Innovations in Glaucoma

October 16, 2005

Adapting an idea from other medical specialties, ophthalmologists are beginning to apply the concept of global risk assessment to their glaucoma patients.

Chicago-Adapting an idea from other medical specialties, ophthalmologists are beginning to apply the concept of global risk assessment to their glaucoma patients. By using a scientific method to detect and treat underlying factors influencing the risk of developing glaucoma, the hope is that physicians can prevent more cases of the disease or intervene earlier. This and other topics that might change the management of glaucoma patients were discussed at a Sunday evening CME symposium held at the Museum of Science and Industry.

Felipe A. Medeiros, MD, University of California at San Diego, described a newly validated risk calculator that can help physicians determine which of their ocular hypertensive patients are likely to convert to glaucoma over a period of 5 years. The calculator assigns point values to a series of risk factors identified in the Ocular Hypertension Treatment Study and is modeled on similar tools used to assess the risk of cardiovascular disease. 

In a recently published study in which more than 100 ocular hypertensive patients were followed for 8 years, “there was good correspondence between what we observed and what was predicted” using the risk calculator at baseline, Dr. Medeiros said.

However, having a relatively reliable estimate of an individual’s risk of progressing to glaucoma does not answer the question of the treatment threshold for ocular hypertensive patients. One guideline Dr. Medeiros suggested it to monitor patients whose risk level is low (<5%), consider treatment for those at moderate risk (5% to 15%), and treat patients at high risk (>15%).

Kuldev Singh, MD, MPH, Stanford University School of Medicine, discussed the topic of whether therapy should go “beyond” IOP. Although much has been learned about IOP, crucial information is still unknown, he suggested. For example, the degree of IOP fluctuation over a 24-hour period has not been accurately gauged, due to the lack of a continuous measurement device, and physicians also don’t know the relative importance of mean IOP, peak IOP, and fluctuations or variability in IOP. The quality of various IOP-lowering therapies is also not as clear as might be implied through the numerous published studies on these drugs.

Dr. Singh also pointed out that factors other than IOP influence the effectiveness of therapy, including safety, tolerability, dosing schedule, and cost. And as for the idea of lowering IOP by other means, therapies such as vasoprotection, neuroprotection, and neuroregeneration are currently unproven.

“Hopefully in years to come we will have other treatment modalities, but for the moment we are stuck with IOP,” he said.

Dale K. Heuer, MD, Medical College of Wisconsin Eye Institute, also looked at alternatives to standard treatment approaches. A safe, effective, and predictable surgical approach would be desirable given the high rate of nonadherence to medical therapy, but nonpenetrating glaucoma surgery (NPGS) cannot yet meet that standard, Dr. Heuer said.

The idea of NPGS has been around for more than 30 years, and progress has been made. However, “We’re still measuring short of the holy grail,” Dr. Heuer said.

Given their relatively short track record, nonpenetrating procedures should probably be reserved for patients with mild-to-moderate glaucomatous damage in whom IOP in the low teens is not desired, he said.

Additional presenters were David S. Friedman, MD, MPH, Wilmer Eye Institute, and Richard K. Parrish II, MD, Bascom Palmer Eye Institute, Miami. Dr. Friedman discussed ways to provide optimal care to all despite widely known issues in screening and compliance. A few of his suggestions for improvement included seeing patients more frequently when they start receiving care to try to instill the message that therapy can prevent blindness and compliance is critical, and identifying potential at-risk patients through links with existing patients.

The prevalence of open-angle glaucoma is 2%, but the risk for a sibling is 10 times higher. Therefore, making an effort to screen the siblings of your patients is an effective way to reach a segment of the at-risk population, he explained.

Dr. Parrish outlined key components of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 and their impact on glaucoma management. The act, which takes effect on January 1, 2006, expands glaucoma screening beyond high-risk groups to coverage for all Medicare beneficiaries though a “welcome to Medicare” physical. Beneficiaries in high-risk categories can receive an annual glaucoma preventive screening.

Dr. Parrish predicted that these regulations would results in more patients seeking glaucoma screening, which in turn would lead to more diagnoses of ocular hypertension or glaucoma.

The new prescription drug coverage, a new “Part D” benefit, will also have an effect. It might increase adherence to therapy, and subsequently improve outcomes, since the high cost of medication is an often-cited reason for poor compliance, Dr. Parrish said.

The plan is not a free drug benefit and its impact depends on the cost of each beneficiary’s annual prescription spending.

The program was jointly sponsored by Ophthalmology Times and the New York Eye and Ear Infirmary and supported by an unrestricted educational grant from Pfizer Ophthalmics.