LASIK — vision correction with a thin corneal flap
The short answer
At Gangnam Central Eye Clinic, LASIK means Safe ATOS LASIK. A laser creates a thin flap in the cornea, the flap is folded back, an excimer laser reshapes the corneal tissue underneath, and the flap is laid back in place. Whether LASIK is possible for you is decided by measuring the thickness and shape of your cornea — if the results do not fit, LASIK is not recommended.
How does LASIK work?
- Step by step: anaesthetic eye drops → a laser creates the corneal flap → the flap is folded back to expose the treatment area → the excimer laser corrects your vision → the flap is laid back in place.
- The flap is made with the SCHWIND ATOS (femtosecond laser), and the cornea is reshaped with the SCHWIND AMARIS RED (excimer laser).
- The AMARIS RED fires at a repetition rate of 1050 Hz with a 0.54 mm laser spot (Super-Gaussian profile), and its eye tracker samples at 1050 Hz.
- The figure of about 1.3 seconds per dioptre is a manufacturer value that holds only under set conditions: myopia without astigmatism, a vertex distance of 12.5 mm and a 6 mm optical zone.
Comparison — LASIK, LASEK, SMILE and ICL
| Safe ATOS LASIK | One-Point LASEK | Smart SMILE LASIK | Implantable lens surgery (ICL) | |
|---|---|---|---|---|
| Corneal flap | Yes | No | No | The cornea is not reshaped |
| How vision is corrected | The flap is lifted, the tissue beneath is reshaped, and the flap is laid back | The surface layer (epithelium) is removed by laser and the tissue beneath is reshaped | A thin disc of tissue (lenticule) is formed inside the cornea and removed through a small incision at its edge | A lens is placed inside the eye |
| Key measurements | Corneal thickness and shape | Corneal thickness and shape | Corneal thickness and shape | Anterior chamber depth, anterior chamber angle and the space in the anterior chamber |
Which one suits you is decided by your test results, not by this table.
Who is LASIK suitable for — and when is it not recommended?
Suitability depends not on your age or what you would like, but on measured values: corneal thickness and shape, your prescription, your tear film and the condition of your retina. In the situations below, LASIK is not recommended or another step comes first.
- A very high prescription — a planned ablation of 160 or more, or myopia of -8.0 D or more with moderate astigmatism → implantable lens surgery, which leaves the cornea untouched, is recommended first.
- Severe dry eye → the dry eye is treated first, and surgery is considered again afterwards.
- In your mid-40s with presbyopia beginning → near vision can become uncomfortable after LASIK or LASEK, so an approach that takes presbyopia into account is explained.
- If your vision has been changing → it is watched until it settles before deciding on surgery.
What is measured, and how?
For LASIK and LASEK, the two most important measurements are corneal thickness and corneal shape. Rather than adding more and more tests, Gangnam Central Eye Clinic repeats these key measurements several times to narrow the margin of error before planning surgery.
- Equipment: SIRIUS (3D corneal topography), PENTACAM, OCT and others.
- Contact lenses before the examination: leave soft lenses out for at least 5 days and hard lenses for at least 7 days.
- After pupil dilation, near vision is blurry and light feels glaring for about 3–6 hours.
Recovery and follow-up
Recovery speed differs from person to person. After vision correction surgery you come back at set points so that the following can be checked.
| When | What is checked |
|---|---|
| The day after surgery | Condition of the cornea, eye pressure, early recovery |
| 1 week | How vision is recovering, signs of inflammation |
| 1 month | Whether the correction has settled; vision measured again |
| 3 months | Final visual acuity check (this is the name of the test — it is not a promise of a particular level of vision) |
| 6 months – 1 year | Long-term stability, night vision, dry eye |
| After that | Annual check-up once a year (free for vision correction patients) |
How are costs explained?
Costs depend on your examination results and on the type of surgery, and fees for international patients are given after consultation. If you contact us by telephone or email before you travel, we will explain in advance so that nothing comes as a surprise when you arrive. — With LASIK, the examination may point to LASEK, SMILE or implantable lens surgery instead, so the cost is explained once the method has been decided.
If you are travelling from abroad
- The clinic is registered as a medical institution for foreign patients (M-2021-01-08-6311); the consultation languages on that registration are Korean, English and Chinese.
- On the day of your examination, near vision stays blurry for a few hours after the dilation test, so it is better not to plan anything demanding for the rest of that day.
- Book your flight home only after the check-up the day after surgery, when the cornea has been examined; the later follow-up schedule is arranged with you at consultation.
