Ocular ischemic syndrome is the constellation of ocular signs and symptoms secondary to severe, chronic arterial hypoperfusion to the eye.

Amaurosis fugax Amaurosis fugax (Greek ''amaurosis'' meaning ''darkening'', ''dark'', or ''obscure'', Latin '' fugax'' meaning ''fleeting'') is a painless temporary loss of vision in one or both eyes. Signs and symptoms The experience of amaurosis fugax is clas ...

is a form of acute

vision loss Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment� ...

caused by reduced blood flow to the eye; it may be a warning sign of an impending stroke, as both stroke and retinal artery occlusion can be caused by

thromboembolism Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (t ...

due to

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis in which the wall of the artery develops abnormalities, called lesions. These lesions may lead to narrowing due to the buildup of atheromatous plaque. At onset there are usually no s ...

elsewhere in the body (such as coronary artery disease and especially carotid atherosclerosis). Consequently, those with transient blurring of vision are advised to urgently seek medical attention for a thorough evaluation of the carotid artery. Anterior segment ischemic syndrome is a similar ischemic condition of

anterior segment The anterior segment or anterior cavity is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens.Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesvill ...

usually seen in post-surgical cases. Retinal artery occlusion (such as

central retinal artery occlusion Central retinal artery occlusion (CRAO) is a disease of the eye where the flow of blood through the central retinal artery is blocked (occluded). There are several different causes of this occlusion; the most common is carotid artery atheroscler ...

branch retinal artery occlusion Branch retinal artery occlusion (BRAO) is a rare retinal vascular disorder in which one of the branches of the central retinal artery is obstructed. Presentation Abrupt painless loss of vision in the visual field corresponding to territory of the ...

) leads to rapid death of retinal cells, thereby resulting in severe loss of vision.

Symptoms and signs

Those with ocular ischemic syndrome are typically between the ages of 50 and 80 (patients over 65);"Ocular Ischemic Syndrome."
Accessed October 25, 2006. twice as many men as women are affected. More than 90% of those presenting with the condition have

. Patients may report a dull, radiating ache over the eye and

eyebrow An eyebrow is an area of short hairs above each eye that follows the shape of the lower margin of the brow ridges of some mammals. In humans, eyebrows serve two main functions: first, communication through facial expression, and second, preven ...

. Those with ocular ischemic syndrome may also present with a history of other systemic diseases including

arterial hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high b ...

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

, coronary artery disease, previous stroke, and

hemodialysis Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinin ...

. The condition presents with visual loss secondary to hypoperfusion of the eye structures. The patient presents with intractable pain or ocular angina. On dilated examination, there may be blot retinal hemorrhages along with dilated and beaded retinal veins. The ocular perfusion pressure is decreased. The corneal layers show edema and striae. There is mild anterior uveitis. A cherry-red spot may be seen in the macula, along with cotton-wool spots elsewhere, due to retinal nerve fiber layer hemorrhages. The retinal arteries may show spontaneous pulsations.

Complications

If carotid occlusive disease results in ophthalmic artery occlusion, general ocular ischemia may result in retinal neovascularization, rubeosis iridis, cells and flare, iris necrosis, and cataract. The condition leads to neovascularization in various eye tissues due to the ischemia. The eye pressure may become high due to associated neovascular glaucoma. An

ischemic optic neuropathy Ischemic optic neuropathy (ION) is the loss of structure and function of a portion of the optic nerve due to obstruction of blood flow to the nerve (i.e. ischemia). Ischemic forms of optic neuropathy are typically classified as either anterior is ...

may eventually occur.

Causes

Severe ipsilateral or bilateral

carotid artery stenosis Carotid artery stenosis is a narrowing or constriction of any part of the carotid arteries, usually caused by atherosclerosis. Signs and symptoms The common carotid artery is the large artery whose pulse can be felt on both sides of the neck ...

or occlusion is the most common cause of ocular ischemic syndrome. The syndrome has been associated with occlusion of the

common carotid artery In anatomy, the left and right common carotid arteries (carotids) (Entry "carotid"
in
internal carotid artery, and less frequently the external carotid artery. Other causes include: *

Takayasu's arteritis Takayasu's arteritis (TA), also known as aortic arch syndrome, nonspecific aortoarteritis, and pulseless disease, is a form of large vessel granulomatous vasculitisAmerican College of Physicians (ACP). Medical Knowledge Self-Assessment Program (MK ...

