Contact Lens-Assisted Cross-Linking (Cacxl) In Spediatric Keratoconus With Thin Cornea Sub400

Cross-linking (CXL) is considered an emergency in pediatric keratoconus to prevent rapid progression. However, protocol personalization is essential to protect the endothelium while maintaining efficacy. We report the successful management of a child treated with the Contact Lens-Assisted Cross-linking (CACXL) protocol for progressive keratoconus on a thin cornea below 400 microns.

A 12-year-old patient presented with advanced bilateral keratoconus.

• Left Eye (OS): Stage 4 with a central corneal scar, visual acuity reduced to Counting Fingers (CF), and a minimum pachymetry of 294 µm.

• Right Eye (OD): Stage 3 with initial visual acuity dropping to 4/10 within two months. Tomography confirmed progression with a Kmax of 69.8 D and a minimum pachymetry of 397 µm.

Given the corneal thinness, the CACXL protocol was performed on the right eye. The procedure involved riboflavin induction followed by UV irradiation at 6 mW/cm² in pulsed mode, with a total dose of 5.40 J/cm². A bandage contact lens without a UV filter was interposed to protect the endothelium during irradiation.

Postoperative recovery was uneventful, with a total absence of haze and complete re-epithelialization within 3 days. Anterior segment OCT (AS-OCT) at 10 days confirmed treatment efficacy by clearly visualizing a demarcation line at an average depth of 180-200 µm. This line demonstrates effective stromal polymerization while maintaining a safety distance from the endothelium. This case demonstrates that even with a starting point of 397 µm, the resulting demarcation line is deep and regular, ensuring stabilization without endothelial toxicity.

The CACXL protocol is an effective alternative to hypo-osmolar CXL for progressive keratoconus on thin corneas. The use of pulsed mode is particularly important to optimize corneal oxygenation, helping to postpone invasive surgery in young patients experiencing rapid progression.