The following are health and medical definitions of terms that appear in the LASIK Eye Surgery article.
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. See the entire definition of Ablation
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).
Aging: The process of becoming older, a process that is genetically determined and environmentally modulated. See the entire definition of Aging
Anisometropia: The condition in which the two eyes have an unequal refractive power. One eye may be myopic (nearsighted) and the other hyperopic (farsighted). See the entire definition of Anisometropia
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
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
Autoimmune: Pertaining to autoimmunity, a misdirected immune response that occurs when the immune system goes awry and attacks the body itself. See the entire definition of Autoimmune
Baseline:1. Information gathered at the beginning of a study from which variations found in the study are measured. 2. A known value or quantity with which an unknown is compared when measured or assessed. 3. The initial time point in a clinical trial, just before a participant starts to receive the experimental treatment which is being tested. At this reference point, measurable values such as CD4 count are recorded. Safety and efficacy of a drug are often determined by monitoring changes from the baseline values.
Complication: In medicine, an additional problem that arises following a procedure, treatment or illness and is secondary to it. A complication complicates the situation.
Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.
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.
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. See the entire definition of Dry eye
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).
Essential:1. Something that cannot be done without. 2. Required in the diet, because the body cannot make it. As in an essential amino acid or an essential fatty acid. 3. Idiopathic. As in essential hypertension. "Essential" is a hallowed term meaning "We don't know the cause."
Excimer laser: A laser that emits very concentrated light in the ultraviolet (UV) region of the spectrum. See the entire definition of Excimer laser
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.
Farsightedness: Medically termed hyperopia; the ability to see distant objects more clearly than close objects. See the entire definition of Farsightedness
Hyperopia: Farsightedness; the ability to see distant objects more clearly than close objects. See the entire definition of Hyperopia
Ibuprofen: A non-steroidal anti-inflammatory drug (NSAID) commonly used to treat pain, swelling, and fever. Common brand names for Ibuprofen include Advil, Motrin, and Nuprin.
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. See the entire definition of In situ
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
Informed consent: A process in which a person learns key facts about a clinical trial, including potential risks and benefits, before deciding whether or not to participate in a study. Informed consent continues throughout the trial.
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
Keratectomy: Removal of part of the cornea. This can be done by surgical excision or by laser. One such laser procedure is PRK (photorefractive keratectomy).
Keratoconus: Cone-shaped cornea with the apex of the cone being forward. Also called conical cornea.
Keratoplasty: Corneal transplant.
Keratotomy: A surgical incision (a cut) made into the cornea. See the entire definition of Keratotomy
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
Laser surgery: A type of surgery that uses the cutting power of a laser beam to make bloodless cuts in tissue or remove a surface lesion such as a skin tumor. There are a number of different types of lasers that differ in emitted light wavelengths and power ranges and in their ability to clot, cut, or vaporize tissue. Among the commonly used lasers are the pulsed-dye laser, the YAG laser, the CO2 (carbon dioxide) laser, the argon laser, the excimer laser, the KTP laser, and the diode laser.
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). See the entire definition of LASIK
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
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. See the entire definition of Lupus
Mapping: Charting the location of genes on chromosomes.
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.
Myopia: Nearsightedness, the ability to see close objects more clearly than distant objects. See the entire definition of Myopia
Nearsightedness: The ability to see near objects more clearly than distant objects. Also called myopia . See the entire definition of Nearsightedness
Ophthalmology: The art and science of eye medicine.
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
Periphery:1. The outside or surface of a structure; the portion outside the central region. See the entire definition of Periphery
Postoperative: After surgery. As opposed to preoperative, before surgery.
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. See the entire definition of Presbyopia
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.
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
Radial: A word with diverse meanings in medicine and the biomedical sciences:
Pertaining to the radius, the smaller bone in the forearm. The radial artery is so named because of its proximity to the radius.
Pertaining to the radius of a circle.
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.
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.
Recuperate: To recover health and strength. From the Latin recuperare meaning to regain, get back, recover. To recuperate is to convalesce.
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
Scrub:1. As a verb, to wash the hands and forearms very thoroughly, as before engaging in surgery. To scrub implies the use of a brush (and often an implement to clean under the nails). To scrub, to scrub in (on a surgical procedure), and to scrub up are synonymous. 2. As a noun, a person who scrubs, as for surgery. 3. As an adjective, pertaining to scrubbing in for surgery, as a scrub nurse or a scrub tech.
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.
Speculum: An instrument used to widen an opening to look within a passage or a cavity. For example, a speculum may be used to widen the opening of the vagina so that the cervix is more easily visible. Other examples include the nasal speculum to look up into the nostrils and the ear speculum to look within the ear canal at the ear drum. The term "speculum" is the Latin word for mirror.
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). See the entire definition of Steroid
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
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. See the entire definition of Surgeon
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
Tear: A drop of the salty secretion of the lacrimal glands which serves to moisten the conjunctiva and cornea.
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
Youth: The time between childhood and maturity. (Unfortunately, as the songwriter Sammy Cahn noted, "youth is wasted on the young.")
Automated lamellar keratoplasty eye surgery, or ALK, is a surgical procedure used to correct vision in people with severe nearsightedness and mild degrees of farsightedness.
What Happens During Keratoplasty Eye Surgery?
Keratoplasty eye surgery, performed under local anesthesia, usually takes less than an hour to complete. A cutting device is used to make a small incomplete flap across the cornea. While still attached at one side, the corneal flap is folded back to reveal the layer of tissue below. Another, very precise cut is made on the sub layer of tissue based on the person's glasses' prescription. After this cut, the corneal flap is placed back over the eye where it reattaches.
What Are the Advantages of Keratoplasty Eye Surgery?
Compared to other vision repair surgeries:
The healing process for keratoplasty eye surgery is relatively quick
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