Abnormal: Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer ). See the entire definition of Abnormal
Antibiotic: A drug used to treat infections caused by bacteria and other microorganisms. Originally, an antibiotic was a substance produced by one microorganism that selectively inhibits the growth of another. Synthetic antibiotics, usually chemically related to natural antibiotics, have since been produced that accomplish comparable tasks. See the entire definition of Antibiotic
Antifungal: A drug used to treat fungal infections. See the entire definition of Antifungal
Antiviral: An agent that kills a virus or that suppresses its ability to replicate and, hence, inhibits its capability to multiply and reproduce. See the entire definition of Antiviral
Aqueous humor: In medicine, humor refers to a fluid (or semifluid) substance. Thus, the aqueous humor is the fluid normally present in the front and rear chambers of the eye. It is a clear, watery fluid that flows between and nourishes the lens and the cornea; it is secreted by the ciliary processes. See the entire definition of Aqueous humor
Astigmatism: A common form of visual impairment in which part of an image is blurred, due to an irregularity in the curvature of the front surface of the eye, the cornea. The curve of the cornea is shaped more like an American football or a rugby ball rather than a normal spherical basketball. Light rays entering the eye there are not uniformly focused on the retina. Rays entering through the more-curved surface are focused before the rays coming through the less-curved surface. The light is focused clearly along one plane but is blurred along the other. The result is blurred vision at all distances. Only part of what you are looking at is in clear focus at any one time. See the entire definition of Astigmatism
Bacteria: Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life). See the entire definition of Bacteria
Blurred vision: Lack of sharpness of vision with, as a result, the inability to see fine detail. Blurred vision can occur when a person who wears corrective lens is without them. Blurred vision can also be an important clue to eye disease.
Chickenpox: A highly infectious viral disease also known medically as varicella -- in many countries, this disease is always called "varicella" -- that causes a blister-like rash, itching, fatigue and fever. The rash crops up first on the face and trunk and can spread over the entire body resulting in 250 to 500 itchy blisters. See the entire definition of Chickenpox
Childhood: (1) The time for a boy or girl from birth until he or she is an adult. (2) The more circumscribed period of time from infancy to the onset of puberty . See the entire definition of Childhood
Condition: The term "condition" has a number of biomedical meanings including the following: - An unhealthy state, such as in "this is a progressive condition."
- A state of fitness, such as "getting into condition."
- Something that is essential to the occurrence of something else; essentially a "precondition."
- As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.
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
Conjunctivitis: Inflammation of the conjunctiva, the membrane on the inner part of the eyelids and the membrane covering the white of the eye. The conjunctival membranes react to a wide range of bacteria , viruses , allergy-provoking agents, irritants and toxic agents. Viral and bacterial forms of conjunctivitis are common in childhood. Conjunctivitis is also called pinkeye and red eye. See the entire definition of Conjunctivitis
Cornea: The clear front window of the eye that transmits and focuses light into the eye. See the entire definition of Cornea
Corneal: Pertaining to the cornea, the clear front window of the eye that transmits and focuses light into the eye.
Corneal transplant: The replacement of the clear window on the front of the eye (cornea) by a healthy cornea. The procedure is typically done under local anesthesia in an outpatient setting. Transplantation of the cornea may be indicated in cases of severe scarring of the cornea by injury or infection (as with corneal ulcers) and in genetic disorders such as keratoconus (inherited corneal thinning with visual distortion) and Fuch's dystrophy (inherited corneal clouding with visual loss). The very limited blood supply of the cornea greatly reduces the risk of transplant rejection. Corneal transplants generally function effectively for many years.
Cure: 1. To heal, to make well, to restore to good health. Cures are easy to claim and, all too often, difficult to confirm. 2. A time without recurrence of a disease so that the risk of recurrence is small, as in the 5-year cure rate for malignant melanoma . 3. Particularly in the past, a course of treatment. For example, take a cure at a spa. See the entire definition of Cure
Discharge: 1.The flow of fluid from part of the body, such as from the nose or vagina. 2. The passing of an action potential, such as through a nerve or muscle fiber . 3. The release of a patient from a course of care. The doctor may then dictate a discharge summary. See the entire definition of Discharge
Disease: Illness or sickness often characterized by typical patient problems (symptoms) and physical findings (signs). Disruption sequence: The events that occur when a fetus that is developing normally is subjected to a destructive agent such as the rubella (German measles) virus.
DOTS: Stands for Directly Observed Treatment, Short-course. See the entire definition of DOTS
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
Ehlers-Danlos syndrome : A heritable disorder of connective tissue with easy bruising, joint hypermobility (loose joints), skin laxity, and weakness of tissues. There are a number of different types of Ehlers-Danlos syndrome (EDS) which share the foregoing features but can be categorized into at least nine different types: See the entire definition of Ehlers-Danlos syndrome
Endothelial: Relating to the endothelium , the layer of flat cells lining the closed spaces of the body such as the inside of blood vessels, lymphatic vessels, the heart , and body cavities . See the entire definition of Endothelial
Endothelium: A layer of flat cells lining the closed internal spaces of the body such as the inside of blood vessels and lymphatic vessels (that convey the lymph , a milky fluid) and the heart. See the entire definition of Endothelium
Epithelial: Relating to the epithelium, the outside layer of cells that covers all the free, open surfaces of the body including the skin, and mucous membranes that communicate with the outside of the body.
