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Ocular Ischemic Syndrome
Ocular ischemic syndrome is the constellation of ocular signs and symptoms secondary to severe, chronic arterial hypoperfusion to the eye. Amaurosis fugax is a form of acute vision loss 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 due to atherosclerosis 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 usually seen in post-surgical cases. Retinal artery occlusion (such as central retinal artery occlusion or branch retinal artery occlusion) leads to rapid death of retinal cells, thereby resulting in severe loss of vision. Symptoms and signs Those with ocular ischemic syndrome are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Sign
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showing on a medical scan. A symptom is something out of the ordinary that is experienced by an individual such as feeling feverish, a headache or other pain or pains in the body. Signs and symptoms Signs A medical sign is an objective observable indication of a disease, injury, or abnormal physiological state that may be detected during a physical examination, examining the patient history, or diagnostic procedure. These signs are visible or otherwise detectable such as a rash or bruise. Medical signs, along with symptoms, assist in formulating diagnostic hypothesis. Examples of signs include elevated blood pressure, nail clubbing of the fingernails or toenails, staggering gait, and arcus senilis and arcus juvenilis of the eyes. Indicati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 appetite. If left untreated, diabetes can cause many health complications. Acute complications can include diabetic ketoacidosis, hyperosmolar hyperglycemic state, or death. Serious long-term complications include cardiovascular disease, stroke, chronic kidney disease, foot ulcers, damage to the nerves, damage to the eyes, and cognitive impairment. Diabetes is due to either the pancreas not producing enough insulin, or the cells of the body not responding properly to the insulin produced. Insulin is a hormone which is responsible for helping glucose from food get into cells to be used for energy. There are three main types of diabetes mellitus: * Type 1 diabetes results from failure of the pancreas to produce enough insulin due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 percent of those who have had both type 1 and type 2 diabetes for 20 years or more. In at least 90% of new cases, progression to more aggressive forms of sight threatening retinopathy and maculopathy could be reduced with proper treatment and monitoring of the eyes The longer a person has diabetes, the higher his or her chances of developing diabetic retinopathy. Each year in the United States, diabetic retinopathy accounts for 12% of all new cases of blindness. It is also the leading cause of blindness in people aged 20 to 64. Signs and symptoms Nearly all people with diabetes develop some degree of retina damage ("retinopathy") over several decades with the disease. For many, that damage can only be detected by a retinal exam, and ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 central retinal artery and vein are the sole source of blood supply and drainage for the retina, such occlusion can lead to severe damage to the retina and blindness, due to ischemia (restriction in blood supply) and edema (swelling). CRVO can cause ocular ischemic syndrome. Nonischemic CRVO is the milder form of the disease. It may progress to the more severe ischemic type. CRVO can also cause glaucoma. Diagnosis Despite the role of thrombosis in the development of CRVO, a systematic review found no increased prevalence of thrombophilia (an inherent propensity to thrombosis) in patients with retinal vascular occlusion. Treatment Treatment consists of Anti-VEGF drugs like Lucentis or intravitreal steroid implant (Ozurdex) and Pan-Retinal Lase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extraocular Muscle
The extraocular muscles (extrinsic ocular muscles), are the seven extrinsic muscles of the human eye. Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye and the other muscle, the levator palpebrae superioris, controls eyelid elevation. The actions of the six muscles responsible for eye movement depend on the position of the eye at the time of muscle contraction. Structure Since only a small part of the eye called the fovea provides sharp vision, the eye must move to follow a target. Eye movements must be precise and fast. This is seen in scenarios like reading, where the reader must shift gaze constantly. Although under voluntary control, most eye movement is accomplished without conscious effort. Precisely how the integration between voluntary and involuntary control of the eye occurs is a subject of continuing research."eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ulti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 structures in the nose, face, and meninges. Occlusion of the ophthalmic artery or its branches can produce sight-threatening conditions. Structure The ophthalmic artery emerges from the internal carotid artery. This is usually just