Am I a candidate for Lasik surgery?
Bruce Siegling, O.D.
Refractive eye surgery refers to any type of eye surgery that improves the refractive state of the eye to decrease or eliminate the patient's dependence on glasses or contact lenses.
The ability to see is an amazing process whereby the light that enters the eye is first bent (or Refracted) by the front surface of the eye, the cornea, which is called the 'window of the eye'. Light then travels thru the pupil, the black hole in the center of the colored part of the eye called the iris. The light is then further bent (Refracted) by the Lens which is located behind the pupil, and back to the retina. The quality of the image is affected by Myopia (Near Sightedness), Hyperopia (Far Sightedness), Asigmatism (differing curvatures of the cornea), and other factors.
There are many types of refractive surgeries. The procedure for each patient will depend on many factors. The patient's Optometrist works with the surgeon to determine the best procedure based on the patient's spectacle correction, the thickness of the cornea, the integrity of the tear film, and other factors. The patient may need to have punctal plugs (small devices that are inserted into the tear ducts) if there is any indication that there may be some post surgical ocular surface issues.
Flap procedures include Lasik, ALK, and Intralase:
Lasik: (Laser-assisted in situ keratomileusis)-this has become the standard for most refractive surgeries. The surgeon makes a small flap with an insrument called a Microkeratome to expose the inner portin of the cornea, uses an excimer (cool) laser to microscopicallly remove then layers of corneal tissue, then replace the corneal flap.
Intralase: This procedure is similar to Lasik, except a laser is used to initially create the 'flap', creating a perfectly precise fit of the flap.
ALK: (Automated lamellar keratoplasy)-similar to Lasik, except the surgeon uses the Microkeratome, then removes minute segments of the cornea, then replaces the flap. It is particularly successful in patients with higher amounts of Myopia(Near Sightedness).
Surface procedures include PRK, LASEK, and Epi-LASEK:
PRK: (Photo-refractive Keratectomy)-This procedure is still used for lower amounts of Myopia. It is computer controlled to customize the surgery to a patient's own unique corneal shape and refractive error. It does not create a flap. Results are not apparent until the cornea heal, which may take several weeks. As it does not create a flap, there is less likelihood of glare and halos post-operatively, but the healing phase is longer.
Other types of procedures include RK, AK, LRI, ICRS, LTK, CK, M.A.R.K., and Astigmatic Keratectomy.
There are numerous new procedures including ICL(Implantable Contact Lens), Intracorneal lens implants, CLE(Clear Lens Extraction), Photophako reduction, and Photophako modulation. Space does not allow discussion of all of them.
Refractive surgery is not for everyone. Patients that have certain eye diseases, or that have Glaucoma, Diabetes, uncontrolled vascular disease, or an auto-immune disease are not good candidates. Also, patients with Keratoconus(an inherited disorder that causes thinning of the cornea) are not suited for refractive surgery as this may cause a progression of the disease.
Despite the mostly successful results with refractive surgery, it does not restore 'perfect vision' in every case. It can not correct the condition called 'presbyopia', the part of the aging process that requires the use of reading glasses. Therefore, patients that undergo refractive surgery at a younger age may enjoy good vision at both distance and near for many years, but at some point everyone over the age of forty will require some additional correction for reading, such as reading glasses.
To deterimine if you are a candidate for 'Refrative Surgery', seek out your Optometrist to discuss your options.