According to the American Refractive Surgery Council, between 15 percent and 20 percent of people who consider LASIK are deemed ineligible by their doctors, surgeons, or both. These patients may want surgery, but their doctors may not think that surgery is right for them.

While LASIK can be incredibly beneficial, a small percentage of patients who want surgery are not considered ideal surgical candidates. (Learn more) Your doctor will need to assess your visual acuity, and if your prescription is strong, surgery might not be right for you. (Learn more)

Your doctor will need to measure the thickness of your corneas and the size of your pupils. (Learn more) Your tear production may also play a role, although low tear production levels can be treated. (Learn more) Your doctor may also ask about your health history and your family health history. (Learn more) And you may need to think about whether or not your correction after surgery will be right for you. (Learn more)

Young tired working woman at work

Who Can Get LASIK?


LASIK is typically considered an elective surgery. People choose to have this procedure based on their health and personal preference. It might seem like anyone who wants to have the procedure would be able to have it done, but in reality, some people just aren't right for this type of surgery.

According to the American Refractive Surgery Council, between 15 percent and 20 percent of people who consider LASIK are deemed ineligible by their doctors, surgeons, or both. These patients may want surgery, but their doctors may not think that surgery is right for them.

The best way to know if you are a good candidate for surgery is to make an appointment with a professional and submit to a comprehensive examination. But these guidelines can help you understand whether you are within surgical parameters, so you can determine whether making an appointment is a smart move for you.

Ophthalmologist doctor with the snellen chart

Measuring Vision Loss to Determine Eligibility


LASIK surgery is performed to improve your vision, so you will not need to wear contacts and glasses to handle everyday activities. If you are considering LASIK, you probably wear contacts or glasses now. You may want to eliminate those lenses from your life altogether, and you might think surgery is the best solution.

In order to provide you with the appropriate contact or glasses prescription, an eye professional measures how well you can see. Prescriptions for vision correction are measured in diopters. As the Prevent Blindness organization clarifies, diopters tend to move in quarter measurements (from 0 to 0.25, for example), and higher numbers indicate the need for a stronger prescription. If you have a prescription of --2.00 to -2.50 diopters, you have an acuity of 20/200.

The U.S. Food and Drug Administration is responsible for assessing the machines used during LASIK procedures. The American Refractive Surgery Council reports that the FDA has approved LASIK for people with these prescriptions:

  • Nearsightedness: up to -12 diopters
  • Farsightedness: up to +6 diopters
  • Astigmatism: up to 6 diopters

If your prescription is stronger than these limits, you might not be considered an appropriate candidate for surgery. The tools available to treat vision deficiency during LASIK are not approved for your level of vision loss, and the correction you may get after surgery might still require you to wear glasses.

Even if you are within limits, you might not be considered an ideal patient. As Mayo Clinic explains, people with a mild level of nearsightedness tend to have the most success with surgery. Since LASIK cannot be reversed, surgeons want to do all they can to ensure that their patients will get the results they expect from surgery. If your prescription is strong and your doctor feels you will not get the most benefit from the procedure, your surgeon may choose not to perform the surgery.

Other Measurements Taken Before Surgery


In addition to measuring your visual acuity, your doctor will need to measure other parts of your eye anatomy in order to ensure that you will have healthy eyes after the surgery is complete.

One of those measurements involves the thickness of your cornea. During surgery, your cornea will be cut and reshaped. If your cornea is too thin or an unusual shape, that can put you at risk for complications during and after surgery.

In a study published in the journal Cornea, abnormal cornea shape was responsible for 34.3 percent of people turned away from LASIK surgery, and 23.1 percent were turned away due to thin corneas. That makes this measurement one of the most common reasons patients were excluded from surgery.

Your surgeon will also need to assess how big your pupil grows when the lights are dim. Experts quoted in Review of Ophthalmology point out that some studies have found a small connection between large pupils and poor night vision after surgery, but surgeons who have conducted surgery on people with large pupils have been sued, and those lawsuits have been large. As a result, many surgeons choose to proceed with caution, and they will not perform surgery on those who have pupils that are larger than average.


Assessing Your Tear Production


Tears help to nourish and moisten the delicate surface of the eye. That protection is vital after eye surgery, and if you do not produce enough tears, you could have a higher risk of complications. You may also feel pain after surgery that can interfere with your daily life.

Measuring tear production takes just a few minutes, and it involves little more than placing special strips of paper or tiny threads beneath the lids of both eyes. The American Academy of Ophthalmology and other eye experts point out, in their Patient's Guide to Refractive Surgery, that patients with dry eye syndrome that is treated have the same success with LASIK as people who do not have dry eye syndrome. But you should have your tear production assessed and treated as part of your screening process.

Smiling family have fun at backyard.

Family and Personal Health History Plays a Role


The flap created by LASIK should heal without any additional help, but some people have unusual cornea growth patterns that put their healing at risk. As experts interviewed in Review of Ophthalmology point out, it's difficult for doctors to screen for those issues. There are no genetic tests for it, and some people show no symptoms in early stages. Your doctor may ask you a number of questions about your family history of eye health and disease, and if symptoms in family members come up, you may not be a good candidate for surgery.

Your doctor will also want to assess your overall health. Diabetes, heart disease, kidney disease, and other health issues can make any kind of surgery hard on your body, and your doctor will want to make sure that underlying problems won't put you at risk for complications.



Your doctor can measure your eye health and your physical health in order to help you understand if surgery is right for you. But there are some personal attributes that your doctor may not be able to measure, but that are vital for your success in surgery.

For example, as the U.S. Food and Drug Administration points out, complications of surgery are just unavoidable in some types of patients. People who are good candidates for surgery are willing to accept those risks. If you consider yourself someone who plays it safe and avoids all risks at all times, surgery might not be right for you.

The American Academy of Ophthalmology also points out that while more than 90 percent of people get somewhere between 20/20 and 20/40 vision after LASIK, that 20/40 vision might not be enough for some people. If your job or hobbies involve precise vision, your correction level after surgery might not be enough for you.

A Doctor Can Help You Decide


Choosing whether or not to have surgery can be complicated, and if you try to make the choice alone, it can also be nerve-wracking. Pulling a doctor into your deliberations is wise. Your doctor can explain the benefits and risks of surgery, and your doctor can take the measurements required to determine whether or not you are a good candidate. We can help you to find a doctor in your area. Contact us to find out more.


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Are You a Candidate for LASIK? 5 Guidelines You Should Know. (April 2018). American Refractive Surgery Council.

How Visual Acuity Is Measured. (October 2003). Prevent Blindness.

LASIK Surgery: Is It Right for You? (March 2017). Mayo Clinic.

Screening of Refractive Surgery Candidates for LASIK and PRK. (October 2014). Cornea.

Screening for LASIK: Tips and Techniques. (July 2006). Review of Ophthalmology.

Is LASIK for Me? A Patient's Guide to Refractive Surgery. (October 2008). American Academy of Ophthalmology, International Society of Refractive Surgery, and Ophthalmologic Mutual Insurance Company.

When Is LASIK Not for Me? (July 2018). U.S. Food and Drug Administration.

LASIK: Laser Eye Surgery. (December 2015). American Academy of Ophthalmology.