Vision Correction Surgery Glossary of Medical Terms

20/20: See; Twenty-twenty .
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Ablation: Removal or excision. Ablation is usually carried out surgically. For example, surgical removal of the thyroid gland (a total thyroidectomy) is ablation of the thyroid. The word ablation comes from the Latin ablatum meaning to carry away.
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Abrasion: An abrasion or "excoriation" is a wearing away of the upper layer of skin as a result of applied friction force. In dentistry an "abrasion" is the wearing away of the tooth substance.
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Anisometropia: The condition in which the two eyes have an unequal refractive power. One eye may be myopic (nearsighted) and the other hyperopic (farsighted).
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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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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.
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Arthritis: Inflammation of a joint. When joints are inflamed they can develop stiffness, warmth, swelling, redness and pain. There are over 100 types of arthritis . (see osteoarthritis , rheumatoid arthritis , ankylosing spondylitis , psoriatic arthritis , lupus , gout , pseudogout ).
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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.
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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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Breastfeeding: Feeding a child human breast milk . According to the American Academy of Pediatrics , human breast milk is preferred for all infants. This includes even premature and sick babies, with rare exceptions. It is the food least likely to cause allergic reactions; it is inexpensive; it is readily available at any hour of the day or night; babies accept the taste readily; and the antibodies in breast milk can help a baby resist infections.
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Collagen: Collagen is the principal protein of the skin, tendons, cartilage, bone and connective tissue.
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Complication: In medicine, an additional problem that arises following a procedure, treatment or illness and is secondary to it. A complication complicates the situation.
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Condition: The term "condition" has a number of biomedical meanings including the following:

1. An unhealthy state, such as in "this is a progressive condition."
2. A state of fitness, such as "getting into condition."
3. Something that is essential to the occurrence of something else; essentially a "precondition."
4. 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.

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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.
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Corneal abrasion: A scratch or scrape on the cornea , the clear front window of the eye that transmits and focuses light into the eye.
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Cuts: Severed skin. Washing a cut or scrape with soap and water and keeping it clean and dry is all that is required to care for most wounds. Putting alcohol hydrogen peroxide, and iodine into a wound can delay healing and should be avoided. Seek medical care early if you think that you might need stitches. Any delay can increase the rate of wound infection. Any puncture wound through tennis shoes has a high risk of infection and should be seen by your healthcare professional. Any redness, swelling, increased pain, or pus draining from the wound may indicate an infection that requires professional care.
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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).
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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.
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Dilation: The process of enlargement, stretching, or expansion. The word "dilatation" means the same thing. Both come from the Latin "dilatare" meaning "to enlarge or expand."
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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.
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Dry eye: A deficiency of tears. The main symptom is usually a scratchy or sandy feeling as if something is in the eye. Other symptoms may include stinging or burning of the eye; episodes of excess tearing that follow periods of very dry sensation; a stringy discharge from the eye; and pain and redness of the eye. Sometimes people with dry eye experience heaviness of the eyelids or blurred, changing, or decreased vision, although loss of vision is uncommon.
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Elective: In medicine, something chosen (elected). An elective procedure is one that is chosen (elected) by the patient or physician that is advantageous to the patient but is not urgent.
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Emergency department: The department of a hospital responsible for the provision of medical and surgical care to patients arriving at the hospital in need of immediate care. Emergency department personnel may also respond to certain situations within the hospital such cardiac arrests.
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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.
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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.
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Farsightedness: Medically termed hyperopia; the ability to see distant objects more clearly than close objects.
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Focal: Pertaining to a focus which in medicine may refer to:
1. The point at which rays converge as, for example, in the focal point.
2. A localized area of disease. A focal cancer is limited to one specific area.
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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.
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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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Hospital: It may seem unnecessary to define a "hospital" since everyone knows the nature of a hospital. A hospital began as a charitable institution for the needy, aged, infirm, or young.
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Hyperopia: Farsightedness; the ability to see distant objects more clearly than close objects.
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Imitrex: Brand name for sumatriptan , a triptan drug for the treatment of migraine .
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Immunosuppressive: 1. Pertaining to immunosuppression , the suppression of the immune system .
2. An agent capable of suppressing the immune response .
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In situ: In the normal location. An "in situ" tumor is one that is confined to its site of origin and has not invaded neighboring tissue or gone elsewhere in the body.
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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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Keloid : A scar that doesn't know when to stop. When the skin is injured, cells grow back to fill in the gap. Somehow, they normally "know" when the scar tissue is level with the skin, at which point the cells stop multiplying. When the cells keep on reproducing, the result is a what is called a overgrown (hypertrophic) scar or a keloid. The result is a keloid -- a tough heaped-up scar that rises quite abruptly above the rest of the skin. It is irregularly shaped and tends to enlarge progressively.
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Keratitis: Inflammation of the cornea (the transparent structure in the front of the eye ).
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Keratoconus: Cone-shaped cornea with the apex of the cone being forward. Also called conical cornea.
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Keratoplasty: Corneal transplant.
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Keratotomy: A surgical incision (a cut) made into the cornea .
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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.
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LASIK : Abbreviation standing for laser-assisted in situ keratomileusis, a kind of laser eye surgery designed to change the shape of the cornea to eliminate or reduce the need for glasses and contact lenses in cases of severe myopia ( nearsightedness ).
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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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Lupus: A chronic inflammatory condition caused by an autoimmune disease. An autoimmune disease occurs when the body's tissues are attacked by its own immune system. Patients with lupus have unusual antibodies in their blood that are targeted against their own body tissues.
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Medication: 1. A drug or medicine. 2. The administration of a drug or medicine. (Note that "medication" does not have the dangerous double meaning of "drug.")
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Myopia: Nearsightedness, the ability to see close objects more clearly than distant objects.
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Nearsightedness: The ability to see near objects more clearly than distant objects. Also called myopia .
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NEI: Stands for National Eye Institute, one of the US National Institutes of Health.
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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.
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Ocular: Having to do with the eye.
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On call: In medicine, the person who is ready to respond, the one on duty. As in "Who is the doctor on call this weekend?" or "This is the on call schedule."
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Operation: Although there are many meanings to the word "operation", in medicine it refers to a surgical procedure.
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Ophthalmologist: An eye doctor. A physician practicing ophthalmology. An ophthalmologist is an M.D.
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Ophthalmology: The art and science of eye medicine.
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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.

