Types of Laser Eye Surgery - How to choose

There are many types of laser eye surgery available (LASIK, PRK, ASA, LASEK, Epi-LASIK, LBV, SMILE, PTK, YAG, SLT, PRP). Nobody has the exact same eyes so the treatment one person may be recommended by their eye surgeon may be different to another person.


Indications : Refractive surgery treating Myopia, Hyperopia, Astigmatism, Presbyopia

LASIK which stands for Laser Assisted In-Situ Keratomileusis is one of the most popular refractive surgeries available. This is because it has the quickest recovery and the least discomfort in the recovery period of all the laser eye surgery methods. More than 90% of patients would choose or have recommended LASIK for their laser eye surgery. The majority of people would have 20/20 vision the next day. It is now blade-free and uses two lasers to reshape the cornea. It can treat myopia, hyperopia, astigmatism and presbyopia. 

The first laser used in this method is a femtosecond laser and creates a flap in the superficial cornea at 105um deep. The average cornea is 550um. The femtosecond laser uses light to create multiple (millions) of small gas bubbles that all join together to the shape of the superficial flap.  This laser is an infrared laser using a wavelength of 1053nm. The laser is silent and takes less than 15 seconds to complete the flap. 

The second laser used is an excimer laser which reshapes the cornea under the flap. In myopia the excimer laser is flattening the curvature of the cornea and in hyperopia the laser is steepening the cornea. The higher the treatment prescription of your glasses or contact lenses the more corneal tissue is reshaped. This laser ablates the corneal tissue. The excimer laser emits a cool beam of ultraviolet light of 193nm. This laser you can hear during the treatment and the treatment can take from 5 seconds to 25 seconds to complete depending on your prescription. You are in the laser room for 10-15minutes.

LASIK is FDA (Food and Drug Administration) approved and at Bowen Eye Clinic we use the latest FDA approved femtosecond and excimer lasers for your treatments. The LASIK procedure can restore your vision to 20:20 and is done as a day procedure and the good news is it only requires eye drops as local anaesthetic. The laser treatment only takes seconds for each eye and the recovery is fast. You will normally be able to drive the next day and do most day to day activities without glasses. The first LASIK surgery was performed in the United States in 1991 and was FDA approved in 1998. In New Zealand over 90% of laser eye surgery is done with the LASIK technique.


Indications : Refractive surgery treating Myopia, Astigmatism, Presbyopia

PRK which stands for Photo Refractive Keratectomy is the original laser eye surgery technique. It has now mainly been replaced by LASIK but still has a place to treat some people with thin corneas. It is also a blade-free technique and can successfully treat and correct myopia (nearsightedness) and astigmatism. PRK is not suitable for moderate to high hyperopia (longsightedness). PRK was the first type of laser eye surgery for vision correction and is the predecessor to the popular LASIK procedure. PRK works by reshaping the cornea in the same way as LASIK but the reshaping is done on the surface once the epithelial cells are removed. At the end of the laser treatment a bandage contact lens is used. The exact same excimer laser used in LASIK is used for PRK. PRK recovery takes a bit longer than recovery from LASIK. Where as LASIK recovery takes only 4-5 hours, PRK can take 4-5 days to settle and the final improvement occurs over 3-4 weeks. PRK has been available since 1988 and was FDA approved in 1995. 


Indications : Refractive surgery treating Myopia, Astigmatism, Presbyopia

ASA stands for Advanced Surface Ablation. This technique is the same as PRK but uses the Zeiss excimer laser Advanced Surface Ablation program to reshape the cornea. This is a form of PRK and was FDA approved in 1995.


Indications : Refractive surgery treating Myopia, Astigmatism, Presbyopia

LASEK which stands for Laser Assisted Sub-Epithelial Keratomileusis is a procedure similar to PRK. Like in PRK, the corneal epithelium is separated from the underlying stromal layer. But instead of completely removing and discarding this tissue, as in PRK, the ultra-thin "flap" of epithelium is pushed off to one side of the cornea, where it remains attached to the eye (like the thicker flap of corneal tissue created during LASIK surgery). 

After the laser treatment is finished, the epithelial tissue is repositioned on the surface of the eye to cover the area that has had laser treatment, and a bandage contact lens is placed on the eye to keep the epithelium in place as it heals. 

It's important to note, however, that LASEK typically involves more discomfort and a longer recovery time compared with LASIK surgery. There is no difference in healing time or visual result of PRK or LASEK.

LASEK is not FDA approved. 


Indications : Refractive surgery treating Myopia, Astigmatism, Presbyopia

EPI-LASIK is another variation to the PRK procedure. The epi-lasik flap is very similar to the thin flap created in LASEK surgery. In both procedures, the flap contains only cells from the very thin outer layer of the cornea, called the epithelium. The difference is how the epi-LASIK and LASEK flaps are produced. 

A LASEK flap is created with a tool that has a sharp blade. In epi-LASIK, the flap is separated from the underlying corneal layer (the stroma) with an instrument called an epithelial separator that has an oscillating plastic blade that has a thin blunt edge. 

And unlike in LASEK, an alcohol solution typically is not applied to the eye in epi-LASIK to loosen epithelial cells from the underlying corneal stroma. The Epi-LASIK refractive surgery has been around since the early 2000s. People that would be most suitable for this type of surgery include those who have thin corneas, with insufficient tissue for LASIK. 

