What are refractive errors?
Refractive errors are vision problems that make it difficult for people to see clearly and they include myopia (short-sightedness), hyperopia (long-sightedness), astigmatism, and presbyopia (‘lao hua’). They occur when light that enters the eye does not focus on the retina resulting in blurry vision.
Refractive errors can be corrected by using prescription glasses, prescription contact lenses, and refractive surgery (eg. LASIK, epi-LASIK, implantable contact lenses). One of the more popular and more commonly performed refractive surgery for those who no longer want to use glasses and contact lenses is LASIK which stands for laser-assisted in situ keratomileusis. During LASIK surgery, corneal tissue is removed to reshape the eye to eliminate the use of glasses and contact lenses post-surgery. The top reasons for those who opt for LASIK surgery include:
- A long history of proven track record in terms of predictability, safety, and reliability
- Fast vision recovery with most regaining about 90% of the vision the very next day
- Low level of discomfort post-surgery (tearing for a few hours)
- Able to correct a wide range of all types of refractive errors (up to -12.00 of myopia and up to -5.00 of astigmatism)
- A quick painless procedure that takes about 10 to 15 minutes for 2 eyes
- A relatively low-risk procedure with a high success rate
Who can consider LASIK Surgery – General qualifications
You will have to be at least 18 years of age, not pregnant (for females), have no pre-existing eye conditions (e.g. cataract, glaucoma) and your eye prescription is stable. To properly assess your suitability for LASIK surgery, you will have to go through a LASIK evaluation where we conduct a series of eye tests including eye prescription tests, corneal thickness, cornea shape and curvature, eye pressure, and pupil dilation.
The ideal age to consider LASIK surgery
Generally, a person needs to be at least 18 years old, and more importantly, the eye prescription needs to settle down and stabilise for at least 12 months before LASIK surgery can be considered. Those below 18 years old are more likely to experience changes to their eye prescription as they are still growing. Therefore, we do not perform LASIK surgery for those below 18 years old.
The effect of laser is permanent, hence LASIK surgery does last a good number of years for most people. However, the eye is a living organ and due to aging, the eyes will change. One such change is the development of presbyopia whereby the eye muscles weaken and it becomes difficult to see near objects clearly; this becomes noticeable for those who are 40 years old and above. Those in this age group will usually opt for Monovision LASIK whereby the master eye is corrected to see far distance well and the non-master (reading) eye is corrected to see near well.
Is LASIK surgery for you?
If you have decided to put an end to waking up every morning without the need to put on glasses or contact lenses to see clearly, then LASIK surgery can be considered as long as your LASIK surgeon deems it safe and suitable for your eyes long-term through a thorough LASIK evaluation.
Who is excluded from LASIK surgery?
1. Those younger than 18 years old
The eye prescription has to be stable with no drastic change in numbers. Minor changes to prescription are acceptable, but if there are major changes every year, it is expected to continue changing post-LASIK. Hence, it will not be beneficial to have LASIK surgery done at this point as the eye prescription can change.
2. Severe dry eye
One of the common temporary side effects of LASIK surgery is dry eye. If you have a pre-existing severe dry eye, you should discuss in depth with your LASIK surgeon on your suitability for surgery.
3. Extreme myopia, hyperopia or astigmatism
The higher the eye prescription, the more corneal tissue will need to be removed during LASIK surgery. No LASIK surgeon will want to remove too much corneal tissue as doing so can weaken the cornea post-surgery and cause issues like ectasia (weakening of the inner layers of the cornea) which can lead to poor vision. Depending on the level of eye prescriptions, if LASIK is deemed unsuitable, an alternate refractive surgery procedure, implantable contact lens (ICL) surgery, can be considered as it does not involve the removal of corneal tissue.
4. Pre-existing eye or systemic conditions
The optimal surgical outcome can be achieved when LASIK is performed on healthy eyes. Having certain chronic eye conditions may affect LASIK surgery suitability. For instance, those with advanced glaucoma and cataract may not be suitable for LASIK surgery. Discuss your suitability with your LASIK surgeon if you have underlying eye conditions.
5. Pregnant (for females)
You can plan to get pregnant after LASIK surgery. Surgery though is not recommended if you are currently pregnant. It is advisable to wait for 3 months post-delivery to consider LASIK surgery. During pregnancy, the hormone level in the woman’s body changes, and these changes can affect the eye prescription, which in turn decreases the reliability of LASIK evaluation test results that are required to assess the suitability for surgery.