To report a case of corneal opacity with postoperative changes of topographic features and visual acuity after laser subepithelial keratomileusis (LASEK) treated with an improper concentration of mitomycin-C.

A 25-year-old female patient who experienced corneal opacity after LASEK treated with mitomycin-C was evaluated for changes in corneal opacity by photography, central corneal power by Orb scan IIz, and best corrected visual acuity (BCVA) over the period of 1 year. The corneal epithelial defect was completely healed 2 weeks after the LASEK operation. Subepithelial and stromal opacity decreased over time, but her cornea did not return to normal. BCVA was 20/25 in the right eye and 20/20 in the left eye at postoperative 1 year, but stromal opacity remained.

An improper concentration of mitomycin-C during LASEK could result in corneal opacity. Long time is needed to recover visual acuity and a normal corneal structure.