Wavefront-guided LASIK

Saturday, December 19, 2009

Wavefront-guided LASIK is a variation of LASIK surgery in which, rather than applying a simple correction of focusing power to the cornea (as in traditional LASIK), an ophthalmologist applies a spatially varying correction, guiding the computer-controlled Excimer laser with measurements from a wavefront sensor. The goal is to achieve a more optically perfect eye, though the final result still depends on the physician's success at predicting changes which occur during healing. In older patients though, scattering from microscopic particles plays a major role and may outweigh any benefit from wavefront correction. Therefore, patients expecting so-called "super vision" from such procedures may be disappointed. Still, surgeons claim patients are generally more satisfied with this technique than with previous methods, particularly regarding lowered incidence of "halos," the visual artifact caused by spherical aberration induced in the eye by earlier methods. Based on their experience, the United States Air Force has described WFG-Lasik as giving "superior vision results".

Source: Wavefront-guided LASIK, Lasik eye surgery at wikipedia.org

LASIK Technology

Monday, December 14, 2009

The LASIK technique was made possible by the Colombia-based Spanish ophthalmologist Jose Barraquer, who, around 1950 in his clinic in Bogotá, Colombia, developed the first microkeratome, and developed the technique used to cut thin flaps in the cornea and alter its shape, in a procedure he called keratomileusis. Barraquer also researched the question of how much of the cornea had to be left unaltered to provide stable long-term results.The creator of the laser was Theodore H. Maiman.

Later technical and procedural developments included RK (radial keratotomy), developed in Russia in the 1970s by Svyatoslav Fyodorov, and PRK (photorefractive keratectomy), developed in 1983 at Columbia University by Dr. Steven Trokel, who in addition published an article in the American Journal of Ophthalmology in 1983 outlining the potential benefits of using the Excimer laser patented in 1973 by Mani Lal Bhaumik in refractive surgeries. (RK is a procedure in which radial corneal cuts are made, typically using a micrometer diamond knife, and is completely different from LASIK).

In 1968 at the Northrop Corporation Research and Technology Center of the University of California, Mani Lal Bhaumik and a group of scientists were working on the development of a carbon-dioxide laser. Their work evolved into what would become the Excimer laser. This type of laser would become the cornerstone for refractive eye surgery. Dr. Bhaumik announced his team's breakthrough in May 1973 at a meeting of the Denver Optical Society of America in Denver, Colorado. He would later patent his discovery.

The general term for changing a patient's optical measurements by means of an operation is Refractive Surgery. The introduction of lasers in refractive surgeries stemmed from Rangaswamy Srinivasan's work. In 1980, Srinivasan, working at IBM Research Lab, discovered that an ultraviolet Excimer laser could etch living tissue in a precise manner with no thermal damage to the surrounding area. He named the phenomenon Ablative Photodecomposition (APD).

The first patent for LASIK was granted by the U.S. Patent Office to Dr. Gholam A. Peyman on June 20, 1989, U.S. Patent #4,840,175, "Method for modifying corneal curvature," encompassing the surgical procedure in which a flap is cut in the cornea and pulled back to expose the corneal bed. The exposed surface is then ablated to the desired shape with an Excimer laser, after which the flap is replaced.

The LASIK technique was successfully applied in other countries before it arrived to the United States. The first U.S. Food and Drug Administration (FDA) trial of the Excimer laser was started in 1989. The first use of the laser was to change the surface shape of the cornea, known as PRK. Dr. Joseph Dello Russo was one of the ten original FDA researchers who tested and got approval for the Visx laser. The LASIK concept was first introduced by Dr. Pallikaris in 1992 to the group of ten surgeons who were selected by the FDA to test the Visx laser at 10 centers in the U.S.

Dr. Pallikaris theorized the benefits of performing PRK after the surface was raised in a layer to be known as a flap performed by the Mikrokeratome developed by Barraquer in 1950. The blending of a flap and PRK became known as LASIK, which is an acronym. It quickly became very popular, since it provided immediate improvements in vision and involved much less pain and discomfort than PRK.

