# Who is not suitable for laser eye surgery?

Source page: https://www.kudretgozistanbul.com/en/blog/eye-laser-treatments/who-is-not-suitable-for-laser-eye-surgery

**Author:** Kudret Eye İstanbul | **Medical Approval:** Op. Dr. Mehmet Ali Özdil | **Date:** 2026-09-17

> **Summary:** Laser eye surgery reshapes the cornea by vaporising micron-thin tissue, so it suits only eyes with sufficient corneal thickness and a prescription within the laser's limits. A thin cornea, a very high prescription, an unstable prescription, uncontrolled diabetes, active autoimmune disease, pregnancy or breastfeeding and certain eye diseases rule it out; patients with very high prescriptions are offered a phakic IOL instead.

## Quick Facts
- **Decisive test:** Corneal thickness and corneal map determine the go/no decision
- **Prescription stability:** A prescription that has changed in the last 1-2 years means waiting
- **Alternative for very high prescriptions:** Phakic IOL (intraocular lens) placed inside the eye
- **Thin cornea risk:** Keratectasia, an irreversible weakening and bulging of the cornea

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## The Limits the Eye Sets: Cornea and High Prescriptions
- The laser corrects the refractive error by vaporising micron-thin tissue from the cornea, so the cornea must be thick enough.
- A naturally thin cornea is the red line: removing too much tissue, especially for a high prescription, endangers the cornea's structural integrity and can lead to irreversible keratectasia, where the cornea weakens, bulges forward and seriously impairs vision.
- Very high myopia, hyperopia or astigmatism can remain outside the laser's effective area, because the higher the prescription, the more tissue must be removed.
- For very high prescriptions, safer technologies such as a phakic IOL placed inside the eye are recommended instead of laser; the aim is quality, healthy vision for a lifetime.

## General Condition of the Body: Age, Diseases and Other Obstacles
The whole body is evaluated, not only the eyes, because systemic conditions affect healing capacity. Conditions that definitely or probably prevent laser surgery:
- **Uncontrolled diabetes:** blood sugar fluctuations temporarily change the prescription and seriously impair wound healing.
- **Autoimmune diseases:** active, uncontrolled diseases such as lupus and rheumatoid arthritis make corneal healing unpredictable.
- **Unstable prescription:** especially in young patients; if the prescription has changed in the last 1-2 years, surgery must wait until it settles, otherwise the result is lost after a few years.
- **Pregnancy and breastfeeding:** hormones cause temporary prescription fluctuations, so measurements are unreliable; wait until this period is over.
- **Certain eye diseases:** advanced glaucoma, a history of keratitis, uveitis or untreated severe dry eye syndrome.

The list is meant to protect patients, not to scare them. Example given: a 19-year-old student whose prescription had still changed in the last year was asked to wait a year or two rather than operate too early.