Corneal densitometry after accelerated corneal collagen cross-linking in progressive keratoconus.

Abstract

To analyze changes in corneal densitometry 3months after accelerated corneal collagen cross-linking (CXL) measured with Scheimpflug tomography. In this study we reviewed charts and anterior segment data of patients who had undergone accelerated pulsed epithelium-off CXL (30 mW/cm2 for 4min, 8min total radiation time) for treatment of progressive keratoconus in the Department of Ophthalmology, Goethe University, Frankfurt, Germany. Visual, topographic, pachymetric and densitometric data were extracted before surgery and at the 3-month follow-up. Corneal densitometry measurements from different corneal layers and zones obtained using Scheimpflug tomography (Pentacam HR, Oculus). The study investigated 12 eyes of 12 patients. The anterior (120μm) stromal layer within the 0.0 to 2.0mm and 2.0 to 6.0mm concentric zones showed a significant elevation of mean densitometry 3months post-surgery (P=0.045; P=0.015) compared to baseline. A mean stromal demarcation line was apparent at a depth of 203.00μm±13.53 (SD). After accelerated CXL, no change in mean corrected distance visual acuity (LogMAR) was observed but a thinning of the cornea measured by a significant reduction in central pachymetry (μm). Accelerated CXL results in an increase in corneal densitometry, particularly in the anterior stromal layer within the two central concentric zones (0.0 to 2.0mm and 2.0 to 6.0mm) of the cornea at 3months postoperatively. The changes in corneal densitometry of the anterior stromal layer did not correlate with postoperative visual acuity or central pachymetry.