CAIRS Keratoplasty for Keratoconus — Brisbane

What is CAIRS?

CAIRS stands for Corneal Allogenic Intrastromal Ring Segments. The procedure uses small arcs of donor human corneal tissue — not synthetic plastic — implanted into a ring-shaped tunnel within the peripheral cornea. By placing these tissue segments into the cornea, CAIRS flattens the irregular cone-shaped bulge that defines keratoconus, improving the clarity and quality of your vision.

The key word in CAIRS is allogenic — meaning the ring material comes from a human donor cornea. This sets CAIRS apart from older synthetic ring procedures such as Intacs or Kerarings, which use plastic or polymethylmethacrylate (PMMA) implants. It also means that in Australia, CAIRS keratoplasty attracts automatic Medicare and private health insurance rebates.

Why donor tissue instead of plastic?

Synthetic corneal rings carry a small but real risk of extrusion (working their way out through the cornea) and can cause corneal thinning at the implant site over time. Because CAIRS segments are natural human tissue, they integrate with your cornea rather than sitting as a foreign body within it. This makes CAIRS a more biologically harmonious option and significantly reduces the risks associated with synthetic implants.

CAIRS keratoplasty was first described in 2018 by Dr Soosan Jacob in India. Since then, it has been adopted by a small number of specialist corneal centres globally. Dr Cronin and Dr David Gunn introduced the procedure to Australia and have contributed to refining both surgical technique and surgical planning through their own peer-reviewed published research.

Is CAIRS Right for You? — Patient Selection

CAIRS keratoplasty is not suitable for every person with keratoconus. It works best for patients who fit a specific clinical profile. Dr Cronin will assess your suitability during a comprehensive corneal consultation in Brisbane.

You may be a candidate for CAIRS if:

• You have mild, moderate or advanced keratoconus that is limiting your vision
• Glasses or soft contact lenses no longer give you acceptable vision
• Your cornea is still thick enough to create the implantation tunnel safely
• You want to avoid or delay a full corneal transplant
• You have irregular astigmatism causing distorted vision that cannot be corrected with spectacles

CAIRS may not be suitable if:

• Your cornea is too thin or too severely scarred for safe tunnel creation
• You have significant corneal scarring in the central visual axis (in which case a corneal transplant may be necessary)

The Brisbane Nomogram — co-authored by Dr Cronin and Dr David Gunn — provides a systematic framework for determining the correct arc length, depth, and diameter of CAIRS rings based on your corneal topography. You can explore the nomogram and its planning logic at cairsplan.com, the same platform now used by CAIRS surgeons around the world. This level of surgical planning precision is what Dr Cronin brings to every CAIRS case performed in Brisbane.

CAIRS Combined with Corneal Collagen Cross-Linking

One of the most powerful aspects of CAIRS keratoplasty is that it can be performed simultaneously with corneal collagen cross-linking (CXL) — a combined approach sometimes referred to as the CAIRS-CXL protocol.

Cross-linking works by using ultraviolet light and riboflavin (vitamin B2) to create new bonds between collagen fibres in your cornea, halting the progression of keratoconus. On its own, CXL stabilises the cornea but does not necessarily improve vision significantly. CAIRS, on the other hand, actively reshapes the cornea to improve its optical quality.

Performing both in the same session means:

• The cornea is stabilised and reshaped in a single operation
• Recovery is consolidated into one period rather than two separate procedures

Dr Cronin uses oxygen-enhanced, topography-guided, epithelium-on (epi-on) cross-linking with pulsed irradiation — a technique he has investigated and published on extensively. This approach is gentler on the corneal surface than traditional CXL, offers faster visual recovery, and allows the procedure to be customised to the exact topographic profile of your cornea. Dr Cronin’s published outcomes data supports its efficacy for progressive keratoconus (Cronin BG, Gunn D, Chang C. J Cataract Refract Surg. 2024. DOI: 10.1097/j.jcrs.0000000000001339).

CAIRS Outcomes — What Results Can You Expect?

CAIRS does not cure keratoconus — no procedure does. However, it offers meaningful improvements in corneal shape, visual acuity, and overall quality of vision for appropriately selected patients.

