The following are health and medical definitions of terms that appear in the Cataracts article.
Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care. See the entire definition of Acute
Aging: The process of becoming older, a process that is genetically determined and environmentally modulated. See the entire definition of Aging
Anesthesia: Loss of feeling or awareness. A general anesthetic puts the person to sleep. A local anesthetic causes loss of feeling in a part of the body such as a tooth or an area of skin without affecting consciousness. Regional anesthesia numbs a larger part of the body such as a leg or arm, also without affecting consciousness. The term "conduction anesthesia" encompasses both local and regional anesthetic techniques. Many surgical procedures can be done with conduction anesthesia without significant pain. In many situations, such as a C-section, conduction anesthesia is safer and therefore preferable to general anesthesia. However, there are also many types of surgery in which general anesthesia is clearly appropriate.
Anterior: The front, as opposed to the posterior. The anterior surface of the heart is toward the breast bone (the sternum). See the entire definition of Anterior
Atopic: Prone to allergies or characterized by allergy.
Atopic dermatitis: A skin disease characterized by areas of severe itching, redness, scaling, and loss of the surface of the skin (excoriation). When the eruption (rash) has been present for a prolonged time, chronic changes occur due to the constant scratching and rubbing known as lichenification (thickening of the skin with accentuation of the skin lines to form a crisscross pattern). See the entire definition of Atopic dermatitis
Blindness: Loss of useful sight. Blindness can be temporary or permanent. Damage to any portion of the eye, the optic nerve, or the area of the brain responsible for vision can lead to blindness. There are numerous (actually, innumerable) causes of blindness. The current politically correct terms for blindness include visually handicapped and visually challenged.
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."
Capsule: Capsule has many meanings in medicine including the following:
In medicine, a membranous structure that envelops an organ, a joint, tumor, or any other part of the body. It is usually made up of dense collagen-containing connective tissue.
In pharmacy, a solid dosage form in which the drug is enclosed in a hard or soft soluble container, usually of a form of gelatin.
In microbiology, a coat around a microbe, such as a bacterium or fungus.
Cataract: A clouding or loss of transparency of the lens in the eye as a result of tissue breakdown and protein clumping. There are many causes of cataracts, including aging, cortisone medication, trauma, diabetes, and other diseases. Cataracts affect most people who live into an old age. Symptoms include double or blurred vision and sensitivity to light and glare. A physician can diagnose cataracts by examining the eyes with a viewing instrument. Sunglasses can help to prevent cataracts. See the entire definition of Cataract
Cataract surgery: Removal of the clouded lens (the cataract) in its entirety by surgery, usually followed by replacement of the lens with an intraocular lens (IOL) made of plastic, silicone, acrylic or other material. The operation typically takes about an hour, is done under local anesthetic only, and does not require hospitalization.
Chemical reaction: A process in which one substance is transformed into another. Thousands of different types of chemical reactions occur in the body and are essential to its structure and function.
Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time. See the entire definition of Chronic
Chronic disease: A disease that persists for a long time. A chronic disease is one lasting 3 months or more, by the definition of the U.S. National Center for Health Statistics. Chronic diseases generally cannot be prevented by vaccines or cured by medication, nor do they just disappear. Eighty-eight percent of Americans over 65 years of age have at least one chronic health condition (as of 1998). Health damaging behaviors - particularly tobacco use, lack of physical activity, and poor eating habits - are major contributors to the leading chronic diseases. See the entire definition of Chronic disease
Complication: In medicine, an additional problem that arises following a procedure, treatment or illness and is secondary to it. A complication complicates the situation.
Congenital: Present at birth. A condition that is congenital is one that is present at birth. There are numerous uses of "congenital" in medicine. There are, for example, congenital abnormalities. (For more examples, see below.) See the entire definition of Congenital
Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.
Cortical: Having to do with the cortex, the outer portion of an organ. See the entire definition of Cortical
Dermatitis: Inflammation of the skin, either due to direct contact with an irritating substance, or to an allergic reaction. Symptoms of dermatitis include redness, itching, and in some cases blistering. See the entire definition of Dermatitis
Diabetes: Refers to diabetes mellitus or, less often, to diabetes insipidus. Diabetes mellitus and diabetes insipidus share the name "diabetes" because they are both conditions characterized by excessive urination (polyuria). See the entire definition of Diabetes
Diabetic retinopathy: A common complication of diabetes affecting the blood vessels in the retina (the thin light-sensitive membrane that covers the back of the eye). If untreated, it may lead to blindness. If diagnosed and treated promptly, blindness is usually preventable. See the entire definition of Diabetic retinopathy
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
Down syndrome: A common chromosome disorder due to an extra chromosome number 21 (trisomy 21). Down syndrome causes mental retardation, a characteristic face, and multiple malformations. Down syndrome is a relatively common birth defect. The chromosome abnormality affects both the physical and intellectual development of the individual. See the entire definition of Down syndrome
Family history: The family structure and relationships within the family, including information about diseases in family members. See the entire definition of Family history
Galactosemia: A genetic metabolic disease in which there is a defect in the body's ability to use the sugar galactose. In classic galactosemia, the basic defect is a deficiency of the enzyme known as GALT (galactose-1-phosphate uridyl transferase). This causes an accumulation of galactose 1-phosphate which damages the liver, eye, brain and kidney. Galactosemia is one of the diseases in many newborn screening panels. The disease can be fatal, if undetected. If detected, it can be treated by avoiding galactose in the diet. See the entire definition of Galactosemia
Genetic: Having to do with genes and genetic information.
