08 Aug, 2025
Keratoconus is a progressive eye condition where the cornea, the clear front surface of the eye, thins and bulges into a cone-like shape. This distortion leads to blurred vision, light sensitivity, and irregular astigmatism. Historically, many patients with keratoconus faced deteriorating sight which could not be corrected with glasses. Their only treatment options were rigid contact lenses, which can be uncomfortable and sometimes painful, or corneal transplants – a procedure with risks and potential complications.
A new procedure – Corneal Collagen Cross-Linking (CXL) – became available in the early 2000s and has since become a cornerstone of treating keratoconus. The procedure strengthens the cornea’s collagen fibres by creating new cross-links between them. The treatment involves saturating the eye with riboflavin (vitamin B2) eye drops, then controlled exposure to ultraviolet (UV) light. This causes a photochemical reaction which stiffens the corneal tissue, halting or slowing the disease.
CXL stabilizes the cornea in more than 95% of cases, often improving sharpness of vision when combined with other therapies. Patients who undergo the treatment report reduced distortion and better tolerance for contact lenses. Recovery is relatively quick, with most patients returning to normal activities within days, though full sight stabilization can take months. Side effects are minimal, typically involving temporary discomfort or haze that resolves in time.
CXL enhances quality of life, allowing individuals to pursue careers, sports, and hobbies without the fear of worsening vision, while also preserving natural corneal tissue.
While CXL has been revolutionary in stabilising the cornea to prevent further deterioration, a more recent treatment offers even more hope to keratoconus sufferers. Corneal Allogenic Intrastromal Ring Segments (CAIRS) uses segments crafted from donated human corneal tissue (allogenic stroma). These rings are inserted into precisely created channels within the cornea’s middle layer (stroma). The segments act as spacers, flattening the cone and regularizing the corneal shape to improve optical performance.
Because CAIRS uses donated human tissue there is less risk of rejection. When combined with CXL, it not only stabilizes but also reshapes the cornea, often leading to significant vision improvements. Patients can achieve better uncorrected vision or easier fitting of glasses and contact lenses.
The procedure is minimally invasive, performed under topical anaesthesia, and allows for rapid return to normal, or improved, vision.
Together, CXL and CAIRS exemplify the shift toward personalised, tissue-preserving treatments in ophthalmology. The procedures not only arrest keratoconus, but they also empower patients with restored confidence and independence.
Drs Brendan Cronin and David Gunn have been at the forefront of CAIRS development globally, training Australian and international colleagues to advance CAIRS adoption and refine techniques. The QEI ophthalmologists pioneered CAIRSplan.com, a free online planning tool that enables surgeons worldwide to customize segment placement based on individual corneal topography. The duo also designed specialized instruments to enhance surgical precision and safety.