LASIK and Refractive Surgery

LASIK and Refractive Surgery Procedures


Laser Vision Correction Procedures

Lens Implants

Other Refractive Surgery Procedures

Laser Vision Correction Procedures


LASIK, which stands for Laser-in-Situ-Keratomileusis, is a laser vision correction surgery procedure for:

LASIK is the most common refractive surgical procedure worldwide and nearly one million procedures are performed annually in the United State. LASIK surgery consists of the creation of a corneal flap with either an IntraLase (femtosecond laser) or a surgical blade (in medical terms, a “mechanical microkeratome”). The flap is gently folded back and the excimer laser resurfaces the cornea to a new shape. LASIK has been approved by the FDA to correct nearsightedness (Myopia), farsightedness (Hyperopia), astigmatism (either combined with nearsightedness or farsightedness), and Presbyopia (where LASIK is performed on one eye to create monovision).

For more information, please visit our LASIK discussion page.  

All-Laser LASIK (Bladeless LASIK)

During an "all laser" LASIK, the laser creates a corneal flap of a precise thickness and diameter with a lower suction level than a standard mechanical microkeratome without using a blade.

There are several femtosecond lasers that have been approved by the FDA for bladeless LASIK.

The first FDA approved method for all laser LASIK was introduced by IntraLase™. IntraLASIK uses the IntraLase™ laser to create the corneal flap.

Other lasers used for bladeless LASIK like the Femto LDV laser made by Zimer, the Femtec laser made by 20/10 Perfect Vision AG, and the VisuMax laser, have since been approved for use in the United States by the FDA.

Bladeless LASIK provides laser eye surgeons with optimal precision and total control, which makes creating a flap safer and more predictable than standard microkeratomes using higher suction and blades.

For more information, please visit our "All Laser" (Bladeless) LASIK discussion page.


PRK, which stands for Photo Refractive Keratectomy, is a laser vision correction procedure for:

PRK (PhotoRefractive Keratectomy) involves reshaping the curvature of the cornea with an excimer laser to correct nearsightedness or farsightedness with or without astigmatism. PRK was the first procedure approved by the FDA in 1996. It is performed by removing the surface layer of the cornea (epithelium is the “skin” of the eye) and applying the laser directly to the layers beneath the surface. It is essentially LASIK without the creation of a LASIK flap. PRK generally produces results similar to LASIK ; however, the patient usually experiences more discomfort and has a slower recovery of vision than in LASIK, since it takes several days for the epithelium to grow back. PRK has been approved by the FDA to correct nearsightedness (Myopia), farsightedness (Hyperopia), and astigmatism (either combined with nearsightedness or farsightedness). Monovision is also an option with PRK, for either nearsighted, farsighted or astigmatic eyes as well as with Presbyopia, although Monovision PRK represents an "off label" use of the lasers since it is not FDA-approved.

For more information, please visit our PRK discussion page.

Custom LASIK and PRK

The Wavefront-Guided procedure is used for LASIK and PRK. All of the Wavefront-guided procedures were approved by the FDA for LASIK. They can be utilized with PRK, but this represents an “off label” use of the laser.

Custom LASIK and PRK are used for treating:

"Custom" LASIK and PRK is an advanced vision correction procedure that offers several advantages over traditional LASIK and PRK. There are three variations of Custom LASIK, each with unique benefits:

  1. Wavefront-Guided LASIK and PRK.  Use of Wavefront-Guided technology for LASIK and PRK can correct both lower and higher-order aberrations, making it suitable for complex prescriptions and eyes that have significant higher-order aberrations.
  2. Wavefront-Optimized LASIK and PRKUse of Wavefront-Optimized technology for LASIK and PRK prioritize maintaining the natural curvature of the cornea while correcting lower-order aberrations. It's ideal for mild to moderate prescriptions and individuals concerned about side effects.
  3. Topography-Guided LASIK.  Topography-Guided LASIK can enhance precision when performing LASIK and is more suited for people who have irregular corneas or who have had prior refractive procedures. Note that this has not been approved by the FDA for PRK.

The choice between these custom LASIK and PRK technologies will depend on a variety of factors, including your prescription complexity, eye health, and specific visual needs.  Consultation with an expert laser vision correction surgeon is always recommended since they can help you to determine the most appropriate treatment for your individual case.

