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CAIRSPlan

Planning system

The Brisbane nomogram.

A published planning system for femtosecond-laser CAIRS — derived from 85 keratoconic eyes at Focus Vision and Queensland Eye Institute, and the default nomogram inside CAIRSPlan.

The paper

Published in Clinical & Experimental Ophthalmology, 2026.

Open-access retrospective case series of 85 keratoconic eyes treated with femto-CAIRS using the Brisbane nomogram — a peak-K-stratified planning system that sits alongside the Istanbul and Awwad nomograms in current practice. The published data also shows what cross-linking adds when it's indicated.

Original article · Clinical Science

Open Access

Femtosecond Laser Created Corneal Allogenic Intrastromal Ring Segments for Keratoconus

David J. Gunn · Rebecca A. Cox · Brendan Cronin

Queensland Eye Institute, Brisbane, Queensland, Australia

Journal
Clinical & Experimental Ophthalmology
Citation
2026; 0:1–14
Accepted
1 March 2026

Methods. Retrospective case series of 85 keratoconic eyes from 75 patients. CDVA, UDVA, refraction, corneal topography and higher-order aberrations measured pre-op and at ≥ 3 months post-op. All CAIRS created with femtosecond laser; segment width, thickness, arc length, axis and channel depth determined by the Brisbane nomogram against individual topography.

CXL composition. 18 eyes had prior cross-linking, 30 underwent simultaneous CXL, 37 had no CXL.

Headline result. UDVA improved by 0.4 logMAR (p < 0.001); CDVA by 0.2 logMAR (p < 0.001). 31 eyes (43.7%) gained ≥ 5 lines. Significant reduction in spherical equivalent, refractive astigmatism, flat K, steep K, mean K and KMax. KMax reduction greater with simultaneous CXL (−4.28 D vs −0.70 D; p = 0.018). No significant complications.

Read on Wiley doi.org/10.1111/ceo.70104

−0.4

UDVA gain

logMAR improvement (≈ 4 Snellen lines), p < 0.001

−0.2

CDVA gain

logMAR improvement (≈ 2 Snellen lines), p < 0.001

43.7%

Gained ≥ 5 lines

31 of 71 eyes with paired UDVA

0

Significant complications

Across the full 85-eye series

Figure 3 · the data, three ways

Change in visual acuity, eye by eye.

Switch between the per-bin distribution of post-op change in UDVA and CDVA, the cumulative gain curve, and the UDVA outcome bands. Hover any bar or point for the underlying numbers.

Adapted from Figure 3, Gunn, Cox & Cronin (2026). Bin widths are 0.1 logMAR; left of the dashed line indicates improvement. A 0.1 logMAR step ≈ 1 Snellen line.

Refractive

Significant reduction in spherical equivalent, refractive astigmatism, flat K, steep K, mean K and KMax (all p < 0.001).

Aberrations

Improvement in total higher-order aberrations and vertical coma (p < 0.001) — central cornea regularised, not just flattened.

Cross-linking

Eyes with simultaneous CXL showed greater KMax reduction (−4.28 D vs −0.70 D; p = 0.018), supporting combined CAIRS + CXL when ectasia is unstable.

The principles

Four ideas behind the nomogram.

  1. 01

    Cross-sectional area sized to peak K

    The cross-sectional area of the segment is customised to the paracentral keratometry — higher K, more tissue added.

  2. 02

    Seven-grade ladder

    Seven sizes spanning the full keratoconus severity range, from forme fruste through to extreme ectasia. Each grade specifies its own segment width, thickness and channel dimensions.

  3. 03

    Channel scales with segment

    Inner diameter, outer diameter, and channel width step together with segment size to seat the implant cleanly.

  4. 04

    Iterated on outcomes

    The Brisbane nomogram is updated over time as we review our clinical results. The latest iteration (Brisbane 2026) is the default in CAIRSPlan; earlier iterations remain available in the legacy tool.

The full size table

Brisbane Nomogram 2026.

Seven sizes, K-stratified from forme fruste through extreme ectasia. Both implant cross-section and channel geometry scale together — more tissue volume for steeper corneas, delivered through progressively wider channels. Values mirror the live presets inside CAIRSPlan.

Size Implant Channel
Peak K (D) Segment width (μm) Segment thickness (μm) Area (mm²) Segment inner ⌀ (mm) Segment outer ⌀ (mm) Channel width (mm) Channel inner ⌀ (mm) Channel outer ⌀ (mm)
X Small 46–48 700 200 0.140 5.2 6.6 1.10 4.8 7.0
Small 48–50 800 350 0.280 5.0 6.6 1.25 4.6 7.1
Medium 50–55 900 450 0.405 5.0 6.8 1.40 4.5 7.3
Large Ref 55–63 1000 550 0.550 5.0 7.0 1.55 4.4 7.5
X Large 63–70 1250 550 0.688 4.8 7.3 1.80 4.2 7.8
2X Large 70–75 1500 550 0.825 4.6 7.6 2.00 4.1 8.1
3X Large > 75 2000 550 1.100 4.4 8.4 2.40 4.0 8.8
Channel depth is set per-eye against pachymetry at the channel zone (typical range 200–600 μm). Cross-section area = width × thickness. Segment ⌀ values are the implant arc inner / outer diameters at the segment centre line.

Use it

Brisbane is the default nomogram in CAIRSPlan.

Upload a topography, and CAIRSPlan applies Brisbane 2026 to recommend a starting plan. You then refine — segment width, thickness, axis, channel depth — with the geometry recomputed live.

Open CAIRSPlan What is CAIRS surgery

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