Refractive Eye Surgery Explained
Refractive eye surgery refers to any surgical procedure used to fix vision problems. In the recent years, we have seen huge advances in this field. Until contact lenses were popularized in the 1950s, eyeglasses had been the only practical way to correct refractive vision errors. Refractive and laser eye surgery allow many patients to see better than any other time in their lives.
Radial keratotomy was one of the first incisional refractive procedures. The concept was first used more than 50 years ago in the Juntendo University in Japan. Now, several modern approaches to refractive eye surgery range from laser reshaping of the eye’s surface in procedures such as LASIK and PRK to surgical insertion of artificial lenses to correct eyesight.
Many types of refractive eye surgery reshape your cornea, the clear front of your eye that lets light travel through and focus properly on the back of your eye, the retina. Artificial lenses that are surgically inserted into the eye can also adjust the focus of light rays to sharpen one’s vision.
Which Is The Right Refractive Eye Surgery For You
Photorefractive Keratectomy (PRK) was the first laser refractive eye surgery used to remove (ablate) tissue directly from the eye’s surface to change the curvature of the eye cornea successfully. Even when the excimer laser was developed in the early 1970s and modified for ophthalmic use in the early 1980s, the Food and Drug Administration did not approve its use for PRK refractive eye surgery until 1995.
PRK is an outpatient surgery and takes only about 5-15 minutes to complete in each eye. Although some pressure sensation may be present during the procedure, it is generally painless. Prior, anesthetic drops are used to numb the eye. During the surgery, an instrument holds the eyelid open and the patient is asked to focus on a target light. The surgeon then removes the surface layer of the cornea (the corneal epithelium) and uses an excimer laser to apply computer-controlled pulses of light energy to reshape the cornea.
Because PRK is a surface procedure, there is no risk of surgical flap complications. PRK does not involve creating a thin, hinged flap on the eye’s surface. PRK may also be a safer procedure in cases when a person’s cornea may be too thin for LASIK surgery.
However, you should consider a different type of refractive eye surgery if you have a thin cornea and high degree of myopia that would need an extra ablation to reshape the eye.
The epithelial layer grows back over the next 3-4 days. The surgeon inserts a bandage contact lens to protect the cornea as it also helps decrease the discomfort one may experience (generally mild to moderate) during early recovery. The cornea heals from the edges towards the center, forming a “ridge” by the fourth or fifth day. The vision has significantly improved by this time, generally ranging between 20/30 and 20/50. Often, the correction is said to be stable within 3 to 6 months from the date of surgery.
LASIK (laser-assisted in situ keratomileusis) is another outpatient laser refractive eye surgery that is used to treat nearsightedness, farsightedness, and astigmatism. With LASIK, the surgeon creates a thin flap in the cornea, folds back the flap and precisely removes a very specific amount of corneal tissue under it with an excimer laser. The flap is then laid back into its original position where it heals in place.
LASIK with laser creating a corneal flap
With normal vision, light rays focus directly on the retina.
Some of the advantages of LASIK surgery:
- generally, there is little to no discomfort at all, during and after the operation,
- rapid recovery of vision, most have useful vision within a day of surgery,
- retreatment can be done if expected outcome has not been met, normally made after three months and involves either lifting the flap that was created and applying an additional amount of laser treatment or doing the retreatment on the surface (similar to PRK).
INSIDER. “How LASIK Eye Surgery Is Performed” Online video clip. YouTube. YouTube, Nov 7, 2017. Web. Nov 7, 2017.
LASIK allows patients to perform daily tasks without corrective lenses and more than 90 percent (%) has achieved somewhere between 20/20 and 20/40 vision without glasses or contact lenses.
Refractive Lens Exchange (RLE) may better serve patients who are in the age range where presbyopia will most likely occur or are developing early cataracts. Speedy recovery and neutral incisions (not causing astigmatism) that are currently being utilized in modern cataract surgery allow this procedure to be used with greater predictability in patients who are not suffering from significant cataracts.
RLE is much like cataract surgery, it consists of the removal of the natural lens and replaces it with an artificial lens of a different shape, to reduce or eliminate high degrees of farsightedness. Multifocal and accommodative intraocular lenses offer the best options today to address presbyopia and other refractive errors. Note that RLE with multifocal lens technology is not for every patient but does offer considerable benefits in high hyperopes, presbyopes, and patients with borderline or soon to be clinically significant cataracts and are requesting refractive eye surgery.
Conductive Keratoplasty (CK) is a noninvasive procedure that utilizes radiofrequency energy to correct presbyopia and low hyperopia with or without astigmatism. CK does not involve laser, change to the central cornea and tissue cutting or removal. It has received initial FDA approval in 2002. It can also be used to correct residual refractive error after LASIK or cataract surgery.
Phakic Intraocular Lens Implants are made for people who are too nearsighted for LASIK and PRK. The implants have received initial FDA approval in 2004. The surgeon makes a small incision at the edge of the cornea and either attaches the implant lens to your iris or inserts it behind your pupil. Unlike RLE, the natural lens stays in place. The implant of pIOLs is normally recommended for severe degrees of refractive error. Ideal candidates are above 21 years of age, have had stable refraction over at least a year, have poor tolerance of contact lenses or eyeglasses and are poor candidates for excimer laser surgery.
Cataract Surgery is performed to remove the clouded lens of the eye. The cloudiness can cause a decrease in visual acuity and may lead to blindness if left untreated. New lens implants that are developed for cataract surgery can restore a person’s near vision and correct nearsightedness and farsightedness.
Cataract surgery may be done in an outpatient center, clinic or hospital. It often takes no longer than 10 minutes to perform. The surgeon will measure your eye to set the proper focusing power for the artificial intraocular lens (IOL). You may be prescribed eyedrop medicines before surgery. The surgeon will enter into the eye through tiny incisions that are near the edge of the cornea, break up the lens that is affected by the cataract and remove it. The new lens is then inserted into place while the “self-sealing” incisions will close naturally over time. Only about 15–30 minutes of rest is advised and one may then be released from the center.
What Are The Risks Of Refractive Eye Surgery
As with any surgical procedure, complications may occur intraoperatively or postoperatively.
Your doctor will discuss the possible risks before the surgery so that you understand the procedure and that any of your concerns will be addressed.
- Any disease or condition that affects your immune system and impairs your ability to heal may increase associated risks. You may be a better candidate for PRK or LASEK than certain types of LASIK.
- Infection of the cornea (infectious keratitis) and inflammation may occur but rarely. Infections are very serious if they do occur.
- Having depression or certain chronic pain conditions, such as migraine and fibromyalgia may be associated with increased problems with dry eye and postoperative pain.
- If you have uncontrolled glaucoma, you likely would not qualify for LASIK or other procedures.
- Some surgeries may also induce astigmatism.
- Halos and glare, especially at night, may occur after the procedure. They are common but typically go away quickly.
- Postoperatively, dry eye symptoms are the most common complaints. Dry eyes following LASIK may occur because of a decrease in corneal sensation as the microkeratome cuts through the superficial corneal nerves. Blink rate may be reduced thus, a decrease in the rewetting of the eye. Most people notice an improvement in the use of artificial tear lubrication.