after the internal carotid artery emerges from the cavernous sinus. In some cases, the ophthalmic artery branches just before the internal carotid exits the cavernous sinus. The ophthalmic artery emerges along the medial side of the anterior clinoid process. It runs anteriorly, passing through the optic canal inferolaterally to the optic nerve. It can also pass superiorly to the optic nerve in a minority of cases. In the posterior third of the cone of the orbit, the ophthalmic artery turns sharply and mediall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Complication can include blockage of the artery to the eye with resulting blindness, as well as aortic dissection, and aortic aneurysm. GCA is frequently associated with polymyalgia rheumatica. The cause is unknown. The underlying mechanism involves inflammation of the small blood vessels that supply the walls of larger arteries. This mainly affects arteries around the head and neck, though some in the chest may also be affected. Diagnosis is suspected based on symptoms, blood tests, and medical imaging, and confirmed by biopsy of the temporal artery. However, in about 10% of people the temporal artery is normal. Treatment is typical with high doses of steroids such as prednisone or prednisolone. Once symptoms have resolved, the dose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (MKSAP-15): Rheumatology. "Systemic Vasculitis." Pg. 65–67. 2009, ACP. with massive intimal fibrosis and vascular narrowing, most commonly affecting young or middle-aged women of Asian descent, though anyone can be affected. It mainly affects the aorta (the main blood vessel leaving the heart) and its branches, as well as the pulmonary arteries. Females are about 8–9 times more likely to be affected than males. Those with the disease often notice symptoms between 15 and 30 years of age. In the Western world, atherosclerosis is a more frequent cause of obstruction of the aortic arch vessels than Takayasu's arteritis. Takayasu's arteritis is similar to other forms of vasculitis, including giant cell arteritis which typically affects olde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Carotid Artery
The external carotid artery is a major artery of the head and neck. It arises from the common carotid artery when it splits into the external and internal carotid artery. External carotid artery supplies blood to the face and neck. Structure The external carotid artery begins at the upper border of thyroid cartilage, and curves, passing forward and upward, and then inclining backward to the space behind the neck of the mandible, where it divides into the superficial temporal and maxillary artery within the parotid gland. It rapidly diminishes in size as it travels up the neck, owing to the number and large size of its branches. At its origin, this artery is closer to the skin and more medial than the internal carotid, and is situated within the carotid triangle. Development In children, the external carotid artery is somewhat smaller than the internal carotid; but in the adult, the two vessels are of nearly equal size. Relations At the origin, external carotid artery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Carotid Artery
The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these bifurcate at cervical vertebrae C3 or C4. The internal carotid artery supplies the brain, including the eyes, while the external carotid nourishes other portions of the head, such as the face, scalp, skull, and meninges. Classification Terminologia Anatomica in 1998 subdivided the artery into four parts: "cervical", "petrous", "cavernous", and "cerebral". However, in clinical settings, the classification system of the internal carotid artery usually follows the 1996 recommendations by Bouthillier, describing seven anatomical segments of the internal carotid artery, each with a corresponding alphanumeric identifier—C1 cervical, C2 petrous, C3 lacerum, C4 cavernous, C5 clinoid, C6 ophthalmic, and C7 communicating. The Bouthillier nome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Carotid Artery
In anatomy, the left and right common carotid arteries (carotids) ( in Merriam-Webster Online Dictionary '.) are arteries that supply the head and neck with ; they divide in the neck to form the external and internal carotid arteries. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ischemic optic neuropathy or posterior ischemic optic neuropathy according to the part of the optic nerve that is affected. People affected will often complain of a loss of visual acuity and a visual field, the latter of which is usually in the superior or inferior field. When ION occurs in patients below the age of 50 years old, other causes should be considered, such as juvenile diabetes mellitus, antiphospholipid antibody-associated clotting disorders, collagen-vascular disease, and migraines. Rarely, complications of intraocular surgery or acute blood loss may cause an ischemic event in the optic nerve. Presentation Anterior ION presents with sudden, painless visual loss, developing over hours to days. Diagnosis Examination findin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