Published outcomes from Dr Cronin’s practice and from the international literature demonstrate:

• Flattening of the corneal cone — reduction in maximum keratometry (Kmax) values, indicating a flatter, more regular corneal shape
• Improvement in corrected and uncorrected visual acuity — many patients see better both with and without their glasses after CAIRS
• Reduction in irregular astigmatism — the distortion and ghosting caused by the irregular cone is reduced
• Improved contact lens tolerance — patients who previously could not wear contact lenses comfortably often find they can do so more successfully after CAIRS

It is important to have realistic expectations. CAIRS keratoplasty significantly reduces the need for corneal transplantation in many patients, but in the most advanced cases of keratoconus — particularly those with central scarring — a full-thickness or Deep Anterior Lamellar Keratoplasty (DALK) may ultimately still be required.

CAIRS vs Other Keratoconus Treatments

CAIRS vs Synthetic Ring Segments (Intacs / Kerarings)

Synthetic intrastromal corneal ring segments have been available since the 1990s. They work on a similar mechanical principle to CAIRS — flattening the cone by placing a ring within the cornea — but are made from synthetic plastic rather than donor tissue. CAIRS avoids the long-term risks of extrusion and corneal thinning associated with synthetic rings.

CAIRS vs Corneal Transplant

For moderate keratoconus, CAIRS can potentially avoid the issues associated with full-thickness corneal transplantation (Penetrating Keratoplasty / PK) or Deep Anterior Lamellar Keratoplasty (DALK). Unlike a full corneal transplant, CAIRS does not require the cornea to be removed and replaced — it works within your existing corneal tissue. This means:

• No prolonged post-operative course with sutures in place for 12+ months
• No significant risk of transplant rejection
• Much faster visual recovery
• The option to still have a corneal transplant later if needed

For severe keratoconus with central scarring, DALK or PK may remain the most appropriate option. Dr Cronin performs all forms of corneal transplantation and will advise honestly and expertly on which procedure — or combination of procedures — offers the best long-term outcome.

CAIRS vs Cross-Linking Alone

Cross-linking halts progression. CAIRS reshapes the cornea. For patients who want both stabilisation and visual improvement, the combined CAIRS-CXL approach delivers both in a single procedure. Cross-linking alone remains the standard of care for early, progressive keratoconus; CAIRS becomes relevant when vision is already significantly compromised.

Dr Cronin’s CAIRS Expertise — Research, Publications, and Global Reach

Dr Brendan Cronin and Dr David Gunn were the first surgeons in Australia to perform CAIRS keratoplasty. Since introducing the procedure at the Queensland Eye Institute and Focus Vision Clinic, Dr Cronin has:

• Co-authored the Brisbane Nomogram — a validated surgical planning framework that calculates optimal CAIRS implant parameters from topographic data, now used by surgeons internationally
• Co-developed cairsplan.com — a free online CAIRS surgical planning tool used by ophthalmologists across Australia, Asia, Europe, and the Americas
• Published peer-reviewed research on CAIRS surgical technique in Cornea and Clinical & Experimental Ophthalmology
• Hosted international visiting surgeons at the Queensland Eye Institute to teach CAIRS technique
• Contributed to the manual CAIRS technique — extending the procedure’s accessibility to surgical centres without femtosecond laser platforms

Dr Cronin holds FRANZCO (Fellow, Royal Australian and New Zealand College of Ophthalmologists) and FWCRS (Founding Fellow, World College of Refractive Surgery and Visual Sciences), and has been Principal Investigator on more than 20 international clinical trials in corneal and refractive surgery.

His approach to keratoconus care is built on the principle that most patients — if diagnosed early enough — should never need a corneal transplant. CAIRS keratoplasty is central to that philosophy.

Published CAIRS research by Dr Cronin

Dr Cronin’s commitment to evidence-based CAIRS care is reflected in his ongoing peer-reviewed research. His team has published two recent studies that directly underpin how CAIRS keratoplasty is planned and performed at the Queensland Eye Institute. The first, published in Clinical & Experimental Ophthalmology in 2026, reports outcomes from femtosecond laser-created corneal allogenic intrastromal ring segments for keratoconus (Gunn DJ, Cox RA, Cronin B) — establishing the efficacy and safety profile of laser-assisted CAIRS in an Australian patient cohort. The second, published in Cornea in 2025, describes a manual technique for CAIRS without a femtosecond laser (Hayashi T, Cronin B, et al.), broadening global access to the procedure for centres without laser platforms. Together, these publications — alongside the freely available cairsplan.com planning tool — demonstrate why Dr Cronin is recognised internationally as a leading authority on CAIRS keratoplasty.