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CAIRSPlan

Procedure

What is CAIRS?

Corneal Allogenic Intrastromal Ring Segments are donor-tissue ring segments implanted within the cornea to reshape it. The next generation of minimally invasive corneal surgery for keratoconus.

The principle

Keratoconus weakens and distorts the cornea, producing a steep cone that scatters light. CAIRS counters this by adding biological tissue rather than removing the patient's own. Donor corneal stroma is shaped into thin arc segments and placed within a femtosecond-laser-cut intrastromal channel. The added volume flattens the cone and regularises the corneal shape.

A biological implant may reduce the risk of extrusion and stromal thinning seen with PMMA segments, and the segments can be exchanged or removed straightforwardly down the track if corneal shape evolves.

A short history

From Chennai to Brisbane.

CAIRS was conceived in India, refined by surgeons in Lebanon, Germany, Türkiye and Australia, and is now planned eye-by-eye with topography-driven nomograms. Each step solved a specific problem.

  1. 2018

    Concept

    Dr Soosan Jacob (Chennai) describes CAIRS — donor corneal stromal arc segments in place of synthetic PMMA implants — and publishes the first peer-reviewed series in the Journal of Refractive Surgery.

  2. Feb 2021

    All-femto CAIRS

    Dr Bader Khayat (Germany) performs the first all-femtosecond-laser CAIRS — both the corneal channel and the donor implant cut by laser, replacing manual graft trephination.

  3. May 2021

    Australian first

    Dr David Gunn and Dr Brendan Cronin follow with Australia's first CAIRS procedures at Focus Vision, Brisbane — all-femto from day one.

  4. 2022

    Istanbul nomogram

    Dr Aylin Kılıç (Istanbul) publishes the first CAIRS planning nomogram in the European Journal of Ophthalmology — a fixed-implant-size protocol using KeraNatural pre-cut allograft segments.

  5. 2023

    All-femto paper

    Jacob, Hafezi and Awwad publish the asymmetric all-femtosecond-laser-cut CAIRS technique in the Journal of Refractive Surgery, formalising laser graft preparation.

  6. 2023

    Custom CAIRS

    Jacob and Awwad publish customised tapered and asymmetric CAIRS for decentred cones in the Indian Journal of Ophthalmology — moving beyond fixed-shape implants to per-eye geometry.

  7. 2026

    Brisbane nomogram

    Gunn and Cronin publish the Brisbane nomogram in Clinical & Experimental Ophthalmology — keratometry stratifies planning across all severity grades.

How CAIRS works

From scan to vision, in five steps.

  1. 01

    Assessment

    Corneal topography, tomography and pachymetry. The cornea is mapped in three dimensions to determine candidacy and plan ring placement.

  2. 02

    Planning

    CAIRSPlan applies the published Brisbane nomogram to the patient's topography to recommend segment width, thickness, axis and channel depth.

  3. 03

    Femto-channel

    A femtosecond laser cuts a precise intrastromal channel at the planned depth and diameter — sutureless, in under 60 seconds.

  4. 04

    Implantation

    Donor corneal stroma — shaped into thin arc segments — is inserted into the channel under topical anaesthetic. The added volume flattens the cone immediately.

  5. 05

    Recovery

    Vision improves over days to weeks. Often combined with corneal cross-linking to lock the new shape in place.

Why CAIRS matters

  • Tissue-additive. No patient cornea is removed, in contrast to synthetic ICRS or excimer-based procedures.
  • Reversible. Segments can be exchanged or removed straightforwardly down the track if corneal shape evolves.
  • Lower complication profile. May reduce risks associated with synthetic segments — extrusion and surrounding stromal thinning.
  • Suitable across severity grades, including patients ineligible for laser-based therapies.
  • Often combinable with corneal cross-linking when there is evidence of disease progression.

The Australian story

Dr David Gunn and Dr Brendan Cronin performed Australia's first CAIRS procedures in May 2021 at Focus Vision, Brisbane. Their Brisbane nomogram for femtosecond-laser-created CAIRS — analysing 85 eyes from 75 patients across all keratoconus severity grades, in Clinical & Experimental Ophthalmology — gives Australian surgeons a peak-K-stratified planning framework alongside the existing Istanbul and Awwad systems.

Frequently asked

How does CAIRS differ from synthetic ICRS?

CAIRS uses biological donor corneal stroma rather than PMMA. The biological implant may reduce the risk of extrusion and surrounding stromal thinning seen with synthetic segments, and the segments can be safely exchanged.

Is CAIRS reversible?

Yes. No native corneal tissue is removed, so implants can be exchanged or removed if the corneal shape evolves — particularly useful in younger patients with potentially progressive disease.

Can CAIRS be combined with cross-linking?

Yes. CAIRS reshapes the cornea; cross-linking stabilises it. Many patients receive both, often staged, to maximise visual gain and arrest disease progression.

Clinical results

CAIRS delivers.

From the published Brisbane nomogram for femtosecond-laser CAIRS, authored by Dr Gunn, Dr Cox and Dr Cronin in Clinical & Experimental Ophthalmology.

85 eyes from 75 patients · all keratoconus severity grades · mean follow-up 7.5 months.

Mean uncorrected vision gain (UCVA)
+3lines
Mean corrected vision gain (CDVA)
+2lines
Patients gaining ≥3 UCVA lines
50%+
Published nomogram cohort
85eyes

Tools

Two ways to plan.

CAIRSPlan is available in two versions while we transition. Both are free for the surgical community.

Recommended · New

CAIRSPlan

Rebuilt planner with the latest femto-CAIRS nomogram, refined topography import, and a faster planning workflow.

Open the new tool Legacy

Legacy CAIRSPlan

The original tool, kept online for surgeons mid-treatment-plan or used to its workflow. Same login as before.

Open the legacy tool