Refractive eye surgery

Refractive eye surgery is a general term for surgical procedures that can improve or correct the eye's focus by permanently changing the shape of the cornea.

The surgery is relatively painless, the full recovery period is as short as a few days, and the whole experience lasts less than 20 minutes in most cases. By the standards of many surgeries, this is a very simple procedure. A large percentage of patients walk out of the surgery and within hours are seeing better than they've seen in years. Within time, generally within a few weeks time at the most, they're seeing at 20/20 or 20/40.

Laser vision correction surgery changes the shape of your eye to increase your visual acuity. The first laser surgery devices were developed in 1975 and tested for a decade before finally being tried on humans in Germany. ( Two years later, patients in the U.S. had the experimental surgery done, but the Federal Drug Administration (FDA) did not approve its use until 1995. The surgery takes only a few minutes. Recovery for all procedures takes from less than 24 hours to five days.

The Excimer laser's potential was discovered by Dr. Srinivasan, who was working in a research laboratory on a laser system to cut plastics and other organic materials. By the early 1980's, he realized the potential for the excimer laser to interact with biological tissue. Ophthalmologist Steven Trokel, working with Srinivasan, introduced the idea of using the excimer laser to reshape the cornea.

The first patient to undergo laser vision correction was treated in Germany in 1988. The highly sophisticated excimer laser uses light energy to correct focusing problems by vaporizing away a small amount of tissue from the central area of the cornea. Most surgical laser beams affect tissue by producing heat that burns it, or by producing a shock wave that separates tissue with micro-explosions.

The excimer laser works differently. It uses a charged mixture of fluorine gases to produce a cool beam of ultra violet light. The beam is unique because it breaks the molecular bonds and vaporizes tissue, one microscopic layer at a time. The excimer precisely sculpts tissue with almost no effect on the surrounding tissue. This ability makes it ideal for changing the shape of the cornea.

At present, refractive surgery is most effective for myopia, astigmatism and hyperopia. LASIK is the most recent advance in laser vision correction. LASIK is an acronym for Laser Assisted In-situ Keratomileusis. Compared to the original laser PRK, the surface of the cornea remains largely intact so that LASIK patients are more comfortable and see better more quickly.

LASIK has been performed internationally for approximately 10 years. It was first performed in U.S. clinical trials in 1991. It is important to note that the major components of the procedure have a long history. Ophthalmologists have been reshaping the cornea for over 50 years, creating a protective layer of tissue for over 35 years, and using the excimer laser since the 1980s.

In 1996, the FDA acted on the data submitted and approved the laser for treatment of low myopia up to -6.00 diopters. In 1997, the FDA approved the laser for treatment of astigmatism up to -4.00 diopters. There are currently three major manufacturers of the excimer laser equipment: Summit Technology, Visx and Nidek.


Oct. 21, 1999 - Summit Technology, Inc. announced that the U.S. Food and Drug Administration (FDA) granted approval for the Company's Apex Plus Excimer Laser Workstation for the LASIK treatment of myopia with or without astigmatism. The approval is for the correction of myopia in the range of 0D to -14.0D with or without astigmatism in the range of -0.5D to -5.0D. This approval gives Summit the widest range of treatments for nearsightedness and astigmatism in the industry.


Nov. 19, 1999 - VISX, INCORPORATED (Nasdaq:VISX) announced today that the U.S. Food and Drug Administration (FDA) has approved the use of its VISX STAR S2 Excimer Laser System(TM) as safe and effective for the treatment of up to 14 diopters of myopia, or nearsightedness, with up to 5 diopters of astigmatism.

September 30, 1999 - Nidek, Inc. announced the FDA had granted PMA supplement approval for the Company's EC-5000 Excimer Laser System for the treatment of Photorefractive Keratectomy for moderate myopia with astigmatism.

The new approval will allow treatment for the reduction or elimination of moderate myopia (nearsightedness) with astigmatism (uneven curvature of the cornea). The approval will allow correction of myopia ranging in severity from -1.00 to -8.00 diopters (D), with refractive astigmatism from -0.50 to -4.00 D cylinder by manifest refraction.


March 2000 - The LADARVision excimer laser, manufactured by Autonomous Technologies, Inc. and recently approved by the FDA, is a self aiming, small spot laser system for the correction of nearsightedness, farsightedness, and astigmatism. We are pleased to offer this next generation laser technology to our patients.

LADARVISION combines both eye tracking and small beam corneal shaping. The built-in eye tracker automatically follows any eye movements during the laser procedure. This allows the system to more accurately aim the laser beam and correct for any movement of the eye during the procedure. The expertise in the area of eye tracking had its origins in many years of research and development for the Strategic Defense Initiative and the National Aeronautic and Space Administration (NASA).

Unlike other laser systems in current use, the LADARVision system also uses a very small laser beam of less than 1 mm to shape the cornea. This beam is moved rapidly across the corneal surface in a computer-controlled pattern of tiny overlapping spots. The amount of corneal tissue removed with each spot is very small, less than the thickness of a single human hair. This changes the shape of the surface of the eye to correct nearsightedness and astigmatism and helps to produce a smooth postoperative corneal surface which may reduce side effects and improve visual recovery.

In addition, by measuring and correcting all eye movements during the laser procedure, the LADARVision system maintains accurate placement of the laser beam. At the same time, your surgeon will carefully monitor your eye on a computer screen which provides additional control.

The actual procedure and its risks and benefits are similar to PRK and LASIK in general. Your surgeon will discuss with you, in depth, if a procedure using the LADARVision system fits your particular needs.