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Advanced Surface Ablation (ASA): Why I opted for epiLASIK in Singapore

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LASIK in Singapore has grown to include other methods to regain perfect eyesight, and one group of procedures particularly caught my eye: Advanced Surface Ablation (ASA) vision correction methods. I remember first hearing about EpiLASIK a few years back from a good friend of mine, that it is a procedure that less invasive since it does not cut a LASIK corneal flap.

I don’t know about you, but the thought of cutting my cornea terrifies me. Actually, the mere thought of having anything touching my eyes is enough to make me weak in the knees, much less cutting.

I’ve been wearing glasses since Primary Two. Growing up, I loved reading. I devoured fiction books with an insatiable appetite. When I turned 11 years old, I had already developed high myopia of 700 degrees on each eye. I remember being called names like four-eyed creature in Mandarin every so often, much to my dismay. Due to my high myopia, my glasses were hideously thick. The thick lenses made my eyes look tiny and because of that, I was always super conscious of how I looked. I felt like I was always hiding behind the lenses, trying to make myself smaller and more unnoticeable. I felt uncool and ugly.

So you can imagine when I was finally allowed to wear contact lenses, I was thrilled. I could finally shed my hideous, be-spectacled look! It was almost like a new lease of life. But alas, that joy was short-lived. Wearing contact lenses brought me a host of new problems: contact lens infections and corneal abrasions became a regular thing I had to cope with. Eventually, my eyes became sensitive to contact lenses and the eye doctor recommended that I stopped wearing them.

Enter EpiLASIK. A friend of mine got EpiLASIK done and raved about it, which led to me begin my own research into the world of laser vision correction. I then discovered this group of procedures called Advanced Surface Ablation (ASA). They are a no cut flap eye laser surgery—a surface-based alternative to the then popular LASIK.

In this article, I share with you my research and thoughts on ASA as well as my experience with Epi-LASIK.

What is Advanced Surface Ablation?

Just as its name suggests, Advanced Surface Ablation (ASA) procedures ablate and sculpt the cornea from the surface using a laser, correcting any refractive error. There is no need to cut a corneal flap like what happens in LASIK.

The thing is, our eyeballs have a tough layer of epithelial cells protecting it, just like how our skin’s epithelial cells. [1] To correct our vision, the laser has to sculpt the cornea’s stroma layer that is just beneath this outermost, protective epithelial layer.

In LASIK, the surgeon simply cuts through the epithelial cells and opens up the corneal flap to reach the stroma layer. In Advanced Surface Ablation techniques, the epithelial cells are first removed so that the laser can reach the cornea stroma.

Advanced Surface Ablation methods comprise four methods: PRK, LASEK, EpiLASIK and TransPRK.

TransPRK, EpiLASIK, LASEK, PRK: What is the difference?

The main difference between the four ASA procedures lie in how the cornea epithelial cells are removed. I’ve listed the procedures here, from the latest to the oldest.

1. TransPRK

The most advanced ASA procedure of the lot. An advanced type of excimer laser is used to remove the cornea epithelium and also ablate the cornea stroma, correcting refractive error. Only one excimer laser is needed.

Oxygen-permeable soft contact lenses are placed over the cornea surface for 4 to 5 days until the epithelial cells grow back. After the epithelium cells have healed, the contact lenses will then be removed.


epilasik procedure

In EpiLASIK, the eye doctor uses an ultrasonic epithelium separator to remove the epithelial cells first. Then the excimer laser is used to reshape the cornea stroma, correcting refractive error.

Oxygen-permeable soft contact lenses are placed over the cornea surface for 4 to 5 days until the epithelial cells grow back. After the epithelium cells have healed, the contact lenses will then be removed.


LASEK is one of the oldest laser vision correction procedures. The ophthalmologist uses alcohol to soften the epithelial cells and an instrument to brush the cells out of the way. The excimer laser is then used to reshape the cornea stroma beneath, correcting refractive error.

