Although LASIK eye surgery can treat severe degrees of myopia (nearsightedness), moderate amounts of hyperopia (farsightedness), and astigmatism, it is not right for everyone.
While the goal of LASIK surgery is to get rid of glasses or contact lenses, undergoing LASIK surgery cannot guarantee 20/20 vision. Fortunately, post-op, most cases are successful in improving visual acuity (or sharpness).
You have to fulfill certain eligibility criteria in order to be fit for Lasik surgery. There are certain contraindications that can make you unfit for this surgery.
Nevertheless, if the opthalmologist says you are not a good Lasik candidate today, you may still be a potential candidate in the future. The technology for laser eye surgery is constantly improving and this enables people ineligible today to become eligible later.
Eligibility criteria for Lasik
There are certain parameters, which govern who can undergo Lasik. They tell the eye surgeon whether you are suitable and fit for Lasik surgery or not. The eye surgeon will perform a general and detailed eye examination before he declares you fit for surgery.
1. Your eyes must be healthy
If you have any eye condition that can adversely affect your eyes after surgery or the healing process later, you should wait until that condition is resolved. Examples are severe dry eye syndrome, conjunctivitis, any eye infection, any type of eye injury, and uncontrolled glaucoma.
2. You must be old enough
LASIK is advised only after the age of 18 years and when the visual acuity has been stable for over a year. If one continues growing in height, the power would also change.
Generally, there is no upper age limit to laser eye surgery. However, in your 40s, you may still need reading glasses to correct near vision due to age-related presbyopia (the gradual loss of your eyes’ ability to focus on nearby objects).
3. Your cornea must have sufficient thickness
Most refractive procedures improve eye power by reshaping the anterior surface of the cornea. Performing laser eye surgery on a thin cornea or a cornea that has an extremely irregular and deformed surface (for example, as in keratoconus) will not yield successful results and your vision could get compromised.
4. Your prescription must be within certain limits
To be eligible for Lasik, you cannot have a high refractive error. Your surgeon will advise you against going in for Lasik, if your glasses prescription, whether due to nearsightedness, farsightedness or astigmatism is very high.
LASIK surgery for treating very high refractive errors is not predictable and may not be worth the risks.
6. Your vision must be stable
Teenagers and many young adults often experience changes in their contact lenses and eyeglass prescription from time to time. To be eligible for Lasik, it’s important that your refractive errors have been stable for at least 12 months.
7. Your general health must be good
Your general health must be good. In cases of hypertension and diabetes, your blood pressure and blood sugar levels must be under control.
Basically, if your body has any trouble with the healing process, you will probably have an unsatisfactory post-surgery outcome.
Surprisingly, people with HIV who have good immune cell counts may be candidates for LASIK. AIDS is a contraindication.
8. If pregnant, delay Lasik surgery
The LASIK procedure is not suitable during pregnancy. Hormonal changes that occur during pregnancy can change the shape of your cornea, leading to temporary changes in your vision.
Surgery should be performed only after your hormones and vision have returned to normal after pregnancy, which could take a few months.
Contraindications
Contraindications for Lasik can be divided into three categories:
Local eye contraindications
General health contraindications
Other contraindications
1. Local eye disorders, which are contraindications for Lasik and make you ineligible
Blepharitis. This is inflammation of the eyelids with crusting of the eyelashes, which increases the risk of infection after surgery.
A thin cornea. A sufficiently thick cornea is necessary for Lasik surgery so that when the corneal flap is created and the laser applied, there is sufficient corneal tissue remaining to maintain the curvature and rigidity of the cornea. The eye surgeon determines whether the thickness of the cornea is sufficient for Lasik surgery, by measuring it with an instrument called the pachymeter.
Size of the Pupil. Too large pupils diminish the benefits of Lasik surgery.
Keratoconus. This is a pathological condition of the cornea, where due to decreased corneal strength, the cornea progressively goes on thinning and bulges out into a conical shape causing distorted vision. Keratoconus is an absolute contraindication for Lasik.
Changing eye prescription. If your prescription for eyeglasses is changing frequently and becomes stronger, then you are not the right candidate. You must have a stable eye prescription, without significant change for at least one year.
Lasik prescription requirements. Your corrected vision at the time of the Lasik operation must be within the following limits:
Myopia or short-sightedness should be less than 8 dioptres.
Hyperopia or long-sightedness should be less than +6 dioptres.
Astigmatism should be less than 4 dioptres.
Eye conditions like cataracts, glaucoma, strabismus, ocular herpes, retinal detachment due to eye surgery, diabetic retinopathy, and macular degeneration are absolute contraindications. Any eye infections must be treated before you become eligible for a Lasik operation.
Dry eyes. History of dry eyes does become a contraindication as this condition may worsen after Lasik. However, the use of artificial tears may help.
2. General health contraindications for Lasik
Auto-Immune diseases. Persons with a compromised immune system and suffering from lupus, multiple sclerosis, rheumatoid arthritis, HIV, and fibromyalgia are not eligible to undergo Lasik. This is because such persons do not heal in the required manner.
Uncontrolled and unstable diabetes is another strong contraindication for Lasik eye surgery. Diabetes also can cause diabetic retinopathy and changes in vision.
3. Other Lasik contraindications
Age. LASIK is FDA-approved for all persons aged 18 and older. Since adult vision is usually at its best between the ages of 19 to 40 years, anyone within this range is a potential candidate. Doing a Lasik on a person below the age of 18 years is contraindicated because the growth of the eye stabilizes after the age of 18 years and till then the eye is still changing. Old age is not a contraindication by itself if other contraindicating factors are not present. However, although there is no upper age limit for LASIK surgery, people above 40 years may suffer from presbyopia, which prevents them from seeing close objects.
Pregnancy. If you are pregnant or planning to become pregnant immediately, you should avoid undergoing Lasik. This is because changes in eye refraction occur during pregnancy.
Nursing mothers should not opt for Lasik till 6 months after pregnancy.
Certain medications. If you are taking certain systemic drugs that alter vision, you are ineligible for Lasik. These drugs include and not limited to cyclosporine and tacrolimus, minocycline, hydroxychloroquine, ethambutol, topiramate, tamsulosin, amiodarone, anticholinergics, erectile dysfunction drugs, blood pressure medications and more.
Certain sports. Trauma to an eye operated for Lasik can result in permanent dislocation of the corneal flap. Therefore, people who engage in sports where such trauma is likely, become an automatic contraindication. Such sports include martial arts, boxing, or wrestling.
