Laser eye surgery, also called laser refractive surgery, is an elective procedure, i.e. it is not required medically. But it is a life-changing procedure that gives you freedom from glasses and contact lenses. That said, if you've ever thought about correcting your vision surgically, you should know a few things first.
What does laser eye surgery do?
Laser refractive surgery corrects refractive errors. When your eye has a refractive error, it doesn't focus light properly onto the back of your eye (retina). As a result, you may have blurry vision, double vision, glare, light sensitivity, and eye strain.
Refractive errors include:
- Myopia (nearsightedness) occurs when the front of your eye (cornea) is too steep, or the eyeball length is too long. Myopia primarily causes blurry vision at a distance.
- Hyperopia (farsightedness) occurs when the front of your eye is too flat, or the eyeball length is too short. Hyperopia primarily causes blurry vision up close.
- Astigmatism develops when the shape of the eye is irregular, causing blurry distance and near vision.
- Presbyopia (age-related farsightedness) is blurry vision up close that results from age-related changes in the eye.
When you put on glasses or contacts, the lenses refocus light onto the retina so you can see clearly. Laser eye surgery reshapes your cornea to accomplish the same thing.
Who is a candidate for laser vision correction?
You might consider vision correction surgery for various reasons:
- You don't like how glasses look on you
- You have sinus problems or other issues where glasses cause discomfort
- You frequently misplace or break glasses
- Contact lenses irritate and dry out your eyes
- You have a difficult time maintaining your contact lens regimen or forget to remove them
- You don't want to spend money every year buying new glasses and contacts
- You have an occupation (such as military or law enforcement personnel) that requires you to be able to see at any given time
- You play sports or engage in activities where glasses and contacts aren't practical
- You travel frequently and don't want to worry about glasses or contacts
- You want the convenience of not having to use contacts or glasses
- You want clearer vision!
However, not everyone is eligible for laser vision correction. To determine if you're a candidate, the surgeon must consider several factors, including:
- Age. You can get laser eye surgery if you are 18 years old. However, many surgeons recommend waiting until your mid-20s, when your eyesight is more stable.
- Prescription. Your glasses prescription should be stable for at least one to two years before surgery. If your vision fluctuates, you might be advised to defer the procedure. Also, you may not qualify for laser eye surgery if your prescription is too strong. The surgeon can recommend alternatives for vision correction.
- Corneal thickness. Laser eye surgery removes a portion of your corneal tissue. Having thin corneas poses a higher risk for surgical complications.
- Eye health. Laser eye surgery may not be recommended if you have existing eye conditions such as dry eye, infections, inflammation, corneal disease, cataracts, glaucoma, or retinal detachment. In some cases, your surgeon may be able to perform laser vision correction if the condition is controlled.
- General health. Certain conditions may affect your eyes' ability to heal after surgery. These may include diabetes, rheumatoid arthritis, lupus, and other autoimmune diseases. Also, tell your doctor about any medications you take, like steroids, isotretinoin, and other drugs that can affect healing.
- Pregnancy. Hormonal fluctuations can cause your vision to change during pregnancy and nursing. Your doctor may advise waiting until you are finished nursing to consider laser vision correction.
While these are general guidelines, your candidacy may vary for each type of laser eye surgery.
What types of laser eye surgery are available?
LASIK (laser-assisted in situ keratomileuses) is the most popular form of laser vision correction. LASIK creates a flap on your cornea with a blade or laser. Next, the flap is folded back, and another laser reshapes the corneal tissue under the flap. After this step, the surgeon replaces the flap without stitches.
Pros and cons of LASIK:
- Quick recovery. Because of the flap, there is little discomfort, and most people see relatively well immediately afterward. Although LASIK can take months to heal fully, many people return to work within a day or two.
- Requires thicker corneas. Since a flap is required, the surgeon needs more corneal tissue to perform LASIK versus other laser eye surgeries.
- May exacerbate dry eyes. Although any laser eye surgery can cause dryness, cutting the flap affects the corneal nerves, which can worsen dry eye.
- Flaps can be dislodged. Your surgeon may not recommend LASIK if you engage in high-impact sports where you can get hit in the eye.
