AAO 2026: Blood pressure and optic nerve perfusion: a complex relationship

There is still a lot to be learned about the complicated relationship between blood pressure (BP) and glaucoma, and it has taken a while to amass the body of knowledge available today. Some of the unknowns have begun to slowly reveal themselves, but there remains a lot of territory to cover.

Anthony Khawaja, FRCOphth, PhD, spoke about the connection between systemic BP, intraocular pressure (IOP), and glaucoma and the suggestion that calcium channel blockers, one of the go-to treatments for high BP, may cause glaucoma during Glaucoma Subspecialty Day at the 2026 American Academy of Ophthalmology annual meeting in New Orleans. He is Professor and Consultant Ophthalmic Surgeon at UCL and Moorfields Eye Hospital, London, specializing in glaucoma and cataract care.

The path through the ocular maze

Khawaja commented that “optic nerve head perfusion may well be important in glaucoma, but the perfusion cannot be measured. The surrogates for the perfusion , ie, the BP minus the intraocular pressure (IOP), have been shown to be flawed and should not be used clinically or in research.”

The relationship between BP and glaucoma seems to be complex and a bit murky. He explained that what is clear currently is that the BP is strongly correlated with the IOP, and this correlation appears to be causal, that is, higher BP causes higher IOP. Within-person-expected differences are difficult to quantify.

However, the BP-glaucoma connection is not that clear and the literature shows no consistent evidence of a relationship. He explained that some studies have suggested that patients with lower BP are more likely to have progressive glaucoma. However, the question remains two-fold: does the BP mediate the progressiveness of the disease or is the lower BP just another outcome from a more fundamental cause that is driving the progression in glaucoma.

The latter is suggested by Mendelian randomization experiments, ie, that lower BP does not cause glaucoma. This raises another question the answer to which might be hidden in plain sight: could common treatments for high BP cause glaucoma?

“There is growing evidence that calcium channel blockers may increase the risk of glaucoma, though it may be a slower form,” Khawaja said. In multiple populations, he explained, it has been shown that people using calcium channel blockers have a higher prevalence of glaucoma and also thinner inner retinas; there was not a similar signal for other common antihypertensive drugs. However, in a patient cohort, calcium channel blocker use was associated with slower progression, suggesting that if they do cause glaucoma, it may be a less aggressive form.