SMILE PRO in Seoul with a high prescription: the corneal measurements that decide it

Often yes, within limits. SMILE-type surgery corrects nearsightedness by removing a thin, lens-shaped piece of corneal tissue (a lenticule) through a small incision, with no flap lifted. A 2014 review in Eye and Vision by Reinstein and colleagues describes the technique as developed for myopia and myopic astigmatism.

For high prescriptions, the limit is geometry. The more correction you need, the thicker that lenticule has to be, so a -9.00 D eye gives up more tissue than a -3.00 D eye. Whether that's acceptable depends less on your prescription than on what your particular cornea has to spare. The same tissue question sits behind what to check first for LASIK in Korea.

Stability matters as well. If your glasses have changed noticeably over the last year or two, most surgeons would rather wait than correct a moving target. Older prescriptions are worth bringing, because the trend says more than any single reading.

Often, it's because surgeons draw their lines at different points on the same measurements, not because anyone misread your eyes. There is no single universal cutoff for the tissue that must remain, so more and less conservative judgments both exist within accepted practice.

The readings themselves can also shift. Contact lenses can change the shape of the corneal surface, which is why the U.S. FDA advises stopping them before the baseline exam, and for longer with rigid lenses. A map taken while you were still wearing lenses may look different from one taken after the lenses have been out for the recommended period.

And sometimes the surgeon at home is simply right. If your cornea shows a pattern that suggests weakness, the answer in Seoul is likely to be no as well. If they suggested an implantable lens instead of laser, that usually means the limiting factor was tissue, not technique.

I diagnose, operate and follow up on my own patients, so when I say yes to a large correction, I'm the person who will be looking at that cornea afterward. That shapes one decision in particular: I would rather recommend an ICL, or waiting, than remove tissue that can't be put back. Hearing “not this procedure” after a long flight is disappointing. It is still a better result than a cornea that becomes unstable.

Glare, halos around lights and dry eye matter most with a high prescription, and they are usually most noticeable in the early weeks and months.

In its guidance for LASIK patients, the FDA describes burning, blurry vision, light sensitivity, glare, starbursts or halos right after surgery, symptoms that should improve considerably within the first few days. SMILE heals differently from a flap procedure, but the early symptoms overlap.

If you drive after dark, ask about night vision directly in your consultation. When the pupil opens wide in dim light, the edge of the treated zone matters more, and larger corrections make that edge more noticeable for some people.

Dry eye is the second concern. Because SMILE works through a small incision instead of a flap, the 2014 Reinstein review discusses less disruption of corneal nerves as a potential advantage; that is a reason for interest, not a promise for your eyes. I co-authored the Textbook of Dry Eye (2019), and the practical point I'd make is simple: if years of contact lenses have already left your surface dry, that surface should be treated and re-measured before any laser decision.

Rare but serious problems include infection, inflammation under the surface, and ectasia, a progressive weakening and bulging of the cornea. Ectasia is the main reason the thickness and shape screening above exists. Results and side effects differ from person to person, and only the in-person exam can tell you whether your eyes suit surgery at all.

After surgery, our Lifetime Aftercare covers re-checks at any time, with re-treatment support if it becomes necessary; the detailed conditions are confirmed during your consultation.

There is no fixed number, because the in-person exam comes first and surgery on the same trip only follows if the measurements support it. Plan around three things: your contact-lens break before flying, the clinic's open days, and a follow-up check before you head to the airport.

The clinic is open Monday, Tuesday, Thursday and Friday 09:00–18:00 and Saturday 09:00–16:00, with a lunch break from 13:00 to 14:00. It is closed on Wednesdays and Sundays, and an appointment is required; registration may close early depending on demand. In practice, landing on a Tuesday evening means your first possible exam day is Thursday.

We're at 5–6F, Duo Sinnonhyeon, 368 Sapyeong-daero, Seocho-gu, Seoul. Directions from Incheon Airport by taxi, by AREX plus subway, or by limousine bus are on the clinic's website, and the wider trip planning is covered in our overview of eye surgery in South Korea.