High blood pressure increases glaucoma risk
New research shows that high blood pressure can make the eye more susceptible to damage from elevated intraocular pressure (IOP) in the long-term, increasing the risk of glaucoma.
While previous research had pointed to a potential protective effect of high blood pressure, the latest findings from researchers at the University of Melbourne show otherwise.
The team looked at how susceptible the eye was to damage from elevated IOP in three groups of rats; with temporarily raised blood pressure (acute hypertension), elevated blood pressure for four weeks (simulating chronic hypertension) and normal blood pressure, respectively. The effects of elevated IOP were then monitored in each group.
The trials showed that hypertension provided an initial level of protection against disruption to blood flow and damage to the retina in those with acute hypertension, but these protective effects subsided in a matter of weeks.
"When we raised blood pressure... for four weeks, we didn't get the same protection against eye pressure elevation as in the [one hour] case," said Dr Bang V. Bui, of the ocular physiology lab at Melbourne.
Explaining the findings, Dr Bui said: "What this means is that having high blood pressure for a longer time has compromised the eye's capacity to cope with high eye pressure. It seems that hypertension might damage the blood vessels in the eye so that they can't compensate for changes in blood flow when eye pressure increases."
Data gathered from large populations of patients with glaucoma revealed that hypertension may provide a protective effect against glaucoma, but it is a risk factor in older patients.
The researchers suggest that chronic high blood pressure should be identified as a risk factor for patients and that further research could help doctors to better treat patients with hypertension and glaucoma.
The findings are published in the online journal Investigative Ophthalmology and Vision Science.
(Taken from Optometry Today www.optometry.co.uk)