LASIK (Laser-Assisted in situ Keratomileusis) and PRK (Photorefractive Keratectomy) are both laser-based corrective eye surgeries that take place in just five minutes per eye. While both procedures cost about the same ($1,000 - $3,000 per eye), LASIK has a faster recovery time and less post-op discomfort. Moreover, LASIK can be performed on both eyes in just one sitting, while PRK patients usually space the procedure two weeks apart for each eye.
Patients are usually able to choose between LASIK and PRK for themselves, but in some cases the condition of the cornea determines which procedure is a better choice.
LASIK is used to treat nearsightedness, farsightedness and astigmatism, and is usually the preferred surgery because of its short recovery time.
PRK was originally developed only to treat patients with myopia, or nearsightedness, but advancements in the technology has extended it as treatment for hyperopia (farsightedness), and astigmatism. PRK is recommended for patients with thin corneas.
Ophthalmologists require patients meet the following criteria for either LASIK or PRK treatments:
- Be between 21 and 40 years of age - the eyes are fully developed only by 21, and they start succumbing to age-related issues at 40.
- Their eye glasses prescription must be stable for one year.
- Patients should have had no eye injuries or infections in the last year
- No history of dry eyes.
- For LASIK only, patients must have a normal-depth cornea.
PRK and LASIK Explained
These videos by PreOp Patient Education explain when PRK and LASIK are performed and what to expect:
What is PRK and how does it work?
What is LASIK? How does LASIK work?
Both procedures work by changing the shape of the cornea so that light is focused correctly for improved vision. The surgeon first numbs the eye with anesthetic drops and inserts eyelid holders to prevent blinking.
For LASIK, a corneal flap is created using either a blade or a laser. The flap is lifted and an excimer laser is used to reshape the cornea by ablation (removing microscopic layers). The cool ultraviolet pulses are controlled by a computer. When finished reshaping, the flap is restored in its original position. There is no need for contact lens, bandages or stitches. The corneal flap heals naturally. The procedure takes approximately five minutes.
For PRK, surgeons remove a central area of the corneal epithelium (cellular layer of the cornea) with a blunt surgical instrument, an alcohol solution or a buffing device. They then use an excimer laser to ablate layers of the cornea. A computer controls the pulses of cool ultraviolet light according to the specifications of patients' vision correction. A soft contact lens is placed as a bandage to protect the eye until the corneal epithelium grows back, which usually takes five days. Like LASIK, the procedure takes approximately five minutes in all. Some patients choose to have the second eye done during a separate visit.
Both surgeries require patients to have someone drive them home. Patients can also expect to wear protective sunglasses and use prescription antibiotic eye drops. In addition, PRK patients may use anti-inflammatory eye drops.
Patients typically recover more quickly from LASIK. They experience blurry vision and discomfort for the first few hours, but improve within 24 hours. Vision is improved immediately in most cases, although some patients are known to have waited a few days or even a few weeks to achieve peak clarity in vision.
Patients who undergo PRK have to wait one to three days for the blurring and discomfort to subside. Vision often takes between a few days to a couple weeks to show improvement. However, patients typically do not achieve peak accuracy and clarity in vision for three to six months.
Patients undergoing either procedure can expect 20/20 vision. Either procedure may call for enhancement surgery, an additional LASIK or PRK, for maximum results.
The corneal reshaping in both LASIK and PRK is permanent, especially if the eyeglass prescription was stable before surgery. It does not, however, prevent age-related vision changes in the future. Age-related changes depend on the family history, and may occur regardless whether you go in for LASIK or PRK.
After-Effects, Risks and Advantages
LASIK and PRK cost about the same - $1,000 - $3,000 per eye - and like any surgical procedure, carry some risks. The most typical side effect is increased dryness in the eyes, necessitating the use of eye drops long after the eyes have healed. Many patients report light sensitivity during the night. This usually manifests as night blindness, or seeing halos around lights. Either procedure can result in an infection. If patients rub their eyes after LASIK, they may dislodge the corneal flap. There are other possible complications that LASIK patients need to be aware of.
The common flap-related complications include thin flap, button holing, free caps, flap dislocation and flap striae. The interface complications of diffuse lamellar keratitis, epithelial ingrowth and microbial keratitis are potentially sight threatening. Compared to PRK, there is less inflammation and faster healing after LASIK, but there is a longer period of sensory denervation leading to the complication of dry eyes. The refractive complications include under-correction, regression, irregular astigmatism, decentration and visual aberrations.
LASIK has some advantages over PRK. Patients recover more quickly and suffer from less risk of infection, inflammation and hazy vision. They feel less post-op discomfort and achieve their peak vision results more quickly. Both eyes are usually done in just one visit. However, LASIK patients sometimes suffer from complications surrounding the corneal flap, such as dislodging it. Surgeons also go deeper with the excimer laser in LASIK than in PRK. Surgeons are able to regulate the thickness of the cornea more easily with PRK. All types of corneal refractive surgery cause transient reduction of tears secretion, especially during the first three postoperative months. But the secretion of tears is reduced most significantly with LASIK.
With PRK, patients sometimes wait one to two weeks between eyes. They feel greater post-op discomfort and have more risk of complications such as infection, inflammation and hazy vision. They also have to wait up to six month to achieve peak acuity and clarity in their vision.
- Postoperative inflammation, microbial complications, and wound healing following - NIH
- A Look at LASIK: Past, Present and Future - The American Academy of Ophthalmology
- Nerve Growth Factor Concentration and Implications in Photorefractive Keratectomy vs Laser In Situ Keratomileusis - American Journal of Ophthalmology
- Complications of laser-in-situ-keratomileusis. - NIH.gov
- Assessment of tears secretion after refractive surgery - NIH.gov
- Symptoms of dry eye and recurrent erosion syndrome after refractive surgery - Journal of Cataract and Refractive Surgery
- Photorefractive keratectomy - Wikipedia
- LASIK - Wikipedia
- PRK Laser Eye Surgery - All About Vision
- The LASIK Procedure: A Complete Guide - All About Vision
- LASIK Surgery: Post-Op Care and Recovery - Eye Surgery Education Council
- PRK Surgery Cost - PRK Surgery
- History of Eye Correction - Visian ICL
- LASIK FAQ - www.clearlylasik.com