The generic term retinopathy describes a range of pathological, noninflammatory, and proliferative changes in the retina. Hypertensive retinopathy (retinopathia hypertensiva) is damage to the retinal vessels caused by chronic high blood pressure, resulting in retinal impairment. This can impair visual acuity and possibly lead to blindness.
Causes of hypertensive retinopathy
For years, most hypertensive patients remain symptom-free, meaning they are subjectively well. Health problems arise from the consequential damage of the constantly elevated blood pressure, which often occurs only after several years. The vessels of the cardiovascular system are particularly affected. Calcification of the arteries leads to an increasing thickening of the inner walls of the vessels, which reduces the diameter of the vessels and thus the blood flow in the vessels. As a result, blood pressure in the vessels increases. In the heart, for example, this can lead to coronary heart disease and even a heart attack. In addition, the vessels become more fragile. In addition, the small blood vessels in the entire organism, such as the so-called capillaries of the retina, can also be affected.
Effect of high blood pressure on the retina
The sensory cells in the retina (the light-sensitive rods and the color-detecting cones) detect the different light stimuli that hit the eye from the outside world and transmit them to the brain, where they are finally processed into the image we perceive. For an undisturbed function of the retina, its supply with nutrients and oxygen via its blood vessels is very important. Chronic high blood pressure and the resulting arteriosclerosis of the vessels can lead to occlusion and/or increased permeability of these blood vessels supplying the retina. As a result, disturbances in the supply of nutrients and oxygen to the retina occur, which can lead to visual impairment and even blindness.
Hypertonic retinopathy: symptoms and progression.
The narrowing and/or perforation of vessels causes streak-like retinal hemorrhages and so-called absorbent cotton foci (small bright cotton wool-like spots caused by occlusions of small retinal vessels), resulting in worsening vision. When larger areas of blood vessels in the retina are occluded by the disease, the retina attempts to compensate for its resulting lack of oxygen supply by forming new vessels. However, these newly formed, intact vessels are extremely fragile and some of them grow into the vitreous body located in front of the retina, where they easily start to bleed. If such a hemorrhage is located in front of the site of sharpest vision (macula), the patient may suffer acute blindness. At the same time, the body’s own attempt to remove the blood from the vitreous again leads to considerable scarring, which is accompanied by shrinkage of the retina and can eventually – due to the resulting pulling effect on the retina – lead to retinal tearing and thus also to blindness.
Early diagnosis is critical
To the hypertensive patient, the changes that destroy his or her vision remain hidden for a long time. Therefore, to ensure that retinal damage can be treated as early as possible, it is imperative that patients with elevated blood pressure have their eyes checked regularly. By examining the back of the eye, the doctor can detect pathological changes in the eye without a doubt, diagnose retinopathy and treat it accordingly before the patient even notices the possible visual disturbances.
Ophthalmoscopy and dye examination
For example, ophthalmoscopy can detect Cotton wool foci, which are caused by the occlusion of small retinal vessels, by their characteristic spot-like appearance. In the case of retinopathy, a dye test (fluorescein angiography) can determine whether laser treatment of the retina is necessary. In this test, a dye is injected into the arm and then images are taken of the eye or the vessels supplying it. This can be used to determine whether and where fluid is leaking through the blood vessels of the retina.These can be sealed by targeting them with laser light, preventing further leakage of fluid from these porous vessels.
Complications of hypertensive retinopathy
If retinopathy is not recognized at its onset and treated in a timely manner, affected individuals are at risk of blindness. The development of retinopathy is particularly unfavorable if the affected person simultaneously suffers from diabetes mellitus, which can also be the trigger for retinopathy (diabetic retinopathy). In this case, another important therapeutic measure is drug regulation of blood glucose.
Drug treatment of hypertensive retinopathy.
Visual deterioration due to hypertension-related retinopathy can often be at least partially reversed by lowering blood pressure with medication. However, this is only if hypertension is the sole cause of the abnormal retinal change.
Laser therapy and icing
If lowering blood pressure with medication does not lead to success, several alternative treatment methods are available: Laser therapy – also known as laser coagulation or photo-coagulation – involves the targeted “bombardment” of abnormal blood vessel growths on the damaged retina with light beams, thereby suppressing the formation of further vascular changes. Laser treatments are virtually painless and must be repeated depending on the stage of the disease. In cryocoagulation (icing), areas of the retina are cooled to minus 70 degrees. This cold treatment is similar in effect to laser treatment. It is used when laser treatment is no longer possible.
Surgery for hypertensive retinopathy
Laser treatment is not sufficient in cases of far-advanced disease with extensive vascular growths and severe bleeding into the interior of the eye. A new surgical procedure is now available for patients affected by this condition: vitrectomy. In this microsurgical procedure, which can usually be performed as an inpatient under local anesthesia, further bleeding can be avoided by removing the blood-filled vitreous and replacing it with a clear solution. If the retina has detached, this damage can also be repaired during vitrectomy. This procedure often restores useful visual acuity.
Preventive measures
Early detection of hypertensive retinopathy is the best protection against vision loss. The risk of vision loss from retinopathy can be reduced by regular ophthalmologic examinations of the fundus. Blood pressure should be checked regularly and adjusted with medication if necessary. In addition, care should be taken to avoid movements that lead to an increase in blood pressure in the head, such as lifting heavy objects or working in a stooped position for long periods of time. Furthermore, patients with chronic high blood pressure should avoid nicotine and excessive alcohol consumption. Diabetics, who are particularly at risk of developing retinopathy, should also be careful to accurately adjust their blood glucose levels and strictly adhere to their dietary regimens.