Conventional laser eye surgery (LASIK and PRK) for years was excellent at reducing or eliminating the lower order aberrations and most patients obtained satisfactory uncorrected vision, usually near 20/20. However, conventional laser eye surgery procedures like LASIK and PRK have often increased the degree of higher order aberrations, which accounted for the possible increased likelihood of night vision problems.

Wavefront Technology.  The basis of Wavefront testing is from the field of adaptive optics, used for years by astronomers to build better lens systems for improving the optics of telescopes.  The human eye has two broad categories of aberrations, lower order and higher order. Lower order aberrations represent the patient’s prescription for glasses. There are many higher order aberrations but the two most important ones for potential LASIK patients are spherical aberration and coma. When these two aberrations are increased above preoperative levels, patients may notice more problems with the quality of their night vision and be more aware of halos, starbursts, flare, and glare. Wavefront technologies measure the amount of both lower and higher order aberrations. 

Wavefront-Guided LASIK and PRK. With Wavefront-Guided LASIK and PRK, this information is then used by the excimer laser in an attempt to either reduce or at least minimize the increase of higher order aberrations. All of the FDA-approved laser systems for LASIK and PRK now offer this type of treatment, so that each patient’s optical system is measured more accurately than ever before, producing in effect a unique “finger print” of their pre-operative visual problems. This truly customized treatment plan is then implemented in the laser eye surgery (LASIK, PRK) for each patient.

This Wavefront "fingerprint" enables the laser eye surgeon to program the laser in order to obtain the best results for the laser eye surgery that is best for you. By using Wavefront testing, there is a possibility that your existing higher order aberrations may not increase at all, and some patients report that they can see even better than they did with glasses or contact lenses. This is known as a "gain in best spectacle corrected visual acuity". The FDA studies of Wavefront-based treatments in LASIK, PRK and other laser eye procedures have improved the chance of obtaining 20/20 vision or better and have decreased the chances of significant night vision problems (due to higher order aberrations).

For more information, please visit our "Custom" LASIK and PRK discussion page.

SMILE Eye Surgery

The SMILE Eye Surgery procedure represents an advanced method for addressing myopia (nearsightedness) and astigmatism through refractive surgery. SMILE, which stands for Small Incision Lenticule Extraction, is a minimally invasive approach that employs a highly precise femtosecond laser to make a small incision in the cornea. This incision permits the removal of a thin lenticule, ultimately altering the cornea's shape to correct the refractive issue and enhance visual acuity. To learn more, please visit our SMILE Eye Surgery discussion.


EpiLasik a form of PRK where the epithelium is removed with a mechanical microkeratome and the underlying surface is then treated with an excimer laser.


LASEK (Laser-Assisted Sub-Epithelial Keratectomy) is a form of PRK where the epithelium is loosened, usually with alcohol, and either reflected like a LASIK flap and replaced after the excimer laser is applied to reshape the cornea. At times the epithelium is simple discarded and allowed to regenerate as it does in standard PRK laser vision correction surgery.

Lens Implants

RLE (Refractive Lens Exchange) or CLE (Clear Lens Exchange)

Refractive Surgery Treatment for:

RLE/CLE  is a vision correction procedure where the refractive surgeon removes the internal lens of the eye (just like in a cataract surgery operation) and inserts an artificial intraocular lens implant (IOL) of a stronger power inside the eye. The eye surgeon will calculate the power of the replacement lens implant through special measurements of the length and curvature of the eye, which are then entered into a special computer formula. RLE, which stands for "Refractive Lens Exchange" (sometimes referred to as Refractive Lensectomy) and CLE, which stands for Clear Lens Exchange (sometimes referred to as Clear Lensectomy), are different terms but refer to the same procedure. 

For FDA-approved lens implants (IOLs) used for RLE/CLE please see the Toric Implants and the Cataract Implants sections below.

For more details on lens implants, please see our Lens Implants (IOL) discussion page.

Phakic Implants

Refractive Surgery Treatment for:

Phakic Implants are intraocular lens implants (inside the eye rather than on the surface of the eye like contact lenses) surgically placed inside the eye in front of the eye’s natural lens by a refractive eye surgeon. Phakic Implants are used to correct higher amounts of nearsightedness (Myopia). Because this refractive surgery procedure is performed inside the eye (as opposed to a laser vision procedure that is performed on the surface of the eye), the risks are slightly higher. Phakic Implants are utilized for higher amounts of nearsightedness (Myopia) usually above -8.00 D to -10.00 D in an eye, which is often not correctable by laser eye surgery. Phakic Implants can also be used in cases with lower amounts of myopia if laser eye surgery is contraindicated because the cornea is too thin or abnormally shaped.  

