Types of Eye Surgery

Overview: Eye Surgery Types

Eye surgery has advanced swiftly over the last 25 years. The development of new technology, tools, and techniques has turned corrective eye surgery into a common procedure.

"More than 843,000 laser vision correction procedures, including LASIK, PRK, and small incision lenticule extraction (SMILE), were performed in 2018.”

— American Refractive Surgery Council

There are many different eye surgery types. This article focuses on procedures that correct your vision and those that treat eye diseases.

9 Types of Corrective Eye Surgeries

Refractive surgery refers to procedures that correct refractive errors, which include:

• Myopia. Also called nearsightedness, this causes blurry distance vision but clear vision up close.
• Hyperopia. Also called farsightedness, this is when nearby objects are blurry and distant ones are clear.
• Astigmatism. This is when the eye is oval-shaped instead of round, causing blurry vision near and far.

Refractive surgery is usually done as an outpatient procedure.

1. LASIK (laser in-situ keratomileusis)

LASIK is a type of laser refractive surgery. During LASIK, your eye surgeon creates a corneal flap on the surface of your eye to reduce recovery time and discomfort. They also use a laser or microkeratome (a special surgical blade) for this type of surgery. 

LASIK was FDA-approved in 1998. It has a very high success rate and a short recovery time.  

2. PRK (photorefractive keratectomy)

PRK is another form of laser refractive surgery. It delivers comparable vision improvement to LASIK. However, PRK doesn't require a corneal flap incision.

Instead, your surgeon removes the upper layer of tissue in your cornea (epithelium). This is done with an alcohol solution and surgical tools before applying the laser.

As a result, there are some key differences between PRK and LASIK:

• PRK involves a longer recovery time
• More discomfort during recovery with PRK
• PRK may be better for people with high prescriptions, or thin corneas
• PRK is preferable for people engaged in high-impact activities such as contact sports, due to risk of flap dislocation with LASIK
• PRK typically costs less than LASIK

3. LASEK (laser subepithelial keratomileusis) and Epi-LASIK

These procedures are modified PRK and LASIK techniques. LASEK involves using an alcohol solution to loosen the corneal epithelium. This forms a thin flap (significantly thinner than that of LASIK). 

Epi-LASIK uses a mechanical epithelial separator to create the flap. Not using alcohol preserves more of the epithelial tissue. 

Benefits of these procedures include:

• Less discomfort during healing versus PRK
• Lower risk of flap complications versus LASIK
• Thinner corneal flap versus LASIK, more suitable for thin corneas

4. Small Incision Lenticule Extraction (SMILE)

Small incision lenticule extraction (SMILE) is a relatively new type of laser surgery that corrects myopia. During SMILE surgery, a laser creates a small disc of tissue within the inner layer of your cornea. Then, your eye surgeon removes tissue, called a lenticule, via a small incision on your cornea.

Some surgeons favor SMILE over LASIK because there is no corneal flap involved. This results in a more stable cornea and less dry eye. SMILE may be less invasive, but some surgeons feel that this technology is too new. More experience may be needed to recommend SMILE over LASIK.

In the U.S., SMILE cannot treat hyperopia and astigmatism.

5. Radial Keratotomy (RK)

Radial keratotomy gained popularity in the 1980s but is now considered obsolete. It is a procedure that corrects low to moderate amounts of myopia. RK has now been replaced by laser eye surgery.

The surgeon makes several incisions on your cornea in a radial pattern. This looks like bicycle spokes or slices of pizza. These incisions flatten your cornea to correct myopia. Most people who have received RK cannot have LASIK but may be eligible for PRK if they experience vision changes.

6. Astigmatic Keratotomy (AK) and Limbal Relaxing Incisions (LRI)

These procedures also include making incisions on the cornea to flatten the tissue. Astigmatic keratotomy and limbal relaxing incisions correct lower levels of astigmatism. They’re often performed after cataract surgery or corneal transplants. 

The surgeon makes incisions where the cornea is steepest. LRIs are more common than AK. One reason is that LRI incisions are closer to the edge of your cornea, resulting in better vision and less glare.  

Now, these procedures may be replaced with laser refractive surgery or toric intraocular lens implants.

7. RLE (refractive lens exchange surgery)

This procedure involves the same steps as cataract surgery. The difference is that these patients don't have cataracts. Their natural lenses are still clear. 

RLE replaces your natural lens with a permanent intraocular lens implant (IOL) that corrects your vision. There are many types of IOLs available, depending on your prescription and visual needs.