PRK (photorefractive keratectomy) is a vision correction procedure in which the surgeon carefully removes the cornea's outer layer with a special solution. A laser then reshapes the corneal tissue underneath.
Pros and cons of PRK:
- Suitable for thin corneas and high prescriptions. If your cornea is too thin for LASIK, PRK is a great alternative that doesn't require removing as much tissue.
- No risk of flap dislocation. Since PRK does not require a flap, there is no risk of accidentally dislodging it if you rub your eye while healing.
- Longer recovery time. Since there is no flap to cover the cornea, visual recovery can take weeks as the cornea's outer layer heals.
- Greater discomfort during recovery. Without a flap, the cornea essentially has an open wound, making recovery more painful. The surgeon places a bandage contact lens on the eye to improve comfort and healing.
SMILE (small incision lenticule extraction) is a newer surgery in which the laser creates a disc of tissue (lenticule) in the inner layer of your cornea. The amount of tissue is based on the vision correction you need. The surgeon then removes the lenticule through a small incision in the cornea.
Pros and cons of SMILE:
- Quick recovery. Similar to LASIK, there is little downtime involved with SMILE.
- Less disruptive to the cornea. Since there is no flap, SMILE does not affect the structural integrity and nerves of the cornea as much as LASIK.
- Lower risk of dry eye. Again, the lack of a flap means less disruption to the corneal nerves.
- Not approved for hyperopia. In the United States, SMILE is only approved to treat myopia and astigmatism.
All three surgeries produce excellent outcomes. Over 90% of LASIK patients, 70% of PRK patients, and 88% of SMILE patients achieve 20/20 vision. About 99% of patients who get LASIK or SMILE and 92% of PRK patients achieve 20/40 vision or better.
What risks are involved with laser vision correction?
As with any surgery, there are risks involved. Side effects are common and resolve after a few weeks to months. Severe complications are rare but can be vision-threatening.
General side effects of laser eye surgery are:
- Irritation or mild pain
- Sensitivity to light
- Redness or broken blood vessels
- Haloes or glare
- Hazy vision
Potential complications include:
- Under- or overcorrection of vision
- Irregular astigmatism
- Severe eye pain
- Corneal thinning
- Corneal flap complications in LASIK (inflammation, infection, flap displacement)
- Worsening of vision
Side effects are usually temporary and may be managed with medicated or lubricating eye drops. However, complications require prompt medical attention. Your surgeon will advise you on the proper care regimen to prevent these problems.
Is laser eye surgery painful?
No, the surgeon numbs your eye with drops before surgery, so you don't feel pain. They may also give you a pill to help you feel relaxed. Some people report a sensation of pressure during LASIK and SMILE, but this only lasts a moment.
How long does laser vision correction last?
The effects of surgery are permanent and corneal tissue doesn't grow back after removal. However, your vision can change for other reasons after surgery, such as cataracts, presbyopia, and other age- or health-related changes.
Overall, laser vision correction provides a long-term solution for clear vision. Although you may still need to wear glasses or receive a touch-up procedure if your vision changes, your vision is unlikely to decline back to its original state. Many people enjoy years of freedom without glasses and contacts!
Spadea, L., & Giovannetti, F. (2019). Main Complications of Photorefractive Keratectomy and their Management. Clinical ophthalmology (Auckland, N.Z.), 13, 2305–2315. https://doi.org/10.2147/OPTH.S233125
Hashmani, N., Hashmani, S., Ramesh, P., Rajani, H., Ahmed, J., Kumar, J., Kumar, A., & Jamali, M. (2017). A Comparison of Visual Outcomes and Patient Satisfaction Between Photorefractive Keratectomy and Femtosecond Laser-Assisted In Situ Keratomileusis. Cureus, 9(9), e1641. https://doi.org/10.7759/cureus.1641
Hatch, Kathryn (May 14, 2020). Small Incision Lenticule Extraction (SMILE): It's What's New in Laser Vision Correction. Harvard Health Blog. https://www.health.harvard.edu/blog/small-incision-lenticule-extraction-smile-its-whats-new-in-laser-vision-correction-2020051419765
Refractive Surgery Council (October 13, 2021). What Is the LASIK Success Rate? https://americanrefractivesurgerycouncil.org/laser-eye-surgery-lasik-success-rate/