Epithelium: The outside layer of cells that covers all the free, open surfaces of the body including the skin, and mucous membranes that communicate with the outside of the body. By contrast the endothelium is the layer of cells lining the closed internal spaces of the body such as the blood vessels and lymphatic vessels (that convey the lymph, a milky fluid).
Erosion: An erosion is an eating away of a surface. ("Erodere" in Latin means to eat out.) See the entire definition of Erosion
Eye: The organ of sight. The eye has a number of components. These components include but are not limited to the cornea, iris, pupil, lens, retina, macula, optic nerve, choroid and vitreous. See the entire definition of Eye
Fever : Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). See the entire definition of Fever
Fungi: Plural of fungus.
Genetics: The scientific study of heredity . Genetics pertains to humans and all other organisms. So, for example, there is human genetics, mouse genetics, fruitfly genetics, etc. See the entire definition of Genetics
Genital: Pertaining to the external and internal organs of reproduction. (Not to be confused with genetic.)
Genital herpes: A viral infection transmitted through intimate contact with the moist mucous linings of the genitals. This contact can involve the mouth, the vagina or the genital skin. The herpes simplex type 2 (HSV-2) enters the mucous membranes through microscopic tears. Once inside the body, HSV-2 travels to nerve roots near the spinal cord and settles there permanently. When an infected person has a herpes outbreak, the virus travels down the nerve fibers to the site of the original infection and when it reaches the skin, the classic redness and blisters occur. See the entire definition of Genital herpes
Heredity: Genetic transmission from parent to child.
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
Herpes zoster: Also called shingles, zona, and zoster. The culprit is the varicella-zoster virus. Primary infection with this virus causes chickenpox (varicella). At this time the virus infects nerves (namely, the dorsal root ganglia) where it remains latent (lies low) for years. It can then be reactivated to cause shingles with blisters over the distribution of the affected nerve accompanied by often intense pain and itching.
Humor: In medicine, humor refers to a fluid (or semifluid) substance. Thus, the aqueous humor is the fluid normally present in the front and rear chambers of the eye. The humors ran through an ancient theory that held that health came from balance between the bodily liquids. These liquids were termed humors. Disease arose when there was imbalance between these humors. See the entire definition of Humor
Immune: Protected against infection. The Latin immunis means free, exempt.
Immune system: A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders. See the entire definition of Immune system
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.
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.
Keratitis: Inflammation of the cornea (the transparent structure in the front of the eye).
Keratoconjunctivitis: Inflammation of the eye involving both the cornea and the conjunctiva . See the entire definition of Keratoconjunctivitis
Keratoconus: Cone-shaped cornea with the apex of the cone being forward. Also called conical cornea.
Lattice dystrophy: A form of hereditary corneal dystrophy in which there is an accumulation of amyloid deposits, or abnormal protein fibers, throughout the middle and anterior stroma of the cornea. These deposits in the stroma appear on an eye examination as clear, comma-shaped overlapping dots and branching filaments, creating a lattice effect. Over time, the lattice lines grow opaque and involve more of the stroma. They also gradually converge, giving the cornea a cloudiness that may also reduce vision. These abnormal protein fibers can accumulate under the cornea's outer layer -- the epithelium -- causing it to erode. This condition is known as recurrent epithelial erosion. These erosions alter the cornea's normal curvature, resulting in temporary vision problems. These erosions also expose the nerves that line the cornea, causing severe pain. Even the involuntary act of blinking can be painful. See the entire definition of Lattice dystrophy
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
Membrane: A very thin layer of tissue that covers a surface.
Nearsightedness: The ability to see near objects more clearly than distant objects. Also called myopia. See the entire definition of Nearsightedness
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.
Ocular: Having to do with the eye. See the entire definition of Ocular
Operation: Although there are many meanings to the word "operation", in medicine it refers to a surgical procedure. See the entire definition of Operation
Ophthalmologist: An eye doctor. A physician practicing ophthalmology. An ophthalmologist is an M.D.
Osteogenesis: The production of bone.
Osteogenesis imperfecta: Brittle bone disease. Osteogenesis imperfecta (OI) is not one but a group of genetic diseases, all of which affect collagen in connective tissue in the body and all of which result in fragile bones. The best known types are types I and II. See the entire definition of Osteogenesis imperfecta
Oxygen: A colorless, odorless and tasteless gas that makes up about 20% of the air we breathe (and at least half the weight of the entire solid crust of the earth) and which combines with most of the other elements to form oxides. Oxygen is essential to human, animal and plant life. See the entire definition of Oxygen
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
Prematurity: Historically, the definition of prematurity was 2500 grams (about 5 1/2 pounds) or less at birth. The current World Health Organization definition of prematurity is a baby born before 37 weeks of gestation, counting from the first day of the Last Menstrual Period (LMP).
Prescription: A physician's order for the preparation and administration of a drug or device for a patient. A prescription has several parts. They include the superscription or heading with the symbol "R" or "Rx", which stands for the word recipe (meaning, in Latin, to take); the inscription, which contains the names and quantities of the ingredients; the subscription or directions for compounding the drug; and the signature which is often preceded by the sign "s" standing for signa (Latin for mark), giving the directions to be marked on the container.
Progressive: Increasing in scope or severity. Advancing. Going forward. In medicine, a disease that is progressive is going from bad to worse. See the entire definition of Progressive
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
Proteins: Large molecules 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 Proteins
Recurrence: The return of a sign, symptom or disease after a remission. The reappearance of cancer cells at the same site or in another location is, unfortunately, a familiar form of recurrence. See the entire definition of Recurrence
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
Retinopathy: Any disease of the retina, the light-sensitive membrane at the back of the eye. The type of retinopathy is often specified. Arteriosclerotic retinopathy is retinal disease due to arteriosclerosis ("hardening of the arteries"). Diabetic retinopathy is retinal disease associated with diabetes. Hypertensive retinopathy is retinal disease due to high blood pressure. Etc.
Sclera: The tough white outer coat over the eyeball that covers approximately the posterior five-sixths of its surface. The sclera is continuous in the front of the eye with the cornea and in the back of the eye with the external sheath of the optic nerve. See the entire definition of Sclera
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.
Shingles: An acute infection caused by the herpes zoster virus, the same virus as causes chickenpox. Shingles is most common after the age of 50 and the risk rises with advancing age. Shingles occurs because of exposure to chickenpox or reactivation of the herpes zoster virus. The virus remains latent (dormant) in nerve roots for many years following chickenpox. See the entire definition of Shingles
Sign: Any objective evidence of disease. Gross blood in the stool is a sign of disease. It can be recognized by the patient, doctor, nurse, or others. In contrast, a symptom is, by its nature, subjective. Abdominal pain is a symptom. It is something only the patient can know. See the entire definition of Sign
Stroma: The supportive framework of an organ (or gland or other structure), usually composed of connective tissue. The stroma is distinct from the parenchyma, which consists of the key functional elements of that organ. The stroma of the thyroid gland is the connective tissue that supports the lobules and follicles of the thyroid gland. See the entire definition of Stroma
Superficial: In anatomy, on the surface or shallow. As opposed to deep. The skin is superficial to the muscles. The cornea is on the superficial surface of the eye. See the entire definition of Superficial
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
Transplant: The grafting of a tissue from one place to another, just as in botany a bud from one plant might be grafted onto the stem of another. The transplanting of tissue can be from one part of the patient to another (autologous transplantation), as in the case of a skin graft using the patient's own skin; or from one patient to another (allogenic transplantation), as in the case of transplanting a donor kidney into a recipient.
Trauma: Any injury , whether physically or emotionally inflicted. "Trauma" has both a medical and a psychiatric definition. Medically, "trauma" refers to a serious or critical bodily injury, wound, or shock . This definition is often associated with trauma medicine practiced in emergency rooms and represents a popular view of the term. In psychiatry , "trauma" has assumed a different meaning and refers to an experience that is emotionally painful, distressful, or shocking, which often results in lasting mental and physical effects. See the entire definition of Trauma
Ulceration: The process or fact of being eroded away, as by an ulcer.
Viral: Of or pertaining to a virus. For example, "My daughter has a viral rash ." See the entire definition of Viral
Viral infection: Infection caused by the presence of a virus in the body. Depending on the virus and the person's state of health, various viruses can infect almost any type of body tissue, from the brain to the skin. Viral infections cannot be treated with antibiotics; in fact, in some cases the use of antibiotics makes the infection worse. The vast majority of human viral infections can be effectively fought by the body's own immune system, with a little help in the form of proper diet, hydration, and rest. As for the rest, treatment depends on the type and location of the virus, and may include anti-viral or other drugs.
Virus: A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult. See the entire definition of Virus
Viruses: Small living particles that can infect cells and change how the cells function. Infection with a virus can cause a person to develop symptoms. The disease and symptoms that are caused depend on the type of virus and the type of cells that are infected.
- LASIK Eye Surgery - Get information about LASIK, refractive surgery for vision correction (of astigmatism, nearsightedness, farsightedness), risk factors (dry eyes, high myopia or hyperopia) and benefits.
- Eye Care - Get information on eye care tips and eye health, disorders and treatment with OTC eye-care products, and when to see an ophthalmologist about an eye infection or condition.
- Keratoconus - Learn about keratoconus, a vision problem relating to the cornea of the eye. Includes keratoconus causes and treatment.
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