ICL and SMILE are two different approaches to correcting myopia, but they work in fundamentally different ways. ICL (Implantable Collamer Lens) places a lens inside the eye, while SMILE (Small Incision Lenticule Extraction) uses a femtosecond laser to remove a small piece of corneal tissue and reshape the cornea.
Both procedures can reduce dependence on glasses or contact lenses, but they are not interchangeable. The better option depends on factors such as your prescription, corneal thickness and shape, eye anatomy, ocular health, lifestyle, and which procedure is considered safest and most appropriate for your eyes. You can learn more about ICL as a vision-correction option on our ICL treatment page.
What Is the Main Difference Between ICL and SMILE?
The simplest way to understand the difference is to look at where each procedure works.
- ICL: A specially designed lens is implanted inside the eye while your natural crystalline lens remains in place.
- SMILE: A laser creates a small lenticule within the cornea, which is then removed through a small incision to change the cornea's focusing power.
In other words, ICL is an intraocular lens-based procedure, while SMILE is a corneal laser procedure.
How Does ICL Work?
During ICL surgery, a thin phakic lens is placed inside the eye, behind the iris and in front of the natural crystalline lens. The implanted lens changes how light is focused onto the retina, correcting the refractive error without removing the natural lens.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
The cornea itself is not reshaped as part of the ICL procedure. This approach can be particularly useful for people with moderate to high myopia, including some prescriptions that may fall outside the treatment range of certain corneal laser procedures.
How Does SMILE Work?
SMILE uses a femtosecond laser to create a small disc-shaped piece of corneal tissue, called a lenticule, inside the corneal stroma. The surgeon removes this lenticule through a small peripheral incision.
Removing the tissue changes the shape of the cornea and alters its focusing power, correcting myopia and, depending on the procedure and approved indication, myopic astigmatism. Unlike LASIK, SMILE does not require the creation of a large corneal flap.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
ICL vs SMILE: Key Differences at a Glance
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
| Feature | ICL | SMILE |
|---|---|---|
| Where it works | Inside the eye | On the cornea |
| Basic approach | Implants a phakic lens | Removes a corneal lenticule |
| Natural lens | Remains in place | Remains in place |
| Corneal tissue removal | No corneal tissue is removed to correct the prescription | A small amount of corneal tissue is removed |
| Corneal flap | No | No |
| Implant remains in the eye | Yes | No |
| Typical use | Often considered for moderate to high myopia and selected astigmatism | Commonly used for myopia and myopic astigmatism within the procedure's approved range |
Which Procedure Can Treat Higher Myopia?
The answer depends on the specific device, country, and approved treatment range. ICL can generally address higher levels of myopia than SMILE in many clinical settings.
For example, the FDA-approved EVO/EVO+ ICL indication includes myopia from -3.0 D through -15.0 D and reduction of myopia greater than -15.0 D up to -20.0 D, subject to additional requirements. The FDA indication for SMILE covers a lower range of myopia.
This does not mean that ICL is automatically better for everyone with high myopia. The health and anatomy of the eye still determine whether an intraocular procedure is appropriate.
What About Thin Corneas?
Corneal thickness and structure are important when considering a corneal laser procedure such as SMILE. Because ICL corrects the prescription with a lens inside the eye rather than by removing corneal tissue, it may be considered for some people whose corneal characteristics make laser vision correction less suitable.
However, ICL has its own anatomical requirements. Adequate internal eye dimensions, anterior chamber depth, endothelial cell health, and other factors must be assessed before surgery.
Which Procedure Has a Faster Recovery?
Both ICL and SMILE are generally performed as outpatient procedures, but the recovery experience can vary between patients.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
SMILE can provide relatively rapid visual recovery, although vision may initially be somewhat hazy and can continue improving during the early postoperative period.
ICL can also provide relatively rapid improvement in vision, but because it involves placing a lens inside the eye, postoperative monitoring is important to ensure that the implant is positioned appropriately and that the eye remains healthy.
Rather than choosing a procedure solely because of a particular recovery timeline, it is better to consider whether the procedure itself is appropriate for your eyes.
Are ICL and SMILE Reversible?
One important distinction is what happens to the treated tissue or implant if circumstances change. With ICL, the implanted lens can generally be removed or exchanged by an ophthalmic surgeon if medically necessary. However, this does not mean that ICL surgery should be viewed as routinely reversible or risk-free after removal.
With SMILE, the corneal lenticule is removed during treatment, so the corneal tissue change is not simply reversed by taking something out later. Any residual or recurrent refractive error may require another form of treatment if the eye is suitable for enhancement.
How Do the Risks Differ?
Because the two procedures involve different parts of the eye, their potential complications are also different.
Potential considerations with ICL
- Increased eye pressure
- Inflammation
- Changes involving the natural lens, including cataract formation
- Corneal endothelial cell loss
- Residual refractive error
- Lens rotation or positioning issues, particularly with toric lenses
- Infection, although uncommon
Potential considerations with SMILE
- Dry-eye symptoms or temporary changes in corneal sensation
- Residual or recurrent refractive error
- Difficulty removing the lenticule in some circumstances
- Visual symptoms such as glare, halos, or other optical disturbances
- Corneal complications, including rare problems affecting corneal stability
Which Procedure Is Better for High Myopia?
For high myopia, ICL may be considered when the prescription is beyond the suitable range for SMILE or when corneal characteristics make a corneal laser procedure less appropriate.
Some comparative studies in highly myopic patients have reported better refractive accuracy and certain visual-quality measures after ICL compared with SMILE. However, these findings should not be interpreted as meaning that ICL is universally superior.
The appropriate choice depends on the individual eye. A procedure that produces excellent results for one patient may not be the safest or most suitable option for another.
When Might SMILE Be Considered?
SMILE may be considered when the patient's prescription falls within its approved range and the cornea and overall eye health are suitable for laser vision correction.
Its small-incision approach, absence of a corneal flap, and ability to correct myopia and certain levels of myopic astigmatism make it an important option among corneal refractive procedures.
People who participate in contact or collision sports may also discuss SMILE with their ophthalmologist because it does not involve a LASIK-style corneal flap.
When Might ICL Be Considered?
ICL may be considered when:
- The degree of myopia is relatively high.
- The prescription falls within the approved range of the selected ICL.
- The cornea may not be an ideal candidate for tissue-removing laser surgery.
- The patient has suitable internal eye anatomy.
- The refractive prescription is stable.
- The corneal endothelium is sufficiently healthy.
- The eye does not have a condition that makes intraocular surgery unsuitable.
These factors need to be assessed together rather than using a single criterion to select the procedure.
The Bottom Line
ICL and SMILE correct myopia in fundamentally different ways. ICL places a lens inside the eye without removing corneal tissue, while SMILE uses a laser to remove a corneal lenticule through a small incision.
ICL may be particularly useful for selected patients with higher myopia or certain corneal characteristics, while SMILE can be an effective option for appropriately selected patients whose prescription and corneal anatomy fall within its treatment range.
The right choice depends on your individual prescription, corneal measurements, internal eye anatomy, ocular health, and visual needs. A comprehensive refractive evaluation is therefore more useful than comparing the procedures based on a single feature such as recovery time or prescription strength.