Oxygen-permeable soft contact lenses are placed over the cornea surface for 4 to 5 days until the epithelial cells grow back. After the epithelium cells have healed, the contact lenses will then be removed.

4. PRK

PRK is oldest laser vision correction procedure and can be considered the very first procedure doctors came out with. Yes, PRK existed even before LASIK surgery! It’s just that PRK was not very popular when it came out as it was often painful.

In PRK, epithelial removal is done using a rotating brush to scrape away epithelial cells. An excimer laser is used to ablate the cornea, correcting refractive error. When PRK was first done in the 1990s, there was no oxygen-permeable contact lenses that could be worn.

Why ASA procedures instead of LASIK?

LASIK has been performed on at least 40 million people worldwide — and is no doubt still the most popular laser vision correction method. [2] It’s probably due to its first-mover’s advantage, being the first widely-accepted laser vision correction procedure amongst the public. Doctors alike are mostly comfortable and experienced with doing LASIK.

However, two big drawbacks of LASIK remain and they center around the cut cornea flap. It has been estimated that LASIK corneal flap complications occur in 0.3% to 5.7% of LASIK patients. [3] The other risk is permanent, LASIK-induced dry eye syndrome.

Some doctors believe that Advanced Surface Ablation provides us a great alternative to LASIK, especially for those who have a tendency toward more clinically significant dry eyes and should not get flap surgery done. [4]

The benefits of ASA procedures like EpiLASIK

Here are three benefits of EpiLASIK and ASA:

1. No corneal flap complications

There is no corneal flap cut and opened up in EpiLASIK and other ASA procedures, so there is no risk of getting corneal flap infections and inflammations.

On the other hand, it is possible to experience flap inflammations post-LASIK surgery, and this is also called the ‘Sands of Sahara’. [3] This occurs when dust or dirt settles between the corneal flap and your eyeball, which interferes with healing and cause your vision to be unclear. If this happens to you after LASIK surgery, you have to go back to see your eye surgeon to get the flap lifted back up and ‘cleaned’.

2. No corneal flap dislodgement

I like that ASA procedures have no risk of corneal flap dislodgement—which to me, is one scary risk indeed!

Due to the cut LASIK flap, it’s possible to have the corneal flap dislodged and shift out of place if you receive a finger poke, injury or blunt force to your eye. [4] The thought of a dangling corneal flap is just too much for me.

If you are at high risk of such things occurring, for example, if you do contact sports like Mixed Martial Arts (MMA), tough rugby or football, it’s safer to steer away from flap surgery like LASIK and opt for ASA procedures instead. Even when you’re playing simple team sports like soccer or netball, you’ll have to be constantly on your guard and not let the ball hit your eye!

3. Lower risk of permanent, LASIK-induced dry eyes

ASA also yields a much lower risk of dry eyes, as found in many clinical studies. For me, I tend to have more sensitive and slightly dry eyes, so this was an important factor for me and is largely why I opted for EpiLASIK.

It was also found that the cut and flap LASIK surgery can give a minority of patients unusually dry eyes after LASIK. It’s possible for dry eyes to plague post-LASIK patients forever and result in a reliance on lubricant eye drops perpetually.

4. Lower risk of corneal thinning (i.e. less risk of cornea ectasia)

With ASA procedures like EpiLASIK, the cornea is not cut, thus your cornea thickness and structure are better preserved.

In LASIK, the cornea is cut. You will be left with a thinner cornea after LASIK as compared to after an ASA procedure. [5] Thus, if you have high myopia or thin cornea, your eye doctor may recommend you to opt for ASA procedures over LASIK.

There you have it! The four benefits of EpiLASIK which led me to eventually opt for this surface-based procedure despite LASIK being the more popular and more obvious choice.

But what about the cons of ASA? What are the disadvantages of EpiLASIK?

