Updated on  February 22, 2024
4 min read

How Bad Can Your Vision Be for LASIK?

6 sources cited
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LASIK (laser-assisted in situ keratomileusis) is laser eye surgery that corrects vision. It is a common procedure for people who wear glasses or contact lenses. 

Not all people who have vision problems should undergo LASIK surgery.

There are specific qualifications you must meet, including: 

  • Up to -12.0 diopters of nearsightedness
  • Up to 6.0 diopters of astigmatism
  • Up to +6.0 diopters of farsightedness
  • If diopters are not lessened by more than 0.5 within one year of the procedure

What are Refractive Errors and Diopters?

Before considering LASIK surgery, it’s essential to understand the following:

Refractive errors or vision problems occur when the cornea and lens do not bend light correctly. This means the cornea and/or the lens are irregular in shape

Nearsightedness, farsightedness, astigmatism, and presbyopia are all refractive errors

Nearsightedness is clear and distinct vision of near objects

Farsightedness is clear and distinct vision of far objects

Astigmatism can cause objects to appear blurry, regardless of their distance

Presbyopia is an age-related refractive error that causes gradual loss of close up vision

A diopter is a unit used to indicate the strength of your lens

Other LASIK Requirements

Aside from the qualifications mentioned above, you should also consider other factors before undergoing laser eye treatment. These include:

1. Eye Health

Your eyes must be healthy before undergoing LASIK surgery. For example, eye infections and chronic dry eyes need to be corrected before the procedure. LASIK is not an option if you have a degenerative eye disease. 

2. Physical Health

During LASIK surgery, the doctor will make an incision into one or both eyes. Your body needs to be in good health to endure this process and heal properly.

3. Age

You have to be 18 years or older to undergo LASIK. However, optometrists and ophthalmologists usually recommend waiting until your mid-20s (or older). 

Vision prescriptions typically change and evolve in your younger years. Waiting until you are at least 25 will make LASIK surgery more effective. 

4. Vision Stability

You must have a vision prescription that has not changed over the last 12 months. LASIK will only correct your current eye prescription. If your vision prescription is not stable and continues to change, the procedure will be less effective. 

5. Corneal Thickness

Because LASIK reshapes the cornea, it must be thick enough to sculpt. LASIK is only safe for corneas that are thick enough to be functional again after the surgery. 

The average corneal thickness is between 540 µm to 560 µm. Corneas thinner than 540µm may not be suitable for LASIK surgery. 

Who Shouldn’t Get LASIK?

Some people should not undergo LASIK surgery. These are people who:

Are Under 18 Years Old

Vision often changes during adolescence, so anyone under 18 is typically not a good candidate for LASIK. Their vision will likely change again after surgery.

Are Pregnant or Nursing

Hormone fluctuations can cause vision changes. Also, medications administered during LASIK might harm the fetus, so it’s not considered a safe surgery if you’re pregnant. 

Take Certain Prescription Drugs

Certain prescription drugs, such as steroids, can interfere with LASIK results. Talk to your eye doctor about any prescription medications you are taking beforehand. 

Have Dry Eye Syndrome

Dry eye syndrome is another eye problem that’s not safe to mix with LASIK surgery. It increases the risk for post-LASIK discomfort and may worsen the condition.

Have Certain Health Conditions

People with the following conditions should not undergo LASIK: 

  • Diabetes
  • Rheumatoid arthritis
  • Lupus
  • Glaucoma
  • Cataracts
  • Eye injuries or infections, which can leave corneal scarring

Have Large Pupils

Pupil dilation should only reach 6 mm. But if your pupil dilates 7 to 8 mm in the dark, this might have a negative effect on your vision if you pursue LASIK. 

How to Find Out if You’re a Candidate for LASIK

Ideally, a good LASIK candidate should have:

  1. Healthy eyes
  2. Stable vision
  3. Enough corneal thickness
  4. Pupil size that is not too large
  5. A prescription that is within limits
  6. Good health

What to Expect During a LASIK Consultation

You can expect a comprehensive eye exam when you schedule a LASIK consultation. Your doctor will assess whether or not you are a good candidate for the surgery. 

During the eye exam, your doctor will: 

  • Determine your prescription
  • Evaluate your eye health
  • Examine the interior of your eyes 
  • Get the exact measurement of the refractive error
  • Other measurements as needed

Other Vision Correction Options 

There are other treatment options available, such as: 

Consult your eye doctor or surgeon to determine the best vision correction option for you. Ask questions like:

  • What are the risks involved with refractive surgery
  • What are the pros and cons of the surgery? 
  • Is vision correction surgery necessary?
  • What are the effects of refractive eye surgery?
  • Will it give me perfect vision?
  • Will I have to wear glasses after LASIK surgery?

Listen In Q&A Format

Is My Vision Too Bad for LASIK?
Vision Center Podcast
Updated on  February 22, 2024
6 sources cited
Updated on  February 22, 2024
  1. What is LASIK?” US Food & Drug Administration.

  2. Bamashmus, M et al. “Functional outcome and patient satisfaction after laser in situ keratomileusis for correction of myopia and myopic astigmatism.” Middle East African journal of ophthalmology vol. 22,1 : 108-14.

  3. What are the risks and how can I find the right doctor for me?” US Food & Drug Administration.

  4. Solomon, K et al. “LASIK world literature review: quality of life and patient satisfaction.” Ophthalmology vol. 116,4 : 691-701.

  5. Wilkinson, J et al. “Refractive Eye Surgery: Helping Patients Make Informed Decisions About LASIK.” American Family Physician, 15 May 2017.

  6. LASIK & Advanced Vision Correction Frequently Asked Questions.” Flaum Eye Institute.

The information provided on VisionCenter.org should not be used in place of actual information provided by a doctor or a specialist.