RLE may be suitable for:

• People with thin corneas who may not be eligible for laser refractive surgery 
• People with higher prescriptions, especially moderate to severe hyperopia or astigmatism

Another benefit is that you don't have to worry about developing a cataract when you're older.

8. PRELEX (presbyopic lens exchange)

Presbyopic lens exchange is a type of refractive lens exchange surgery. While RLE can be performed on younger people, PRELEX focuses on correcting  near vision in people over age 45. Typically, this is when people experience presbyopia (age-related farsightedness).

This surgery corrects both distance and near vision. You won't need reading glasses or other corrective lenses after surgery. There are many intraocular lens implant (IOL) options:

• Multifocal IOL. This is similar to progressive eyeglasses, with multiple focus zones to provide distance and near vision
• Accommodating IOL. This is a flexible lens implant that can adjust its focus, similar to your natural lens before presbyopia
• Monovision. This is when your surgeon places an IOL in one eye to correct your distance vision, and another IOL in the other eye to correct near vision

9. Phakic Intraocular Lens Implants (Phakic IOL)

Unlike a refractive lens exchange, phakic IOLs leave your natural lens in place. This surgery is an excellent option for people with severe myopia who aren't candidates for laser refractive surgery. 

A benefit of this procedure is that the phakic IOL may be removed later if needed. For example, if you receive a phakic IOL but develop cataracts, the surgeon can remove the phakic IOL before performing cataract surgery.

There are two main types of phakic IOLs:

• Anterior chamber phakic IOL. This is inserted into the eye between the cornea and iris
• Posterior chamber phakic IOL. This is inserted behind the iris, in front of your natural lens

Types of Keratoplasty Surgeries

Keratoplasty refers to surgeries performed on the cornea. The following procedures correct various refractive errors. 

Conductive Keratoplasty (CK)

This is a non-invasive procedure to correct mild hyperopia and presbyopia. It doesn't require lasers. Some people undergo conductive keratoplasty to reduce or eliminate the need for reading glasses. 

CK uses a probe tip to deliver radiofrequency currents to your cornea. This shrinks the peripheral areas of the cornea, steepening its shape. The result is reduced hyperopia and improved near vision. 

CK can be performed after LASIK or cataract surgery for additional vision correction.

Laser Thermal Keratoplasty (LTK)

Like conductive keratoplasty, laser thermal keratoplasty uses a holmium laser. This shrinks the corneal tissue to correct low to moderate hyperopia. 

Unlike LASIK, this is a non-contact procedure, meaning there is no cutting into the cornea or other direct contact. 

Automated Lamellar Keratoplasty (ALK)

Automated lamellar keratoplasty corrects severe myopia or low hyperopia without using a laser. Like LASIK, your surgeon uses a microkeratome to create a flap on your cornea. 

In ALK, your surgeon doesn't use a laser to reshape the cornea underneath the flap. Instead, they remove a small disc of corneal tissue before replacing the flap.

Eye surgeons rarely perform ALK since safer and more reliable refractive surgeries are available.

Other Common Types of Eye Surgery

Diabetic Retinopathy Surgery

Diabetes causes bleeding, fluid leakage, and abnormal blood vessel growth in your retina. Mild diabetic retinopathy does not always require treatment. 

Treatment options for severe diabetic retinopathy include:

• Laser treatment. This helps stop bleeding and leakage from blood vessels. This procedure is performed in the peripheral areas of the retina.
• Anti-vascular endothelial growth factor (anti-VEGF). These eye injections help prevent macular edema (swelling in the central part of the retina).
• Steroid injections. These also treat macular edema.
• Vitrectomy. This type of eye surgery is performed when the bleeding or fluid swelling can’t be controlled with other treatments.

Laser Cataract Surgery

Traditional cataract surgery involves a procedure called phacoemulsification. This includes the following steps:

1. Your eye surgeon makes an incision in your cornea
2. They insert an ultrasound device into your eye
3. The ultrasound waves break up the cataract into small pieces
4. Your surgeon uses a suction device to remove the pieces from your eye

Laser cataract surgery incorporates a laser to replace some steps of phacoemulsification. Instead of a surgical blade, the laser can make an incision on the cornea and create an opening in the lens capsule.

The laser can also soften the cataract. This uses less energy than ultrasound and is less disruptive to the eye.

Laser Glaucoma Surgery

There are several treatments for glaucoma, including laser procedures. Laser glaucoma surgery is designed to lower eye pressure by increasing the amount of fluid draining out of the eye.

