The following are health and medical definitions of terms that appear in the Visual Field Test article.
Amsler grid: While conducting an eye examination, the eye care professional may ask the patient to look at an Amsler grid. This grid is a pattern that resembles a checkerboard. The patient covers one eye and stares at a black dot in the center of the grid. While staring at the dot, the patient may notice that the straight lines in the pattern appear wavy.
Brain: That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."
Central vision: Straight-ahead vision. Central vision is the work of the macula, a small area in the center of the retina that contains a rich collection of cones. (The retina is made up of two types of cells, the cones and the rods. Millions of cones are packed into the macula. The cones are nerve cells sensitive to light, fine detail, and color.) Central vision permits a person to read, drive, and perform other activities that require fine, sharp, straight-ahead vision. As opposed to peripheral vision.
Chin: Medically, the mentum. The lower portion of the face below the lower lip including the prominence of the lower jaw and the line of fusion of the two separate halves of the jawbone (mandible). This line of fusion (called the symphysis menti) encloses a triangular area at tip of the chin (termed the mental protuberance). On each side, below the second premolar tooth, is the mental foramen, an opening for the passage of blood vessels and a nerve that supply the chin.
Circulation: The movement of fluid in a regular or circuitous course. Although the noun "circulation" does not necessarily refer to the circulation of the blood, for all practical purposes today it does. Heart failure is an example of a problem with the circulation.
Contralateral: On the other side. The contralateral breast is the breast on the other breast. A stroke affecting the right side of the brain may cause contralateral paralysis, affecting the left arm and leg. The opposite of contralateral is ipsilateral which refers to the same side.
Developmental delay: Behind schedule in reaching milestones of early childhood development.
Diagnosis:1 The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV. See the entire definition of Diagnosis
Eyelid: The lid or cover of the eye, a movable fold of skin and muscle that can be closed over the eyeball or opened at will. Each eye has an upper and a lower lid. An eyelid is also called a palpebra.
Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist. See the entire definition of Fatigue
Glaucoma: A common eye condition in which the fluid pressure inside the eyes rises because of slowed fluid drainage from the eye. If untreated, it may damage the optic nerve and other parts of the eye, causing the loss of vision or even blindness. See the entire definition of Glaucoma
Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated.
Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury. The injury may be accidental or deliberate, as with a needlestick injury. The term "injury" may be synonymous (depending on the context) with a wound or with trauma.
Kinetic: With movement. The opposite of kinetic is akinetic. It means without movement. In neurology, kinetic and akinetic denote the presence or absence of movement. Kinetic comes from the Greek word "kinesis" for motion. The term "akinetic" is put together from the prefix "a-" meaning "without" + "kinesis" = without motion. "Kinetic" (an adjective) should be distinguished from "kinetics" (a noun). Kinetics (with an "s" at the end) refers to the rate of change in a biochemical (or other) reaction, the study of reaction rates.
Macular: Pertaining to the macula. A macula is a small spot. A macula on the skin is a small flat spot while the macula in the eye is a small spot where vision is keenest in the retina.
Macular degeneration: A disease that progressively destroys the macula, the central portion of the retina, impairing central vision. Macular degeneration rarely causes blindness because only the center of vision is affected. However, injury to the macula in the center of the retina can impair the ability to see straight ahead clearly and sometimes make it difficult to read, drive, or perform other daily activities that require fine central vision. See the entire definition of Macular degeneration
Macular vision: The macula is a special area in the center of the retina, the light-sensitive layer of tissue at the back of the eye. As we read, light is focused onto our macula. There, millions of cells change the light into nerve signals that tell the brain what we are seeing. This is called our macular or central vision. See the entire definition of Macular vision
Nerve: A bundle of fibers that uses chemical and electrical signals to transmit sensory and motor information from one body part to another. See: Nervous system.
Neurological: Having to do with the nerves or the nervous system.
Occipital:1. Pertaining to the occiput, the back of head. 2. Located near the occipital bone as, for example, the occipital lobe of the brain.
Optic nerve: The optic nerve connects the eye to the brain. The optic nerve carries the impulses formed by the retina, the nerve layer that lines the back of the eye and senses light and creates impulses. These impulses are dispatched through the optic nerve to the brain, which interprets them as images. Using an ophthalmoscope, the head of the optic nerve can be easily seen. It can be viewed as the only visible part of the brain (or extension of it). See the entire definition of Optic nerve
Orbit: In medicine, the bony cavity in which the eyeball sits together with its associated muscles, blood vessels, and nerves. The orbit is formed of parts of the ethmoid, frontal, lacrimal, nasal, palatine, sphenoid, and zygomatic bones and the maxilla.
Peripheral: Situated away from the center, as opposed to centrally located. See the entire definition of Peripheral
Periphery:1. The outside or surface of a structure; the portion outside the central region. See the entire definition of Periphery
Poor circulation: An inadequacy of blood flow. Inadequate blood flow to a particular area of the body can result in too little oxygen being delivered to that area, a condition known as hypoxia. The term poor circulation may be used to refer to peripheral vascular disease (or peripheral arterial disease), a condition that develops when the arteries that supply blood to the internal organs, arms, and legs become completely or partially blocked as a result of atherosclerosis.
Ptosis: Downward displacement. Ptosis of the eyelids is drooping of the eyelids.