Today, faster lasers, larger spot areas, bladeless flap incisions, intraoperative pachymetry, and wavefront-optimized and -guided techniques have significantly improved the reliability of the procedure compared to that of 1991. Nonetheless, the fundamental limitations of Excimer lasers and undesirable destruction of the eye's nerves have spawned research into many alternatives to "plain" LASIK, including LASEK, Epi-LASIK, sub-Bowman’s Keratomileusis aka thin-flap LASIK, wavefront-guided PRK and modern intraocular lenses.

LASIK may one day be replaced by intrastromal ablation via all-femtosecond correction (like Femtosecond Lenticule Extraction, FLIVC, or IntraCOR), or other techniques that avoid weakening the cornea with large incisions and deliver less energy to surrounding tissues. The 20/10 (now Technolas) FEMTEC laser has recently been used for incision-less IntraCOR ablation on several hundred human eyes and achieved very successful results for presbyopia, with trials ongoing for myopia and other disorders.

Source: LASIK Technology, Lasik Eye Surgery at wikipedia.org

Understanding Its Different Types of Lasik Eye Surgery

Sunday, November 1, 2009

Author: Ventura Eye Institute

When it comes to the matter of eye surgery, the first thing that comes to our mind is Lasik surgery. For corrective vision procedures, Lasik surgery is all what we think about. There are various alternatives to Lasik surgery today. You can choose the option that rests upon your eye condition, the surgeon who is going to operate and the budget you are comfortable in paying. Hence it is important for you to know the different types of Lasik surgery available so that you make the right click.

LASEK SURGERY: This type of surgery is a refractive procedure that uses alcohol to separate the outer layer of the cornea. The recovery time with Lasek surgery is longer as compared to Lasik surgery. It is useful for people with thin cornea.

PRK: It removes the epithelium with a metal surgical tool. The tissue is removed from the cornea under this treatment. It is a longer recovery process and is suitable for people with thin cornea and large pupils. It is effective for treatments including near-sightedness and far-sightedness. As compared to other forms of refractive surgery, ‘dry eyes’ is the most common complication of this surgery.

EPI-LASIK: A technique used to reduce dependency of a person on contact lenses or eyeglasses. It is a refractive surgery which is similar to Lasek without any use of alcohol. It makes use of a fine surgical blade that reduces the risk of wide corneal flap. A device similar to a microkeratome (called epi-keratome) slides over the surface of the cornea, just underneath the epithelial layer of cells while suction is applied. Epi-Lasik surgery involves less pain and is a fast healing process.

INTRAOCULAR LENS: It is a form of refractive surgery to change the eye’s optical power. In other words, it is done on the patients suffering from cataract. These intraocular lenses are implanted in the eye by replacing the existing crystalline lens. Most of the intraocular lenses are fixed monofocal lenses matched according to the distant vision. The procedure of surgery in the hands of experienced ophthalmologist takes less than 30 minutes and the recovery period is usually 2-3 weeks.

CK: In this type of refractive surgery, radio waves are passed to adjust the contour of the cornea by shrinking the collagen around it. Conductive Keratoplasty is a very fast procedure and a non-invasive alternative to other types of eye surgery.

Majority of people are not aware of the types of surgery best suited to improve their kind of vision impairment. Hence it is important to be well informed about your health so that you can make the right choice of treatment. Moreover, it is crucial to take advice from friends and relatives who have gone through these procedures while making the right choice of surgeon.

