How Does Laser Eye Surgery Work?
In laser eye surgery, a laser is used to reshape the cornea to restore normal vision. The epithelium, or outermost layer of the cornea, must be removed in some way in order to get to the cornea for reshaping.
In LASIK surgery, a very thin layer of skin called a “flap” is cut in the cornea using an exceptionally precise instrument. Having exposed the cornea, the laser is then used to reshape it for proper vision, much like sculpting. After the procedure, the flap is replaced back to finish the laser eye surgery procedure. Over a period of months, the flap bonds to the cornea.
In PRK and LASEK surgery, the epithelium is removed either by scraping or with a chemical. In PRK, the epithelium grows back during the healing process. In LASEK, the epithelium is replaced after the reshaping of the cornea, and it bonds to the cornea again during the healing period.
How Does Laser Eye Surgery Correct Vision?
Impaired vision is often caused by a cornea that is not perfectly shaped. Hyperopia (farsightedness) and myopia (nearsightedness) are caused by a cornea that is too long or too short from front to back. Astigmatism is caused by a cornea with an uneven surface so that it is flat on one side and curved on the other, creating blurry vision. These conditions are called “refractive errors.” Today’s lasers are so advanced that they can customise your procedure to correct your sight precisely, reshaping the cornea to match the prescription of your corrective lenses.
While some types of laser eye surgery, such as LASIK, do require an incision, the cut is small and heals quickly. No two laser eye surgery practices operate exactly the same, but in general you can expect the following before, during, and after your surgery.
Before Laser Eye Surgery
Before committing to any surgical procedure on your eyes, you must have a consultation with a qualified surgeon to make sure laser eye surgery is advised for you. Most people are good candidates for this surgery, but not everyone.
Your prospective surgeon will give you a thorough examination to make sure you have no eye diseases or conditions that could make laser surgery risky for you. These diseases can include cataracts, glaucoma, or problems with the retina.
This exam will also include checking the prescription of your eyeglasses or contact lenses.
A number of tests are conducted, such as:
- A check of your vision just as you would have when getting new eyeglasses.
- A topography, which involves shining a painless light on your eye so that a topographical “map” of the eye can be photographed. This shows the curves and flat areas of the cornea and can alert the surgeon as to the likelihood of a condition called keratoconus. If you have that condition, your cornea may be too thin for LASIK surgery.
- Another test, also painless, is generally performed to measure the thickness of your cornea.
- A test may also be conducted to determine the amount of tears your eyes produce. This test may cause some momentary discomfort but is not painful.
After reviewing your test results, your surgeon will advise you about the best type of laser eye surgery for you and the degree of vision correction you can expect. It’s a good idea to take notes during this meeting because it is very easy to forget some of what you have been told.
Once you have made the decision to get laser eye surgery, additional prescription tests will be conducted to ensure that your vision correction during surgery is accurate.
The Day Of Your Surgery
The morning of your procedure, you must not wear any eye makeup. Perfumes are also discouraged.
When you arrive at the surgical facility, you may be offered a sedative, such as valium, to relax you. A scan may be performed again before the procedure to double check the results from your previous visit.
Right before surgery, numbing drops are placed in your eyes. During the procedure, you may be asked to fixate on a target such as a flashing light. This prevents your eyes from moving during the surgery. The laser tracks the movements of your eyes, but it is best if you keep your eyes still. Most procedures require only a few minutes per eye.
Afterward, if a flap has been cut, it is checked to make sure that no particles have fallen underneath it. If so, that debris can be removed right away. If a “wrinkle” in the flap occurs, that can also be immediately corrected.
What To Expect After Your Surgery
You can expect slightly blurred vision when you open your eyes after your surgery. In most cases, this resolves within hours. For some, there is a slight blurring for a period of days.
Someone else must drive you home, and you will be required to wear protective eye guards/goggles at night to prevent you from rubbing your eyes during your sleep. In the case of LASEK or PRK, you will be required to wear a bandage contact lens for 3-4 days.
You will also be given eye drops to put in your eyes on a regular basis for a period of time to lubricate the eyes, prevent infection, and decrease swelling.
Most people return to work either the next day or within a few days of surgery. You cannot swim, participate in sports, or wear eye makeup for a period of time.
Vision continues to improve gradually after all types of laser eye surgery. Some people experience tearing, burning, inflammation, dryness, redness, irritation, and mild pain. Medication can be taken to ease discomfort, although many people experience no pain at all.
Most people have some sensitivity to light and possibly even impairment of night vision, halos, or glare for a short time after surgery. These conditions are not usually permanent. Dry eye conditions can sometimes last for a few months and are permanent in a small number of patients. This condition can be treated with medications, however.
You will visit your surgeon for a post-op appointment 1-2 days after your surgery and usually a week after. Subsequent visits will be scheduled to monitor your progress during the months following the surgery.