Laser Eye Surgery - What is laser eye surgery?

Diagram of the eye (Courtesy of the National Eye Institute, National Institutes of Health)

The different laser eye surgery techniques
There are a number of different laser eye surgery techniques, the two most popular are LASIK (Laser In-situ Keratomileusis), sometimes referred to as LASIX and PRK (Photo refractive Keratectomy) although there are other less well known types of laser eye surgery such as INTRALASIK, also called "all laser LASIK", LASEK (laser epithelial keratomileusis) a relatively new technical variation of PRK and LASEK also called epithelial LASIK or E-LASIK.

LASIK
Laser in-situ keratomileusis, or LASIK is the most commonly performed type of laser eye surgery and is generally considered to be a relatively safe and effective treatment for a wide range of common eye problems. However as with all surgical techniques there is a risk and you should ask your surgeon about them. Some example questions to ask your surgeon are here. Possible problems can be read here laser eye surgery risks.

The LASIK operation can take less than 30 minutes. First of all you lie back in a reclining chair in an exam ination room containing the laser system (a large machine with a microscope attached to it and a computer screen) and an anaesthetic solution is dropped into the eye to be treated. The eye is then cleaned, and a surgical instrument designed to keep the eyelids open (a lid speculum) is fitted over the eye. A ring is then attached directly onto the eyeball and suction is applied around the cornea. This will cause your vision to blur and dim. A precision surgical blade known as a microkeratome is attached to the ring and a flap is cut in the outer layer of the cornea, known as the epithelium.

Once the flap has been cut in the epithelium the microkeratome and ring are removed leaving you with blurred vision. The flap is folded back out of the way and the surgeon will ask you to focus on a light. This is not the laser. You will have to focus on the light whilst the laser is on, if you cannot you may not be a good candidate for laser eye surgery but your surgeon will explain this prior to the operation.

Once you are focusing on the light you will hear the laser system making a loud ticking sound (as the laser is pulsed) and you may smell something like burning hair whilst the excimer laser reshapes the middle section of the cornea, known as the stroma. The stroma is reshaped by precisely removing ("ablating") very tiny bits of the corneal tissue. When the cornea is reshaped in the right way, it focuses the light into the eye and onto the retina, resulting in clearer vision. The flap on the cornea is then precisely replaced covering the area where the corneal tissue was removed and a shield is placed over the eyes to stop irritation.

Both nearsighted and farsighted people can benefit from the LASIK laser eye surgery procedure. With nearsightedness the cornea is flattened by the laser whilst with farsightedness the cornea is steepened by the laser. Excimer lasers can also be used to correct astigmatism by smoothing the cornea into a more regular shape.

PRK
PRK (Photo refractive Keratectomy) is very similar to LASIK surgery, except that the entire procedure is carried out with an excimer laser. Instead of creating a flap the surface cells of the cornea are ablated using the laser resulting in a reshaped cornea. Although PRK is considered to be a safer procedure than LASIK, the healing time takes longer. PRK laser eye surgery can be used to treat nearsightedness, mild to moderate farsightedness and astigmatism.

LASEK
LASEK (laser epithelial keratomileusis) is a relatively new technical variation of PRK also called epithelial LASIK or E-LASIK, and is mostly used for people that have corneas that are too thin or too flat for LASIK eye surgery.

In LASEK, the epithelium is cut with a finer blade than a microkeratome called a trephine. The surgeon covers the eye with an alcohol solution for around 30 seconds to loosen the edges of the epithelium.

The alcohol solution is sponged away from the eye and the surgeon lifts the edge of the epithelial flap and gently folds it back out of the way. An excimer laser, such as that used in in LASIK or PRK laser eye surgery procedures, ablates the corneal tissue reshaping the cornea. After the laser ablation the epithelial flap is then placed precisely back in position.

EPI-LASIK
Epi-Lasik is like LASEK but the epithelium is cut into a flap using a separator known as an epikeratome that creates an epithelial sheet. No alcohol is used in this eye surgery procedure hence patients are likely to feel less pain and to heal faster.

ALK
Automated Lamellar Keratoplasty (ALK) is used to treat severe nearsightedness and mild to moderate farsightedness. The laser eye surgeon cuts a flap in the cornea. For nearsightedness a microkeratome is used to remove the corneal material under the flap whilst for farsightedness eye pressure alone will cause the cornea to steepen reducing farsightedness. The ALK eye surgery technique is used substantially less now because of better results achieved using other techniques such as LASIK and PRK.

WAVEFRONT LASIK ("CUSTOM" LASIK)
Wavefront treatment is the most technologically advanced laser eye surgery technique. A visual Wavefront analyzer or aberrometer is used to study the way your eye bends (refracts) light rays. The analysis is then fed to the computer attached to the laser and associated software calculates the exact laser procedure required to improve vision.

INTRALASIK
INTRALASIK also known as "all laser LASIK", is similar to LASIK except the corneal flap is created using a laser rather than a mechanical microkeratome. The IntraLASIK laser eye surgery technique may be carried out using conventional laser ablation or wavefront-guided custom LASIK laser ablation.

After laser eye surgery
Immediately after eye surgery, you will not have perfect eye sight. It can take anywhere from 3 to 6 months for your vision to completely stabilize. After all types of laser eye surgical procedures your eye may burn, itch, or feel like there is a foreign object in it. You can also experience discomfort and occasionally mild pain. Your eyes may also water and your vision will probably be blurry. However you must not rub your eyes. If you rub your eye you could easily dislodge the flap and therefore you would need further laser treatment to repair the problem. Additionally patients may also experience light sensitivity, and see star bursts or haloes round lights and the whites of your eye may look red or bloodshot. All these side effects should improve over the next few days. If you experience severe pain, or if your vision or other symptoms get worse you should contact your doctor immediately.

The doctor should carry out a post-operative inspection within the first 24 to 48 hours after laser eye surgery and at subsequent regular intervals for at least the first six months. At the first post-operative visit your doctor will remove the eye shield, test your vision, and examine your eye. Your doctor may then give you one or more types of eye drops to administer at home to help prevent infection and/or inflammation. You may also be advised to use artificial tears to help lubricate the eye. Do not resume wearing a contact lens in the operated eye, even if your vision is blurry.

More information about laser eye surgery
This website contains much more information about all the laser eye correction procedures including laser eye surgery videos, laser eye surgery costs and laser eye surgery links just use the menus at the top and bottom of the page.