Queensland Eye Institute has become only the second clinic in the world to deploy newly released software enabling fully customised corneal allogenic intrastromal ring segments (CAIRS) to be cut with extraordinary precision using femtosecond laser technology.
The breakthrough coincides with confirmation that the Brisbane Nomogram for CAIRS, developed by the clinic’s corneal and laser eye surgeons Dr Brendan Cronin and Dr David Gunn, will be published in Clinical and Experimental Ophthalmology.
The Brisbane Nomogram is the world’s first surgical planning nomogram for CAIRS that can be customised for mild, medium, moderate, and severe disease.
Until now, there has been no nomogram that accounts for different severity of disease in keratoconus,… Our nomogram lets surgeons look at mild, moderate, and severe disease. And that’s pretty exciting
What’s Changed — and Why It Matters
CAIRS, conceived by Dr Soosan Jacob of Dr Agarwal’s Eye Hospital in Chennai, India, involves implanting a sliver of donor corneal tissue into a laser-created tunnel within the patient’s cornea. Positioned at a depth of just 200–280 microns – far shallower than traditional plastic intracorneal ring segments – it reshapes the distorted cornea to improve vision while preserving precious viable donor tissue for full-thickness transplants.
Until now the donor segments used in CAIRS were largely uniform in dimension. However, the new software changes that entirely.
“The donor tissue that we now cut by laser can be customised to the individual patient’s topographic phenotype and refractive requirement,” Dr Cronin explained. “So instead of being one standard piece that’s the same dimension the whole way around, we can customise it to account for parts of a patient’s cornea that are steeper or narrower.”
The implications are significant. In keratoconus, the cornea progressively thins and bulges into an irregular cone shape, distorting vision. Because the condition varies considerably from patient to patient – even within different zones of the same cornea – a truly customised implant represents a meaningful clinical advance.
Dr Cronin performed his first cases using the new system just weeks ago, and early patient outcomes have been encouraging. “Most of them are pretty happy,” he said with characteristic understatement. “I saw a guy from Emerald (in central Queensland) yesterday – he’s ecstatic.”
Brisbane Nomogram Enables Further Personalisation
Dr Cronin and Dr Gunn’s Brisbane Nomogram enhances the precision achievable with CAIRS using femtosecond laser by providing a refined formula that models outcomes and guides how much correction to apply. Prior to its availability, surgeons have relied on generalised approaches that applied roughly the same parameters regardless of disease severity.
“Until now, there has been no nomogram that accounts for different severity of disease in keratoconus,” Dr Cronin said. “Our nomogram lets surgeons look at mild, moderate, and severe disease. And that’s pretty exciting.”
Dr Cronin said the nomogram will soon be updated to incorporate data generated by the new laser software – because for the first time, surgeons can record the exact volume of tissue implanted per patient.
“Because we now know exactly how much volume of tissue we put into each patient, we can use this information, combined with reported outcomes, to update the algorithm,” Dr Cronin explained. “A bit like evolving intraocular lens calculation formulas that have enabled us to increasingly refine the options for individual patients.”
The Brisbane Nomogram can be accessed via CAIRSPlan.com – a free surgical planning tool developed by Dr Cronin and Dr Gunn to support surgeons worldwide in mapping and executing the procedure for individual patients.
