# SMILE (Small Incision Lenticule Extraction)

> Citation bundle for SMILE (Small Incision Lenticule Extraction) on The Treatment Registry.
> URL: https://thetreatmentregistry.com/procedures/smile
> Bundle URL: https://thetreatmentregistry.com/api/citations/procedures/smile

- Category: ophthalmology
- Average recovery: 3 days
- Typical sessions: 1
- Price range (USD international): $2,000–$4,500

## Description

SMILE is a refractive laser eye procedure in which a femtosecond laser creates a small lens-shaped piece of corneal tissue (a lenticule) within the intact cornea, which is then extracted through a small peripheral incision typically 2-4mm wide. Because no corneal flap is created, SMILE preserves more of the cornea's anterior biomechanical strength than LASIK. SMILE is approved for the correction of myopia and myopic astigmatism; hyperopic SMILE has been approved in some markets more recently.

## Overview

SMILE was developed by Carl Zeiss Meditec and approved by the US FDA in 2016 (for myopia) and 2018 (for astigmatism). The procedure uses a femtosecond laser to create both surfaces of a corneal lenticule in a single step, which is then extracted manually. Compared to LASIK, the smaller incision and absence of a flap means less disruption to corneal nerves, theoretically reducing dry-eye symptoms and preserving more biomechanical strength.

## Peer-reviewed outcome rates

- **Complication rate:** 1.50% (range 0.50–3.00%) — from 1 cited source
- **Revision rate:** 4.00% (range 2.00–8.00%) — from 1 cited source

## Common risks

- Dry eye (less than LASIK)
- Diffuse lamellar keratitis
- Cap perforation (rare)
- Suction loss during lenticule creation
- Under-correction
- Slow visual recovery

## FAQs

### How does SMILE differ from LASIK?

Both procedures use a femtosecond laser to modify corneal tissue. LASIK creates a hinged flap and uses an excimer laser to ablate the underlying stroma. SMILE creates a small lens-shaped piece of tissue (a lenticule) inside the intact cornea using only the femtosecond laser, and the lenticule is extracted through a small 2-4mm incision. Because no flap is created, more of the cornea's biomechanical strength is preserved.

### Is SMILE safer than LASIK?

The biomechanical preservation theoretically makes SMILE less prone to ectasia and to long-term flap-related complications. However, the absolute risk of these events with modern LASIK is already very low. Most clinical comparison studies show equivalent visual outcomes; the difference is in the long-tail safety profile, which is hard to measure in short-term studies.

### Can SMILE correct astigmatism and hyperopia?

SMILE is approved for myopia and myopic astigmatism in all markets where it is available. Hyperopic SMILE has been approved by the FDA more recently (2024) and in some other markets, but availability and surgeon experience varies.

### What happens if SMILE doesn't fully correct my vision?

Enhancement (re-treatment) is less straightforward than for LASIK because there is no flap to re-lift. The most common enhancement approach is to perform a PRK on the surface of the cornea, which adds a separate recovery period. Modern surgeons increasingly offer 'flap-lift after SMILE' techniques in selected cases.

### How long does SMILE take?

The laser portion is approximately 30 seconds per eye, and the lenticule extraction adds 1-2 minutes. Total time in the laser room is typically 10-15 minutes per eye.

### How much does SMILE cost?

SMILE is typically priced 20-30% above LASIK at the same clinic. Total cost per eye varies by country and clinic.

### Can SMILE be combined with cataract surgery later in life?

Yes — because SMILE leaves the cornea structurally well-preserved (no flap, smaller incision), patients undergoing cataract surgery decades later have a more predictable corneal optical landscape. IOL calculations after refractive surgery still require specific formulas (e.g. Barrett True-K) regardless of the original refractive procedure.

### Why is SMILE more expensive than LASIK at the same clinic?

The Carl Zeiss femtosecond laser used for SMILE is proprietary, has higher upfront equipment cost than excimer-laser-based LASIK systems, and the procedure requires additional surgeon training. These factors typically translate to a 20-30% price premium over LASIK at the same provider.

## Alternative treatments

- **LASIK** — Wider indication range (broader prescription envelope, astigmatism correction).
- **PRK** — Surface ablation when corneal biomechanics or thin-cornea concerns preclude SMILE.

## Sources

- [ESCRS — Clinical research and guidelines](https://www.escrs.org/clinical-research/) — European Society of Cataract and Refractive Surgeons (accessed 2026-05-09)
- [American Academy of Ophthalmology — Preferred Practice Patterns including Refractive Surgery](https://www.aao.org/preferred-practice-pattern) — American Academy of Ophthalmology (accessed 2026-05-09)