Glaucoma risk factors other than IOP may not be treatable

Leopold Schmetterer

PARIS — There are several recognized risk factors for glaucoma besides IOP, but there is little evidence that any of them can be treated, according to one specialist.

"There are factors like old age which cannot, of course, be modified. But even a potentially modifiable risk factor such as low systolic perfusion pressure is not so easily managed because we should be able to target not only pressure levels, but also fluctuation. Calcium channel blockers have shown some efficacy, but there is no evidence that they can reduce visual field progression," Leopold Schmetterer, MD, said at the World Glaucoma Congress here.

Research on how to address risk factors other than IOP is ongoing. Phenotyping, according to Dr. Schmetterer, would be essential to establish an individual's predisposition to certain risk factors.

"There are reasons to believe that different phenotypes have different risk factors," he said.

Some small-scale studies indicate that there might be differences in visual field preservation with well-known glaucoma drugs, such as timolol, brimonidine and dorzolamide, with identical effects on IOP reduction.

"A possible explanation is that what some of these drugs target is not just IOP, but also other risk factors. Dorzolamide might have an effect on blood flow, and brimonidine might have an additional neuroprotective function. We need further studies investigating these aspects," Dr. Schmetterer said.

Disclosures: Dr. Schmetterer has no relevant financial disclosures.