"Ineligible for LASIK?" When is Vision Correction Surgery Not Possible?

Essential Criteria to Check for Safety Before SMILE LASIK

Hello, this is BGN Eye Clinic Jamsil Lotte Tower Main Branch.

Today, a patient came in for a SMILE LASIK consultation. After a thorough examination and consultation, our head surgeon gently informed them, "It seems LASIK surgery will be difficult for you." The patient was quite taken aback.

"Isn't LASIK something anyone can get?"

Like this patient, many people assume that almost anyone is eligible for LASIK or SMILE LASIK. However, based on precise examination results and the surgeon's expert diagnosis, there are definitely cases where patients are deemed ineligible for the procedure.

Today, we will explain when surgery is not recommended, what the exact eligibility criteria are, and what alternative options exist if LASIK is not possible. If you are considering SMILE LASIK, please read this post to the end.

Are There Specific Criteria for LASIK and SMILE LASIK Ineligibility?

As mentioned earlier, many patients visit our clinic believing that SMILE LASIK is suitable for everyone. However, SMILE LASIK involves reshaping the cornea, a thin, transparent tissue, to correct vision. Therefore, eligibility cannot be determined by visual acuity alone.

In our examination room, we comprehensively evaluate the following factors:

• • Visual acuity measurements
• • Corneal thickness
• • Corneal shape and overall stability
• • Anterior chamber depth (space for lens insertion)
• • Pupil size, intraocular pressure (IOP), etc.

Based on these precise measurements, the surgeon makes the final decision on whether the surgery is safe and possible. Our optometrists are here to help you fully understand your test results and explore your eligibility together.

Cases Where LASIK or SMILE LASIK is Not Recommended

So, when might someone be advised against LASIK? There are three main instances where we typically inform patients that surgery is not possible.

1. Excessively Thin Corneas

Vision correction surgery involves reshaping the cornea with a laser, making corneal thickness a critical factor. For safety, it is medically advised that at least 250μm of residual cornea remains after the laser ablation. If your current cornea is too thin, we often have to inform you that LASIK is not possible. In such cases, depending on the surgeon's diagnosis, we may recommend Implantable Collamer Lens (ICL) surgery as an alternative.

2. Severe Astigmatism

Astigmatism is a refractive error where light fails to focus perfectly on a single point on the retina, causing blurred or overlapping images. We often explain this by saying the cornea is shaped more like an oval. Because light entering from horizontal and vertical directions has different focal points, these visual distortions occur.

The diopter (D) is the unit used to measure astigmatism; a higher number indicates a more severe condition. Generally, 4 to 5 diopters or higher is classified as severe astigmatism. Both LASIK and SMILE LASIK require a significant amount of corneal ablation to correct severe astigmatism, which can compromise corneal stability. In these instances, the surgeon may determine that LASIK is unsuitable.

3. Ineligibility for Implantable Collamer Lens (ICL) Surgery

When the surgeon concludes that LASIK is not an option, ICL surgery is often suggested as an alternative. As the name implies, this procedure involves inserting a customized lens inside the eye. Therefore, the anterior chamber depth (ACD), the space where the lens will sit, is crucial. If this depth is too shallow, even ICL surgery may not be possible.

Ineligible for LASIK? Don't Be Too Discouraged

Recently, a patient who strongly desired SMILE LASIK was deemed ineligible. Their corneas were too thin, so the surgeon suggested ICL as an alternative. However, further detailed examinations revealed insufficient space for the lens insertion. In situations like this, even if the patient strongly wishes to proceed, the surgery is objectively and medically impossible.

It is unfortunate, but when surgery is difficult, we consult with the surgeon to guide you toward other methods or plan a re-examination for the future. Most patients who come in for SMILE LASIK arrive with high hopes, so hearing "surgery is not possible" often brings great disappointment. Seeing patients feel this way always makes us feel heavy-hearted as well.

The Utmost Priority is "Safety"

We always emphasize that surgery shouldn't just be performed on anyone who wants it; it must be performed on eyes that can safely handle it. This is a choice made strictly to protect your eye health. LASIK is not something you can get just because you want it right now. The surgeon only decides to proceed when the eyes are suitable and when it is deemed medically safe.

That is ultimately the best choice for your eyes. The optometrists at BGN Eye Clinic Jamsil Main Branch think comprehensively alongside you to ensure your comfort and well-being. Everyone's eyes are unique, so please don't be too disappointed even if you are told surgery isn't possible right now. Never forget that this decision is the absolute best choice for your eyes!