Photorefractive keratectomy after intrastromal corneal ring segment explantation

To describe a case of photorefractive keratectomy after removal of intrastromal corneal ring segments from the cornea.

During United States Food and Drug Administration Phase III Trials for intrastromal corneal ring segments (ICRS), the implanted segments were removed from the cornea of the right eye of a patient because of dissatisfaction with glare, halos, and fluctuating vision. Ten months after ICRS explantation, the-patient underwent a photorefractive keratectomy procedure to the same eye.

One month after removal of the ICRS, the patient's manifest refraction was within +/- 0.50 diopters of his original manifest refraction. Photorefractive keratectomy was planned to the same eye 6 months later. At the first attempt, the epithelium could not be removed with the laser and scrape technique, and residual epithelium was noted at the vertical meridian (12 o'clock) corneal incision site, which had been used for ICRS surgery and explant; therefore, the procedure was aborted. At the second attempt, with a mechanical epithelial brush (AMOILS Epithelial Scrubber; Innova, Inc, Toronto, Canada), the epithelium was removed with ease. After this, photorefractive keratectomy was done without difficulty or complication. At his most recent 8-month postphotorefractive keratectomy examination, the patient had an uncorrected visual acuity of RE: 20/16, with a manifest refraction of -0.75 to 0.75 x 170 degrees, a faint haze at the site of the stromal channel, and a small scar at the incision site on slit-lamp examination.

Intrastromal corneal ring segments can be readily removed from the cornea, if required. In this case, the refraction returned to its preoperative state soon after the explant procedure and remained stable over time. Photorefractive keratectomy was performed as a secondary refractive surgical procedure after the removal of ICRS without difficulty or complication. However, removal of the epithelium is probably best accomplished with the use of an epithelial brush, considering the changes in the epithelial adherence in a postsurgical cornea. Further studies are required to establish the safety and efficacy of secondary refractive surgical procedures after ICRS explantation.