Glossary
Although QualSight and your surgeon will carefully explain to you the surgery and answer any questions you may have on a one-on-one basis, patients have requested such a glossary to help them understand some of the more technical elements of the procedure. To be comprehensive, we have included most terms related to laser vision correction.
Ablate: to remove, in surgical terms.
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.
CK: CK (Conductive Keratoplasty) uses radio waves to reshape the cornea and bring near vision back into focus (i.e., to treat presbyopia, the close-vision problem that afflicts nearly everyone by age 50).
Conventional LASIK: another term for LASIK which refers to creating a flap in the cornea with a microkeratome and using a laser to reshape the underlying cornea.
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.
Custom: Also known as wavefront LASIK or wavefront-guided LASIK, uses 3-dimensional measurements of how your eye processes images to guide the laser in re-shaping the front part of the eye (cornea).
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.
Ghost Image: a faint 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, which 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.
IntraLase: IntraLase is the manufacturer of a femtosecond laser for use in creating a LASIK flap and other precise corneal incisions.
IntraLASIK: LASIK with the corneal flap being created by a femtosecond laser rather than with a mechanical microkeratome.
In Situ: a Latin term meaning "in place" or not removed.
IOL: an acronym for Intraocular Lens, an IOL is a man-made silicon or plastic lens used to replace the natural crystalline lens of the eye. IOL’s are used in cataract surgery,
Phakic Intraocular Lens (P-IOL) implantation, or Clear Lens Exchange: 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.
LASEK: LASEK is similar to PRK in that the top layer of the cornea is removed, and no flap is cut. The difference between LASEK and PRK is that the top layer of the cornea is removed by a laser instead of being scraped away as with PRK.
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.
Laser Vision Correction: a generic term for any the variations of the LASIK procedure.
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 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.
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.
Pachymetry: Measuring of the thickness of the cornea with ultrasound machine. The purpose of measuring is to determine the thickness of the cornea prior to PRK or LASIK treatment, so as not to exceed the maximum treatment depth.
Post-Operative Care: Post-Operative Care includes check up visits to the Doctor for up to one year after the surgery date as recommended by the practicing physician. The following is typically included in Post-Operative Care: a examination 1 day after surgery, 1 week, 1 month and 3 months (as recommended by the physician).
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.
Pre-Operative Care: Pre-Operative care is the preparation of a patient prior to surgery. This includes the consultation and evaluation of the patient’s cornea by the physician prior to surgery.
Presbyopia: the inability to maintain a clear image (focus) as objects move closer and is due to reduced elasticity of the lens with increasing age.
Pupil: the 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.
Standard LASIK: another term for LASIK which refers to creating a flap in the cornea with a microkeratome and using a laser to reshape the underlying cornea.
Stroma: the middle, thickest layer of tissue in the cornea.
Traditional LASIK: another term for LASIK which refers to creating a flap in the cornea with a microkeratome and using a laser to reshape the underlying 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.
- Please note: the majority of these definitions were written by the FDA and referenced from their website at http://www.fda.gov/cdrh/LASIK/glossary.htm