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
Herpes: A family of viruses. Herpes also refers to infection with one of the human herpesviruses, especially herpes simplex types 1 and 2. See the entire definition of Herpes
Homocystinuria: A genetic disease due to an enzyme deficiency. Among other events, there is a buildup of the amino acid homocystine. Progressive mental retardation is common in untreated cases. The finding of vascular disease and premature arteriosclerosis in persons with homocystinuria led to the theory that homocystine may be a factor in heart disease.
Hyperparathyroidism: Too much parathyroid hormone resulting in abnormally high levels of calcium in the blood (hypercalcemia). This can cause bone resorption and osteoporosis, calcium deposits in the kidneys, muscular weakness, nausea, vomiting, abdominal pains, and drowsiness. Hyperparathyroidism can be primary or secondary. Primary hyperparathyroidism is a disorder of the parathyroid glands in which one or more of the parathyroid glands are enlarged (hyperplastic), overactive, and secrete too much parathyroid hormone. In secondary hyperparathyroidism, the parathyroid glands themselves are normal but a problem such as kidney failure makes the body resistant to the action of parathyroid hormone. See the entire definition of Hyperparathyroidism
Hypothyroid: Deficiency of thyroid hormone which is normally made by the thyroid gland which is located in the front of the neck:
Implant:1. To embed; to set in firmly. In embryology, the fertilized egg implants in the uterine lining 6 or 7 days after conception (fertilization). In medicine today, many things may be implanted. 2. That which is embedded. For example: lens implants, breast implants, cochlear implants, defibrillator implants, pacemaker implants, etc.
Incidence: The frequency with which something, such as a disease, appears in a particular population or area. In disease epidemiology, the incidence is the number of newly diagnosed cases during a specific time period. The incidence is distinct from the prevalence which refers to the number of cases alive on a certain date.
Incision: A cut. When making an incision, a surgeon is making a cut.
Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person. See the entire definition of Infection
Inflammation: A basic way in which the body reacts to infection, irritation or other injury, the key feature being redness, warmth, swelling and pain. Inflammation is now recognized as a type of nonspecific immune response. See the entire definition of Inflammation
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.
Intraocular: In the eye. The intraocular pressure is the pressure within the eye.
Intraocular lens: An artificial lens made of plastic, silicone, acrylic or other material that is implanted inside the eye during cataract surgery. Abbreviated IOL. See the entire definition of Intraocular lens
Intrauterine: In the uterus (the womb). As opposed to extrauterine: outside the uterus. See the entire definition of Intrauterine
Iritis: Inflammation of the iris. The iris is the circular, colored curtain in the front of the visible of the eye. (The opening of the iris forms the pupil.)
Laser: A powerful beam of light that can produce intense heat when focused at close range. Lasers are used in medicine in microsurgery, cauterization, for diagnostic purposes, etc. For example, lasers are employed in microsurgery to cut tissue and remove tissue. See the entire definition of Laser
Lens: The transparent structure inside the eye that focuses light rays onto the retina (the nerve layer that lines the back of the eye, senses light and creates impulses that go through the optic nerve to the brain). The lens was named after the lentil bean because it resembled it in shape and size. See the entire definition of Lens
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
Mucous: Pertaining to mucus, a thick fluid produced by the lining of some tissues of the body. See the entire definition of Mucous
Myotonic dystrophy: An inherited disease in which the muscles contract but have decreasing power to relax -- this phenomenon is termed myotonia (irritability and prolonged contraction of muscles). The disease also leads to a mask-like expressionless face, premature balding, cataracts, and heart arrhythmias (abnormalities in heart rhythm). The onset of such problems is usually in young adulthood. However, onset can be at any age and the disease is extremely variable in the degree of severity. See the entire definition of Myotonic dystrophy
NEI: Stands for National Eye Institute, one of the US National Institutes of Health. See the entire definition of NEI
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.
