One Case Of Irregular Astigmatism After Lasik Treated With Trans-Epithelial Photorefractive Keratectomy

To present our approach treating one case of irregular astigmatism after LASIK with trans-epithelial photorefractive keratectomy (PRK) 

Instituto Oftalmologico Hoyos. Sabadell-Barcelona (Spain)

32-year-old male patient operated on with Laser assisted in-situ keratomileusis (LASIK) in both eyes twelve years ago, who referred to bad vision in the left eye (LE) from the early postoperative days. His uncorrected visual acuity (UCVA) in the LE was 20/60 and best corrected visual acuity (BCVA) was 20/30 with a refraction of -1.75 -2 x 30º.  In the cornea there was a star-shaped scar in the pupillary area that resembled a broken flap or buttonhole from the LASIK surgery. Pentacam topography showed an irregular astigmatism with a central island of 49.7 D without posterior elevation. We plan to treat this scar with excimer laser. In the corneal tomography the scar was at a depth of 100 microns and the epithelium had 65 microns of thickness. Due to our suspicion of broken flap, we decided to use the excimer laser for epithelial removal, but this patient had a myopic residual error and in our experience phototherapeutic keratectomy (PTK) induces a myopic shift. For this reason we plan a trans-epithelial PRK as a PTK, treating 65 microns for the epithelium and then, -1.75 diopters with a 7 mm optical zone to remove 35 microns of stroma. The result was a transparent cornea with neither scar nor haze. Six months after treatment UCVA was 20/25 and BCVA was 20/15 with a refraction of -2 x 35º. The comparative Pentacam topography showed a flattening of 5.4 D in the previous central island.

Trans-epithelial PRK used as a PTK is a good option to treat irregular astigmatism induced by corneal scars on the corneal flap after LASIK. Trans-epithelial treatment avoids further damage to the flap.