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Comparing procedures · SNU Eye Clinic

ICL vs SMILE: which might be suitable for you?

Compare how the procedures work, the eye tests you will need and the risks of each.

How are ICL and SMILE different?

SMILE reshapes the cornea by removing a small piece of tissue called a lenticule. ICL surgery places a corrective lens inside the eye, behind the iris and in front of your natural lens. The natural lens stays in place.

ICL does not remove corneal tissue, but it does involve surgery and an implant inside the eye. An ICL can sometimes be removed or replaced in another operation. This does not guarantee that your eye will return to its original condition.

Sources: SNU: SMILE pro, SMILE and LASIK · SNU: ICL examinations and lens planning · FDA: risks of phakic intraocular lenses

Which eye measurements help determine the choice?

For SMILE, the examination looks at your prescription, corneal shape and thickness, the tissue that would remain after treatment, and the tear film. For ICL, the space inside the eye and the cornea's endothelial cells are also important when assessing suitability and choosing a lens.

High myopia, a thin cornea or dry eyes may affect the options, but none determines the choice on its own. Both procedures require a review of prescription stability, age, other eye conditions and your visual needs. A full examination gives more useful information than a prescription number alone.

Sources: SNU: SMILE pro, SMILE and LASIK · SNU: ICL examinations and lens planning · FDA: assessing suitability for phakic lenses

How do the risks of ICL and SMILE compare?

SMILE can cause dry-eye symptoms, leave some of the prescription uncorrected or, rarely, lead to corneal ectasia. ICL surgery carries risks inside the eye, including increased eye pressure, cataracts and loss of corneal endothelial cells. Infection, glare and halos also need to be discussed.

Ask which risks matter most for your eyes and how they would be monitored or treated. ICL still needs ongoing follow-up even though it preserves corneal tissue. SMILE still changes the cornea even though it does not create a flap.

Sources: ZEISS: SMILE side effects and complications · FDA: risks of phakic intraocular lenses

What have studies comparing ICL and SMILE found?

A 2019 study followed 48 eyes treated with ICL and 48 treated with SMILE for high myopia over three months. Some measures of visual quality favoured ICL in that group. The short follow-up and the patients' particular prescriptions limit what the study can tell us about long-term risks or the best choice for someone else.

Visual acuity, the remaining prescription, night-vision symptoms and complications each tell you something different. A better average result in one study does not necessarily make that procedure right for your eyes.

Sources: 2019 study of ICL and SMILE in high myopia

What should you consider when planning treatment?

Alongside the price, allow time for examinations, any lens order, recovery and follow-up. ICL surgery depends on the right lens being available and needs checks on the implant afterwards. For SMILE, planning centres on corneal suitability and recovery after surgery.

Our SMILE cost guide and ICL cost guide explain what to compare for one or both eyes and the included follow-up. Before booking travel, discuss when you can return home and, for ICL, which longer-term checks you will need.

Sources: SNU: ICL examinations and lens planning · SNU: SMILE aftercare and returning home

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