Updated on  February 21, 2024
7 min read

What Is Refractive Surgery?

8 sources cited
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What is Refractive Surgery?

Refractive surgery is a procedure that corrects common vision problems resulting from refractive errors. It’s an eye surgery that changes the cornea’s shape to improve your vision. 

Refractive errors occur when your eyes cannot accurately focus images onto the retina, the tissue in the back of your eye that senses light. As a result, refractive errors cause blurry vision. 

Types of refractive errors include:

graphic comparing normal vision, myopia refractive error, and hyperopia refractive error

Types of Refractive Surgeries

There are several forms of refractive surgeries. 

Although LASIK (laser in-situ keratomileusis) is one of the most popular options, not everyone is a candidate. Your ophthalmologist (eye doctor) can determine which eye surgery is best for you.

PRK surgery photo of a patient in operating room

LASIK (laser in-situ keratomileusis)

LASIK eye surgery corrects your vision by reshaping the clear surface of your eye, called the cornea. 

The surgeon uses a femtosecond laser or a microkeratome blade to create a flap on your cornea. Once the flap is lifted, an excimer laser reshapes the corneal tissue underneath.

  • If you’re nearsighted, the laser flattens the curvature of your cornea to reduce your eye’s focusing power
  • If you’re farsighted, the laser steepens your cornea to increase focusing power
  • If you have astigmatism, LASIK evens out the irregular shape of your cornea so that it’s more symmetrical. After this, the flap is replaced, which acts as a bandage to reduce recovery time

There are custom LASIK procedures that deliver more precise and personalized visual results. These include:

  • Wavefront-guided LASIK
  • Wavefront-optimized LASIK
  • Topography-guided LASIK

PRK (photorefractive keratectomy)

PRK is also performed with a laser, but unlike LASIK, the surgeon doesn’t create a corneal flap. Instead, he applies an alcohol solution or uses surgical instruments to remove the cornea’s outer layer (epithelium).

Then, the surgeon applies the excimer laser to reshape your cornea. Because there’s no flap, a bandage contact lens is applied, protecting your eye as the epithelium heals. 

The healing time for PRK is also longer than LASIK. With LASIK, some people go back to work the next day. With PRK, many people take a week off work to recover.  

LASEK (laser subepithelial keratomileusis) and Epi-LASIK

LASEK includes a combination of LASIK and PRK techniques. An alcohol solution loosens the epithelium, but instead of removing the tissue, the surgeon creates a flap in the epithelium.

This flap is thinner than the one created during LASIK, making this procedure suitable for thin corneas.

Epi-LASIK also creates a thin epithelial flap with a microkeratome blade. Because it doesn’t involve using an alcohol solution, this procedure is less damaging to the cornea than LASEK. 

SMILE (small incision lenticule extraction)

SMILE primarily corrects myopia and some astigmatism. It uses a femtosecond laser to create a circular piece of tissue in the inner layer of your cornea, called a lenticule.

Then, the surgeon creates a small incision on your cornea and removes the lenticule through this incision. 

Although this is a newer procedure, some studies show that SMILE is a promising alternative to LASIK. Benefits include less dry eye and a more stable corneal structure after surgery.

RLE (refractive lens exchange surgery)

RLE is similar to cataract surgery; only it’s performed before one develops a cataract. During the procedure, the surgeon removes your natural lens and replaces it with an intraocular lens (IOL).

This surgery is particularly beneficial for people with high prescriptions who may not be eligible for laser refractive surgery.

The surgeon selects the type of IOL depending on the vision correction you need, which may include:

  • Toric IOL for astigmatism
  • Multifocal or accommodating IOL for presbyopia (presbyopic lens exchange or PRELEX)

Phakic intraocular lens implants (Phakic IOL)

Phakic IOL is a lens implant that corrects high levels of myopia. Instead of removing the natural lens like in RLE procedures, the natural lens stays in place. A phakic IOL can be removed or replaced later on. 

There are two types of phakic IOLs:

  • Anterior chamber phakic IOL (inserted between the cornea and iris)
  • Posterior chamber phakic IOL (inserted in front of the natural lens)

Intracorneal rings (Intacs)

Intracorneal rings (or Intacs) are small plastic rings inserted into the cornea to correct nearsightedness. The rings reshape the cornea, allowing light to focus properly on the retina.

During the procedure, your surgeon will make two incisions in the cornea and insert the rings. Intacs was used to treat mild to moderate nearsightedness, but it’s now used to fix keratoconus.

