Laser Refractive Surgery

By Richard Phinney, M.D.

Laser refractive surgery is the term given to a number of procedures designed to change the focusing properties of the eye.  The clear curved cornea is modified by the application of laser energy in such a way that the images of distant objects are more accurately focused on the retina.

The excimer laser energy may be placed on the surface of the cornea.  This form of treatment is termed photo refractive keratectomy or PRK.  It is the procedure first approved to correct nearsightedness and astigmatism by the FDA in 1996.  It is typically suggested as the procedure of choice for patients with thin corneas, corneal surface disorders and dry eye. Regression of effect and corneal haze was a common problem after PRK for higher degrees of refractive error, but application of a dilute medicine called mitomicin C to the corneal surface after ablation significantly reduces these complications. Because PRK is performed on the corneal surface, there is a corneal abrasion that takes two to three days to heal.  This is typically uncomfortable and limits activities for a few days. 

Advances in instruments known as microkeratomes in the late 1990’s made the procedure know as LASIK (laser-assisted intrastromal keratomileusis) commonplace. LASIK surgery employs the same excimer laser used in PRK, but the application in the cornea is below the biologically active surface.  In order to apply the laser energy in the substance of the cornea, a thin corneal flap (much like a contact lens on a hinge) is first formed by a microkeratome, or more recently, another type of laser.  The microkeratome is a mechanical device which uses a blade to cut the flap, whereas the femtosecond laser (IntraLase) creates the flap by accurate application of energy within the cornea. Both techniques take less than a half minute per eye to perform. The laser method of flap creation is increasing in popularity. This flap is retracted on the hinge prior to application of the laser energy in the cornea’s center.  The flap is then laid back in place and adheres by natural means.  Distance vision is usually good enough for people to be back to work and drive without glasses within 24 hours.  Eye drops are used for a few days after LASIK and for several weeks after PRK.

Laser refractive surgery performed by experienced practitioners provides the opportunity for freedom from glasses and contact lenses.  Middle-aged people who require a bifocal segment in glasses to assist reading will still need reading glasses or may opt for something known as monovision.  In this situation, one eye is corrected for distance while the other is made somewhat nearsighted.  In this case, people are able to see a distance with the fully corrected eye and at near with the other.  Many people easily adapt to this condition which admittedly, sounds somewhat bizarre.  If this option is elected and later the patient finds that they can’t adapt, it is possible to convert the near eye to a distance eye. Reading glasses can then be used.

Today’s laser technology has provided hundreds of thousands of people worldwide with freedom from glasses and contact lenses.  The risk of surgical complications exist with all operations, and imperfect vision may be the consequence of laser refractive surgery.  National studies indicate that mild uncorrectable vision loss (two lines on the eye chart) occurs in 1 – 2% of patients following conventional laser application.  Advances in the programming of laser application with information gathered from the eye by a device known as an aberrometer have resulted in so-called “custom” treatment. These custom applications have improved visual outcomes and reduced the risk of vision loss. Not all lasers are approved for this type of treatment.

The laser vision correction marketplace can be confusing for patients.  There are differences in the capabilities of FDA approved lasers, differences in surgeon experience, and differences in post-operative care. Sometimes people get caught up in the hype of advertising and forget this is surgery that demands pre and post-operative attention to details by an easily accessed, experienced eye doctor.

Eye Surgeons Associates located in Bettendorf, Muscatine, Rock Island, Silvis and Geneseo, provides comprehensive eye care for the entire family, for a lifetime. Our medical doctors are fully fellowship trained in their specialties and board certified. For more information visit us online at www.esaeyecare.com. Dr. Richard Phinney was trained as a physician and surgeon at the University of Iowa and has been board certified by the American Board of Ophthalmology since 1983. Dr. Phinney is also certified by the American Board of Eye Surgeons in LASIK surgery. Dr. Phinney received subspecialty credentials in diseases and surgery of the cornea at UCLA’s prestigious Jules Stein Eye Institute. He established the first refractive surgical practice in the Quad Cities at Eye Surgeons Associates in 1991 and to date has performed more than 4,000 LASIK procedures.