As with PRK the visual recovery is delayed and more discomfort is experienced during the recovery. In three days many patients do have 20:40 or even 20:20 but others take longer, possibly three or six months to reach their final result. Usually you can drive within a week after surgery. 

Epi-LASIK is not FDA approved.  


Indications : Refractive surgery treating Presbyopia

LBV which stands for Laser Blended Vision is a laser technique to give over 45 year olds distance and reading vision. It uses mono-vision with the dominant eye treated for distance and the non dominant eye treated for near. It commonly uses LASIK but the PRK techniques can also be used in myopic patients. 

Both LASIK and PRK are FDA approved.


Indications : Refractive surgery treating high Myopia

SMILE which stands for Small Incision Lenticule Extraction, is a new technique. It is blade free and uses one laser. SMILE uses a femtosecond laser to create a lens-shaped disc of tissue within the cornea. This disc of tissue is called a ‘lenticule’ because it is lenticular in shape, this is removable. The lenticule size and shape is adjusted to the refractive error of the patient.  The laser eye surgeon removes the lenticule through a 4-5mm incision on the cornea. The removal reshapes and flattens the cornea and therefore corrects vision. 

The visual recovery is slower than LASIK. Any enhancements required are more difficult needing either PRK or LASIK to fix any residual refractive error. 

SMILE is not FDA approved for myopia <1.0D nor astigmatism nor hyperopia (long sightedness).


Indications : Recurrent Epithelial Erosion Syndrome, Basement Membrane Disorder, Corneal scarring

PTK stands for Photo Therapeutic Keratectomy. This laser treatment uses the excimer laser to polish the corneal surface and removes any irregular tissue. In some cases a refractive error treatment such as PRK can be used at the same time.


Indications : Laser eye surgery treating Secondary Cataract

YAG stands for neodymium-Yttrium Aluminium Garnet. This laser provides fast, effective and painless treatment for posterior capsule opacity (PCO), also known as ‘secondary cataracts’. The procedure is called YAG laser posterior capsulotomy. 

In a cataract operation, the cloudy lens from your eye is replaced with an artificial lens. In about 10% of cataract surgery patients, the thin membrane behind the lens (called the posterior capsule) can become hazy. This causes blurred vision, much like a cataract, which is why posterior capsule opacity is often called a ‘secondary cataract’. 

A YAG laser capsulotomy procedure is extremely fast, simple and effective. It can be performed in the consulting room, so there’s no need for you to go into surgery, and it’s completely painless. 

Patients will notice an immediate improvement after their YAG laser capsulotomy treatment. There is a chance that you may have some ‘floaters’ in your vision for a few weeks afterwards, but serious side effects with YAG laser capsulotomy are very rare. 

YAG laser is FDA approved.


Indications : Laser eye surgery treating Glaucoma

SLT stands for Selective Laser Trabeculoplasty, is a form of laser surgery that is used to lower intraocular pressure in glaucoma. It is used when eye drop medications are not lowering the eye pressure enough or are causing significant side effects. It may sometimes be used as initial treatment in glaucoma. 

People who have open-angle glaucoma (the drainage system in the front part of the eye is open) and are in need of lowering of their intraocular pressure (IOP) are eligible for the procedure. 

How SLT works is that the Laser energy is applied to the drainage tissue in the eye. This starts a chemical and biological change in the tissue that results in better drainage of fluid through the drain and out of the eye. This eventually results in lowering of IOP. It may take 1-3 months for the results to appear. 

SLT lowers the IOP by about 30% when used as initial therapy. This is comparable to the IOP lowering of the most powerful and commonly used class of glaucoma eye drops (prostaglandin analogs). This effect may be reduced if the patient is already on glaucoma medications. 

The effect will generally last between 1-5 years, and in rare cases, longer than that. If it does not last at least 6-12 months, it is usually not considered successful. 

Some people with glaucoma can be managed with just laser treatment. Others require additional IOP lowering and may therefore need to use glaucoma eyedrops as well. Think of the SLT as equivalent to one glaucoma medication. Just as some people will require more than one glaucoma medication to control their IOP, some may also require laser plus one or more glaucoma medications. It is important to remember that SLT is not a cure for glaucoma, just as medication and surgery are not. Whatever method is used to treat glaucoma, appropriate follow up and testing with your eye care professional is critical.

SLT has been in use for 15 years in the United States and around the world. SLT laser is FDA approved


Indications : Laser eye surgery treating Diabetic Retinopathy

PRP stands for Pan Retinal Photocoagulation. This laser does not improve eye sight but is used to prevent further visual loss. Normally used in diabetic eye disease or eye conditions where the blood supply has been compromised. The laser causes a small photocoagulation in the retina and decreases the overall oxygen demand for the eye. The original laser used for PRP was an Argon laser and uses light in the 488nm and 532nm green spectrum. Newer lasers used in PRP include double frequency Nd-YAG, Dye Yellow and Diode lasers. 

PRP laser is FDA approved.


Very few eye clinics have all the laser treatments mentioned above. At Bowen Eye Clinic we offer FDA approved laser eye treatments that include LASIK, PRK (ASA), LBV, PTK, YAG, and SLT. This offers great personalised options for you so that the laser procedure recommended gives you the best visual results. These laser eye surgery options can treat myopia, hyperopia, astigmatism, presbyopia, recurrent corneal erosion sydnrome, cornea scarring, secondary cataracts and glaucoma.