Who Qualifies for Laser Eye Surgery?
LASIK and other laser vision correction procedures have an excellent track record, but they are not appropriate for everyone. Candidacy is determined through a thorough pre-operative evaluation. Understanding the general criteria in advance can help you set realistic expectations and know what questions to ask during your consultation.
General Candidacy Requirements
Age
Most surgeons recommend waiting until you are at least 18–21 years old before having LASIK. The reason: your prescription needs to be stable. Younger eyes are still changing, and operating on a prescription that hasn't settled can lead to under- or over-correction. Many surgeons also prefer to see two consecutive years of minimal prescription change before proceeding.
Stable Prescription
Your glasses or contact lens prescription should have remained relatively unchanged for at least one to two years. If your prescription is still shifting, laser surgery may not hold its correction long-term.
Prescription Range
LASIK is FDA-approved to treat:
- Nearsightedness (myopia): up to approximately -12.00 diopters
- Farsightedness (hyperopia): up to approximately +6.00 diopters
- Astigmatism: up to approximately 6.00 diopters
Prescriptions outside these ranges may not be treatable, or alternative procedures may be more appropriate.
Corneal Thickness
LASIK requires removing a small amount of corneal tissue to reshape the eye. If your corneas are too thin, there may not be enough tissue to safely create a flap and perform the correction. A detailed measurement called pachymetry measures corneal thickness during your evaluation. Patients with thin corneas may be better candidates for PRK or SMILE.
Corneal Shape
Corneal mapping (topography) detects irregular curvature. A condition called keratoconus — a progressive thinning and bulging of the cornea — is a contraindication for LASIK. Even subtle early signs of keratoconus (called forme fruste keratoconus) can disqualify a patient. This is why topography screening is critical.
Overall Eye Health
Active eye diseases such as glaucoma, cataracts, or significant dry eye disease may disqualify you from LASIK. Dry eye in particular is both a contraindication and a potential side effect of the procedure. Surgeons will assess tear production and quality as part of your evaluation.
General Health Considerations
Certain systemic health conditions can affect healing or increase risks:
- Autoimmune conditions (e.g., lupus, rheumatoid arthritis) may impair healing
- Diabetes that affects the eyes
- Medications that affect wound healing
Factors That May Disqualify You
- Keratoconus or suspected keratoconus
- Corneas that are too thin for safe tissue removal
- Severe or uncontrolled dry eye disease
- Very large pupils in dim light (may increase glare risk)
- Pregnancy or breastfeeding (hormonal changes affect vision)
- Unstable prescription
What Happens During a LASIK Evaluation?
- Corneal topography: Maps the shape and surface of your cornea
- Pachymetry: Measures corneal thickness
- Refraction: Determines your exact prescription
- Pupil measurement: Assesses pupil size in various lighting conditions
- Tear film assessment: Evaluates dry eye risk
- Dilated eye exam: Checks overall eye health, retina, and optic nerve
The Bottom Line
Being a good LASIK candidate requires meeting several overlapping criteria — age, prescription stability, corneal anatomy, and general eye health. The only way to know for certain is through a comprehensive pre-operative evaluation with a qualified refractive surgeon. If LASIK isn't right for you, other procedures like PRK, SMILE, or implantable collamer lenses (ICL) may still provide excellent vision correction.