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 disorders. There are three primary types of refractive errors: myopia, hyperopia and astigmatism.
Refractive errors
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.
LASIK surgery
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.
What is LASIK? - M3T2 Group 2 PBL
LASIK stands for laser in situ keratomileusis, which means using a laser underneath a corneal flap (in situ) to reshape the cornea (keratomileusis). This procedure utilizes a highly specialized laser designed to treat refractive errors, improve vision, and reduce or eliminate the need for glasses or contact lenses. This laser procedure alters the shape of the cornea, which is the transparent front covering of the eye. Though the excimer laser had been used for many years before, the development of LASIK is generally credited to Ioannis Pallikaris from Greece around 1991.
During the LASIK procedure, a specially trained eye surgeon first creates a precise, thin hinged corneal flap using a microkeratome. The surgeon then pulls back the flap to expose the underlying corneal tissue, and then the excimer laser ablates (reshapes) the cornea in a unique pre-specified pattern for each patient. The flap is then gently repositioned onto the underlying cornea without sutures.
There are a variety of different types of lasers used in ophthalmology. All LASIK procedures are performed with a specific type of laser (excimer laser), so in one sense, all LASIK procedures are similar. However, there are a variety of different laser manufacturers, including Visx, Wavelight, Alcon, Bausch & Lomb, and Nidek, among others, that have all designed specific excimer lasers. Further, there are different types of laser ablations that can be performed (see below), including conventional laser treatments, wavefront-optimized treatments, and wavefront-guided treatments. Finally, a completely different type of laser (femtosecond laser) can be used instead of a mechanical microkeratome to create the LASIK (corneal) flap.
Introduction to LASIK
This is a featured page
Eye and vision refraction disorders
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 disorders. 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.
LASIK surgery
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.
LASIK stands for laser in situ keratomileusis, which means using a laser underneath a corneal flap (in situ) to reshape the cornea (keratomileusis). This procedure utilizes a highly specialized laser designed to treat refractive errors, improve vision, and reduce or eliminate the need for glasses or contact lenses. This laser procedure alters the shape of the cornea, which is the transparent front covering of the eye. Though the excimer laser had been used for many years before, the development of LASIK is generally credited to Ioannis Pallikaris from Greece around 1991.
During the LASIK procedure, a specially trained eye surgeon first creates a precise, thin hinged corneal flap using a microkeratome. The surgeon then pulls back the flap to expose the underlying corneal tissue, and then the excimer laser ablates (reshapes) the cornea in a unique pre-specified pattern for each patient. The flap is then gently repositioned onto the underlying cornea without sutures.
There are a variety of different types of lasers used in ophthalmology. All LASIK procedures are performed with a specific type of laser (excimer laser), so in one sense, all LASIK procedures are similar. However, there are a variety of different laser manufacturers, including Visx, Wavelight, Alcon, Bausch & Lomb, and Nidek, among others, that have all designed specific excimer lasers. Further, there are different types of laser ablations that can be performed (see below), including conventional laser treatments, wavefront-optimized treatments, and wavefront-guided treatments. Finally, a completely different type of laser (femtosecond laser) can be used instead of a mechanical microkeratome to create the LASIK (corneal) flap.