Most people who wear glasses or contacts are good candidates for LASIK, but not everyone. Whether it will work for you depends on your prescription, your corneal thickness, the stability of your vision, and a handful of health factors. About 95% of people who get LASIK report being satisfied with the results, and 97% achieve driving-level vision (20/40 or better) without correction. The question is whether your eyes meet the criteria to get there safely.
Your Prescription Needs to Fall Within Range
LASIK reshapes your cornea to correct how light focuses on your retina, and there are limits to how much reshaping the laser can do. Current systems can treat nearsightedness up to about -12.00 diopters, farsightedness up to +6.00 diopters, and astigmatism up to 6.00 diopters. If your prescription falls within those ranges, you clear the first hurdle.
That said, people at the extreme ends of those ranges are more likely to need a touch-up procedure or experience some residual blurriness. The sweet spot for highly predictable results tends to be mild to moderate prescriptions. If you’re a -2.00, your odds of walking away with crisp 20/20 vision are higher than if you’re a -10.00. About 62% of all LASIK patients achieve 20/20 uncorrected vision, but that average includes the full spectrum of prescriptions.
Your Corneas Need Enough Tissue
During LASIK, a thin flap is created on the surface of your cornea, and the laser removes tissue underneath to change its shape. After the procedure, the FDA requires at least 250 microns of corneal tissue to remain intact, and most surgeons prefer to leave 270 microns or more. The average cornea is about 540 microns thick, so most people have plenty to work with. But if your corneas are naturally thin, or your prescription is high (meaning more tissue needs to be removed), you may not have enough margin.
This is one of the main reasons people get disqualified. A pre-operative scan maps your corneal thickness precisely, and your surgeon uses that measurement along with your prescription to calculate whether the math works. If it doesn’t, alternatives like PRK (which skips the flap and preserves more tissue) or implantable lenses may be better options.
Your Prescription Must Be Stable
LASIK corrects your vision at a fixed point in time. If your prescription is still shifting, the correction won’t hold. The FDA flags anyone whose glasses or contact lens prescription changed in the past year as a poor candidate. People in their early 20s or younger are especially likely to have unstable vision simply because their eyes are still developing.
Most surgeons want to see at least 12 months of stable prescription before they’ll proceed. If you’re 22 and your prescription shifted half a diopter last year, you’ll likely be told to wait and recheck. This isn’t a permanent disqualification. It just means your eyes aren’t ready yet.
Health Conditions That Can Rule You Out
Certain medical conditions interfere with how your cornea heals after surgery. Autoimmune diseases like lupus and rheumatoid arthritis, immunodeficiency conditions like HIV, and uncontrolled diabetes all raise red flags because they can slow or complicate wound healing. Some medications, including steroids and retinoids, have a similar effect.
Eye-specific conditions matter too. Keratoconus, a progressive thinning and bulging of the cornea, is one of the clearest disqualifiers because LASIK would make it worse. A history of glaucoma, recurring eye herpes (herpes simplex or zoster affecting the eye area), chronic eye inflammation, or previous eye surgeries all require careful evaluation. Chronic dry eye is another concern your surgeon will screen for, since LASIK temporarily worsens dryness during the healing period.
Pregnancy and Hormonal Changes
If you’re pregnant, breastfeeding, or recently stopped either, now isn’t the time for LASIK. Hormonal fluctuations during pregnancy can temporarily change your corneal shape and shift your prescription. The hormone prolactin, elevated during breastfeeding, may also affect the cornea in ways that aren’t fully understood yet.
The standard recommendation is to wait until you’ve completely stopped breastfeeding, your menstrual cycle has returned to normal, and your eye doctor confirms that your prescription has returned to its pre-pregnancy baseline. For most people, that means waiting several months after breastfeeding ends before even scheduling a consultation.
Pupil Size and Night Vision
Your pupil size in dim light plays a role in how you’ll see after LASIK. When your pupils dilate larger than the treatment zone the laser corrected, light entering the untreated edges of your cornea can scatter. This shows up as halos, starbursts, or glare around lights at night. Research has found a significant correlation between large pupil size measured before surgery and worsened night vision afterward.
Modern lasers use larger treatment zones than older systems, which has reduced this problem considerably. But if you drive a lot at night or work in low-light conditions, it’s worth asking your surgeon specifically how your pupil measurements look relative to the planned treatment zone.
What Happens at Your Evaluation
The consultation appointment is where all of these factors get measured. You’ll have your corneal thickness mapped, your prescription verified, your pupil size measured in dim light, and your tear production assessed. Your surgeon will also examine your cornea for signs of keratoconus or other irregularities and review your medical history.
One practical note: if you wear contact lenses, you need to switch to glasses before your evaluation. Contacts temporarily reshape your cornea, and the measurements taken while that reshaping is still present won’t be accurate. For soft lenses, you should stop wearing them at least 24 hours before your pre-operative evaluation, though many clinics ask for a week or more to be safe. Rigid or hard lenses reshape the cornea more aggressively and typically require a longer break, sometimes several weeks.
Realistic Expectations for Results
LASIK has high satisfaction rates, consistently landing between 95% and 98% across large studies. Most people achieve functional vision without glasses. But “functional” and “perfect” aren’t the same thing. While 97% of patients see 20/40 or better (the legal standard for driving without corrective lenses), only about 62% hit 20/20. Many of the rest see 20/25 or 20/30, which is excellent for daily life but not razor-sharp at every distance.
Temporary dry eye is the most common side effect. In one study of LASIK patients, about 14% experienced transient dryness that resolved during the healing period, while less than 1% developed chronic dry eye. Most people use lubricating drops for a few weeks to a few months after surgery.
The national average cost is about $2,250 per eye, though prices vary by region, technology, and surgeon experience. Insurance rarely covers LASIK since it’s considered elective, but many practices offer financing plans. Some employers offer flexible spending or health savings accounts that can be used for the procedure.
If You’re Not a Candidate
Being told LASIK won’t work for you doesn’t necessarily mean you’re stuck with glasses forever. PRK uses the same laser technology but removes the outer layer of the cornea instead of creating a flap, making it viable for thinner corneas. Implantable collamer lenses (ICL) are placed inside the eye and work well for very high prescriptions that exceed LASIK’s range. Refractive lens exchange replaces your natural lens entirely and can correct vision at all distances, though it’s more commonly recommended for people over 40.
The only way to know for certain whether LASIK will work for you is a comprehensive evaluation. The screening takes about an hour or two, and most providers offer it at no cost or apply the fee toward surgery if you proceed.