25 percent,1 it is not surprising that our glaucoma patients show rates of ocular surface dysfunction that may surpass the general population.
Age is a factor because most patients with glaucoma are age 60 or older and have lower baseline tear quality. Commonly, elderly patients can have meibomian gland dysfunction (MGD), which results in evaporative loss and dry eye discomfort.
Add a glaucoma drug to this environment, and the insufficient buffer of tears will leave the ocular surface stinging, red, and potentially damaged.
Related: How ODs can do better with dry eye
Even if patients are younger and exhibit no pre-existing ocular surface problems, in my experience long-term glaucoma therapy is likely to cause dry eye symptoms eventually, due in large part due to the cumulative toxicity of BAK preservative and the primary molecule on the ocular surface. This is especially common with chronic prostaglandin analog use. Even low levels of BAK can cause patients to develop irritation, foreign body sensation, and other common symptoms of dry eye.
I attempt to continually balance the imperative to reduce intraocular pressure (IOP) in glaucoma patients with the need to keep the ocular surface healthy and comfortable in the presence of chronic disease therapy. Quality of life is important.
Equally pressing is the role of comfort in compliance with glaucoma medication. Patients will not put stinging eyedrops into red, irritated eyes, so dry eye disease becomes an impediment to controlling glaucoma and its potential for damage and vision loss. Before and during glaucoma treatment, proactive, accurate diagnosis of dry eye disease is essential.
In my practice, when we identify symptomatic patients on the check-in questionnaire, we perform a sidebar series of tests directed at identifying ocular surface concerns. Our selection of point-of-care diagnostic systems includes only technologies that have been proven by trials published in the peer-reviewed literature. Tests tell us different things about the ocular surface and are used in a complementary way.
Two key tests, tear osmolarity and MMP-9, are used to identify ocular surface dysfunction with baseline results and trend lines based on multiple measurements over time.