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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 .
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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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Peripheral: Situated away from the center, as opposed to centrally located.
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Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.
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Pregnant: The state of carrying a developing fetus within the body.
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Presbyopia: The loss of the eye's ability to change focus to see near objects. The reasons for this loss of the power of accommodation are not yet fully known. It is conventionally said to be due to the lens becoming less elastic with time.
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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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Radial: A word with diverse meanings in medicine and the biomedical sciences:

1. Pertaining to the radius, the smaller bone in the forearm . The radial artery is so named because of its proximity to the radius.
2. Pertaining to the radius of a circle.
3. Spreading from a central point. A radial keratotomy is an eye operation in which incisions are made in the cornea that resemble the spokes in a wheel.

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Radial keratotomy: An eye surgery procedure designed to flatten the cornea , reducing its optical power, to correct nearsightedness ( myopia ). In the procedure, incisions (cuts) are made in the cornea . The procedure is said to be radial because the incisions resemble the spokes in a bicycle wheel.
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Refraction: In ophthalmology, the bending of light that takes place within the human eye.
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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.
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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.
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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.
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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.
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Rule out: A term much used in medicine, meaning to eliminate or exclude something from consideration. The ACB (albumin cobalt binding) test helps rule out a heart attack in the differential diagnosis of severe chest pain.
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Sensation: In medicine and physiology , sensation refers to the registration of an incoming ( afferent ) nerve impulse in that part of the brain called the sensorium , which is capable of such perception. Therefore, the awareness of a stimulus as a result of its perception by sensory receptors. (Sensory is here synonymous with sensation.)
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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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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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Surgeon: A physician who treats disease, injury, or deformity by operative or manual methods. A medical doctor specialized in the removal of organs, masses and tumors and in doing other procedures using a knife (scalpel). The definition of a "surgeon" has begun to blur in recent years as surgeons have begun to minimize the cutting, employ new technologies that are "minimally invasive," use scopes, etc.
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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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Tear: A drop of the salty secretion of the lacrimal glands which serves to moisten the conjunctiva and cornea .
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Tissue: A tissue in medicine is not like a piece of tissue paper. It is a broad term that is applied to any group of cells that perform specific functions. A tissue in medicine need not form a layer. Thus,

• The bone marrow is a tissue;
• Connective tissue consists of cells that make up fibers in the framework supporting other body tissues; and
• Lymphoid tissue is the part of the body's immune system that helps protect it from bacteria and other foreign entities.

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Vascular: Relating to the blood vessels of the body. The blood vessels of the body, as a group, are referred to as the vascular system.
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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.
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