Long-term outcome of central toxic keratopathy after photorefractive keratectomy

To describe long-term postoperative results of 5 eyes that had central toxic keratopathy after photorefractive keratectomy (PRK).

In a period of 2 months, 74 eyes were subjected to refractive surgery (21 by PRK and 53 by laser in situ keratomileusis) in 2006. Laser ablations were performed with a VISX S4 (VISX, Santa Ana, CA) excimer laser. Five eyes of 5 different patients in the PRK group experienced a corneal stromal thinning associated with a central opacification (haze), hyperopic shift, and central striae in the first postoperative week. Follow-up examinations were at 1 month and at 2, 6, and 12 months and included uncorrected visual acuity, best spectacle-corrected visual acuity (BCVA), manifest refraction, biomicroscopy, and ultrasound pachymetry. At the last follow-up, confocal microscopy was performed in 3 eyes.

Corneal thickness measured by ultrasound pachymetry at the first month postoperatively showed an unexpected stromal thinning of 48 ± 39 μm (range, 19-116 μm) compared with the expected postoperative value. At the last postoperative follow-up, corneal thickness had gained 44 ± 22 μm (range, 20-80 μm) compared with the thickness obtained at 1 month. Uncorrected visual acuity, BCVA, haze, and corneal thickness improved in the first postoperative months and stabilized after 6 months.

Central toxic keratopathy is not related to laser in situ keratomileusis (LASIK) only. The presence of 5 cases after PRK in a short period (2 months) associated with a period of simultaneous change of both postoperative medications and postoperative bandage lens practice suggests a link with an unknown pharmacological response leading to stromal dehydration.