The two primary forms of laser treatment are:

• Trabeculoplasty. This involves lasering the tissue in the angle, which is the structure that controls fluid drainage out of the eye.
• Iridotomy. This procedure uses a laser to create a tiny hole in the periphery of your iris. This opening allows fluid to flow through. Iridotomyis often performed if you have narrow angles and are at risk for angle-closure glaucoma.

Trabeculectomy

Trabeculectomy is another form of glaucoma surgery that lowers eye pressure. During this procedure, the surgeon creates a small flap in your sclera (the white of your eye). This opening serves as a fluid channel.

The sclera is covered by a tissue called the conjunctiva. The surgeon uses this tissue to form a bleb, a reservoir for fluid draining out of the eye. The upper eyelid hides the bleb, so it is not visible to others.

Macular Degeneration Surgery

There are two main types of age-related macular degeneration (AMD), dry and wet AMD. The dry form is an earlier stage of the disease, and there are no specific treatments other than nutritional supplements.

Wet AMD is more advanced. It causes significant vision loss as abnormal blood vessels start to leak into the macula. 

Treatment for wet AMD includes:

• Anti-vascular endothelial growth factor (anti-VEGF) eye injections. These are the primary form of treatment.
• Photodynamic therapy (PDT). This uses a drug called verteporfin to seal leaking blood vessels. Verteporfin is injected into your veins, and once it reaches your eye, the doctor uses laser light to activate the drug.

Laser treatment is no longer widely used because the laser can damage the macular tissue and cause vision loss.

Intacs (Intracorneal Ring Segments)

Intacs corneal implants primarily treat keratoconus. This condition causes your cornea to steepen and thin out progressively. Many people with keratoconus do not see well with glasses and contact lenses. 

Intacs improve vision by flattening the cornea to reduce myopia and astigmatism.

It may eliminate the need for glasses or contacts. The implants are two crescent-shaped pieces of plastic placed inside your cornea. 

The surgeon can remove the implants or replace them with thicker implants. This will depend on the type and amount of vision correction needed.

Eyelid Surgery

Eyelid surgery is also known as blepharoplasty or an "eye lift." It is a surgical procedure that modifies the eyelid skin and the skin around the eyes. It can improve the eye’s functioning and give you a more youthful appearance.

Strabismus Surgery

During strabismus surgery, ophthalmologists manipulate muscles around the eye. They may loosen, tighten, or reposition them to improve the eyes' alignment and vision.

The more extensive it is, the longer the healing period. It may take adults up to seven days to begin feeling comfortable. The eyelids may also be swollen and make it challenging to open the eye shortly after surgery.

Artificial Eye

An ocular prosthesis is an artificial eye that ocularists implant in patients who have lost eyes or have eye abnormalities.

First, the surgeon completely removes the actual human eye. Once the artificial eye is ready, it will fit behind the upper and lower lid. It goes over the shrunken eyeball or orbital implant.

What to Expect from Eye Surgery

What happens before, during, and after eye surgery varies. Your experience depends on the type of eye surgery, your specific condition, and your eye surgeon. In general, you might expect the following:

Before Surgery

All types of eye surgery require an eye exam beforehand. Depending on your needs, this may include measurements of:

• Eye pressure
• Corneal thickness
• Refraction

Your eye surgeon will describe what to expect during and after your specific surgery type. They may provide you with instructions on how to prepare for surgery. For example, some people must stop wearing contact lenses for a few weeks before eye surgery.

During Surgery

You will likely get numbing eye drops beforehand. This makes the procedure painless. Depending on the type of eye surgery, your procedure might involve general anesthesia. In this case, you’ll be asleep during the surgery.

However, most eye surgeries are done with monitored sedation and take less than 20 minutes. If your procedure uses monitored sedation, you’ll be awake but won’t see what your surgeon is doing.

Recovery

After eye surgery, you may experience minor discomfort. This usually resolves in a day or two, and you can use eye drops or pain medication for relief. The most common side effects of eye surgery include:

• Blurry vision
• Dry eyes
• Light sensitivity
• Minor discomfort

Recovery time varies based on the type of surgery, the patient, and the condition. Some people who get eye surgery have clear vision within one day. Others can take several days, weeks, or even months to recover fully.

Summary

• Eye surgery has evolved rapidly over the past 25 years, making these procedures more common
• Advances in laser technology have made corrective eye surgeries safer and easier to recover from
• People get eye surgery to improve their vision or treat an eye disorder like cataracts
• Eye surgery is usually an outpatient procedure using local anesthetic
• The specific details of your procedure will depend on the type of eye surgery you need and the condition being treated