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Vision
Care Center | What
is LASIK? | When is
LASIK not for me?
LASIK
Surgery Checklist | Glossary
LASIK Surgery
Glossary
Ablate - in surgery, is to
remove.
Ablation zone - the area of tissue that is removed during laser
surgery.
Accommodation - the ability of the eye to change its focus from
distant objects to near objects.
Acuity - clearness, or sharpness of vision.
Astigmatism - a distortion of the image on the retina caused by
irregularities in the cornea or lens.
Cornea - the clear, front part of the eye. The cornea is the first
part of the eye that bends (or refracts) the light and provides most of
the focusing power.
Diopter - the measurement of refractive error. A negative diopter
value signifies an eye with myopia and positive diopter value signifies
an eye with hyperopia.
Dry Eye Syndrome - a common condition that occurs when the eyes do
not produce enough tears to keep the eye moist and comfortable. Common
symptoms of dry eye include pain, stinging, burning, scratchiness, and
intermittent blurring of vision.
Endothelium - the inner layer of cells on the inside surface of the
cornea.
Epithelium - the outermost layer of cells of the cornea and the
eye's first defense against infection.
Excimer laser - an ultraviolet laser used in refractive surgery to
remove corneal tissue.
Farsightedness - the common term for hyperopia.
FDA - the abbreviation for the Food and Drug Administration. It is
the United States governmental agency responsible for the evaluation and
approval of medical devices.
Flap & Zap - a slang term for LASIK.
Ghost Image - a fainter second image of the object you are viewing.
Glare - scatter from bright light that decreases vision.
Halos - are rings around lights due to optical imperfections in or
in front of the eye.
Haze - corneal clouding that causes the sensation of looking through
smoke or fog.
Higher order aberrations - refractive errors, other than
nearsightedness, farsightedness, and astigmatism, that cannot be
corrected with glasses or contacts.
Hyperopia - the inability to see near objects as clearly as distant
objects, and the need for accommodation to see distant objects clearly.
Inflammation - the body's reaction to trauma, infection, or a
foreign substance, often associated with pain, heat, redness, swelling,
and/or loss of function.
Informed Consent Form - a document disclosing the risks, benefits,
and alternatives to a procedure.
In Situ - a Latin term meaning "in place" or not removed.
Iris - the colored ring of tissue suspended behind the cornea and
immediately in front of the lens.
Keratectomy - the surgical removal of corneal tissue.
Keratotomy - a surgical incision (cut) of the cornea.
Keratitis - inflammation of the cornea.
Kerato - prefix indicating relationship to the cornea.
Keratoconus - a disorder characterized by an irregular corneal
surface (cone-shaped) resulting in blurred and distorted images.
Keratomileusis - carving of the cornea to reshape it.
Laser - the acronym for light amplification by stimulated emission
of radiation. A laser is an instrument that produces a powerful beam of
light that can vaporize tissue.
LASIK - the acronym for laser assisted in situ keratomileusis which
refers to creating a flap in the cornea with a microkeratome and using a
laser to reshape the underlying cornea.
Lens - a part of the eye that provides some focusing power. The lens
is able to change shape allowing the eye to focus at different
distances.
Microkeratome - a surgical device that is affixed to the eye by use
of a vacuum ring. When secured, a very sharp blade cuts a layer of the
cornea at a predetermined depth.
Monovision - the purposeful adjustment of one eye for near vision
and the other eye fordistance vision.
Myopia - the inability to see distant objects as clearly as near
objects.
Nearsightedness - the common term for myopia.
Ophthalmologist - a medical doctor specializing in the diagnosis and
medical or surgical treatment of visual disorders and eye disease.
Optician - an expert in the art and science of making and fitting
glasses and may also dispense contact lenses.
Optometrist - a primary eye care provider who diagnoses, manages,
and treats disorders of the visual system and eye diseases.
Overcorrection - a complication of refractive surgery where the
achieved amount of correction is more than desired.
PRK - the acronym for photorefractive keratectomy which is a
procedure involving the removal of the surface layer of the cornea
(epithelium) by gentle scraping and use of a computer-controlled excimer
laser to reshape the stroma.
Presbyopia - the inability to maintain a clear image (focus) as
objects are moved closer. Presbyopia is due to reduced elasticity of the
lens with increasing age.
Pupil - a hole in the center of the iris that changes size in
response to changes in lighting. It gets larger in dim lighting
conditions and gets smaller in brighter lighting conditions.
Radial Keratotomy - commonly referred to as RK; a surgical procedure
designed to correct myopia (nearsightedness) by flattening the cornea
using radial cuts.
Refraction - a test to determine the refractive power of the eye;
also, the bending of light as it passes from one medium into another.
Refractive Errors - imperfections in the focusing power of the eye,
for example, hyperopia, myopia, and astigmatism.
Refractive Power - the ability of an object, such as the eye, to
bend light as light passes through it.
Retina - a layer of fine sensory tissue that lines the inside wall
of the eye. The retina acts like the film in a camera to capture images,
transforms the images into electrical signals, and sends the signals to
the brain.
Sclera - the tough, white, outer layer (coat) of the eyeball that,
along with the cornea, protects the eyeball.
Snellen Visual Acuity Chart - one of many charts used to measure
vision.
Stroma - the middle, thickest layer of tissue in the cornea.
Undercorrection - a complication of refractive surgery where the
achieved amount of correction is less than desired.
Visual Acuity - the clearness of vision; the ability to distinguish
details and shapes.
Vitreous Humor - the transparent, colorless mass of gel that lies
behind the lens and in front of the retina and fills the center of the
eyeball.
Wavefront - a measure of the total refractive errors of the eye,
including nearsightedness, farsightedness, astigmatism, and other
refractive errors that cannot be corrected with glasses or contacts.
Source: U.S. FDA Center for
Devices and Radiological Health
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Note: The above information is intended to supplement, not substitute
for, the expertise and judgment of your physician, pharmacist, or other
healthcare professional. It is not intended to diagnose a health
condition, but it can be used as a guide to help you decide if you
should seek professional treatment or to help you learn more about your
condition once it has been diagnosed.
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