Hypertensive retinopathy develops in patients who had high blood pressure for a long time. Chronic spasm of the smaller arteries, called arterioles cause this condition.
This leads to accelerated hardening of the arteries (arteriosclerosis), which in turn leads to leakage of some diseased arterial vessels (seen as flame-shaped hemorrhages by fundoscopy) and to a lack of blood supply in other areas of the retina (ischemic changes and infarcts).
With leakage of exudate (containing blood proteins and lipids) swelling and scarring occurs in the area of sharpest vision (fovea) with a resulting loss of vision. There are 4 categories of severity that have been identified. This has significance as untreated there would be an enormous difference of survival as detailed in this link. (thanks to www.eyeweb.org for the link).
Signs, Symptoms and Diagnostic Tests
Painless and gradual loss of vision in both eyes is what eventually occurs when blood pressure is undetected and not controlled. The physician who looks through the ophthalmoscope or uses the slit lamp, depending on the grade of severity of hypertensive retinopathy, would see the kind of images depicted here (from A to D increasing severity of hypertensive retinal changes).
These images have over the years received strangely sounding names (thanks to www.island-retina.com for this link) like “cotton wool spots” (looks like that, due to mini-infarcts of the retina) and “macular star” (this is a ring of exudate from the optic disc to the fovea or macula, the area normally of sharpest vision). Such changes severely affect the vision of the person who has this finding. The most dreaded of all hypertensive retinopathy cases is grade IV retinopathy where the optic disc is included in the edematous process leading to “papilledema“. The reason this is so dangerous is that with this condition the central artery and vein are both compressed effectively shutting down the circulation to the retina. This is a medical emergency that needs to be treated in an Intensive Care Unit setting.
The treatment is directed at controlling the blood pressure. In the case of “malignant hypertension”, which corresponds with papilledema and grade IV retinopathy, intravenous titration of the blood pressure in an Intensive Care Unit setting might have to be done in an attempt to rescue the patient’s vision. Otherwise the patient will be permanently blind. All other forms of hypertensive retinopathy are treated in the office setting, but close blood pressure control and self blood pressure monitoring at home are an important part of any therapy. Longterm follow-up eye examinations and longterm blood pressure monitoring are important.
2. Eye conditions: http://www.stlukeseye.com/Conditions/
3. Ferri: Ferri’s Clinical Advisor: Instant Diagnosis and Treatment, 2004 ed., Copyright © 2004 Mosby, Inc.
4. Rakel: Conn’s Current Therapy 2004, 56th ed., Copyright © 2004 Elsevier