Bilateral Central Toxic Keratopathy After Photorefractive Keratectomy

To report 3 cases of bilateral central toxic keratopathy (CTK) developed after photorefractive keratectomy (PRK).

A retrospective case series included 6 eyes of 3 patients diagnosed with CTK after PRK. Two of three patients had meibomian gland dysfunction and were treated before the surgery. All patients underwent simultaneous bilateral PRK for myopic correction. The standard epithelial-off PRK with 20% alcohol and an adjunct of Mitomycin C were performed in all cases. Fluoromethalone eye drop and Gatifloxacin eye drop were prescribed postoperatively. 

On the first day of post-operation, all eyes showed clean corneal epithelial defect and clear stromal tissue with no sign of inflammatory reaction.  None of the patients had an underlying systemic disease. Two patients had meibomian gland dysfunction preoperatively treated before the surgery. All patients developed asymmetrical bilateral corneal opacity on postoperative day 4, 5 and 6, respectively. The severity of corneal opacity was worse in right eyes. Fluoromethalone eye drops were switched to prednisolone acetate eye drops, but the corneal haze was not declined. The refraction turned into hyperopia, corresponding to the central corneal flattening and thinning revealed in the corneal topography. Then, the CTK was suspected. The topical corticosteroids were tapered off The corneal opacity started to improve at 6 weeks and had a complete resolution with preserved best corrected visual acuity Final uncorrected visual acuity was 20/20 or better in all eyes. Time to resolution varied from 3 -7 months.

CTK can occur in early postoperative PRK resulting corneal opacity. A conjunction of corneal thinning and hyperopic shift is the most predominant sign detected in this condition. The CTK can be resolved by itself without any specific intervention. Corticosteroids have no role in the treatment.