NIH: The National Institutes of Health. The NIH is an important U.S. health agency. It is devoted to medical research. Administratively under the Department of Health and Human Services (HHS), the NIH consists of 20-some separate Institutes and Centers. NIH's program activities are represented by these Institutes and Centers. See the entire definition of NIH
Nucleus: 1) In cell biology, the structure that houses the chromosomes. 2) In neuroanatomy, a group of nerve cells.
Ophthalmologist: An eye doctor. A physician practicing ophthalmology. An ophthalmologist is an M.D.
Optic: Having to do with vision.
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
Optometrist: A health care professional who is licensed to provide primary eye care services:
to examine and diagnose eye diseases such as glaucoma, cataracts, and retinal diseases and, in certain states in the U.S., to treat them;
to diagnose related systemic (bodywide) conditions such as hypertension and diabetes that may affect the eyes;
to examine, diagnose and treat visual conditions such as nearsightedness, farsightedness, astigmatism and presbyopia; and
to prescribe glasses, contact lenses, low vision rehabilitation and medications as well as perform minor surgical procedures such as the removal of foreign bodies.
Outpatient: A patient who is not an inpatient (not hospitalized) but instead is cared for elsewhere -- as in a doctor's office, clinic, or day surgery center. The term outpatient dates back at least to 1715. Outpatient care today is also called ambulatory care.
Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia. Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors. See the entire definition of Pain
Peripheral: Situated away from the center, as opposed to centrally located. See the entire definition of Peripheral
Posterior: The back or behind, as opposed to the anterior. See the entire definition of Posterior
Prognosis:1. The expected course of a disease. 2. The patient's chance of recovery. The prognosis predicts the outcome of a disease and therefore the future for the patient. His prognosis is grim, for example, while hers is good. See the entire definition of Prognosis
Progressive: Increasing in scope or severity. Advancing. Going forward. In medicine, a disease that is progressive is going from bad to worse.
Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein. See the entire definition of Protein
Pupil: The opening of the iris. The pupil may appear to open (dilate) and close (constrict) but it is really the iris that is the prime mover; the pupil is merely the absence of iris. The pupil determines how much light is let into the eye. Both pupils are usually of equal size. If they are not, that is termed anisocoria (from "a-", not + "iso", equal + "kore", pupil = not equal pupils). See the entire definition of Pupil
Radiation:1. Rays of energy. Gamma rays and X-rays are two of the types of energy waves often used in medicine. 2. The use of energy waves to diagnose or treat disease. See also: Irradiation.
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
Risk factor: Something that increases a person's chances of developing a disease.
Sclerosis: Localized hardening of skin.
Senile:1. Pertaining to old age. 2. Pertaining to the physical decline associated with old age. 3. Pertaining to the mental decline once associated with old age but now known to be due to dementia, such as Alzheimer's disease or cerebral atherosclerosis. "The road to senility is paved with plaques." (Paul F. Wehrle, MD [1921-2004] pediatrician and vaccine researcher) See the entire definition of Senile
Sensitivity:1. In psychology, the quality of being sensitive. As, for example, sensitivity training, training in small groups to develop a sensitive awareness and understanding of oneself and of ones relationships with others. 2. In disease epidemiology, the ability of a system to detect epidemics and other changes in disease occurrence. 3. In screening for a disease, the proportion of persons with the disease who are correctly identified by a screening test. 4. In the definition of a disease, the proportion of persons with the disease who are correctly identified by defined criteria.
Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office. See the entire definition of Surgery
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
Syphilis: A sexually transmitted disease caused by Treponema pallidum, a microscopic organism called a spirochete. This worm-like, spiral-shaped organism infects people by burrowing into the moist mucous membranes of the mouth or genitals. From there, the spirochete produces a non-painful ulcer known as a chancre. There are three stages of syphilis: See the entire definition of Syphilis
Tear: A drop of the salty secretion of the lacrimal glands which serves to moisten the conjunctiva and cornea.
Tobacco: A South American herb, formally known as Nicotiana tabacum, whose leaves contain 2-8% nicotine and serve as the source of smoking and smokeless tobacco. See the entire definition of Tobacco
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
Ultraviolet radiation: Invisible rays that are part of the energy that comes from the sun. Ultraviolet radiation can burn the skin and cause skin cancer. See the entire definition of Ultraviolet radiation
Uveitis: Inflammation of the uvea, the part of the eye that collectively refers to the iris, the choroid of the eye, and the ciliary body. The uvea provides most of the blood supply to the retina. Uveitis as a rule signifies inflammation involving the iris, choroid, and ciliary body -- all three components of the uveal tract. See the entire definition of Uveitis
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 acuity test: This test measures how well you see at various distances. It is the familiar eye chart test. See the entire definition of Visual acuity test
X-ray:1. High-energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances (to varying extents), of acting on a photographic film or plate (permitting radiography), and of causing a fluorescent screen to give off light (permitting fluoroscopy). In low doses X-rays are used for making images that help to diagnose disease, and in high doses to treat cancer. Formerly called a Roentgen ray. 2. An image obtained by means of X-rays.
