Differences between LASIK and PRK

LASIK vs. PRK

Laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) are the two most common forms of laser eye surgery used to treat refractive errors such as myopia, hyperopia, and astigmatism. Both procedures use an excimer laser to reshape the cornea, though they differ in how they access the corneal stroma.

Comparison table

The following table outlines the primary differences between the two surgical methods.

Category	LASIK	PRK
Surgical method	Corneal flap creation	Epithelial layer removal
Recovery time	24 to 48 hours	1 to 4 weeks
Initial discomfort	Mild to minimal	Moderate to significant
Corneal thickness	Requires thicker tissue	Suitable for thin corneas
Flap complications	Possible (dislocation)	None
Haze risk	Negligible	Possible (corneal haze)
Dry eye risk	Higher incidence	Lower incidence
Activity restrictions	1 to 3 days	1 to 2 weeks

Venn diagram comparing Differences between LASIK and PRK

Procedural differences

In LASIK, a surgeon creates a thin flap in the cornea using either a microkeratome blade or a femtosecond laser. This flap is folded back, the underlying stroma is reshaped by an excimer laser, and the flap is replaced. The flap serves as a natural bandage, allowing for rapid healing.

PRK does not involve a flap. Instead, the surgeon removes the outer layer of the cornea, known as the epithelium, which is discarded or moved aside. The laser then reshapes the exposed surface of the cornea. Because the epithelium must regrow, a clear bandage contact lens is placed on the eye for several days post-surgery to protect the surface and manage discomfort.

Recovery and visual outcomes

Recovery for LASIK is characterized by a rapid return to functional vision, with many patients reaching 20/20 vision within 24 hours. Post-operative pain is typically low, with patients reporting a gritty sensation that subsides within a day.

PRK recovery is slower and involves a period of blurred vision and light sensitivity while the epithelium regenerates. Functional vision often takes four to seven days to return, and peak visual clarity may take three to six months to stabilize. Studies show that by the six-month mark, visual outcomes for both procedures are statistically comparable, with over 90% of patients achieving 20/20 vision.

Suitability and risks

Clinical suitability depends on corneal anatomy and lifestyle. LASIK is often preferred for its convenience, but it requires sufficient corneal thickness to safely create the flap. PRK is the standard alternative for patients with thin or irregular corneas. It is also recommended for individuals in high-impact professions, such as military personnel or contact sports athletes, where a traumatic injury could potentially dislodge a LASIK flap.

LASIK carries a higher risk of chronic dry eye because the flap incision severs corneal nerves that signal for tear production. PRK preserves more nerve function but carries a risk of corneal haze, which is often managed with the application of mitomycin-C during surgery or steroid drops during recovery.