Giant cell arteritis Giant cell arteritis (GCA), also called temporal arteritis, is an inflammatory autoimmune disease of large blood vessels. Symptoms may include headache, pain over the temples, flu-like symptoms, double vision, and difficulty opening the mouth. ...

*Severe

ophthalmic artery The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some s ...

occlusion, due to

. *Surgical interruption of anterior ciliary blood vessels supplying the eye, particularly during extensive strabismus surgery on 3 or more rectus muscles, leading to an anterior segment ischemic syndrome.

Diagnosis

Differential diagnoses

Central retinal vein occlusion Central retinal vein occlusion, also CRVO, is when the central retinal vein becomes occluded, usually through thrombosis. The central retinal vein is the venous equivalent of the central retinal artery and both may become occluded. Since the centra ...

Diabetic retinopathy Diabetic retinopathy (also known as diabetic eye disease), is a medical condition in which damage occurs to the retina due to diabetes mellitus. It is a leading cause of blindness in developed countries. Diabetic retinopathy affects up to 80 perc ...

: The presence of retinal hemorrhages, particularly in those who have diabetes, may also be caused by diabetic retinopathy. Given the bilateral nature of diabetic retinopathy, however, one should suspect ocular ischemic syndrome when retinal ischemia is unilateral.

Treatment

Quick determination of the cause may lead to urgent measures to save the eye and life of the patient. High clinical suspicion should be kept for painless vision loss in patients with

deep venous thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...

, atrial fibrillation, pulmonary thromboembolism or other previous embolic episodes. Those caused by a carotid artery

embolism An embolism is the lodging of an embolus, a blockage-causing piece of material, inside a blood vessel. The embolus may be a blood clot (thrombus), a fat globule (fat embolism), a bubble of air or other gas ( gas embolism), amniotic fluid (am ...

or occlusion have the potential for further stroke by detachment of embolus and migration to an end-artery of the brain. Hence, proper steps to prevent such an eventuality need to be taken. Retinal arterial occlusion is an ophthalmic emergency, and prompt treatment is essential. Completely anoxic retina in animal models causes irreversible damage in about 90 minutes. Nonspecific methods to increase blood flow and dislodge emboli include digital massage, 500 mg IV

acetazolamide Acetazolamide, sold under the trade name Diamox among others, is a medication used to treat glaucoma, epilepsy, altitude sickness, periodic paralysis, idiopathic intracranial hypertension (raised brain pressure of unclear cause), urine alkal ...

and 100 mg IV

methylprednisolone Methylprednisolone (Depo-Medrol, Medrol, Solu-Medrol) is a synthetic glucocorticoid, primarily prescribed for its anti-inflammatory and immunosuppressive effects. It is either used at low doses for chronic illnesses or used concomitantly at hig ...

(for possible arteritis). Additional measures include paracentesis of aqueous humor to decrease IOP acutely. An ESR should be drawn to detect possible giant cell arteritis. Improvement can be determined by visual acuity,

visual field test A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits. V ...

ing, and by ophthalmoscopic examination. At a later stage, pan-retinal photocoagulation (PRP) with an argon laser appears effective in reducing the neovascular components and their sequelae. The visual prognosis for ocular ischemic syndrome varies from usually poor to fair, depending on speed and effectiveness of the intervention. However, prompt diagnosis is crucial as the condition may be a presenting sign of serious cerebrovascular and ischemic heart diseases. In 2009, the

Undersea and Hyperbaric Medical Society The underwater environment is the region below the surface of, and immersed in, liquid water in a natural or artificial feature (called a body of water), such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer. Some charac ...

added "central retinal artery occlusion" to their list of approved indications for

hyperbaric oxygen Hyperbaric medicine is medical treatment in which an ambient pressure greater than sea level atmospheric pressure is a necessary component. The treatment comprises hyperbaric oxygen therapy (HBOT), the medical use of oxygen at an ambient pressure ...

(HBO).The Undersea and Hyperbaric Medical Society (UHMS), Hyperbaric Oxygen Therapy Committee. Guidelines: Indications for Hyperbaric Oxygen. Durham, NC: UHMS; 2009. When used as an adjunctive therapy, the edema reducing properties of HBO, along with down regulation of inflammatory

cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...

s may contribute to the improvement in vision. Prevention of vision loss requires that certain conditions be met: the treatment be started before irreversible damage has occurred (over 24 hours), the occlusion must not also occur at the

, and treatment must continue until the inner layers of the retina are again oxygenated by the retinal arteries.

References

External links

{{Eye pathology Disorders of choroid and retina Syndromes