Saturday, June 5, 2010

Dr. Boothe Eye Care - Corneal Epithelium

Dr. Boothe Laser Center


HOW LONG WILL MY LASIK PROCEDURE TAKE?
The LASIK procedure time is between five and fifteen minutes. We ask our patients to plan to be with us for approximately two hours on the day of their treatment. This gives our medical team adequate time for your procedure preparation, additional paperwork, final examination, and give you an opportunity to ask questions after your vision correction. Dr. Boothe Eye Center

Keratomileusis- Keratos is the greek word for cornea, and mileusis means to reshape. Together they mean to reshape the cornea.
Microkeratome- A blade that creates a flap in the cornea during LASIK Surgery.


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.
Boothe Laser Center: LADAR

Using laser and radar technology developed by NASA, LADARVision® was the first approved system with active eye tracking, which compensates for involuntary eye movements. Although other laser systems have now developed eye-tracking systems, LADARVision® has the only system utilizing laser radar tracking technology, a system that measures eye movement 4,000 times each second and is capable of following eye movements regardless of how rapid or erratic they may be. Successful laser application does not rely on your ability to hold your eye perfectly still.

LASIK

LASIK is a more complex procedure than PRK. It is performed for all degrees of nearsightedness. The surgeon uses a knife called a microkeratome to cut a flap of corneal tissue, removes the targeted tissue beneath it with the laser, and then replaces the flap.
"With LASIK, the skill of the surgeon is important because he'll be making an incision," says Stephen Crawford, O.D., an optometrist practicing in Virginia, "compared to the PRK method where the machine does more of the work." Crawford urges people to find qualified, experienced doctors to perform this surgery. "You'll want someone who's done a number of LASIK procedures since this is a surgeon-dependent operation," he said.
According to Ken Taylor, O.D., vice president of Arthur D. Little, Inc., a technology and management consultant firm in Cambridge, Mass., "Last year, across the country, 40 to 45 percent of refractive surgeries performed by physicians were LASIK, which equates to approximately 80,000 procedures." Doctors not participating in clinical trials may choose to use the approved laser to perform LASIK procedures at their discretion, says Morris Waxler, Ph.D., chief of FDA's diagnostic and surgical devices section. But most uses are considered "off label" and are not regulated by FDA.

Boothe Eye Center



Keratotomy- Keratos is the greek word for cornea, and otomy means to create an incision. Together they mean to create an incision in the cornea.
Refractive Error- This word refers to vision problems associated with the cornea: Astigmatism, Hyperopia, and Myopia. Boothe Eye Care


Precision Surgery

PRK is an outpatient procedure generally performed with local anesthetic eye drops. This type of refractive surgery gently reshapes the cornea by removing microscopic amounts of tissue from the outer surface with a cool, computer-controlled ultraviolet beam of light. The beam is so precise it can cut notches in a strand of human hair without breaking it, and each pulse can remove 39 millionths of an inch of tissue in 12 billionths of a second. The procedure itself takes only a few minutes, and patients are typically back to daily routines in one to three days.
Before the procedure begins, the patient's eye is measured to determine the degree of visual problem, and a map of the eye's surface is constructed. The required corneal change is calculated based on this information, and then entered into the laser's computer.
Since 1995, a limited number of laser systems has been approved by FDA to treat various refractive errors, both with PRK and LASIK.
According to FDA's Center for Devices and Radiological Health, clinical studies showed that about 5 percent of patients continued to always need glasses following PRK for distance, and up to 15 percent needed glasses occasionally, such as when driving. In addition, many patients experienced mild corneal haze following surgery, which is part of the normal healing process. The haze appeared to have little or no effect on final vision, and could only be seen by a doctor with a microscope. Some patients experienced glare and halos around lights. These conditions, however, diminished or disappeared in most patients in six months. For about 5 percent of patients, however, best-corrected vision without corrective lenses was slightly worse after surgery than before. In view of these findings, FDA and the Federal Trade Commission (which oversees advertising) issued a letter to the eye-care community in May 1996 warning that unrealistic advertising claims, such as "throw away your eyeglasses," and unsubstantiated claims about success rates could be misleading to consumers.
Dr. Boothe Eye Care Corneal Epithelium- The corneal epithelium is the thin, protective layer encasing the eyeball. Prior to LASIK eye surgery, the epithelium must be lifted or polished away to expose the underlying cornea. The epithelium is regenerative and heals quickly.