The following are health and medical definitions of terms that appear in the Keratoconus article.
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
Blind:1. Unable to see. Without part or all of the sense of sight. 2. In a clinical trial, not to know the treatment given or received. The participant is not told whether they are in the experimental or control arm of the study. Also called masked.
Cone: A type of specialized light-sensitive cell (photoreceptor) in the retina of the eye that provide sharp central vision and color vision. See the entire definition of Cone
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 topography: Also known as videokeratography or corneal mapping, corneal topography is a method of computer-assisted examination of the cornea, the clear front portion of the eye that transmits and focuses light into the eye. Corneal topography is performed by projecting illuminated rings onto the corneal surface which are reflected back and measured by the instrument. The test results in the generation of a topographical map of the cornea. See the entire definition of Corneal topography
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.
Keratoconus: Cone-shaped cornea with the apex of the cone being forward. Also called conical cornea.
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
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
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.
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
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.
LASIK stands for laser in situ keratomileusis, which means
using a laser underneath a corneal flap (in situ) to reshape the cornea (keratomileusis).
This procedure utilizes a highly specialized laser (excimer laser) designed to
treat refractive errors, improve vision, and reduce or eliminate the need for
glasses or contact lenses. This laser procedure alters the shape of the cornea,
which is the transparent front covering of the eye. Though the excimer laser had
been used for many years before, the development of LASIK is generally credited
to Ioannis Pallikaris from Greece around 1991.
How does LASIK work?
During the LASIK procedure, a specially trained eye
surgeon first creates a precise, thin hinged corneal flap using a microkeratome.
The surgeon then pulls back the flap to expose the underlying corneal tissue,
and then the excimer laser ablates (reshapes) the cornea in a unique
pre-specified p...
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