Photorefractive Keratectomy, commonly known as PRK, is a laser eye surgery that reshapes the cornea, the clear front surface of the eye. This procedure improves how light focuses onto the retina, reducing reliance on glasses or contact lenses by correcting common refractive errors.
What is PRK Surgery?
PRK is a refractive surgery that uses an excimer laser to reshape the cornea. This corrects refractive errors such as nearsightedness (myopia), farsightedness (hyperopia), and astigmatism, which occur when the eye does not bend light properly. The laser removes microscopic amounts of tissue from the corneal surface, altering its curvature for clearer vision.
Unlike other laser vision correction procedures, PRK does not create a corneal flap. Instead, the outermost layer of the cornea, the epithelium, is removed before laser treatment. This “no flap” approach means the corneal surface heals naturally after the procedure.
The PRK Surgical Process
The PRK surgical process begins with anesthetic eye drops to numb the eye. An eyelid holder is then placed to keep the eye open.
The next step involves removing the corneal epithelium, the thin, superficial layer of cells on the cornea. This can be achieved through various methods, including manual debridement or by applying a diluted alcohol solution.
Once the underlying corneal tissue is exposed, the excimer laser reshapes it. This laser emits pulses of ultraviolet light, vaporizing tiny amounts of tissue to correct the refractive error. The laser is guided by a pre-determined treatment plan based on the individual’s eye measurements, and modern lasers track eye movements for accurate placement. Following the laser application, a soft bandage contact lens is placed over the treated eye. This lens acts as a protective cover, aiding the healing process of the regenerating epithelial layer. The entire procedure typically takes between five and 15 minutes per eye.
Determining PRK Candidacy
Determining suitability for PRK surgery involves several factors. Candidates should be at least 18 years old, with a stable vision prescription, meaning no significant changes in the last year.
Candidates must have good eye health, free from active infections or significant dry eye symptoms. PRK can be a suitable option for individuals with thinner corneas who might not qualify for other procedures. Additionally, those with certain occupations or active lifestyles that carry a higher risk of eye trauma may find PRK advantageous due to the absence of a corneal flap.
The PRK Recovery Period
The recovery period following PRK surgery is a gradual process, and patients should anticipate some initial discomfort. Immediately after the procedure, common sensations include mild to moderate pain, burning, irritation, and light sensitivity. Blurry vision is also typical, and it may even temporarily worsen a few days after surgery as the new epithelial layer begins to grow back.
The epithelial layer usually regenerates within three to five days, during which the bandage contact lens remains in place to protect the healing surface. Full visual recovery can take several weeks to months, with vision gradually becoming clearer and more stable. Post-operative care involves diligently using prescribed eye drops, which typically include antibiotics to prevent infection and anti-inflammatory medications to aid healing. Patients are advised to rest during the first few days, avoid strenuous activities, and wear sunglasses outdoors to protect their healing eyes from UV rays. Regular follow-up appointments with the eye care specialist are important to monitor the healing progress.
PRK Compared to LASIK
PRK and LASIK are both effective laser vision correction procedures, but they differ significantly in their approach and recovery profiles. The primary procedural distinction lies in how the cornea is prepared for laser application. In PRK, the surgeon removes the outermost epithelial layer of the cornea before reshaping the underlying tissue with a laser. LASIK, conversely, involves the creation of a thin corneal flap, which is lifted to allow the laser to reshape the deeper corneal tissue, and then repositioned.
PRK typically involves more discomfort and a longer initial recovery period compared to LASIK, as the epithelial layer needs time to regenerate. Patients undergoing PRK may experience pain, light sensitivity, and blurry vision for several days after surgery. While LASIK often offers quicker visual recovery, with many patients experiencing improved vision within a few days, PRK’s vision improvement is more gradual, unfolding over weeks to months.
Despite these differences in recovery, the long-term visual outcomes of PRK and LASIK are often comparable, with both procedures achieving similar levels of visual acuity. A notable advantage of PRK is the absence of flap-related complications, making it a preferred option for patients with thinner corneas, certain occupations, or those at higher risk of eye trauma. PRK may also carry a lower risk of post-operative dry eye symptoms compared to LASIK, as the creation of a corneal flap in LASIK can sometimes induce temporary dry eye.