Laser Vision Correction
Laser vision correction procedures such as LASIK, Epi-LASIK, Custom LASIK, LASEK and PRK have allowed millions of people worldwide to enjoy clear vision and eliminate the need for glasses or contact lenses.
These procedures improve vision safely and precisely by reshaping the cornea to correct the following refractive errors:
- Nearsightedness, or myopia
- Farsightedness, or hyperopia
Most patients enjoy 20/20 vision or better after treatment.
LASIK, also known as Laser-Assisted In Situ Keratomileusis or laser vision correction, is a refractive procedure that reshapes the cornea to correct nearsightedness, farsightedness and astigmatism.
LASIK is the most common type of refractive surgery. Using targeted excimer laser beam energy, the LASIK procedure reshapes corneal tissue to correct refractive errors so that light rays are focused more precisely on the retina to produce clear, sharp vision. Patients who choose to undergo LASIK achieve clear vision without the need for glasses or contact lenses, while also benefiting from minimal downtime and little to no post-operative discomfort.
LASIK offers many improvements over other refractive surgery procedures. These include little or no post-operative discomfort, immediate vision improvement, and the ability to drive or return to work quickly-sometimes as soon as the next day. Most patients require no corrective eyewear after surgery although patients over 40 may require reading glasses.
Introduced by the inventor of LASIK, Epi-LASIK combines the best features of LASIK and PRK while reducing complications such as haze and halos, dry eye, loss of nerve sensitivity, post-operative pain, vision regression and continued need for eyewear.
Candidates for the Epi-LASIK Procedure
Patients who would be eligible for the Epi-LASIK procedure include those with the following conditions:
- Thin corneas
- People who have a risk of being exposed to trauma
- Dry eye
- Large pupils
- Abnormalities of the eye
The Epi-LASIK Procedure
While Epi-LASIK is considered safe for most patients, there are certain risks associated with any surgical procedure.
During the Epi-LASIK procedure, the epithelium is smoothly separated by an epikeratome and lifted, like a sheet, from the rest of the cornea. Using an excimer laser, the underlying corneal tissue is then reshaped. The epithelial sheet is placed back on the eye and covered with a protective contact lens to keep the flap in place and to aid in the healing process.
Custom or Wavefront LASIK
Custom LASIK, also known as wavefront LASIK or wavefront-guided LASIK, is the standard in laser vision correction. It offers the most accurate, individualized results for each patient. This FDA-approved procedure uses three-dimensional measurements of the eye to guide the laser as it reshapes the cornea and corrects your vision.
Custom LASIK benefits patients benefit by achieving 20/20 vision, with many patients obtaining vision that is better than 20/20, a goal that has not been achieved with traditional LASIK, glasses, or contacts. Custom LASIK also reduces the risk of poor night vision and glare, side effects that are common with traditional LASIK.
During the custom LASIK procedure, a wavefront device transmits a ray of light into your eye that is received and arranged into a unique pattern to create a 3-D map of your eye, including both lower and higher order aberrations. This information is transferred to the laser and applied to your eye's position, allowing the doctor to achieve customized vision correction for each patient.
While custom LASIK is considered safe for most patients, there are certain risks associated with any surgical procedure.
LASEK, also known as Laser Epithelial Keratomileusis, is a laser vision correction procedure that is recommended for patients with very thin or very steep corneas.
More of the cornea is exposed for treatment with LASEK than with LASIK, making LASEK a better choice for patients who require greater vision correction. LASEK does require a longer period of recovery.
The LASEK Procedure
An extremely thin layer of the epithelium, the outer layer of the cornea, is removed with a microsurgical instrument known as a trephine. The eye is then bathed with a special alcohol solution that loosens the edge of the epithelium to allow for the creation of an epithelial flap. The epithelial flap is created and lifted aside so that the central cornea is exposed for treatment with an excimer laser. After the laser treatment, the epithelial flap is put back in place and covered with a soft contact lens so that the eye may heal. The contact lens will be worn for a few days until recovery is complete.
Risks and Complications of the LASEK Procedure
During the post-operative recovery period, patients may experience some discomfort which may be alleviated by over-the-counter pain medication.
Photorefractive keratectomy, or PRK, is a laser vision correction procedure that reshapes the cornea to correct mild to moderate conditions of:
- Nearsightedness, or myopia
- Farsightedness, or hyperopia
PRK uses an excimer laser to remove a small amount of the anterior portion, or front, of the cornea to correct refractive errors. Unlike the LASIK procedure, where a flap is created to access the cornea, PRK removes the epithelial, or outer layer, of the cornea so that it can be reshaped with an excimer laser to remove tissue from the surface. This process flattens the cornea and achieves the corneal steepening needed for vision correction.
Advantages of the Photorefractive Keratectomy Procedure
The PRK procedure provides the surgeon with greater control over the location and amount of tissue being removed, which allows patients to enjoy much more accurate results. The PRK method involves gently sculpting the cornea rather than cutting, allowing the surgeon to treat greater degrees of nearsightedness, as well as farsightedness and astigmatism.
Up to 95 percent of patients with a correction of up to -6.00 diopters achieved a vision of 20/40 or better after PRK, with up to 70 percent achieving 20/20.
Some of the advantages of the PRK procedure include:
- Less depth of laser treatment
- Patients with thin corneas are eligible for PRK
- No corneal flap complications
Results of the Photorefractive Keratectomy Procedure
The results of PRK are considered comparable to those of LASIK, although some patients may experience vision of only 20/40, and others may still need glasses or contact lenses after their procedure. PRK does not correct presbyopia, a natural change in the eyes that affects everyone over the age of 40, so patients that need reading glasses will continue to need them after surgery. It is important for patients to maintain realistic expectations in order to be satisfied with the results of PRK.