What is LASIK eye surgery?
LASIK is a type of refractive surgery, which refers to any surgery done to correct a refractive error in your eyes.
In a normal eye, light enters through the cornea, and passes through the pupil and lens, where the light rays are then focused onto the retina. The optic nerves then send the information to the brain, which interprets it as images seen by our eyes.
A refractive error occurs when the shape of your eye prevents light from being focused on the retina. This causes blurred vision, which can be corrected if you wear glasses or contact lenses, or undergo refractive surgery to correct the refractive error.
The common types of refractive errors are:
- Myopia (short-sightedness), or difficulty in seeing distant objects clearly
- Hyperopia (far-sightedness), or difficulty in seeing close objects clearly
- Astigmatism, which refers to distorted vision resulting from an irregularly curved cornea
- Presbyopia, which refers to the gradual loss of your near focusing ability that occurs with age
How it works
Refractive surgery is usually done by laser. The most common form of refractive surgery done is LASIK (laser-assisted in situ keratomileusis). The laser procedure reshapes the cornea to correct the refractive error in your vision.
Other forms of refractive surgeries include:
- Surface ablation
- SMILE (small incision lenticule extraction)
- ICL, also known as implantable contact lens
Why do you need LASIK surgery?
If you have myopia, hyperopia, astigmatism or presbyopia, but do not wish to wear spectacles or contact lenses anymore, refractive surgery would be an option to consider.
- Allows you to achieve perfect spectacle-free vision, as early as a day after the procedure
- Is relatively pain-free
- Is a well-established procedure
- Has very few complications
Who should not undergo LASIK surgery?
LASIK is not recommended if you have any eye condition, disorder or injury that may result in increased risks of complications or poor surgery outcome. These include:
- Severe dry eyes, as LASIK may make it worse.
- Glaucoma, as your eye pressure may increase during the procedure.
- Inflammation (such as keratitis or uveitis) and infections (such as herpes simplex) that affect the eye.
- Keratoconus, an eye disease that affects the cornea and may result in vision loss. If keratoconus runs in your family, discuss with your doctor before undergoing any elective eye surgery even if you do not have the condition.
- Large pupils, especially in dim light, as you may have to live with night vision problems such as glares, haloes and multiple images after the surgery.
- Other eye diseases that can result in a progressive deterioration of your vision and thinning of your cornea.
LASIK carries higher risks if you have certain medical conditions such as:
- Disease or condition that affects your immune system e.g. HIV, lupus, or rheumatoid arthritis. You may be more prone to infections or your surgical wound may take longer to heal. Likewise, your risks are higher if you are taking an immunosuppressive medication for any reason.
- Uncontrolled diabetes, which may put you at risk of complications, such as infection.
LASIK may not be suitable for you if:
- You actively participate in contact sports which deliver blows to your face and eyes, such as martial arts or boxing.
- You are under the age of 18 and myopic. This is because your vision may not have stabilised.
- You are pregnant, breastfeeding or taking steroids. These may cause temporary fluctuations in your vision.
- You are taking drugs that contain retinoic acids or tretinoin for acne treatment.
In addition, do note that the benefits you are likely to gain from LASIK may not outweigh the risks involved if you have:
- Fairly good vision (e.g. you do not need to wear glasses all the time)
- High refractive error or severe myopia
What are the risks and complications of LASIK surgery?
LASIK may result in side effects, which usually resolve after a few weeks or months:
- Residual astigmatism may result if tissue removal is uneven. But with the advent of wavefront customised iLASIK, this incidence has reduced largely.
- Corneal thinning, also known as corneal ectasia, is one of the most severe complications from LASIK.
- Dry eyes is a common side effect of LASIK. Your eyes may feel dry after the surgery for up to 6 months or longer.
- Flap problems such as infection, excess tears or abnormal tissue growth under the flap.
- Undercorrection or overcorrection of the refractive error, which may require further enhancement surgery.
- Vision problems including difficulty seeing clearly at night. You may see glares or haloes around bright lights, or even experience double vision.
- Vision loss, which is rare, or vision deterioration after the surgery.
There is a chance that you will still need to wear reading glasses if you develop presbyopia as you age.