Evaluation of corneal and lens density changes after cross-linking in keratoconus

Abstract

Background Corneal cross-linking (CXL) is an important modality for keratoconus therapy. Lens and corneal density are reported to change in keratoconus and with CXL. However, these changes are not well studied. Aim The aim of this study was to evaluate the changes in corneal and lens density in patients with keratoconus after corneal CXL. Patients and methods This is a prospective case series study that was conducted in a private Eye Laser Center, Menoufia Governorate, Egypt. The study consisted of patients with bilateral clinical keratoconus whose age ranging between 15 and 40 years with clear lenses. Bilateral minimum corneal thickness of 400 µm, measured with Pentacam, was essential. All study patients were examined preoperatively and 1, 3, and 6 months postoperatively. Ophthalmic examination included uncorrected distance visual acuity, corrected distance visual acuity, and manifest refraction as well as corneal thickness, thinnest location, maximal keratometric reading (Kmax), and corneal and lens densitometry measured by Pentacam. Results The preoperative mean corneal density on the axis 0–180 was 17.3±1.8, which changed to 20.7±2.01 after 6 months postoperatively (P=0.001). Although the preoperative mean corneal density on the axis of 90–270 was 17.4±2.06, it changed to 19.9±2.4 after 6 months postoperatively (P=0.04). No significant changes were encountered in lens density after CXL. Conclusion Corneal CXL significantly increased the corneal but not the lens density. This increase was maximal after 1 month and gradually returned toward the baseline. CXL is considered as a safe procedure for the lens.

Keywords

• corneal density
• cross-linking
• keratoconus
• lens density