PRK vs SMILE: What's the Difference?

PRK and SMILE (KLEx) are both flap-free laser methods. PRK applies the laser directly to the corneal surface, while SMILE removes a small lens-shaped piece of corneal tissue (the lenticule) through a tiny incision. SMILE recovery can often progress faster, whereas PRK is a long-established technique usable across a wider range of patients. The final choice depends on your corneal structure and personal priorities, decided at your assessment. This isn't only about incision size — the type of refractive error matters too, since SMILE is only used for myopia and astigmatism and is not an option for hyperopia. The definitive decision rests on corneal measurements taken at your assessment.

PRK (TransPRK) is a flap-free method: the laser is applied directly to the corneal surface without touching the outermost epithelial layer, which regenerates naturally over the following few days. A protective bandage contact lens covers the treated area until healing is underway, then is removed under the doctor's supervision. PRK has been performed for many years, with its reliability observed across a wide range of patients. During recovery, avoiding eye rubbing, swimming and prolonged sunlight helps the epithelium regenerate properly, and the protective drops your doctor recommends should be used consistently.

SMILE (KLEx) is a flap-free method in which a femtosecond laser shapes a small, lens-shaped piece of tissue (the lenticule) within the cornea's inner layers, then removes it through a tiny incision only a few millimetres wide. This incision is planned by the femtosecond laser in advance, leaving the rest of the corneal surface largely untouched. Because SMILE doesn't remove a large area of surface epithelium the way PRK does, healing in the first few days follows a different course. Protective eyewear is still recommended afterwards, though PRK's extensive surface healing isn't expected with SMILE.

With PRK, the corneal surface is reshaped directly by the laser; with SMILE, reshaping comes from removing tissue created within the cornea, so PRK's extensive surface healing isn't expected. This affects comfort in the first few days and also which method suits which refractive error — SMILE isn't an option for hyperopia. Protective drops follow both procedures; PRK's are typically used for longer, until the epithelium regenerates, while SMILE's smaller incision can mean a shorter course. In the first few weeks, both can bring mild sensitivity to night-time glare, which usually eases over time. Incision width is roughly 0 mm for PRK and around 3 mm for SMILE; the chart below illustrates this.

The table below summarises six key differences between PRK and SMILE. A mark shows which method generally stands out on that point; the final decision depends on your refractive error, corneal structure and lifestyle. No mark implies absolute superiority overall — it only reflects a general tendency.

PRK is considered for patients with borderline corneal thickness or hyperopia, where SMILE isn't an option. Because SMILE isn't clinically suitable for hyperopia, assessment proceeds directly with PRK. Borderline corneal thickness can also be assessed for PRK, since no tissue is separated to create a flap. Patients with previous dry eye who lack a SMILE option because of hyperopia may likewise be assessed for PRK. Follow-up visits in the first week after PRK may be scheduled slightly more often than after SMILE, to monitor epithelial healing.

SMILE can be considered for patients with myopia and/or astigmatism who prefer a flap-free, less invasive method and whose corneal structure suits it. SMILE isn't used clinically for hyperopia. It can stand out for those who value a short recovery and prefer a smaller incision because of a tendency towards dry eye. It can also suit myopic or astigmatic patients whose work or social life makes quick visual comfort in the first few days a priority. The first follow-up after SMILE is generally the next day; the small incision keeps follow-up relatively simple.

Op. Dr. Anıl Kaya, an eye surgeon (ophthalmologist), decides with the patient which method may suit them by assessing the refractive error, corneal thickness and topography findings — with SMILE's exclusion in hyperopia specifically taken into account. The refractive error type is the decisive first step: hyperopia rules out SMILE immediately, while myopia or astigmatism brings corneal structure and dry eye history into the decision. Afterwards, the patient receives guidance on the first follow-up date and what to watch for during recovery — protective eyewear, drop use, sun protection.

To help clarify which method may suit you, review the decision-support content on which laser method may be right for you, then book a laser suitability assessment. Your refractive error type is the first step; the myopia and astigmatism pages, together with a suitability assessment, give a clearer picture. This page only summarises general tendencies — which method suits your particular case can only be confirmed by the measurements taken at your assessment. Both methods aim for a lasting solution, reducing dependence on glasses or contact lenses.

To clarify which method may suit you, request an appointment through the contact page, then arrange a laser suitability assessment. Sharing your current prescription and any previous eye examination records when booking helps speed up the assessment. Reach us by phone or through the contact page form.