Diabetes mellitus is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin dependent). Symptoms of diabetes include increased urine output, thirst, hunger, and fatigue. Treatment of diabetes depends on the type.
Retinal detachment is the separation of the retina from its attachments to the underlying eye tissue. Symptoms of retinal detachment include flashing lights and floaters. Highly nearsighted young adults and those who've had cataract surgery are at higher risk for retinal detachment.
Alcoholism is a disease that includes alcohol craving and continued drinking despite repeated alcohol-related problems, such as losing a job or getting into trouble with the law.
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.
Eye floaters are deposits or condensation that forms in the eye's vitreous humor. These deposits cast shadows on the retina, and as the eye moves, the deposits shift position, making it appear as though the shadows are moving or floating.
Smoking is an addiction. More than 430,000 deaths occur each year in the U.S. from smoking related illnesses. Secondhand smoke or "passive smoke" also harm family members, coworkers, and others around smokers. There are a number of techniques available to assist people who want to quit smoking.
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.
Uveitis is inflammation of the eye. Symptoms include blurred vision, eye pain, eye redness, and floating spots before the eyes. Treatment may involve prescription eyedrops, antibiotics, and wearing dark glasses.
Sunburn is caused by overexposure to UV radiation from the sun. UV rays can also damage the eyes. Repeated overexposure to UV rays also increases the risk for scarring, freckles, wrinkles, and dry skin. Symptoms of sunburn include painful, red, tender, and hot skin. The skin may blister, swell, and peel. Sun poisoning (severe sunburn) include nausea, fever, chills, rapid pulse, dizziness and more. Treatment for sunburn depends upon the severity. Sun protection and sunscreen for an individual's skin type is recommended to decrease the chance of sunburn.
Blindness is the state of being sightless. Causes of blindness include macular degeneration, stroke, cataract, glaucoma, infection and trauma. Symptoms and signs may include eye pain, eye discharge, or the cornea or pupil turning white. Treatment of blindness depends upon the cause of the blindness.
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.
Diabetes and eye problems are generally caused by high blood sugar levels over an extended period of time. Types of eye problems in a person with diabetes include glaucoma, cataracts, and retinopathy. Examples of symptoms include blurred vision, headaches, eye aches, pain, halos around lights, loss of vision, watering eyes. Treatment for eye problems in people with diabetes depend on the type of eye problem. Prevention of eye problems include reducing blood pressure, cholesterol levels, quitting smoking, and maintaining proper blood glucose levels.
Double vision (diplopia) is a symptom that my indicate Graves' disease, myasthenia gravis, stroke, multiple sclerosis, Guillain-Barre syndrome, diabetes, cataracts, aneurysm, brain tumor, or migraine. Symptoms and signs include eye pain, droopy eyelids, nausea, headache, and a cross-eyed appearance. Treatment of double vision depends upon the underlying cause.
eye. Read about symptoms, signs, diagnosis, treatment, and prognosis.
Coats' disease is a rare eye condition that typically progresses to vision loss or blindness in one eye. Gradual vision loss is usually the first symptom, followed by a cloudy white or yellow pupil due to the presence of a cataract. Treatment focuses on limiting the blood vessel progression and may involve cryotherapy or laser photocoagulation.
Nonprescription eyeglasses are available over the counter (OTC) and are typically used by people who can no longer read fine print. OTC trifocals are helpful for those who require multiple distances or focal lengths for near and intermediate tasks. OTC sunglasses should offer 100% protection from the sun's UVA and UVB rays. OTC magnifying glasses are useful for viewing tiny objects or fine print.
The retina is an extremely thin tissue that lines the inside of the back of the eye. When we look around, light from the objects we are trying to see enters the eye. The light image is focused onto the retina by
both the cornea and the lens. This light striking the retina causes a complex biochemical change within layers of the retina and this, in turn, stimulates an electrical response in other layers of the retina. Nerve endings within the retina transmit these
electrical signals to the brain through the optic nerve. Within specific areas of the brain, this electrical energy is processed to allow us both to see and to understand what we are seeing. The retina has been compared to the film of a camera. However, film, once used, has a permanent image on it. The retina continually renews itself chemically and electrically, allowing us to see millions of different images every day without them being superimposed.
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