Peripheral corneal relaxing incisions (PCRIs) are performed on an outpatient to improve the Astigmatism of the eye without significantly affecting its spherical focus. PCRIs are a form of astigmatic keratotomy (AK) in which the corneal incisions are made very peripherally.
In the PCRI procedure, the surgeon makes one or two arcuate incisions in the peripheral cornea using a diamond knife or femtosecond laser. The incisions flatten the cornea in the meridian in which they are made and steepen the cornea in the meridian 90 degrees away, a phenomenon known as coupling. The length and depth of the incisions determines the amount of astigmatism corrected.
PCRIs can be used to treat naturally occurring mixed astigmatism or astigmatism that develops after corneal refractive or lens-based surgery, such as cataract surgery.
Not every patient is a candidate for PCRIs. Patients with significant spherical refractive errors such as Myopia and Hyperopia may be ineligible and laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), or small incision lenticule extraction (SMILE) may be more appropriate. Your surgeon, or one of the optometrists in his or her practice, can determine if you are a suitable candidate during a free screening examination.
PCRIs typically take 10 to 15 minutes to perform. Both eyes can be treated at the same time, if necessary. The procedure is associated with minimal discomfort while it is being performed. When the anesthesia wears off, the level of discomfort increases. Most patients develop redness, tearing, and a foreign body sensation that lasts 6 to 12 hours. Visual recovery is fast.
As with any procedure, there is a risk of complications with PCRIs, including the possibility of an under correction or over correction. The risks should be discussed with your doctor before you undergo the procedure.