Keratitis Glossary of Terms

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Acanthamoeba: A microscopic organism, an amoeba, found in soil, dust and fresh water (lakes, rivers, hot springs and hot tubs). Acanthamoeba also occur in brackish water and sea water as well as in heating, venting, and air conditioner units, humidifiers, and dialysis units.
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Acanthamoeba keratitis: Infection of the cornea by acanthamoeba, a microscopic water-borne ameba. The disease tends to occur in people who wear contact lens. It can accompany a bacterial infection of the eye. Acanthamoeba keratitis can produce corneal ulceration and result in severe loss of vision and even blindness. Signs and symptoms are persistent redness and pain in the eye. Treatment is with multiple antibiotics, often including antifungal drugs, and sometimes surgery after the infection has subsided.

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.
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Anterior: The front, as opposed to the posterior. The anterior surface of the heart is toward the breast bone (the sternum).
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Anterior chamber: The space in the eye that is behind the cornea and in front of the iris.
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Antibacterial: Anything that destroys bacteria or suppresses their growth or their ability to reproduce. Heat, chemicals such as chlorine, and antibiotic drugs all have antibacterial properties. Many antibacterial products for cleaning and handwashing are sold today. Such products do not reduce the risk for symptoms of viral infectious diseases in otherwise healthy persons. This does not preclude the potential contribution of antibacterial products to reducing symptoms of bacterial diseases in the home.

Antifungal: A drug used to treat fungal infections.
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Antiviral: An agent that kills a virus or that suppresses its ability to replicate and, hence, inhibits its capability to multiply and reproduce.
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Aspergillus: A family of fungal organisms and molds, some of which can cause disease (aspergillosis).

Atypical: Not typical, not usual, not normal, abnormal. Atypical is often used to refer to the appearance of precancerous or cancerous cells.

Autoimmune: Pertaining to autoimmunity, a misdirected immune response that occurs when the immune system goes awry and attacks the body itself.
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Bacteria: Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life).
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Bacterial: Of or pertaining to bacteria. For example, a bacterial lung infection.

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.

Chemotherapy: 1. In the original sense, a chemical that binds to and specifically kills microbes or tumor cells. The term chemotherapy was coined in this regard by Paul Ehrlich (1854-1915).
2. In oncology, drug therapy for cancer. Also called "chemo" for short.
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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.

Choroid: In the eye, a thin vascular layer between the sclera and the retina. The choroid supplies blood to the retina and conducts arteries and nerves to other structures in the eye.

Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
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Ciliary body: Part of the eye, the ciliary body is a thin vascular (blood vessel-filled) middle layer of the eye that is situated between the sclera (the white of the eye) and the retina (the nerve layer that lines the back of the eye, senses light, and creates impulses that travel through the optic nerve to the brain).
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Common cold: A viral upper respiratory tract infection. This contagious illness can be caused by many different types of viruses, and the body can never build up resistance to all of them. For this reason, colds are a frequent and recurring problem. In fact kindergarten children average 12 colds per year, while adolescents and adults have around seven colds per year.
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Conjunctiva: A thin clear moist membrane that coats the inner surfaces of the eyelids and the outer surface of the eye.
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Conjunctival: Pertaining to the conjunctiva, the clear moist membrane that covers the inner surfaces of the eyelids and the front of eyeball.

Cornea: The clear front window of the eye that transmits and focuses light into the eye.
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Corneal: Pertaining to the cornea, the clear front window of the eye that transmits and focuses light into the eye.

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.
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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).

Fungal: Pertaining to a fungus. For example, a fungal skin infection.

Fungi: Plural of fungus.

Fungus: A single-celled or multicellular organism. Fungi can be true pathogens (such as histoplasmosis and coccidioidomycosis) that cause infections in healthy persons or they can be opportunistic pathogens (such as aspergillosis, candidiasis, and cryptococcosis) that cause infections in immunocompromised persons (including cancer patients, transplant recipients, and persons with AIDS). An example of a common fungus is the yeast organism which causes thrush and diaper rash (diaper dermatitis). Fungi are also used for the development of antibiotics, antitoxins, and other drugs used to control various human diseases.

Herpes: A family of viruses. Herpes also refers to infection with one of the human herpesviruses, especially herpes simplex types 1 and 2.
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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.

Hygiene: The science of preventive medicine and the preservation of health. From the name of Hygeia, the daughter of Asklepios, the Greek god of medicine (whose staff with entwined snake is the symbol of medicine). Asklepios (known to the Romans as Aesculapius) had a number of children including not only Hygeia but also Panaceia, the patroness of clinical medicine. Hygeia also followed her father into medicine. As the patroness of health, Hygeia was charged with providing a healthy environment to prevent illness. In Greek, "hygieia" means health.

Immune: Protected against infection. The Latin immunis means free, exempt.

Immunocompromised: Having an immune system that has been impaired by disease or treatment.

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.
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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.
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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.

Interstitial: Pertaining to being between things, especially between things that are normally closely spaced.
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Iris: The iris is the circular, colored curtain of the eye. Its opening forms the pupil. The iris helps regulate the amount of light that enters the eye.
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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.
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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.
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Medical history: 1. In clinical medicine, the patient's past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed.
2. The history of medicine.

Microscope: An optical instrument that augments the power of the eye to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in 1628 borrowed from the Greek to combined micro-, small with skopein, to view. Although the first microscopes were simple microscopes, most (if not all) optical microscopes today are compound microscopes.

Mycobacteria: Plural of mycobacterium.

Ocular: Having to do with the eye.
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Ophthalmologist: An eye doctor. A physician practicing ophthalmology. An ophthalmologist is an M.D.

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.
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Parasite: An organism that lives in or on and takes its nourishment from another organism. A parasite cannot live independently.
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Parasitic: Having to do with a parasite, as in a parasitic infection; or acting like a parasite by taking nourishment from another.

Peripheral: Situated away from the center, as opposed to centrally located.
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Periphery: 1. The outside or surface of a structure; the portion outside the central region.
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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.

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).
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Recurrent: Back again. A recurrent fever is a fever that has returned after an intermission: a recrudescent fever.

Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.

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.
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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.
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Steroid: A general class of chemical substances that are structurally related to one another and share the same chemical skeleton (a tetracyclic cyclopenta[a]phenanthrene skeleton).
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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.
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Stromal: Pertaining to the stroma of an organ. See: 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.
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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.
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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:
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Tear: A drop of the salty secretion of the lacrimal glands which serves to moisten the conjunctiva and cornea.

Tear film: The liquid layer bathing the cornea and conjunctiva. It creates a perfectly smooth liquid outer layer that polishes the corneal surface, mechanically traps and flushes out foreign bodies and chemicals, contains bacteriostatic substances that inhibit the growth of microorganisms, and reduces the surface friction associated with eyelid blinking and eye movement.

Therapy: The treatment of disease.
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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.
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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.
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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.