It’s true that every surgical procedure has its pros and cons. Be very wary if the doctor tells you there are no cons to a particular procedure.

For EpiLASIK and ASA, the biggest disadvantage is its long downtime. This is largely because your corneal epithelial cells were removed during EpiLASIK surgery and they will need time to heal and grow back, just like a wound on your skin.

This is why you are usually given 5 days of MC for ASA procedures; for LASIK or ReLEx SMILE, you may need 3 days of MC. Even though you are given 5 days of MC, I would strongly recommend you to take additional leave from work if you can and make sure you factor in weekends to rest! 7 to 10 days of rest at home would be best.

There is also some discomfort during the healing process for EpiLASIK and ASA as your epithelial cells grow back during the first few days. Vision can also be fuzzy for weeks—even though vision is still largely functional, it can be quite annoying to put up with blurriness for weeks. It may take 6 to 8 weeks for full vision stabilisation.

If you opt for LASIK or ReLEx SMILE, you should be able to see clearly within 3 days! That’s quite a lot of difference so if you can’t afford to take so much downtime or are the impatient sort, LASIK or ReLEx SMILE would be better options for you.

Why I opted for EpiLASIK instead of LASIK.

I simply wanted the peace of mind that came with EpiLASIK—no flap risks, no dry eye worries—and was willing to suffer the longer downtime and discomfort during the healing process.

If you’re like me and want to play it safe, you may also want to opt for EpiLASIK. Or if you are an active sportsperson who is at risk of receiving a force or impact to your face/eyes, then of course, opt for ASA procedures! Another thing to consider is your eye condition. If you already know you have dry eyes, you’re probably playing with fire if you opt for cut-and-flap LASIK surgery. It is likely that going for LASIK can exacerbate your dry eye condition!

The point is, no matter which procedure you pick, you should first weigh it pros and cons according to your lifestyle and eye condition. Everyone’s needs are different so go for laser vision correction with your eyes wide open: knowing the benefits of what the procedure will bring while accepting the cons and possible risks that come along with it.

Things to take note of after EpiLASIK

It’s pretty amazing what medical technology can do nowadays—you can literally throw away your glasses and contact lenses after EpiLASIK as you won’t be needing them anymore!

But here are some post-op care you ought to know after the surgery:

  • Don’t rub your eyes during the first week post-op
  • Apply the prescribed eye drops to ensure smooth recovery
  • Wear UV-protected sunglasses for at least 6 to 8 weeks to protect your eyes from the harmful ultraviolet rays of the sun
  • Only resume light exercise or sports after about 1 week
  • Only resume water and contact sports after 2 to 3 weeks, when your epithelium layer has completely healed.
  • Don’t go for any jacuzzi and sauna sessions for about 2 – 3 weeks

Final thoughts

One more thing: you’ll need to first undergo a pre-surgery eye assessment to determine if you are suitable for EpiLASIK or any other laser vision correction procedure. The whole eye assessment is about 2 hours long and take this opportunity to talk to your surgeon and discuss any concerns. Download our free Must-have Doctor’s Visit Checklist  for a useful roadmap of questions to ask the doctor during your visit. 

Onward to perfect 20/20 vision, my friend! 


[1] Sun, T., Tseng, S. & Lavker, R. Location of corneal epithelial stem cells. Nature 463, E10–E11 (2010). https://doi.org/10.1038/nature08805

[2] Stodola E. (2016). Refractive editors corner of the world: LASIK Worldwide, from https://www.eyeworld.org/article-lasik-worldwide

[3] Wachler B. S. B..LASIK risks and complications, from https://www.allaboutvision.com/visionsurgery/lasik_complication_1.htm

[4] McKinney S. (2020). Time to Revisit Surface Ablation?, from https://www.reviewofophthalmology.com/article/time-to-revisit-surface-ablation

[5] Karmel M. (2008). Ectasia After LASIK, from https://www.aao.org/eyenet/article/ectasia-after-lasik

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