High Myopia and Astigmatism: Is SMILE pro or ICL Right for You?

The short answer The two procedures have different suitability criteria. For SMILE pro, the prescription and the cornea’s thickness and shape determine whether there is enough tissue to perform the correction. For ICL surgery, the space and structures inside the eye matter more than the prescription alone. High myopia and astigmatism may leave insufficient corneal tissue after laser correction, while reduced corneal biomechanical strength or structural abnormalities may also limit procedures such as SMILE or PRK. That does not automatically make ICL suitable. We examine both the cornea and the inside of the eye before deciding.

If your myopia is around −8 or −9 diopters and you also have astigmatism, you may have heard that SMILE would be difficult or that high myopia requires ICL. Without an explanation of the criteria, it can be hard to understand which option suits your eyes.

These procedures correct vision in different parts of the eye. SMILE pro uses the cornea; ICL surgery uses the space inside the eye. Their requirements therefore differ. The medical team at EYEREUM Eye Clinic explains the deciding factors, examinations, return to daily activities, and follow-up care.

Does high myopia with astigmatism make SMILE pro difficult?

A higher prescription can limit the suitability of SMILE pro. Even with a lower prescription, the cornea must have enough tissue to allow the procedure. We assess the cornea as a whole, alongside myopia and astigmatism, to determine a suitable approach.

SMILE pro uses the SMILE surgical method with an upgraded laser platform, the VISUMAX 800. A laser creates a lenticule—a small piece of tissue corresponding to the correction required—within the corneal stroma. It is removed through a small incision of around 2 mm. The greater the correction, the thicker the lenticule and the thinner the cornea remaining afterward. This is why corneal thickness and shape become particularly important at higher prescriptions.

When determining whether an eye is suitable for SMILE, EYEREUM considers the predicted remaining corneal thickness, corneal biomechanics, and structural findings such as the shape of the front and back surfaces. If laser correction is limited, ICL suitability is assessed separately through the required lens implantation examinations.

How do SMILE pro and ICL surgery differ?

SMILE pro corrects vision through the cornea by removing a lenticule formed within it. ICL surgery corrects vision by adding a lens inside the eye without removing corneal tissue.

At EYEREUM, SMILE pro uses a low-energy approach, adjusting the laser to a low energy level appropriate for each person’s eyes. EYEREUM first introduced low-energy SMILE in Korea in 2016 and has published 16 related SCI-indexed papers. Treatment planning considers visual quality—nighttime halos, glare, and clarity—as well as visual acuity. The VISUMAX 800 can form a lenticule in around eight seconds, which may reduce the time a patient needs to keep the eye steady during that part of surgery.

ICL surgery is a posterior chamber lens procedure: the lens is placed between the iris and the natural lens, which remains in place. EYEREUM uses the EVO+ Aqua ICL, made from Collamer®. Because it does not remove corneal tissue, it can be considered across a broad range of myopia. It may also be considered for high myopia or high astigmatism, a thin cornea that would leave insufficient tissue after laser correction, or an asymmetric corneal shape.

However, suitability for ICL depends on the internal structures of the eye, not just the prescription. EYEREUM uses CASIA2 anterior segment OCT to image and analyze anterior chamber depth (ACD, the distance from the inner corneal surface to the front of the natural lens), crystalline lens rise (CLR, how far forward the natural lens projects), and the anterior chamber angle (TIA, the angle associated with aqueous fluid drainage), over 360°. Even if the depth appears sufficient, a narrow angle can lead to increased pressure after implantation. We consider these measurements together to assess whether there is adequate space for lens implantation. They also guide lens size selection and planning for appropriate vaulting—the gap between the implant and the natural lens. We check endothelial cell measurements and for conditions such as glaucoma, cataract, and iritis. Corneal endothelial cells have very limited regenerative capacity, so they are assessed before surgery and monitored afterward.

Can astigmatism be corrected at the same time?

Both procedures can correct myopia and astigmatism together. When correcting astigmatism with ICL surgery, an EVO+ Toric Aqua ICL is ordered to match the astigmatic prescription and axis.