Limbal Relaxing Incisions (LRI) 

Limbal Relaxing Incisions (LRI) is a type of refractive surgery that corrects astigmatism. It involves making small incisions in the peripheral cornea. This procedure relaxes the tension on the cornea and allows it to assume a more spherical shape.

LRI aims to reduce or eliminate astigmatism and improve vision. They can be performed alone or with other refractive surgeries, such as LASIK.

Potential Risks of Refractive Surgery

In general, refractive surgeries are considered safe and effective. Of course, all surgeries come with some risk. The rate of complications varies depending on the type of procedure. 

Some potential risks of refractive surgery include:

  • Glare or halos (that do not improve after a typical recovery period)
  • Blurry vision (that does not improve after a typical recovery period)
  • Infection
  • Pain
  • Elevated eye pressure
  • Retinal detachment

A review of several LASIK studies published between 2008 and 2015 found that over 98% of patients were satisfied with their LASIK outcome.7 The complication rate is less than 1%, which is considered low.8 

Lens implant surgeries are more invasive than laser refractive surgeries and generally carry a higher risk of complications.

For example, the risk of retinal detachment is higher with an RLE procedure (about 1.5% to 8.1% in those with high myopia) versus laser refractive surgery (about 0.05% to 0.19% among LASIK patients).6

Is Refractive Surgery Right for You?

With many options for refractive surgery, choosing the right procedure can be overwhelming. Here are some areas to consider:

Existing Eye Conditions

During LASIK, creating a corneal flap can lead to increased dry eye. Although these symptoms typically improve over time, people with chronic dry eye may want to avoid LASIK. 


PRK is recommended for people who engage in high-impact sports and military or law enforcement personnel. 

Because of the corneal flap created during LASIK, the corneal structure is weaker versus procedures that do not involve a flap. PRK is a better option in this case (or SMILE if you have myopia).

Eye Structure

Your cornea’s thickness may also determine what kind of refractive surgery is recommended. The surgeon can perform a quick test to determine the thickness of your corneas. 

If they are thin, your surgeon may perform PRK instead of LASIK. Alternatively, the surgeon may recommend an RLE or phakic IOL to avoid the risk of abnormal corneal thinning (ectasia).

Prescription Strength

If your prescription is very high, you may not be eligible for LASIK or other laser refractive surgeries. 

The higher your prescription, the more corneal tissue the surgeon must remove, which increases your risk for corneal ectasia. An RLE or phakic IOL may be a more suitable option.


LASIK and SMILE have rapid recovery times and allow you to resume most normal activities within a day. The other procedures may require a little more downtime.


Most people experience presbyopia (loss of ability to see up close) shortly after age 40. Additionally, age-related cataracts develop around age 60. 

In these cases, your surgeon may recommend an RLE. An RLE can correct presbyopia with multifocal or accommodating IOLs. Since the RLE removes your natural lens, you cannot develop a cataract afterward. 

Consult your ophthalmologist to determine which procedure is best for you.


Refractive surgery can help you reduce or eliminate your dependence on glasses and contact lenses. 

However, it’s important to consider each procedure’s risks and benefits before deciding. A consultation with an ophthalmologist will help determine which refractive surgery is best for you.

Updated on  February 21, 2024
8 sources cited
Updated on  February 21, 2024
  1. Arevalo, JF. “Managing Retinal Detachment After Refractive Surgery.” Retina Today.
  2. Sandova, et al. “Modern Laser in Situ Keratomileusis Outcomes.” Journal of Cataract & Refractive Surgery, 2016.
  3. Schallhorn, et al. “Refractive lens exchange in younger and older presbyopes: comparison of complication rates, 3 months clinical and patient-reported outcomes.” Clinical ophthalmology (Auckland, N.Z.), 2017.
  4. Moshirfar, et al. “Meta-Analysis of the FDA Reports on Patient-Reported Outcomes Using the Three Latest Platforms for LASIK.” Journal of Refractive Surgery, 2017.
  5. McCabe, CM. “PRK Versus LASIK After Cataract Surgery.” Cataract & Refractive Surgery Today, 2016.
  6. Alió JL, Grzybowski A, Romaniuk D. “Refractive lens exchange in modern practice: when and when not to do it?” Eye Vis (Lond), 2014.
  7. Moshirfar M, Shah TJ, Skanchy DF, Linn SH, Durrie DS. “Meta-analysis of the FDA Reports on Patient-Reported Outcomes Using the Three Latest Platforms for LASIK.” J Refract Surg, 2017.
  8. “LASIK Complications and LASIK Eye Surgery Risks.” Refractive Surgery Council, 2022.
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