Photorefractive Keratectomy (PRK) Retreatment of Residual Refractive Errors after Laser in Situ Keratomileusis (LASIK)

Laser in situ keratomileusis (LASIK) is the most frequently performed corneal refractive procedure. Despite technological improvements, residual postoperative refractive errors are still an issue that needs to be dealt with, especially when they interfere with the patient ́s quality of life. Retreatment after LASIK is commonly performed by lifting the flap created during the first operation followed by further application of laser. Other possible techniques are: creating a new flap, performing incisional treatment, or performing a PRK. More remote options are inserting a phakic intraocular lens (IOL) or performing surgery over the crystalline lens. These two last options are reserved for much larger errors or those cases in which further laser is not a possibility. The choice is usually between lifting the flap and performing a PRK over the flap. Febbraro [1] and Agarwal [2] described the advantages and disadvantages of both options. PRK retreatment is known to potentially cause haze/corneal scarring, more frequent regression, tissue melting, irregular astigmatism and overcorrection. LASIK retreatment may cause dry eye syndrome, flap striae, epithelial in growth and mechanical flap tearing [3,4]. LASIK retreatment is also claimed to be more predictable than PRK retreatment [5], and infections are more likely to happen after PRK [6] than after LASIK [7] Relifting a flap is not always possible due, in most occasions, to the time passed between the first operation and the second treatment and, sometimes, even if it is surgically possible, it is not recommended because of one of the following reasons: