Big picture of glaucoma care presents with shades of gray

By Liz Meszaros

The big picture with regard to glaucoma care in the United States has changed very little over the past 20 years.

According to large prevalence surveys, only 25% to 50% of Americans with glaucoma are aware that they have the disease, and many who are aware are not under regular care, according to Kuldev Singh, MD.

Patients who are under regular care may not be compliant with prescribed therapy and, thus, there is much room for improvement in the diagnosis and treatment of this glaucomatous disease from a public health perspective.

Dr. Singh is president of the American Glaucoma Society and professor of ophthalmology and director of the glaucoma service, Stanford University, Palo Alto, CA. 

Fortunately, not all individuals who are unaware that they have the disease are destined for vision loss.

“There is great variability in the natural history of glaucomatous disease, and many may have good vision despite not seeking care for glaucoma, or even knowing that they have the disease,” explained Dr. Singh. “Treatment is unquestionably beneficial but does not eliminate risk and there are certainly patients under appropriate care who do poorly with regard to visual preservation.

“The great variability in the natural history of the disease amongst those who are given a glaucoma diagnosis perhaps trumps all other factors in determining individual outcomes. Some are destined to do more poorly than others based upon risk factors, many of which are inherited,” said Dr. Singh.

“As with any disease for which treatment is beneficial, identifying and providing adequate surveillance for all individuals at risk for glaucoma should be given high priority,” he added.

Dispelling myths

Dr. Singh pointed out that several myths and misconceptions have emerged with regard to glaucoma care, including the belief that disease progression can be predicted and that lowering IOP below a predetermined target will completely halt progression.

Another dogmatic message that is sometimes conveyed to patients is that if they take their glaucoma medications, their disease will be stable, and if they don’t take their medications, they will lose vision and perhaps go blind.

“Yet, we all know that there are patients who adhere to therapy and continue to get worse; while others, who are clearly non-compliant with medications, somehow do better than expected,” Dr. Singh said. “We should definitely encourage good compliance with therapy, but patients should not have the false sense of security that compliance with medications alone will ensure a good outcome.”

Recent research by Dr. Singh with Shan Lin, MD, at the University of California, San Francisco, which gathered data on refill rates, follow-up adherence, disease severity, and progression at San Francisco General Hospital, showed that the only predictor for compliance, with the surrogate for compliance being pharmacy-refill rates, was disease severity. Those patients with more severe disease were more likely to be getting their medications refilled.

“Age, gender, race, and even the number of medications used were not found to be predictors of refill rates,” outlined Dr. Singh. “The investigators also found in this population that subjects with poor follow-up adherence were significantly more likely to have severe glaucoma.

“While such a study only provides information on association between variables rather than proving causality, it strongly suggests that poor adherence to follow-up visits may be an important predictor of poor outcomes in glaucoma care. Interestingly, medication adherence in this study did not correlate with adherence to follow up,” he added.

“One might think that those who are not taking their medications are also the ones most likely to miss follow-up appointments, but such an association was not found in the study population,” Dr. Singh said. “There were clearly a substantial proportion of patients who were non-compliant with medications, yet came in for regular appointments; and others who refilled their medication prescriptions but did not come to their appointments. The multivariate analysis suggests that the latter group, all other things being equal, may be at greater risk than the former.”

It is possible that some patients who take their medications may have a false sense of security that they don’t need regular follow-up visits, despite the fact that medical therapy does not always work. Returning for regular follow-up visits allows the practitioner an opportunity to adjust therapy as needed and consider surgical options if the disease continues to progress on medications.

“From a practical standpoint, there may not be much of a difference between how one approaches a patient with disease progression due to noncompliance with medical therapy versus the one who takes their medications but continues to get worse,” Dr. Singh added. “Both will likely require laser and/or surgical therapy for glaucoma and this is only possible if the patient returns for regular visits. You can’t offer treatment to someone who doesn’t show up.” 

Dr. Singh also pointed out that most practitioners are well aware of the phenomenon of patients who disappear for several years may come back with severe glaucomatous vision loss that could have been prevented with timely therapy.

Success depends on surveillance

Adequate disease identification and surveillance is critical in decreasing the public health burden of glaucomatous disease, and there are many challenges that make appropriate surveillance so difficult, even in industrialized countries such as the United States.

“One reason we haven’t focused as much attention as needed on this issue may relate to a workforce shortage,” Dr. Singh said. “We probably don’t have enough ophthalmologists to find and care for every single glaucoma patient and the situation is only going to get worse with an aging population and the consequent higher prevalence of glaucomatous disease.”

Ophthalmology leaders will need to be creative and enlist the help of others in finding and providing adequate surveillance for glaucoma patients. Telemedicine may play an important role, particularly with regard to disease surveillance.

In summary, follow-up adherence is the elephant in the room and may be more important than adherence with medications when it comes to the big picture of glaucoma care in the United States.  Finding and keeping close ties of those patients at glaucoma risk is a huge challenge that should be a focus of public health policy, concluded Dr. Singh.