What lasik mean?

What is LASIK?

The eye and vision errors The cornea is a part of the eye that helps focus light to create an image on the retina. It works in much the same way that the lens of a camera focuses light to create an image on film. The bending and focusing of light is also known as refraction. Usually the shape of the cornea and the eye are not perfect and the image on the retina is out-of-focus (blurred) or distorted. These imperfections in the focusing power of the eye are called refractive errors. There are three primary types of refractive errors: myopia, hyperopia and astigmatism. Persons with myopia, or nearsightedness, have more difficulty seeing distant objects as clearly as near objects. Persons with hyperopia, or farsightedness, have more difficulty seeing near objects as clearly as distant objects. Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye. Combinations of myopia and astigmatism or hyperopia and astigmatism are common. Glasses or contact lenses are designed to compensate for the eye's imperfections. Surgical procedures aimed at improving the focusing power of the eye are called refractive surgery. In LASIK surgery, precise and controlled removal of corneal tissue by a special laser reshapes the cornea changing its focusing power.
Other types of refractive surgery Radial Keratotomy or RK and Photorefractive Keratectomy or PRK are other refractive surgeries used to reshape the cornea. In RK, a very sharp knife is used to cut slits in the cornea changing its shape. PRK was the first surgical procedure developed to reshape the cornea, by sculpting, using a laser. Later, LASIK was developed. The same type of laser is used for LASIK and PRK. Often the exact same laser is used for the two types of surgery. The major difference between the two surgeries is the way that the stroma, the middle layer of the cornea, is exposed before it is vaporized with the laser. In PRK, the top layer of the cornea, called the epithelium, is scraped away to expose the stromal layer underneath. In LASIK, a flap is cut in the stromal layer and the flap is folded back.
Another type of refractive surgery is thermokeratoplasty in which heat is used to reshape the cornea. The source of the heat can be a laser, but it is a different kind of laser than is used for LASIK and PRK. Other refractive devices include corneal ring segments that are inserted into the stroma and special contact lenses that temporarily reshape the cornea (orthokeratology).
What the FDA regulatesIn the United States, the Food and Drug Administration (FDA) regulates the sale of medical devices such as the lasers used for LASIK. Before a medical device can be legally sold in the U.S., the person or company that wants to sell the device must seek approval from the FDA. To gain approval, they must present evidence that the device is reasonably safe and effective for a particular use, the "indication." Once the FDA has approved a medical device, a doctor may decide to use that device for other indications if the doctor feels it is in the best interest of a patient. The use of an approved device for other than its FDA-approved indication is called "off-label use." The FDA does not regulate off-label use or the practice of medicine.
The FDA does not have the authority to:
Regulate a doctor's practice. In other words, FDA does not tell doctors what to do when running their business or what they can or cannot tell their patients.
Set the amount a doctor can charge for LASIK eye surgery.
"Insist" the patient information booklet from the laser manufacturer be provided to the potential patient.
Make recommendations for individual doctors, clinics, or eye centers. FDA does not maintain nor have access to any such list of doctors performing LASIK eye surgery.
Conduct or provide a rating system on any medical device it regulates.
The first refractive laser systems approved by FDA were excimer lasers for use in PRK to treat myopia and later to treat astigmatism. However, doctors began using these lasers for LASIK (not just PRK), and to treat other refractive errors (not just myopia). Over the last several years, LASIK has become the main surgery doctors use to treat myopia in the United States. More recently, some laser manufacturers have gained FDA approval for laser systems for LASIK to treat myopia, hyperopia and astigmatism and for PRK to treat hyperopia and astigmatism.
See the section on FDA-approved lasers for more details on which lasers have received FDA approval and the specific indications and treatment ranges for which they were approved.

Possible LASIK Complications

Possible LASIK Complications


There are risks involved with any surgical procedure, and patients who are considering undergoing LASIK eye surgery should be aware of possible complications and side effects that can occur. The most common side effects associated with LASIK include glare, halos with night vision, and dry eyes. Additionally, some patients’ vision may be undercorrected or overcorrected and require additional treatment, contact lenses, or glasses after LASIK eye surgery. For more information on statistics related to LASIK laser eye surgery complications, visit our LASIK Statistics page.

In many cases, LASIK eye surgery complications disappear within a few days to a few months following the procedure. It is best to speak with your LASIK doctor if you are experiencing complications after LASIK surgery, have questions about the risks associated with laser eye surgery, or are interested in learning more about how recent developments can help reduce LASIK eye surgery complications.

Prospective LASIK candidates should be aware that LASIK does not prevent presbyopia – the decline of near vision as an individual enters middle age. Generally thought to be caused by a gradual loss of flexibility in the eye’s natural crystalline lens, presbyopia affects virtually everyone and generally requires the use of reading glasses. Learn more about presbyopia and other presbyopia treatments, such as IOLs, by visiting the appropriate DocShop pages.

Eye Anatomy

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.

Lasik Eye Surgery

Learning About LASIK

LASIK is a surgical procedure intended to reduce a person's dependency on glasses or contact lenses. The goal of this Web site is to provide objective information to the public about LASIK surgery. See other sections of this site to learn about what you should know before surgery, what will happen during the surgery, and what you should expect after surgery. There is a glossary of terms and a checklist of issues for you to consider, practices to follow, and questions to ask your doctor before undergoing LASIK surgery.
LASIK stands for Laser-Assisted In Situ Keratomileusis and is a procedure that permanently changes the shape of the cornea, the clear covering of the front of the eye, using an excimer laser. A knife, called a microkeratome, is used to cut a flap in the cornea. A hinge is left at one end of this flap. The flap is folded back revealing the stroma, the middlesection of the cornea. Pulses from a computer-controlled laser vaporize a portion of the stroma and the flap is replaced. There are other techniques and many new terms related to LASIK that you may hear about