Natural history of corneal haze after corneal collagen crosslinking in keratoconus using Scheimpflug analysis

PURPOSE: To analyze corneal haze after corneal collagen crosslinking (CXL) for progressive keratoconus using Scheimpflug densitometry. SETTING: Auckland District Health Board, Auckland, New Zealand. DESIGN: Prospective randomized controlled study. METHODS: Both eyes of all patients were examined preoperatively and 1, 3, 6, and 12 months postoperatively. One eye of each patient was treated with corneal CXL, with the contralateral eye serving as the control. Examinations included uncorrected distance visual acuity and corrected distance visual acuity (CDVA), slitlamp biomicroscopy, and Scheimpflug tomography (Pentacam). RESULTS: Thirty-six eyes of 36 patients were enrolled. The mean preoperative corneal densitometry was 19.0 ± 3.2 (SD). Postoperatively, the mean densitometry peaked at 1 month, decreasing to baseline level after 6 months without application of topical corticosteroids. The development of haze was significant compared with the contralateral untreated eyes (P < .01). The anterior (120 μm) and inner (central 0.0 to 2.0 mm) zones of the cornea had the highest densitometry after treatment. Lower preoperative central corneal thickness (CCT) was significantly correlated with higher corneal densitometry (P = .03). However, the preoperative CCT, keratometry, and astigmatism did not influence the difference in densitometry between the treated eyes and untreated eyes. There was no evidence of a relationship between densitometry and CDVA (P = .30). CONCLUSIONS: After corneal CXL, patients with keratoconus developed transient corneal haze in the anterior central cornea that might not require specific treatment. Thin corneas were associated with higher densitometry; thus, there might be a greater expectancy of corneal haze in patients with advanced keratoconus. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.