Laser vision correction. Are you eligible for laser eye surgery?

Laser eye surgery, also called refractive laser surgery, is an elective procedure, meaning it is not medically required. But it’s a life-changing procedure that frees you from glasses and contact lenses. That said, if you’ve ever thought about correcting your vision surgically, there are a few things you should know first.

What does laser eye surgery do?

Refractive laser surgery corrects refractive errors. When your eye has a refractive error, it doesn’t properly focus light onto the back of your eye (retina). As a result, you may experience blurred vision, double vision, glare, light sensitivity, and eye strain.

Refractive errors include:

  • Nearsightedness (myopia) occurs when the front of the eye (cornea) is too steep or the length of the eyeball is too long. Myopia mainly causes blurred vision at a distance.

  • Hyperopia (farsightedness) occurs when the front of the eye is too flat or the length of the eyeball is too short. Hyperopia mainly causes blurry near vision.

  • Astigmatism develops when the shape of the eye is irregular, causing blurred distance and near vision.

  • Presbyopia (age-related hyperopia) is blurred near vision that results from age-related eye changes.

When you put on glasses or contacts, the lenses refocus light on 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 a variety of reasons:

  • You don’t like the look of glasses 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 the eyes

  • You find it difficult to maintain 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 a profession (such as military or law enforcement personnel) that requires you to be able to see at all times

  • You play sports or engage in activities where glasses and contacts are not 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 a clearer view!

However, not everyone is eligible for laser vision correction. To determine if you are a candidate, the surgeon must consider several factors, including:

  • Age. You can have laser eye surgery if you are 18 years old. However, many surgeons recommend waiting until your mid-twenties, when your sight is more stable.
  • Prescription. Your eyeglass prescription should be stable for at least one to two years before surgery. If your vision fluctuates, you may be advised to delay the procedure. Also, you might not qualify for laser eye surgery if your prescription is too strong. The surgeon may recommend alternatives for vision correction.
  • Corneal thickness. Laser eye surgery removes some of your corneal tissue. Having thin corneas poses a higher risk of 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 can affect your eyes’ ability to heal after surgery. These can include diabetes, rheumatoid arthritis, lupus, and other autoimmune diseases. Also tell your doctor about any medications you are taking, such as steroids, isotretinoin, and other medications that may affect healing.
  • Pregnancy. Hormonal fluctuations can alter your vision during pregnancy and breastfeeding. Your doctor may advise you to wait until you are finished breastfeeding to consider laser vision correction.

Although these are general guidelines, your application may vary for each type of laser eye surgery.

What types of laser eye surgery are available?

LASIK (laser-assisted in situ keratomilosis) is the most popular form of laser vision correction. LASIK creates a flap on your cornea with a blade or laser. Then 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.

Advantages and disadvantages of LASIK:

  • Speedy recovery. Because of the flap, there is little discomfort and most people see relatively well immediately afterwards. Although LASIK can take months to fully heal, 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 compared to other laser eye surgeries.

  • May exacerbate dry eyes. Although any laser eye surgery can cause dry eye, cutting the flap affects the corneal nerves, which can make dry eye worse.

  • The shutters can be dislodged. Your surgeon may not recommend LASIK if you play high-impact sports where you can be hit in the eye.

PRK (photorefractive keratectomy) is a vision correction procedure in which the surgeon carefully removes the outer layer of the cornea with a special solution. A laser then reshapes the corneal tissue underneath.

Advantages and disadvantages 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 during healing.

  • Longer recovery time. Since there is no flap to cover the cornea, visual recovery can take weeks as the outer layer of the cornea heals.

  • No more discomfort during recovery. Without a flap, the cornea essentially has an open wound, which makes recovery more painful. The surgeon places a bandaged contact lens over the eye to improve comfort and healing.

SMILE (small incision lenticule extraction) is a newer surgical procedure in which the laser creates a disc of tissue (lenticule) in the inner layer of your cornea. The amount of fabric is based on the vision correction you need. The surgeon then removes the lenticule through a small incision in the cornea.

Advantages and disadvantages of SMILE:

  • Speedy recovery. Similar to LASIK, there is little downtime with SMILE.

  • Less disturbing for the cornea. Since there is no flap, SMILE does not affect the structural integrity and nerves of the cornea as much as LASIK.

  • Less risk of dry eye. Again, the absence of a flap means less disruption of the corneal nerves.

  • Not approved for farsightedness. In the United States, SMILE is only approved to treat myopia and astigmatism.

All three surgeries produce excellent results. More than 90% of LASIK patients, 70% of PRK patients and 88% of SMILE patients achieve 20/20 vision. About 99% of patients who receive LASIK or SMILE and 92% of patients with PRK achieve vision of 20/40 or better.

What are the risks associated with laser vision correction?

As with any surgery, there are risks. Side effects are common and disappear after a few weeks to a few months. Serious complications are rare but can be sight-threatening.

General side effects of laser eye surgery are:

  • Drought

  • Mild irritation or pain

  • Light sensitivity

  • Redness or broken blood vessels

  • Halos or glare

  • Blurred vision

Potential complications include:

  • Under or overcorrection of vision

  • Irregular astigmatism

  • Severe eye pain

  • Infection

  • Inflammation

  • Corneal thinning

  • Complications of the corneal flap in LASIK (inflammation, infection, displacement of the flap)

  • Worsening of vision

Side effects are usually temporary and can be managed with medicated or lubricating eye drops. However, complications require prompt medical attention. Your surgeon will advise you on the appropriate care regimen to prevent these problems.

Is laser eye surgery painful?

No, the surgeon numbs your eye with drops before the operation, so you won’t feel any pain. They may also give you a pill to help you feel relaxed. Some people report a feeling of pressure during LASIK and SMILE, but it only lasts for a moment.

How long does laser vision correction take?

The effects of surgery are permanent and the corneal tissue does not grow back after removal. However, your vision may change for other reasons after surgery, such as cataracts, presbyopia, and other age or health-related changes.

Overall, laser vision correction offers a long-term solution for clear vision. Although you should always wear glasses or receive a touch-up procedure if your vision changes, your vision is unlikely to return to its original state. Many people enjoy years of freedom without glasses or contacts!

References

Spadea, L., & Giovannetti, F. (2019). Main complications of photorefractive keratectomy and their management. Clinical Ophthalmology (Auckland, New Zealand), 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 Laser-Assisted Femtosecond In Situ Keratomileusis. Cureus, 9(9), e1641. https://doi.org/10.7759/cureus.1641

Hatch, Catherine (14 May 2020). Small Incision Lenticule Extraction (SMILE): This is 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 success rate of LASIK? https://americanrefractivesurgerycouncil.org/laser-eye-surgery-lasik-success-rate/


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