What is one characteristic of photorefractive keratectomy?

Photorefractive keratectomy (PRK) is a type of refractive surgery that aims to correct vision by reshaping the cornea. A key characteristic of PRK is that the corneal epithelium, which is the outermost layer of the cornea, is mechanically removed prior to the application of the excimer laser. This step is crucial because it allows the laser to directly reshape the underlying stromal layer of the cornea. After the laser treatment, the epithelium will gradually heal and regenerate over time.

The other options do not accurately describe PRK. Intraocular lenses are associated with procedures like cataract surgery, not PRK, which is focused on reshaping the corneal surface. While PRK involves reshaping the cornea, this reshaping occurs internally rather than externally, distinguishing it from any procedure that would reshape the lens itself. Lastly, PRK does involve the removal of corneal tissue, specifically the epithelium, which is an integral part of the procedure, as opposed to not requiring any corneal tissue removal.