In LASIK, PRK, and similar procedures, laser energy reshapes the curvature of the eye’s clear front surface (cornea) to alter the way light rays enter the eye.
LASIK is a surgical procedure to correct nearsightedness, farsightedness, and astigmatism that utilizes the microkeratome to create a corneal flap of about one-third of the total corneal thickness. The excimer laser is then used to reshape the exposed middle layer of the cornea. The flap is finally put back to assume a new shape created by the excimer laser
All laser vision correction surgeries work by reshaping the cornea, the clear front part of the eye, so that light traveling through it is properly focused onto the retina located in the back of the eye. LASIK is one of a number of different surgical techniques used to reshape the cornea.
Conductive Keratoplasty (NearVision CK)
Conductive Keratoplasty (NearVision CK by Refractec) uses a tiny probe and low heat radio waves to apply “spots” around the periphery of the eye’s clear front surface. This relatively non-invasive method steepens the cornea, to provide near vision correction for people who are farsighted. CK also can be used to correct presbyopia or enhance near vision for people who have had LASIK or cataract surgery. CK received initial FDA approval in 2002.
FemtoLASIK is a technologically advanced form of LASIK which has gained popularity worldwide among both patients and surgeons, and may be considered the future of LASIK. The FemtoLASIK procedure is slightly different than conventional LASIK in the first step of the LASIK surgery. When creating the corneal flap, FemtoLASIK uses the Carl Zeiss (Germany) VisuMax Femtosecond laser instead of the conventional microkeratome blade. This makes FemtoLASIK a bladeless, all-laser form of LASIK. Once the corneal flap is made, the Carl Zeiss MEL 80 excimer laser is used to provide wavefront correction which will give patients the clear vision without glasses they are dreaming of. The advanced technology of the Carl Zeiss VisuMax femtosecond laser allows for a smoother flap interface, and its patented curved contact surface increases patient comfort by inducing minimal pressure on the cornea.
Photorefractive Kerototomy (PRK)
PRK was the first type of laser eye surgery for vision correction and is the predecessor to the popular LASIK procedure. Though PRK recovery takes a bit longer than recovery from LASIK eye surgery, PRK is still commonly performed and offers advantages over LASIK for some patients.
Like LASIK and other types of laser eye surgery, PRK works by reshaping the cornea using an excimer laser, allowing light entering the eye to be properly focused onto the retina for clear vision.
ReLEx uses the femtosecond laser from Carl Zeiss VisuMax in its most advanced form to correct myopia and astigmatism. Similar to the LASIK approach, ReLEx changes the corneal curvature to correct for the refractive error. However, instead of using the microkeratome blade to cut the flap as in LASIK, it uses the femtosecond laser to make a small (2-5 mm) incision for more accuracy and precision. With a special software program from Carl Zeiss Meditec, Germany, the Visumax calculates the amount and shape of corneal curvature change required to correct the refractive error and makes a customized lenticule in the middle layer of the cornea. This refractive lenticule is extracted (instead of using excimer laser to change curvature of the cornea as in LASIK/FemtoLASIK/PRK) from the small incision.
There are two types of cataract surgery.
Phacoemulsification, or phaco. A small incision is made on the side of the cornea, the clear, dome-shaped surface that covers the front of the eye. Your doctor inserts a tiny probe into the eye. This device emits ultrasound waves that soften and break up the lens so that it can be removed by suction. Most cataract surgery today is done by phacoemulsification, also called “small incision cataract surgery.”
Extracapsular surgery. Your doctor makes a longer incision on the side of the cornea and removes the cloudy core of the lens in one piece. The rest of the lens is removed by suction.
After the natural lens has been removed, it often is replaced by an artificial lens, called an intraocular lens (IOL). An IOL is a clear, plastic lens that requires no care and becomes a permanent part of your eye. Light is focused clearly by the IOL onto the retina, improving your vision. You will not feel or see the new lens.
Some people cannot have an IOL. They may have another eye disease or have problems during surgery. For these patients, a soft contact lens, or glasses that provide high magnification, may be suggested.
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