LASIK is also known as the flap-and-zap method. During LASIK, a cut is made across the cornea such that a flap is created. The flap is then lifted, and laser correction will be applied to the underlying cornea tissue. After which, the flap is closed back without any form of stitches.
Epi-LASIK (Epi is short for epithelium), on the other hand, is an advanced surface ablation where no cut is made to the cornea. During Epi-LASIK, the uppermost surface layer of cells – also known as the epithelium layer – is removed. Laser correction is then applied to the underlying cornea. As the epithelium cells have regenerative properties, these cells will grow back on its own in 3-5 days. In this way, corneal tissue loss and nerve damage can be better preserved.
You will need to go through an in-depth pre-LASIK evaluation, where the optometrists and eye doctor will check your eyes thoroughly. In general, these are some of the factors that determines your suitability: (1) cornea shape (2) cornea thickness (3) any existing eye conditions such as glaucoma, cataracts, etc. There is no minimum power for Epi-LASIK, i.e. people with 100 degrees or less can still go for refractive surgery if they wish to. The maximum power for safe correction is usually limited to 1,200 degrees.
- You do not want to cut a cornea flap.
- You do not want to suffer from flap related complications such as flap infection, inflammation and flap dislodgement or flap wrinkles.
- You do not want to worry about suffering from dry eyes after Lasik as the cornea nerves are not cut.
- You have an active lifestyle and participate in contact and rugged sports such soccer, rugby, water skiing, competitive basketball or martial arts where the risk of traumatic cornea flap damage is higher.
- You want to better preserve precious cornea tissue for possible upgrade surgeries in future as your eyes age naturally. (such as future “lao hua” or presbyopia surgery)
For every surgery, the surgeon is of paramount importance. In LASIK and Epi-LASIK, an experienced and capable surgeon will keep surgical complications in check. Furthermore, reduced time taken during surgery done by an experience surgeon will result in more accurate results. As such, you may want to make sure the surgeon is well experienced in laser refractive procedures and is board certified. You may also want to check if he has a good reputation in the community, and if he is committed to his patients before, during and after the surgery.
Your eye will be held firmly by a suction force exerted through the suction ring. After which, you will be required to keep your gaze fixed at the blinking red light straight ahead. You may also want to check if the technology used at the LASIK centre of your choice has advanced eye tracking and iris recognition technology, so that the laser application is applied more accurately and will cease immediately should your eye shift out of focus.
Epi-LASIK only takes approximately 5 to 6 minutes per eye, while standard LASIK takes 10 minutes to 15 minutes per eye, about double the time – mostly due to the additional stage of cutting of the cornea flap.
No, the procedure is done completely under local anesthesia via eye drops. The eye drops are instilled just before the surgery and will numb the eyes so that there is no pain felt throughout the procedure.
Because there is a cut made across the cornea, LASIK has the additional risk of flap complications. These include: flap infection, flap inflammation, risk of flap dislodgement caused by rubbing or a finger poke or sports injury. Another complication resulting from a cut flap is acute and chronic dry eye because of the thousands of tiny cornea nerve endings are being severed in the process of cutting the cornea flap.
You will be given up to 5 days of MC, including the day of the surgery itself. Many patients report that they see and feel well and are tempted to go back to work early. However, it is advisable not to go back to work the first three days after the operation so as to reduce the risk of infection and to put in the prescribed eye drops at the prescribed intervals for fast and safe recovery.
You should rest at home and observe good hygiene. Do not touch your eyes and eyelids with dirty hands or apply the prescribed eyedrops without first washing your hands clean. Avoid crowded and dirty places and take care to ensure that dirty water from washing your face or hair do not get into your eyes. You should also refrain from rubbing your eyes for the first five days post surgery. At this first sign of severe pain or redness of the eyes or abnormal eye discharges, you should contact your eye doctor for an immediate eye review to avoid an eye infection.
Most surgeons will set it as 18 years and above. Some will set it as 16 years and above but the eye power should also have been stable for the past two years. Parents’ consent will also be needed for the younger patients. There is no oldest age limit but those over 60 years of age frequently have cataracts developing and would be better served by a cataract operation.
There is no minimum power i.e. people with 100 degrees of myopia can still go for refractive surgery. The maximum power for safe myopia correction is usually limited to 1,300 degrees. For astigmatism, we usually do not treat patients with more than 400 degrees of astigmatism. For hyperopia of more than 300 degrees or for those suffering from more than 1,300 degrees of myopia, lens implant or ICL surgery is the more suitable option.
You should stop soft contact lens wear for 3 days before coming for the procedure. For hard contact lens wearer, a full 14 days of cessation is necessary.
All laser vision correction procedures are done under eye drops anesthesia. In other words, only numbing drops are used. There is no injections given and rest assured that the procedure is painless.
Most patients will find that they are able to see clearly without the need
to wear glasses or contact lenses after laser vision correction. But there is no absolute guarantee that you do not need to wear glasses after surgery. For those patients with high powers, sometimes residual power remains that may require glasses to be worn to achieve 6/6 or perfect vision. When glasses need to be worn after surgery, they will be of significantly reduced power and dependence.
Enhancement surgery may be recommended for some patients who have significant amounts of residual eye power six months or more after the initial procedure. However, this depends on whether there is enough cornea tissue thickness to allow safe enhancement. For ReLEx SMILE patients, enhancement is possible only through a different technique i.e. Advanced Surface Ablation methods such as epi-LASIK. For LASIK patients who need enhancements, if the residual cornea thickness beneath the flap is too thin, Advanced Surface Ablation methods such as epi-LASIK can be done on the flap surface.
In theory yes, but in practical reality, very unlikely. It is like asking if you can die from a car crash or bicycle ride, possible but very unlikely!
When laser vision correction first started, the industry standard was to do one eye at a time. However with advances in technology and technique, it is acceptable and safe to go for bilateral laser vision correction as the risk of serious simultaneous bilateral complications is extremely low. Today, most patients (over 98%) will opt to do the surgery on both eyes at the same time for convenience in terms of taking medical leave and having to go through the discomfort of the recovery process twice. Furthermore, if patients opt to do one eye at a time, they will experience the discomfort and disruption of having imbalance vision during the interim period between the first and the second eye.
The procedure is contra-indicated in pregnancy. Women who are breastfeeding should not go for the procedure unless the baby is over eighteen months of age where the risk of eye drops medications affecting the child is low. But if you want to be completely safe, go for the surgery only after you have stopped breastfeeding your child.
In general, medical insurance cannot be used to claim for laser vision correction as the procedure falls under the category of a “cosmetic” op. CPF Medisave can be claimed if your myopia power difference in refractive power between the two eyes is more than 300 degrees.
Yes, soft contact lenses, including cosmetic lenses can still be worn but only after three months. Hard lenses cannot be worn as they tend to slip due to the altered cornea curvatures.
Will going for laser vision correction make future eye surgery such as cataract surgery more difficult?
No, as the entry wound for cataract surgery is at a different part of the eye. But your eye surgeon will need to factor in the new cornea curvature when he does the calculation and selection of the intra-ocular lens implant for the cataract surgery.
Yes. The most common strategy for those who have presbyopia is to aim for close to perfect vision in the dominant eye (usually the right eye) and deliberately aim for some under-correction in the other eye. This strategy is sometimes called “monovision correction”.
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