OVERVIEW
The fundus is the only part of the body where blood vessels and their related changes can be seen under direct vision, and to a certain extent reflects the condition of other important organs in the body. In the early stage of hypertension, the fundus is often normal and can be maintained for a long period of time. When the blood pressure continues to rise, it can cause systemic atherosclerosis of the small arteries, which occurs in the retinal lesions, called hypertensive retinopathy. About 70% of patients with hypertension can be complicated by hypertensive retinopathy. The older the patient, the longer the duration of hypertension, and the higher the incidence.
Causes
1. Changes in retinal arteries
(1) Alteration of arterial diameter: In the early stage of hypertension, local autoregulation mechanism causes retinal vasoconstriction and vascular tension increases. Continuous elevation of blood pressure causes spasm of retinal arteries, which is manifested as limited or generalized narrowing of arterial diameters. In addition, hypertension leads to the closure of local microvascular beds, causing microinfarcts with desmoplastic cotton-like spots and superficial hemorrhages.
(2) Changes in the arterial wall: If the blood pressure remains persistently elevated, long-term spasm of the retinal arteries undergoes sclerosis, which is manifested by a decrease in the transparency of the wall and an increase in the light reflection of the wall.
2. Changes of retinal veins
(1) Venous filling and tortuosity: due to the narrowing and thinning of the retinal arterial vessels, while there is no obvious change in the diameter of the venous vessels, there is a large difference in blood pressure between the two. After the blood flow passes through the capillaries, the flow rate decreases abruptly, and the venous blood return is stagnant, resulting in venous filling and tortuous walking.
(2) Retinal vein obstruction: central vein or retinal branch vein obstruction is a common manifestation of hypertension.
3. Changes at the intersection of arteries and veins
Important basis for determining the degree of retinal arteriosclerosis.
Symptoms
Generally there are no obvious symptoms, but in serious cases, there may be headache, blurred vision, small or distorted vision. In the early stage, vision is not affected, and in the late stage, vision decreases to different degrees.
Examination
1. Fundus examination
(1) Malignant hypertensive retinopathy: the optic papilla and its surrounding retina are obviously edematous with blurred edges. The small arteries are very thin, straightened and partly white, and the veins are curved and dilated. The whole retina is pale, turbid, edematous, flame-like and with large hemorrhages.
(2) Chronic hypertensive retinopathy: retinal arteries change from initial spasm to sclerosis, stenosis, enhanced light reflection of the wall, copper or silver wire, cross-pressure of arterioles and venules, followed by dilatation of distal veins and capillaries, retinal edema, hemorrhage and exudation.
2. Fundus fluorescence imaging examination
It can be seen that the optic disk capillaries are dilated and tortuous, and microangioma formation, with fluorescein leakage in the late stage, and there is a large amount of fluorescein leakage from the retinal capillaries, which is equivalent to the occlusion of the capillaries in the area of the cotton wool spot and the formation of a small perfusion-free zone, and the surrounding capillaries are dilated, with the formation of microangiomas and fluorescein leakage, which is equivalent to the choroidal capillaries in the Elschnig’s spot, which are hypoperfused or non-perfused, with the formation of a small perfused zone. In the advanced stage, there is fluorescein leakage, with thin and narrow arteries and filling and tortuous veins.
Diagnosis
The diagnosis is easy to make based on the patient’s history of hypertension, elevated blood pressure and fundus signs.
Treatment
The first step is to lower the blood pressure; usually, the abnormal fundus changes in acute hypertension usually disappear within a few months of the blood pressure drop, but the loss of vision in some patients with grade 4 fundus changes will not be restored due to irreversible vascular occlusion.
Retinal artery wall clouding was significantly reduced after 26 weeks of enalapril treatment. Symptomatic treatment is taken in the eye, such as blood activation to promote the absorption of exudates and hemorrhages, and oral vitamins C and E and rutin.
Prevention
Aggressive treatment of hypertension and early intervention of risk factors such as atherosclerosis to prevent hypertensive retinopathy.