Who Is Eligible for SMILE Pro?

Most people researching SMILE Pro want to know whether they qualify before they book anything. That instinct is reasonable, and it runs into a wall: the answer depends on measurements that can only be taken in an examination. What can be done before that is understanding the factors, so the assessment holds no surprises and so you can tell whether it was done properly.

Why can’t eligibility be determined online?

Because the decisive inputs are physical. Corneal thickness is measured with an instrument, not inferred from your prescription. Corneal shape is mapped by topography, and a cornea with a subclinical irregularity will look unremarkable on a standard eye test. Tear film quality is assessed rather than assumed.

An online questionnaire can tell you whether your prescription is broadly in a range that is sometimes treatable. It cannot tell you whether your cornea can safely lose the tissue that would require, and that is the actual question.

Does age matter?

Age matters less as a number than through what it implies about the other factors.

Refractive surgery is generally considered for adults, and most clinics want a prescription that has been stable for a period rather than one that is still shifting. Around the early forties, the equation changes: reading vision starts to alter, and a full distance correction can mean trading reading comfort for distance clarity. That is a genuine planning conversation rather than a contraindication, and it is worth having explicitly.

What a clinic should be checking is your refraction history (ideally across more than one visit, or from records) rather than simply asking whether it feels stable.

What prescriptions can be treated?

SMILE corrects short-sightedness (myopia) and astigmatism, and is often used to correct both at once. Long-sightedness (hyperopia) is a more limited situation: hyperopic correction is not available with SMILE in every market or on every platform, so this is a question to ask rather than an assumption to make.

Higher prescriptions are treatable up to a point that depends on how much cornea you have. There is no universal ceiling. Someone with a thick cornea and a moderate prescription and someone with a thin cornea and the same prescription are not in the same situation.

What are the corneal measurements looking at?

Thickness. The cornea has to retain enough tissue beneath the treated area for structural integrity. A thin cornea is the most common reason for being declined.

Shape and regularity. Topography maps the surface. Corneas that show early signs of irregularity (including forms of keratoconus that have not yet caused symptoms) are generally unsuitable, and surgery on them risks making things worse.

Presence of any surface disease. Recurrent erosion, significant blepharitis or an unstable tear film all change the picture.

How does dry eye affect eligibility?

Pre-existing dry eye is one of the more common reasons a clinic pauses rather than proceeds. It matters twice over: it can affect the accuracy of the pre-operative measurements, and it affects comfort afterwards.

A cornea that is too dry can also produce measurements that are themselves unreliable, which is a reason a clinic may ask you to treat the dry eye for a few weeks and come back. That is a sign of a careful assessment, not a delaying tactic.

There is more on this, including how the assessment is done, in our SMILE Pro and dry eyes article.

What medical history is relevant?

Several categories are routinely discussed:

• Autoimmune and connective tissue conditions, particularly active or unstable ones, because of their effect on healing.
• Diabetes, where control and any retinopathy matter.
• Pregnancy and breastfeeding, where hormonal changes affect refraction and measurements; most clinics advise waiting until these are behind you and your prescription has re-stabilised.
• Certain medications, including some that affect tear production or healing.
• Previous refractive or corneal surgery. A previous procedure does not necessarily rule anything out, but it changes what is possible and what can be measured, and it usually narrows the options.
• History of eye disease, such as glaucoma, retinal problems or amblyopia, which need to be considered on their own terms.

What about contact lenses?

Soft contact lenses change the shape of the cornea and need to be out for a period before measurements are accurate: the duration depends on the lens type and your history. Hard and rigid gas-permeable lenses need considerably longer. Turning up to an assessment in contact lenses is one of the most common ways to waste an appointment.

What this means for you

You cannot self-assess into or out of eligibility in any reliable way, and you should be sceptical of any tool that claims you can. What you can do is arrive prepared: bring your prescription history if you have it, follow the contact lens instructions, and go in expecting that the answer might be no, or not yet.

The outcome of a good assessment is not always yes. Being declined, or being told to wait six months, is a result, and often a better one than proceeding.

Our eligibility page has an educational checklist covering the same factors, with the explicit caveat that only an ophthalmologist can decide. For what actually happens in the appointment, see what happens during a SMILE Pro consultation.