Patent review: Laser eye surgery advances may improve results for patients

The proliferation of medical laser technology is bringing new scrutiny, particularly in eye surgery. Patients are reporting complications involving chronic eye dryness, visual distortions, and chronic pain. In some cases, post-surgery depression has led to suicide. The United States Food and Drug Administration is now being challenged to find out why this is happening and to approve better, safer products.

Laser eye surgery has been around since the late 1980s, but not much research has evaluated patient quality-of-life before and after treatment. In 2006, the FDA began to look into LASIK complications and quality-of-life issues and determined that more research was needed. Some researchers believe that changes in vision may affect the mind, and in response to patient complaints, the Food and Drug Administration plans to congregate a national study to examine the relationship of LASIK complications and psychological problems, such as depression.

Versatile Medical Tool

In addition to corrective eye surgery, lasers are currently employed in a wide range of medical uses. A laser can act as a cauterizing tool in delicate surgical procedures. It can clean obstructed arteries. It can remove dental cavities and whiten teeth. They are used for hair removal and other for dermatological applications such as removal of skin blemishes and tattoos. And they are used for restructuring as in plastic surgery procedures.

In corrective eye surgery, the laser that is more commonly used is the excimer. Also known as the exciplex laser, the excimer emits invisible ultraviolet light that triggers a photochemical reaction on the target tissue. This very short wavelength is capable of high resolution. The most common eye surgery excimer-type laser is the Argon:Fluorine (Ar:F) laser at 193 nm, used for photorefractive keratectomy (PRK) and LASIK (Laser-Assisted In-Situ Keratomilieusis), two procedures for correcting nearsightedness, farsightedness, and astigmatism. The laser is used to permanently reshape the cornea.

Eye Surgery Well-Established

Excimer lasers were introduced in 1975, and the first human eye treatment with VISX laser technology was in 1987. Laser technology and computer control software has evolved significantly since then bringing advances in LASIK surgery. Related diagnostic and control techniques have led to improved vision correction with over 95 percent of patients corrected to 20/20 vision or better. The American Society of Cataract and Refractive Surgery, which represents about 9,000 ophthalmologists specializing in laser eye surgery, suggests that only 2 to 3 percent of LASIK patients experience some sort of physical complications. Again, possible psychological complications are not being considered, so this number may be higher.

We will continue to see improved vision-correction lasers as the technology advances. In 2006, Technolas GmbH Ophthalmologische Systeme patented a compact excimer laser system (US 07022119), using an integrated system for easier control during LASIK.

In 2007, VISX Inc. filed US patent 07238177, "Methods and systems for laser calibration and eye tracker camera alignment", which is related to methods and systems for laser calibration and eye tracker camera alignment.

Also in 2007, Carl Zeiss Meditec AG, filed US patent 07211078, "Method and device for monitoring the energy and/or the position of a pulsed and scanned laser beam", which describes a monitoring method to be used with excimer lasers for refractive corneal surgery.

New products first must prove their effectiveness and safety. The excimer lasers being used for eye surgery in the United States have received FDA approval, and the physical risks associated with the procedure are well known. The unanswered question is whether these products are safe in the long term and whether the FDA criteria are adequate. We might have to wait to see the conclusions of the national study regarding the after-effects of laser eye surgery to be able to assess psychological problems that are now being reported.

Ruth Larabee is a Nerac Analyst who works with computer science and aerospace companies as well as with companies dealing with the study, design, development, implementation, support, or management of computer-based information systems, particularly software applications. She also helps companies analyze laser scanning and 3-D reconstruction modeling applications.

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