Retina: The retina is the nerve layer that lines the back of the eye, senses light, and creates impulses that travel through the optic nerve to the brain. There is a small area, called the macula, in the retina that contains special light-sensitive cells. The macula allows us to see fine details clearly. See the entire definition of Retina
Retinal: Pertaining to the retina, the extraordinary layer of neurons (nerve cells) that line the back of the eye, which can sense light and create impulses capable of voyaging through the optic nerve to the brain where the impulses are recognized as an image. See the entire definition of Retinal
Retinal detachment: A separation of the retina from its connection at the back of the eye. The separation usually results from a tear (that is, a rent or rip, not a tear drop) in the retina. The tear often occurs when the vitreous gel pulls loose or separates from its attachment to the retina, usually in the outside edges of the eye. The vitreous is a clear gel that fills most of the inside of the eye between the retina and the lens. If the retina is weak when the vitreous gel pulls loose, the retina will tear. This rip is sometimes accompanied by bleeding, or hemorrhage, if a blood vessel is also torn. See the entire definition of Retinal detachment
Retinal disease: In medicine, called retinopathy. See: Retinopathy.
Retinitis pigmentosa: Any one of a large group of inherited disorders in which abnormalities of the photoreceptors (the rods and cones) in the retina lead to progressive visual loss. People with retinitis pigmentosa (RP) first experience defective dark adaptation ("night blindness"), then constriction of the visual field ("tunnel vision") and eventually loss of central vision. See the entire definition of Retinitis pigmentosa
Rheumatoid arthritis: An autoimmune disease which causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Autoimmune diseases occur when the body tissues are mistakenly attacked by its own immune system. The immune system is a complex organization of cells and antibodies designed normally to "seek and destroy" invaders of the body, particularly infections. Patients with these diseases have antibodies in their blood which target their own body tissues, where they can be associated with inflammation. Because it can affect multiple other organs of the body, rheumatoid arthritis is referred to as a systemic illness and is sometimes called rheumatoid disease. While rheumatoid arthritis is a chronic illness (meaning it can last for years) patients may experience long periods without symptoms. See the entire definition of Rheumatoid arthritis
Stroke: The sudden death of some brain cells due to a lack of oxygen when the blood flow to the brain is impaired by blockage or rupture of an artery to the brain. A stroke is also called a cerebrovascular accident or, for short, a CVA. See the entire definition of Stroke
Syndrome: A set of signs and symptoms that tend to occur together and which reflect the presence of a particular disease or an increased chance of developing a particular disease. See the entire definition of Syndrome
Toxicity: The degree to which a substance can harm humans or animals. See the entire definition of Toxicity
Tumor: An abnormal mass of tissue. Tumors are a classic sign of inflammation, and can be benign or malignant (cancerous). There are dozens of different types of tumors. Their names usually reflect the kind of tissue they arise in, and may also tell you something about their shape or how they grow. For example, a medulloblastoma is a tumor that arises from embryonic cells (a blastoma) in the inner part of the brain (the medulla). Diagnosis depends on the type and location of the tumor. Tumor marker tests and imaging may be used; some tumors can be seen (for example, tumors on the exterior of the skin) or felt (palpated with the hands). See the entire definition of Tumor
Visual acuity: The clarity or clearness of the vision, a measure of how well a person sees. The ability to distinguish details and shapes of objects; also called central vision. See the entire definition of Visual acuity
Visual field: The entire area that can be seen when the eye is directed forward, including that which is seen with peripheral vision. See the entire definition of Visual field
Visual field test: A test which measures the extent and distribution of the field of vision. See the entire definition of Visual field test
Glaucoma is a common eye condition in which the fluid pressure inside the eye rises because of slowed fluid drainage from the eye. If untreated, glaucoma may damage the optic nerve and other parts of the eye, causing the loss of vision or even blindness.
Many common eye disorders resolve without treatment and some may be managed with over-the-counter (OTC) products. It's important to visit a physician or ophthalmologist is the problem involves the eyeball itself or the condition hasn't improved after 72 hours of use of an eye-care OTC product.
Age-related macular degeneration (AMD) is a disease that gradually destroys the central vision. In people over 60, AMD is a leading cause of vision loss. Wet AMD occurs when abnormal blood vessels behind the retina start to grow under the macula, leaking blood and fluid and causing rapid vision loss. In dry AMD, light-sensitive cells slowly break down in the macula, resulting in gradual vision loss. Pain is not associated with either form of AMD.
Retinitis pigmentosa (RP) is a genetic condition that causes retinal degeneration and eventual vision loss. Symptoms include night blindness and tunnel vision. Visual field testing and electrophysiological testing are essential in diagnosing RP. Though there is no cure for RP, vitamin A therapy and an omega-3-rich diet may be recommended for patients to slow disease progression.
There are three types of Usher (Usher's) syndrome, the most common condition that affects both vision and hearing. The major symptoms of Usher syndrome include retinitis pigmentosa (night-blindness and a loss of peripheral vision), and hearing loss. Usher syndrome is a genetic condition. There is no cure for Usher syndrome.
Neuromyelitis optica (Devic's syndrome) is a disease of the CNS that affects the optic nerves and spinal cord. People with neuromyelitis optica develop optic neuritis and transverse myelitis. There is no cure for neuromyelitis optica; however, there are therapies to treat attacks when they occur.
Usher syndrome is the most common condition that affects
both hearing and vision. A syndrome is a disease or disorder that has more than
one feature or symptom. The major symptoms of Usher syndrome are
hearing loss and an eye
disorder called retinitis pigmentosa, or RP. RP causes night-blindness and a
loss of peripheral vision
(side vision) through the progressive degeneration of
the retina. The retina is a light-sensitive tissue at the back of the eye and is
crucial for vision. As RP progresses, the field of vision narrows - a condition
known as "tunnel vision" - until only central vision (the ability to see straight
ahead) remains. Many people with Usher syndrome also have severe balance
problems.
There are three clinical types of Usher syndrome:
type 1,
type 2, and
type 3.
In the United States, types 1 and 2 are the most common types. Together, they...
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