Laser Surgery
Home ] Up ] Eye on the News ] Services ] Staff ] More Practice Photographs ] Contact Us ] Children's pages ] Community Donations ]

This information sheet has been produced in response to patients' questions about laser surgery, and is as neutral as possible so patients can take a balanced view of the risk versus benefits of having the procedures carried out.  We always recommend that anyone considering laser surgery read as much as they can before going ahead so they are fully informed.

LASER SURGERY

Reasons to consider refractive surgery:

  1. A desire to maintain a lifestyle that would be hampered somewhat by wearing glasses or contacts.
  2. Wearing glasses or contacts might be a handicap in certain occupations- pilot, sportsman, etc.
  3. Many people who would be satisfied with contacts have difficulty in wearing them for various reasons.

Advantages of surgery

  1. After high initial cost there is no running cost.
  2. Cosmetic.
  3. Greater freedom for sport and leisure.

Disadvantages of surgery

  1. Cost.
  2. Irreversible (canít "try it to see").
  3. Possible loss of quality of the best corrected vision, e.g. may be a line or two less good on a letter chart, or may find a loss of sharpness driving at night.
  4. Any surgery carries a small degree of risk- "disasters" have, very rarely, occurred.

Types of surgery

There are now a variety of different options available to the surgeon- the most common methods are PRK and LASIK.

PRK (Photorefractive Keratectomy)

The key element is the excimer laser.

The laser focuses a powerful, minute beam of "cold" energy on a microscopic target without affecting the surrounding area.

The surface of the cornea is treated after the first few layers of cells have been removed using alcohol.

The purpose of the PRK procedure is to change the shape of the cornea as required to correct the refractive vision problem.

It does this by the precise sculpting of layers of tissue from the central zone (visual axis of the cornea).

These layers are less than the thickness of a human hair.

The operation of the laser is computer controlled in accordance with a precise pattern based on extensive preoperative tests and evaluations.

The results are fed into the computer by the surgeon or expert technicians.

The computer then determines the extent and depth of sculpturing or ablation of corneal tissue required to correct the refractive vision problem.

This information guides the surgeon in the operation of the laser.

Advantages

  1. There are no corneal flap risks.
  2. Extremely high predictability for low degrees of myopia

Disadvantages

  1. Risk of infection (1/1000-1/3500).
  2. Post-surgical pain is greater.
  3. Scarring/healing haze 1-5%.
  4. Visual recovery takes 1-2 weeks.
  5. Steroid drops may be needed for up to six months with the attendant risks associated with that.
  6. Bilateral surgery on the same day is inadvisable as 95% of complications with PRK occur postoperatively.

 

LASIK (Laser In-Situ Keratomileusis)

In LASIK the eye surgeon uses a sophisticated, automated surgical instrument known as a microkeratome.

This is used to slice a micro-thin, disc-shaped flap from the top layer of the central zone of the cornea.

This flap is then held out of the way whilst the excimer laser is used to sculpt the underlying corneal tissue to the degree required to flatten its shape and thereby correct the refractive error.

The flap is then replaced and allowed to heal without the use of sutures.

Advantages

  1. Low risk of infection (1/5000).
  2. Very little incidence of post-surgical pain (1/50).
  3. The risk of haze is less than 0.2% for all degrees of correction.
  4. Visual recovery is quick (1-7 days) some patients have had it done in their lunch hour!
  5. Steroid drops may only need to be used for a week.
  6. Although it is advisable to correct one eye, then, a few days later, the other, most clinics now seem to do both eyes simultaneously.

Disadvantages

  1. A cut is involved which adds to the risk of a serious complication.
  2. Although LASIK is generally considered the best procedure for high myopes (>-6.00D), in some cases not all the myopia may be corrected.

Pre-requisites for laser surgery

  1. Aged 21+.
  2. Stable refractive error.
  3. Contact lenses must be left out for at least one month.
  4. No eye condition or disease present.
  5. Good sight in both eyes.
  6. No thin corneas are operable with LASIK.