- Design
- Prospective cohort with 24-hour ambulatory blood pressure monitoring
- Population
- 79 eyes of 42 patients with primary open-angle glaucoma
- Primary outcome
- Rate of peripapillary RNFL loss on OCT
- Effect
- Each 10 mmHg lower minimum MAP: 0.54 µm/y faster loss (P < .001)
Low systemic blood pressure has long been suspected as a risk factor for glaucoma progression. This prospective cohort, published in June, gave 24-hour ambulatory blood pressure monitoring to 42 people (79 eyes) with primary open-angle glaucoma and followed them with OCT every four months for about 3.5 years.
After adjustment for age, IOP, central corneal thickness and baseline nerve fibre thickness, every 10 mmHg lower minimum 24-hour MAP was associated with 0.54 µm a year faster nerve fibre layer loss. Eyes in the lowest quartile of average 24-hour MAP (81-90 mmHg) lost 0.68 µm a year more than those in the highest quartile, and a similar pattern held for minimum diastolic pressure.
The cohort is small and from one centre, and it shows an association, not that raising blood pressure protects the nerve.
The practical step is a question: in a patient who is progressing despite controlled IOP, ask about antihypertensive treatment, bedtime dosing and symptoms of low pressure, and discuss 24-hour monitoring with the treating physician. Do not advise stopping blood pressure treatment on this evidence.
- Ask glaucoma patients who progress despite controlled IOP about antihypertensive drugs and dosing times.
- Each 10 mmHg lower minimum 24-hour MAP was linked to faster nerve fibre loss.
- Discuss 24-hour blood pressure monitoring with the patient's physician where progression is unexplained.
- Do not stop or reduce blood pressure treatment on this evidence alone.
- Record systemic blood pressure and treatment changes in the glaucoma notes.
Why it matters
It points to a risk factor that sits outside the eye clinic and is often set by another doctor.
Don't overread it
This small observational study shows an association; it does not show that changing blood pressure treatment slows glaucoma.
The statistics, in plain English
A difference of about 0.5 µm a year is small on one scan but adds up over a decade. With 79 eyes from 42 people, the estimates are uncertain and need confirmation.
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