- Contact: telephone +82-2-555-1369 · email gnceyecenter@naver.com (during clinic hours, Korea Standard Time) · WhatsApp
Side effects and individual differences
Vision correction surgery carries the possibility of side effects, including dry eye, glare or halos at night, fluctuating vision during recovery and, rarely, infection, regression of myopia or the need for further treatment. Results and recovery differ from person to person, and no particular level of vision is promised. Please decide only after a precision examination and consultation with your doctor.
At follow-up after surgery, dry eye, night vision including glare, and regression of myopia are checked. Results differ from person to person, and no particular level of vision is promised.
Frequently asked questions (19)
Does LASIK involve cutting a flap in the cornea?
Yes. A laser creates a thin flap in the cornea, which is folded back so the excimer laser can reshape the tissue underneath, and then the flap is laid back down. LASEK and SMILE are the methods that do not use a flap.
Is LASEK safer than LASIK?
That is a common misconception. One is not better than the other — they differ in where the cornea is reshaped. Which suits you is decided by measuring the thickness and shape of your cornea.
LASIK, LASEK, SMILE or ICL — which one is right for me?
Your test results decide. For LASIK, LASEK and SMILE the key factors are corneal thickness and shape; for ICL they are the depth, angle and space of the anterior chamber. Without test results, none of them is recommended in advance.
I've been told my corneas are thin. Can I still have LASIK?
Your corneal thickness is measured again before deciding. If too little would be left after reshaping, LASIK is not recommended, and implantable lens surgery, which does not reshape the cornea, is considered as well.
My prescription is very high. Is LASIK still possible?
If the planned ablation is 160 or more, or you have myopia of -8.0 D or more together with moderate astigmatism, implantable lens surgery is recommended before any procedure that reshapes the cornea.
Can I have LASIK if I have dry eyes?
Your tear film is checked first. If the dryness is severe, it is treated first and surgery is considered again afterwards.
What are the chances of complications?
The risk differs from eye to eye, so it is not given as a number. Instead, the examination first looks for conditions that raise the risk — such as severe dry eye or high astigmatism — and anything that can be treated is treated first.
What equipment is used?
The flap is made with the SCHWIND ATOS femtosecond laser, and the cornea is reshaped with the SCHWIND AMARIS RED excimer laser. The AMARIS RED has a repetition rate of 1050 Hz and a 0.54 mm spot size.
What tests are done before surgery?
Corneal thickness and shape, your prescription, the tear film, pupil size and the condition of the retina. For LASIK, corneal thickness and shape are measured several times to reduce the margin of error.
When should I stop wearing contact lenses?
Soft lenses need to be left out for at least 5 days and hard lenses for at least 7 days for the measurements to be accurate. If you are coming from abroad, take them out before you fly so that you can be examined as soon as you arrive.
What kind of anaesthesia is used?
Anaesthetic eye drops are standard; being put to sleep is, as a rule, not necessary. If you feel very nervous, this is discussed separately at consultation.
When do I need to come back after surgery?
Check-ups are the day after surgery, then at 1 week, 1 month and 3 months, with long-term follow-up between 6 months and 1 year. After that, you can have a free check-up once a year.
Can my eyesight get worse again after surgery?
Regression of myopia is one of the things checked at follow-up. If your vision drops, revision surgery is not suggested straight away; first it is established whether the cause is regression, a problem with the optic nerve or retina, or an early cataract.
Is there a guarantee for revision surgery?
Revision surgery is offered free of charge only within 7 years of the first operation and only if the examination shows that revision is possible. Both conditions must be met.
I'm worried about glare and halos at night.
Pupil size is measured separately in bright and dim light and taken into account in the plan. Glare is one of the things checked at follow-up, but an improvement is not promised.
I'm in my 40s. Can I still have LASIK?
The first question is whether presbyopia has started. If you are in your mid-40s with presbyopia and have standard LASIK or LASEK, close-up vision can become uncomfortable, so an approach that takes presbyopia into account (such as Signature presbyopic LASIK) is explained based on your test results.
Can international patients have surgery here?
Yes. The clinic is registered as a medical institution for foreign patients (M-2021-01-08-6311), and the consultation languages on that registration are Korean, English and Chinese. Please contact the clinic by telephone or email before your visit.
How much does it cost?
It depends on your test results and the type of surgery, and fees for international patients are given after consultation. Please ask before you travel.
When should I book my flight home?
Please decide only after the check-up the day after surgery, once the cornea has been examined. The later follow-up schedule is also taken into account and arranged with you at consultation.