Blood pressure and eyes
David Kinshuck 2014
- blood pressure=BP
- hypertension=medical term for high blood pressure
- ARMD = age related macular degeneration
- systolic blood pressure (the high figure, eg 160/85)
The retina, arteries and veins
a side 'cut through'
diagram of an eye
The retina is the 'film' at the back of the eye, like the film of a camera. Light enters the front of the eye and passes onto the retina, which turns the light into electrical signals. These are sent on to the brain, allowing us to see.
Blood flows into the retina in small arteries, shown in red in these diagrams. The blood then passes flows out in tiny veins (blue in the diagrams here).
The fovea is the centre of the retina. All the light is focused at the fovea. As a result, damage to the fovea will reduce the sight more than damage elsewhere in the retina. In these diagrams the fovea is marked with a yellow spot in the centre of the retina.
view of the retina from the front: what the doctor sees looking into
The retinal veins are blue, and the arteries red. The yellow spot is the fovea, the centre of the retina.
Some notes from Congress 2014
- hypertension increases eye disease by 2.5 times
- increases glaucoma by 2.3 times
- ARMD ...each 1mmHg increases risk by 1.5%,
- so a systolic blood pressure of 160 (the high figure, eg 160/85), is 30mmHg too high (prefer BP <130) and this results in 45% (30 x 1.5) increase in problems.
- when treating blood pressure, we need to note end organ damage, such as as an enlarged heart (LVH), atrial fibrillation, or retinal artery or vein occlusion.
- treatment is described here as for diabetes and blood pressure; target BP for none-diabetic is about 130-135 systolic, sometimes accepting pressures a little higher;
- the blood pressure may cause or contribute to