Treat vascular risk factors in glaucoma

San Francisco-Physicians who treat glaucoma have a problem. They see glaucoma one way and treat it another.

“Glaucoma is multifactorial, but in our treatment and thinking we are unifactorial - IOP,” said Louis B. Cantor, MD, professor and chairman of ophthalmology and director of glaucoma at the Eugene and Marilyn Glick Eye Institute at Indiana University, Indianapolis.
    
Clearly, other risk factors are at work, said Dr. Cantor during the Shaffer-Hetherington-Hoskins Lecture during the Glaucoma 360 CME Symposium on Saturday. Age and gender increase risk for diabetes, as do family history and race. So, probably, do hypertension, diabetes, and cardiovascular disease. Behavioral factors, including exercise, smoking, body mass index, alcohol, and caffeine, may also influence the risk of glaucoma.
    
But separating risk factors from causal factors is difficult. And changing risk factors can be difficult.
    
“A risk factor is only important if you can modify it,” Dr. Cantor said. “You can exercise, but you can’t do anything about age, ethnicity, or gender.”
    
Beyond admonitions to exercise, that leaves clinicians with just one modifiable risk factor, diastolic perfusion pressure (DPP), the diastolic blood pressure minus the IOP. Anything over 50 is normal but multiple studies suggest that lower DPP is associated with increased risk for progression in glaucoma.
    
Dr. Cantor advised clinicians to add two measures to the standard glaucoma visit, blood pressure and a calculated DPP. A simple blood pressure reading may uncover unrecognized hypertension as well as over-treated hypertension.

If patients are taking anti-hypertensive medication, he adds a third measure, asking when they take their blood pressure medication. Many patients take blood pressure medications at night, which can lead to nocturnal hypotension. Nocturnal hypotension is a recognized risk factor for glaucoma and drops night-time DPP below 50. Simply moving anti-hypertensive medications to daytime use may reduce the glaucoma risk by altering nocturnal hypotension patterns.
    
“This is not a complicated thing to do, it doesn’t require any sophisticated technology,” he pointed out. “It could prompt a change in your own treatment recommendations and it could spark a conversation with both the patient and the patient’s hypertension manager. We can go beyond IOP by ensuring that hypertension is not over-treated and avoiding nocturnal hypotension.”

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