Quick Answer
The most common LASIK disqualifiers are: thin corneas (insufficient tissue for safe treatment), unstable prescriptions (changing by more than 0.50 D in the past year), keratoconus or irregular corneal shape, severe dry eye disease, extreme prescriptions outside FDA-approved ranges, certain autoimmune conditions, and pregnancy or breastfeeding. Approximately 15–20% of patients who seek LASIK evaluation are not good candidates.
Detailed Explanation
LASIK candidacy is determined by a comprehensive pre-operative evaluation. The disqualifying factors fall into four broad categories: corneal anatomy, refractive stability, ocular health, and systemic health.
1. Corneal anatomy
The cornea is the structure LASIK reshapes. If it does not meet minimum requirements, the procedure cannot be performed safely.
- Thin corneas: LASIK requires sufficient corneal tissue to create a flap and still leave an adequate residual stromal bed (minimum ~250 microns after treatment). Patients with thin corneas (typically below 500 microns total, though this varies by prescription) may not have enough tissue. For these patients, surface ablation (PRK, LASEK) may be an alternative.
- Keratoconus: This progressive condition causes the cornea to thin and bulge outward. LASIK is contraindicated in patients with keratoconus — removing tissue from an already-compromised cornea can accelerate ectasia progression and cause irreversible vision loss. Subclinical keratoconus (not yet visible clinically but detectable on tomography) is one of the most critical screening findings.
- Irregular corneal shape: Irregular astigmatism, asymmetric corneas, or other surface irregularities detected on topography or tomography can disqualify patients or redirect them to alternative procedures.
- Excessively steep or flat corneas: Corneal curvature outside normal ranges affects the safety and predictability of laser treatment.
2. Prescription (refractive stability)
- Unstable prescription: A prescription that has changed by more than 0.50 diopters in the past 12 months indicates the eye is still changing. LASIK performed on an unstable prescription is likely to produce a result that doesn’t hold. Most surgeons require documented stability for at least 1–2 years.
- Prescription outside approved ranges: Current FDA-approved laser platforms treat myopia up to approximately -11.00 D and hyperopia up to +6.00 D, with astigmatism up to approximately -6.00 D. Prescriptions beyond these ranges cannot be fully corrected with LASIK and may require alternative approaches (phakic IOLs, refractive lens exchange).
3. Ocular health
- Severe dry eye disease: LASIK transiently reduces corneal nerve density, which impairs tear production. Patients with significant pre-existing dry eye are at high risk for severe, prolonged post-operative dry eye. Mild dry eye is not an absolute contraindication but requires pre-treatment and careful post-operative management.
- Glaucoma: Elevated intraocular pressure and glaucomatous optic nerve changes complicate the intraoperative pressure changes during LASIK flap creation. Most patients with controlled glaucoma are disqualified.
- History of herpes simplex eye infection: HSV keratitis can be reactivated by the laser treatment and by the stress of surgery. This is typically a disqualifying factor.
- Cataracts: Clouding of the natural lens reduces the effectiveness of corneal refractive surgery. Patients with visually significant cataracts are better served by cataract surgery with premium IOLs.
- Retinal disease: Active retinal conditions, particularly those requiring laser treatment, may be contraindicated.
- Amblyopia (“lazy eye”): LASIK cannot improve the visual system’s neural processing. Patients whose vision cannot be corrected to 20/20 even with glasses may not achieve that level after LASIK.
4. Systemic health conditions
- Autoimmune conditions: Rheumatoid arthritis, lupus, Sjogren’s syndrome, and other autoimmune diseases can impair corneal healing and worsen dry eye. These are not absolute disqualifiers in all cases but require careful evaluation.
- Uncontrolled diabetes: Poor glycemic control affects healing and can cause prescription fluctuations. Well-controlled diabetics may be candidates with careful monitoring.
- Immunosuppressive medications: Certain medications reduce healing capacity and infection resistance.
- Corticosteroid use: Long-term steroid use can affect intraocular pressure and healing.
- Pregnancy and breastfeeding: Hormonal changes cause temporary refractive fluctuations. LASIK should be deferred until hormones have normalized and the prescription has restabilized — typically 3–6 months after breastfeeding concludes.
- Underage patients: FDA minimum is 18 years; most surgeons prefer mid-20s for prescription stability reasons.
Alternatives when LASIK is not an option
Being disqualified from LASIK does not mean permanent dependence on glasses or contacts. Alternatives include:
- PRK/LASEK: Surface ablation that does not require a flap — suitable for thin corneas
- Visian ICL (Implantable Collamer Lens): A phakic lens placed inside the eye, suitable for high prescriptions and thin corneas
- Refractive lens exchange: Replacement of the natural lens with a corrective IOL
- Orthokeratology: Overnight rigid lenses that temporarily reshape the cornea
LASIK Surgery Awards specifically highlights practices that apply rigorous candidacy screening — because the most important thing a practice can do for patient safety is correctly identify who should not have LASIK.
Important Considerations
Honest disclosure is essential. Patients who withhold information about systemic conditions, medication use, or family history of eye disease may receive an inaccurate candidacy assessment. The risks from an incomplete history fall entirely on the patient.
A second evaluation is reasonable. If you are told you are not a candidate and want confirmation, seeking an evaluation at a second reputable practice is entirely appropriate.
“Not a candidate” may mean “not a candidate yet.” Pregnancy-related disqualifications are temporary. Unstable prescriptions become stable. Some systemic conditions can be optimized. A clear conversation about whether disqualification is permanent or situational is worth having.
What to Do Next
1. Gather your prescription history — at least 2 years of documented exams — before your LASIK evaluation. 2. Disclose all medications and medical history to your evaluating surgeon. 3. Ask specifically about alternatives if you are told you do not qualify for LASIK. In most cases, a suitable alternative exists.
For information on the evaluation process itself, see How to Prepare for LASIK Surgery.
Related Questions
Wondering about the specific age considerations for candidacy? Read What Is the Best Age to Get LASIK?.
Concerned about dry eye specifically and whether it would disqualify you? See What Are the Side Effects of LASIK? for how dry eye is managed pre- and post-operatively.
Want to understand how surgeons evaluate your specific anatomy during screening? Read What to Look for in a LASIK Surgeon.