The EVO ICL is a phakic lens implant that was approved by the FDA in 2022.  The EVO-ICL is becoming a more popular option among people aged 21-45 who have extreme nearsightedness and astigmatism.  For more information on the EVO-ICL by STAAR Surgical, please visit Discover EVO-ICL.

Toric Implants

Lens Implant Surgery Procedure for:

Toric Implants have the astigmatism correction incorporated in the power of the implant and they are available for some eyes undergoing RLE/CLE as well as for cataract surgery.  FDA-approved Toric Lens Implants include:

Cataract Lens Implants

Refractive Surgery Treatment for:

Cataract surgery is performed under local anesthesia on an out-patient basis. The surgery is accomplished in 15 to 30 minutes, utilizing a very small incision, usually without sutures. The cataract is broken up (emulsified) with an ultrasonic vibrating needle and the liquefied cataract is aspirated through this same needle. The cataractous lens is then replaced with a lens implant designed to replace the natural lens. This new lens can usually reduce or eliminate the previous need for glasses in near sighted or farsighted patients so they may no longer require glasses for distance. Lens implants can also create a monovision situation similar to the monovision form LASIK or PRK. Below are some of the IOLs used in cataract surgery which also also used in RLE/CLE lens implant procedures, please: 

Please also see the section above regarding Toric Lenses which can also be used for cataract surgery to correct astigmatism.  As noted above all IOLs that can be used for cataract surgery can also be used for RLE/CLE).  For more information, please visit our Cataract Surgery and Lens Implant (IOL) discussion pages.

Other Refractive Surgery Procedures

Astigmatic Incisions

Astigmatic Incisions, which may also be referred to as Cornea Relaxing Incisions (CRIs), consist of Arcuate Incisions and Limbal Relaxing Incisions (LRIs). Not surprisingly, Astigmatic Incisions are  to help correct vision problems due to:

Astigmatic Incisions are made by an ophthalmologist using a blade or a femtosecond laser. 

Arcuate Incisions. Arcuate Incisions are placed in the steep or more curved portion of the cornea (toward the edge of your cornea) in order to reduce the curvature of the cornea and thereby potentially reduce astigmatism.  Arcuate Incisions may be performed in conjunction with Cataract Surgery or a Lens Implant (IOL) procedure. The medical term for Arcuate Incisions is "Astigmatic Keratectomy" (AK).

Limbal Relaxing Incisions (LRIs).  Limbal Relaxing Incisions are made with incisions at the corneal periphery for the treatment which is toward the corneal limbus (edge) which will be just inside the white portion of the eye (sclera).  

Arcuate Incisions are placed in closer proximity to the visual axis compared to the peripheral placement of Limbal Relaxing Incisions.

In sum, Arcuate Incisions (AK) and Limbal Relaxing Incisions are made to reshape the cornea to improve vision, but these procedures differ in where the incisions are made and their specific applications. These Astigmatic Incisions (or Corneal Relaxing Incisions (LRIs)) can be a safe, reliable and predictable option to help correct mild astigmatism especially when more expensive methods such as toric implants or the use of a laser to make the Astigmatic Incisions are not affordable options for you.  An experienced refractive surgeon who offers a range of vision correction procedures and one with proven expertise can help you choose the most suitable option for your needs to best improve your eyesight.

For more information, please visit our Astigmatic Incisions and Limbal Relaxing Incisions discussion pages.

Looking for a True Expert LASIK, Cataract and Refractive Surgeon?

To find a vision correction exp ert surgeon who has qualified to be listed in our Trusted LASIK Surgeons™ Directory or our Trusted Cataract Surgeons™ Directory nearest to you, please ciick on the links below.  Most of the LASIk surgeons in our directory offer other procedures beyond LASIK and most of the cataract surgeons will offer IOLs, including EVO-ICLs).

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Find a Trusted Cataract Surgeon™  (most cataract surgeons will typically also offer lens implant procedures like EVO-ICLs). 

We invite you to review our qualification process, each eye surgeon's profile and select your LASIK, cataract or other refractive surgery expert with confidence.  

To learn more about screening process and standards we use to screen and qualify surgeons please visit:

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