LASIK Glossary
Ablation zone
the area of tissue that is removed during LASIK surgery.
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 after LASIK surgery 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 LASIK surgery to remove corneal tissue.
Farsightedness
the common term for hyperopia.
Flap & Zap
a slang term for LASIK.
Higher order aberrations
refractive errors, other than nearsightedness, farsightedness, and astigmatism, that can only be corrected with LASIK surgery.
Hyperopia
the inability to see near objects as clearly as distant objects.
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.
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
A medical device used to produce a powerful beam of light that can vaporize eye tissue to correct vision.
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
in LASIK surgery, the adjustment of one eye for near vision and the other eye for distance 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. All LASIK surgeons are ophthalmologists.
Optometrist
a primary eye care provider who diagnoses, manages, and treats disorders of the visual system and eye diseases.
Overcorrection
a complication of LASIK 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 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.
Radial Keratotomy
commonly referred to as RK; a non-laser surgical procedure designed to correct myopia (nearsightedness) by flattening the cornea using radial cuts.
Refractive Errors
imperfections in the focusing power of the eye, for example, hyperopia, myopia, and astigmatism.
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.
Stroma
the middle, thickest layer of tissue in the cornea.
Undercorrection
a complication of LASIK surgery 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 can only be corrected with LASIK surgery.
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