For SMILE pro at EYEREUM, the CentraLign and OcuLign features of the VISUMAX 800 help compensate for centration and astigmatic axis rotation during surgery. We also apply Vector Planning, which takes individual astigmatic characteristics into account, aiming to improve the accuracy of astigmatism correction and overall treatment precision. Outcomes with Vector Planning have also been demonstrated in SCI-indexed research.

For ICL surgery, accurately matching the direction, or axis, of astigmatism is as important as selecting the prescription. An EVO+ Toric Aqua ICL is selected with the patient’s myopic and astigmatic prescriptions and astigmatism axis in mind. Lens position and rotation are checked after surgery.

Which examinations help determine the procedure for my eyes?

Choosing a vision correction procedure involves more than measuring myopia and astigmatism. We also assess corneal shape and thickness, structural stability, and the optical characteristics of the whole eye.

EYEREUM performs approximately 70 detailed examinations, including Corvis ST corneal biomechanics testing. PERAMIS measures corneal and whole-eye wavefront aberrations together to analyze optical characteristics that affect visual quality. MS-39 high-resolution corneal OCT also provides detailed assessment of the front and back corneal surfaces, epithelium, stroma, and other corneal structures.

If ICL is being considered, additional lens implantation examinations assess the space for the lens and the condition of the eye. These tests help determine the appropriate lens and surgical plan.

The retina may be vulnerable in high myopia. If the dilated examination indicates a need, retinal laser treatment may be performed before proceeding with ICL surgery.

Plan your examination day in advance. An initial examination takes approximately 2–2.5 hours. After dilation, near vision may be blurred and light sensitivity may persist for an average of 3–6 hours, so public transportation is preferable to driving yourself. If you have been advised that lens implantation may be possible and are attending the dedicated examination, allow approximately 2.5–3 hours. Drops used for cycloplegic refraction may make near vision difficult for an average of 2–3 days. If your work involves prolonged computer use, you may want to allow some flexibility in your schedule for the next few days.

How do recovery times differ between SMILE pro and ICL?

After SMILE pro, activities such as face washing and light exercise can resume from the next day. After ICL surgery, face washing and basic face makeup can resume from three days after surgery has been completed in both eyes.

Recovery speed and the time needed for vision to stabilize vary from person to person. Eyes may become dry during recovery, and persistent dryness can also affect visual recovery. Use prescribed drops and artificial tears as directed, and rest your eyes periodically during extended computer or smartphone use.

After ICL surgery, regular examinations remain important even when vision is clear. These visits monitor the vault between the implanted and natural lenses, corneal endothelial cells, and eye pressure.

In 2025, EYEREUM’s medical team published a 10-year follow-up study of V4c ICL implantation in the American Journal of Ophthalmology. Vision remained stable over the study’s 10-year follow-up, and no serious implantation-related complications such as cataract or glaucoma were reported. Continuing regular examinations is important for monitoring long-term eye health after surgery.

Questions to ask before choosing surgery

• Do my myopia and astigmatism, corneal thickness, and corneal shape allow SMILE pro?

• Are my anterior chamber depth, crystalline lens rise, and anterior chamber angle suitable for an ICL?

• Is my astigmatism sufficient to require an EVO+ Toric Aqua ICL? Will the lens need time to be prepared?

• Has the retinal examination identified anything that needs treatment before surgery?

• Can the examination and surgery take place on the same day, and have I stopped wearing contact lenses for long enough?

• When will I need postoperative examinations, and what will be checked?

Frequently asked questions

Can I have surgery on the day of my examination?

Under EYEREUM’s one-day vision correction program, surgery may take place on the examination day if the results show that it is suitable. This includes laser procedures such as SMILE, SMILE pro, and EYEREUM’s “투데이라섹” PRK procedure, as well as ICL surgery.

However, same-day surgery may not be possible if additional tests or separate lens preparation are needed, as with an EVO+ Toric Aqua ICL.

If you are planning same-day surgery, stop wearing soft contact lenses at least five days and hard contact lenses at least seven days before surgery. When booking, tell us which lenses you wear and about work or travel plans so we can advise on examination and surgery scheduling.

Can an ICL be removed or exchanged later?

An implanted lens can be exchanged or removed surgically if necessary. EYEREUM performs lens removal when unavoidable circumstances after surgery require removal or exchange. Protecting the corneal endothelial cells—which do not regenerate after damage—is a central priority during removal.