What Is Retinal Artery Occlusion?

The central retinal artery is a terminal artery. Its obstruction causes acute retina ischemia and severe vision loss, which is one of the blind emergencies. Ciliary vascular systems communicate with each other, so obstructive disorders are rare. If the ophthalmic artery is obstructed, the branches of the central retinal artery and posterior ciliary artery ischemia, and the nutrition of the inner and outer layers of the retina is completely cut off. The blinding rate is higher and the consequences are more serious. There are three characteristics: sudden loss of vision; milky white opacities in the posterior pole retina; cherry red spots in the macula.

Basic Information

English name: retinal arterial obstruction
Visiting department: Ophthalmology
Common locations: Retinal artery
Common causes: A combination of embolism, arterial wall changes, and thrombosis, vasospasm, or more

Common symptoms: Vision disappears instantly or within minutes, painless transient blindness, can be relieved after a few minutes, no light perception, dilated pupils, and the direct reaction to light disappears, etc.

Causes of retinal artery occlusion

The causes of retinal arterial occlusion can be summarized as a combination of embolism, changes in arterial wall and thrombosis, vasospasm or the above factors. Clinically, 90% of patients can detect some related systemic conditions. Arterial obstructive diseases in young patients are mostly related to migraine, abnormal coagulation mechanism, trauma, heart disease, sickle cell blood disease, and ocular abnormalities, such as optic nipples with buried glass warts and anterior optic nipple rings.

Clinical manifestations of retinal artery occlusion

When the central retinal artery is completely obstructed, vision disappears instantly or within minutes. Some patients have aura symptoms and painless transient blindness, which can be resolved within a few minutes. After repeated episodes, vision suddenly dropped suddenly and severely. The eyesight of most eyes is reduced to manual or finger counting. A narrow area of light perception is often reserved around the temporal side of the visual field. About 4% of patients are non-photosensitive, dilated pupils, and disappear directly in response to light. In addition to the obstruction of the central retinal artery, this non-light-sensitive eye may be combined with ciliary circulation block and blood supply disturbance of the optic nerve.

Retinal artery occlusion

Fluorescein angiography of retinal artery occlusion

Manifested as:

(1) When the central artery is blocked, the retinal arteries are slow to fill, the small arteries are blunt stumps, the small arteries around the macula are branched, and the "forward" phenomenon is obvious. When the branch artery is blocked, the blood flow is interrupted or retrograde at a certain point Filling (dye perfusion at the distal end of the blocked arteries predates the proximal end of the arterial occlusion site), and late occlusion sites have high fluorescence.

(2) Filling delay The circulatory time of the retinal artery is normally about 1 to 2 seconds. In blocked arteries, it can be extended to 30 to 40 seconds.

(3) No perfusion of small branches of arteries around the macula . Artery blood flow reappeared after several days of angiography.

(4) No retinal capillary bed perfusion. Retinal arterial filling is slow. The radial capillaries of the visual papilla extend outward from the papilla.

2. Ocular electrophysiology

The b wave of ERG decreases, and the a wave is generally normal.

Visual field changes are related to the site of the arterial occlusion. The central arterial occlusion can detect the small island-like visual field on the temporal side. Branch arterial occlusion can have visual field defects in the corresponding area. If there is a ciliary artery, central vision / field of vision can be retained.

Differential diagnosis of retinal artery occlusion

Anterior ischemic optic neuropathy

Often the eyes develop successively, the fundus manifests as obvious papillary edema, mild or moderate decrease in vision, and the typical visual field damage is a curved dark spot connected to the physiological blind spot.

2. Ophthalmic artery occlusion

Visual impairment is more severe, and vision is usually light or non-light. The intraocular pressure is reduced, and the retinal edema is more serious, and there may be no "cherry red" in the macular area.

Retinal artery occlusion complications

Retinal hemorrhage

Retinal hemorrhage is not typical of retinal artery occlusion. Occasionally small bleeding spots, especially near the optic nipples, are mostly caused by capillary leaks due to hypoxia. If there is more bleeding, it should be considered with central retinal vein occlusion.

2. Secondary glaucoma

Recent literature reports that the incidence of neovascular glaucoma is 15% to 20%. May be due to chronic hyporetinal reperfusion, ischemia, and hypoxia. Or combined with venous occlusion and carotid stenosis.

Retinal artery occlusion treatment

The principle of treatment is emergency rescue, race against time. Those with short onset time should be treated as emergency, and the best treatment is within 48 hours of onset, otherwise the treatment effect is not good.

1. Reduce intraocular pressure reduces arterial perfusion resistance

Can be taken to massage the eyeballs for at least 1 minute to reduce intraocular pressure, or for anterior chamber puncture, or oral or intravenous acetazolamide.

Oxygen

Inhaling a mixture of 95% oxygen and 5% carbon dioxide can increase the oxygen content of choroidal capillaries, thereby relieving the hypoxia of the retina and dilating the blood vessels. Inhaling oxygen once an hour for 10 minutes during the day and once every 4 hours at night .

3. Vasodilators

Isoamyl nitrite or nitroglycerin under the tongue should be inhaled immediately in the emergency department. After the ball was injected with tolazoline, papaverine was administered intravenously once a day or every other day. Niacin can also be taken orally, 3 times a day.

4. Fibrinolytic preparation

Fibrinolytic preparations can be used in patients suspected of thrombosis or increased fibrinogen. Intravenous infusion or slow bolus urokinase; or intravenous infusion with defibrase. During the treatment process, attention should be paid to checking fibrinogen, and those who drop below 200mg% should stop taking the drug.

5. Other

Can be taken orally aspirin, dipyridamole and other platelet inhibitors and traditional Chinese medicine for promoting blood circulation and removing blood stasis.

6. Surgical treatment

Catheter technology combined with intra-arterial injection of thrombolytic drugs and vitreous cutting combined with direct central retinal artery massage can restore blood supply and improve vision in time.

In addition, according to the possible cause of lowering blood pressure to treat carotid artery disease, corticosteroids, indomethacin and other drugs and nerve support drugs can be used for those with inflammation.