About the Author:

Dr. Michael Ragen expert in laser eye surgery,lasik eye surgery,vision correction,eye surgery,lasik surgery,epilasik,ck eye surgery,eyelid surgery,cataract surgery.Visit: eye surgery, lasik surgery, epilasik

Article Source: Lasik Eye Surgery ArticlesBase.com - Lasik Eye Surgery – Understanding Its Different Types

LASIK Eye Technology

Monday, September 7, 2009

LASIK Eye Surgery - LASIK Technology

The LASIK technique was made possible by the Colombia-based Spanish ophthalmologist Jose Barraquer, who, around 1950 in his clinic in Bogotá, Colombia, developed the first microkeratome, and developed the technique used to cut thin flaps in the cornea and alter its shape, in a procedure he called keratomileusis. Barraquer also researched the question of how much of the cornea had to be left unaltered to provide stable long-term results.
Later technical and procedural developments included RK (radial keratotomy), developed in Russia in the 1970s by Svyatoslav Fyodorov, and PRK (photorefractive keratectomy), developed in 1983 at Columbia University by Dr. Steven Trokel, who in addition published an article in the American Journal of Ophthalmology in 1983 outlining the potential benefits of using the Excimer laser in refractive surgeries. (RK is a procedure in which radial corneal cuts are made, typically using a micrometer diamond knife, and is completely different from LASIK).

In 1968 at the Northrop Corporation Research and Technology Center of the University of California, Mani Lal Bhaumik and a group of scientists were working on the development of a carbon-dioxide laser. Their work evolved into what would become the Excimer laser. This type of laser would become the cornerstone for refractive eye surgery. Dr. Bhaumik announced his team's breakthrough in May 1973 at a meeting of the Denver Optical Society of America in Denver, Colorado. He would later patent his discovery.[2]

The general term for changing a patient's optical measurements by means of an operation is Refractive Surgery. The introduction of lasers in refractive surgeries stemmed from Rangaswamy Srinivasan's work. In 1980, Srinivasan, working at IBM Research Lab, discovered that an ultraviolet Excimer laser could etch living tissue in a precise manner with no thermal damage to the surrounding area. He named the phenomenon Ablative Photodecomposition (APD).[3]

The first patent for LASIK was granted by the U.S. Patent Office to Dr. Gholam A. Peyman on June 20, 1989, U.S. Patent #4,840,175, "Method for modifying corneal curvature," encompassing the surgical procedure in which a flap is cut in the cornea and pulled back to expose the corneal bed. The exposed surface is then ablated to the desired shape with an Excimer laser, after which the flap is replaced.[citation needed]

The LASIK technique was successfully applied in other countries before it arrived to the United States. The first U.S. Food and Drug Administration (FDA) trial of the Excimer laser was started in 1989. The first use of the laser was to change the surface shape of the cornea, known as PRK. Dr. Joseph Dello Russo was one of the ten original FDA researchers who tested and got approval for the Visx laser. The LASIK concept was first introduced by Dr. Palliakaris in 1992 to the group of ten surgeons who were selected by the FDA to test the Visx laser at 10 centers in the U.S.

Dr. Palliakaris theorized the benefits of performing PRK after the surface was raised in a layer to be known as a flap performed by the Mikrokeratome developed by Barraquer in 1950. The blending of a flap and PRK became known as LASIK, which is an acronym. It quickly became very popular, since it provided immediate improvements in vision and involved much less pain and discomfort than PRK.

Today, faster lasers, larger spot areas, bladeless flap incisions, intraoperative pachymetry, and wavefront-optimized and -guided techniques have significantly improved the reliability of the procedure compared to that of 1991. Nonetheless, the fundamental limitations of Excimer lasers and undesirable destruction of the eye's nerves have spawned research into many alternatives to "plain" LASIK, including LASEK, Epi-LASIK, sub-Bowman’s Keratomileusis aka thin-flap LASIK, wavefront-guided PRK and modern intraocular lenses.

LASIK may one day be replaced by intrastromal ablation[4] via all-femtosecond correction (like Femtosecond Lenticule Extraction, FLIVC, or IntraCOR), or other techniques that avoid weakening the cornea with large incisions and deliver less energy to surrounding tissues. The 20/10 (now Technolas) FEMTEC laser has recently been used for incision-less ablation on several hundred human eyes and achieved very successful results for presbyopia,[5] with trials ongoing for myopia and other disorders.

Source: Lasik eye technology at wikipedia.org