LASIK vs SMILE laser eye surgery

The front surface of the eye, the cornea, provides much of the eye's focusing power. Laser vision correction changes its shape so light focuses accurately on the retina. In LASIK, a femtosecond laser or blade creates a thin hinged flap, the flap is lifted, an excimer laser removes microscopic layers of tissue under it, and the flap is laid back down.

In SMILE (small incision lenticule extraction), a femtosecond laser carves a thin disc of tissue inside the intact cornea and a small incision allows the surgeon to remove it. This changes the corneal shape without lifting a flap.

Both procedures are quick and usually done on both eyes in one session under anaesthetic drops. LASIK often gives sharp vision within a day or so; SMILE may take a little longer for the vision to settle in some people, though this varies. Both need lubricating and anti-inflammatory drops for a period afterwards.

Dry eye is the commonest side effect and is usually temporary. Glare, haloes and night-vision disturbance can occur, particularly in the early months. Rare but serious complications include infection, flap problems in LASIK, and corneal thinning (ectasia), which is why screening scans of the cornea are carried out beforehand.

The choice follows corneal thickness and shape on scanning, the prescription, any previous eye surgery, dry eye status, and the surgeon's experience. Many surgeons offer both and match the procedure to the eye. High long-sightedness is a LASIK or lens-based question, and very high short-sightedness or thin corneas may push toward implantable lenses instead.

Professional guidance from the Royal College of Ophthalmologists emphasises a thorough pre-operative assessment, a clear explanation of risks and realistic expectations, and an assessment with a surgeon rather than only a technician.

• Short-sighted with healthy, adequately thick corneas: both are options; ask which your surgeon performs most and why they suggest it.

• Long-sighted: LASIK, or lens-based options, since SMILE is not generally used for long-sightedness.

• Contact sport or an occupation with risk of eye impact: ask about flapless options.

• Chronic dry eye: discuss risks and consider whether laser correction is wise at all.

• Prescription still changing or under 21: laser correction is usually postponed until stable.

Neither procedure is risk free or guaranteed to remove all dependence on glasses; many people still need reading glasses after their forties regardless of laser surgery. And "flapless" does not mean complication-free.

It is also not true that one is universally safer. Outcomes depend on screening, surgeon experience and the individual eye.

• Which procedure suits my corneal scans and prescription, and why?

• How many of each procedure do you perform each year?

• What are the chances I will need an enhancement, and how is that done?

• What will happen to my near vision as I age?