A great alternative for those who wear glasses or contact lenses and no longer wish to is LASIK. LASIK is currently the most popular refractive surgery to correct refractive error, eliminating the need for glasses or contacts in many individuals.
What is Refractive Error?
Refractive error is the amount of glasses prescription an individual has. Refractive error is multifactorial, meaning there are several things that contribute two a prescription.
Ultimately, refractive error is created when light is not properly refracted to come to a single point source on the retina (the backmost structure of the eye that contains light-detecting cells). This can occur when light is refracted too little (hyperopia/far-sightedness), too much (myopia/near-sightedness), or obliquely (astigmatism).
The main two contributing factors to a prescription are the cornea and lens of the eye, as both these structures are responsible for bending incoming light.
The cornea is the frontmost structure of the eye. It is clear and covers the colored part of the eye (iris).
If the cornea’s curvature is too flat it will not bend light enough, causing light to come to a focus “behind” the retina. This results in an individual who is farsighted, or hyperopic.
If the cornea’s curvature is too steep it will bend light too much, causing light to come to a focus in front of the retina. This results in an individual who is nearsighted, or myopic.
If the cornea has two different meridian curvatures (i.e. is shaped more like a football than a basketball) it creates two separate points of focus with blur in-between. This creates astigmatic refractive error.
The lens is a structure located near the equator of the eye. It is flexible to allow clear vision at a variety of distances (near and far).
When the lens loses flexibility, it can no longer focus light at variable distances. Therefore, the individual will need glasses to see at varying distances. Loss of lens flexibility is the underlying cause for the need for reading glasses as we age.
How Does LASIK Work?
LASIK stands for laser-assisted in-situ keratomileusis. It is a procedure that utilizes a excimer laser to alter the shape of the cornea.
Several measurements are taken to map out the shape of your cornea to determine what changes to the corneal structure are needed to optimize your refractive error.
The day of surgery, the eye is numbed with topical eye drops. Many offices will also give you an anti-anxiety medication such as Xanax or Valium to calm your nervous.
Once prepped, you will lie down on a table face up. The doctor will gently tape your eyelids open to expose the entire cornea. Next, the laser will be applied to the corneal surface. This takes 10-30 seconds—depending on how much the cornea needs to be altered.
Once the treatment has been applied, the doctor will apply an anti-biotic eye drop and steroid eye drop to the eye to decrease inflammation and reduce risk of secondary eye infection.
Vision the day of surgery may not be perfect—the eye will be a bit swollen post-surgery and a recovery of 2-3 days is expected. Vision can fluctuate up to 2 weeks post-surgery as the cornea stabilizes. Expected visual results post-LASIK are 20/30 or better.
Q: What is the minimum age requirement for LASIK?
A: You must be at least 18 years of age to undergo LASIK surgery. This is because prescriptions really do not stabilize completely until around the age of 18.
Q: What prescriptions can be corrected by LASIK?
A: Prescription is not necessarily the limiting factor with LASIK—corneal thickness is. Higher prescriptions require removal of more corneal tissue. The cornea can only safely be thinned down so much. Currently, it is estimated that LASIK can correct prescriptions up to -11.00 to +6.00, with up to 6.00 diopters of astigmatism. Your surgeon will need to take measurements to see how thick your corneas are before determining if your prescription can be corrected via LASIK treatment.
Q: Will the LASIK laser burn me?
A: No. The laser works similarly to a magnifying glass and the sun—it will only “burn” the designated tissue that is perfectly in focus. Anything in front of or behind the target will not be affected by the laser.
Q: Will I be awake during surgery?
A: Yes. The surgeon needs you to keep your eyes open during surgery. However, LASIK does not hurt and only lasts a few seconds. The eye will be topically anesthetized and relaxing pills will be given to make the surgery as comfortable as possible.
Q: Will I ever need glasses again after getting LASIK surgery?
A: Yes. You will eventually need reading glasses, as LASIK corrects corneal refractive error but does not affect the lens. Therefore, later in life when the lens loses its flexibility you will need reading glasses to see up close. There currently are no surgeries to prevent nor correct this process from occurring.
Q: Are there any side effects from LASIK?
A: There are some adverse effects that can occur after LASIK with the most common being dry eye. Others include increased glare at night and light sensitivity. Often times these symptoms improve by month 3 post-opt, but these side effects can also become permanent.