A free Australian-designed online planning tool to help plan for corneal allogenic intrastromal ring segments (CAIRS) surgery has received unexpected acclaim at the 41st Congress of the European Society of Cataract and Refractive Surgeons (ESCRS) in Vienna.
Developed by colleagues Drs Brendan Cronin and David Gunn, CAIRSPlan.com enables surgeons to plan and map CAIRS surgery for an individual patient, then supports them through the surgery process.
Dr Cronin said what started as a tool for use by himself and Dr Gunn has quickly attracted interest from both surgeons and device companies keen to optimise outcomes from an “amazing” surgical technique that can be life changing for patients with keratoconus, a debilitating disease that affects one in 84 Australians.
He explained that CAIRS was described by Dr Soosan Jacob in 2018 as a new treatment for keratoconus. While for most patients, corneal cross linking and scleral contact lenses are sufficient to stabilise and restore vision in a keratoconic cornea, for some – particularly those who suffer from allergies, who have a physical or mental disability, or live in remote communities without town water – the contact lens approach is not suitable.
“Patients with Down syndrome, for example, often have steep corneas and they can’t physically manage contact lenses. Indigenous kids living in remote communities that rely on bore water are susceptible to acanthamoeba keratitis if they wear contact lenses,” Dr Cronin explained.
Until recently, options for these patients included laser treatment (which is typically not as successful for severe keratoconics), corneal transplantation for advanced keratoconus or corneal scarring, or intracorneal ring surgery – a procedure that involves the insertion of a plastic ring segment into the cornea.
The latter are unsuited to thin corneas and must be implanted deep into the cornea to be safe, which reduces their effectiveness. Additionally, Dr Cronin said, being an artificial material, plastic intracorneal ring segments can trigger foreign body reactions and can cause vision issues for night driving.
“In the worst cases, these plastic rings can eventually erode to the surface and cause infection and melting of the cornea,” Dr Gunn said. “For these reasons acrylic intracorneal ring segments have waned in popularity in recent years.”
ALL-ROUND LEGEND
As an alternative approach, Dr Soosan Jacob, Head of the Department of Ophthalmology at Dr Agarwal’s Eye Hospital in Chennai, India and an “all-round legend”, came up with the idea of implanting “segments of donor cornea” instead of the plastic rings. Implanted at a depth of 200–250 microns, the implant is much shallower than when using acrylic segments, making the procedure safer and more effective.
Furthermore, Dr Cronin explained, the procedure uses non-viable corneas that would otherwise have been used for research or training.
This means the Eye Bank can find a use and provide more of the precious tissue that is donated without reducing its supply of viable corneas that would otherwise be used for full corneal transplants.
With this in mind, Dr Cronin and Dr Gunn recognised the potential for CAIRS to become a ‘win-win’ procedure and performed the first surgeries in Australia in Brisbane in May 2021. With great success in the first surgeries, the team developed a spreadsheet planning document to help design operations. They shared this spreadsheet with Australian surgeons via email and then started working on a website that would be more intuitive and accessible worldwide.
“It doesn’t give surgeons medical advice, but it lets them upload corneal topography, and use sliding scales to work out where they want to make incisions and position the donor ring of corneal tissue for maximum effect.”
Once the mapping is complete, the surgeon can print a PDF to take into the operating theatre and put into their electronic medical records.
“With CAIRS, it doesn’t matter whether you’re new to the surgery or experienced, you still want to plan beforehand and have a printout in your hand, so you know how to proceed,” Dr Cronin said.
“Lack of planning can lead to mistakes, and CAIRS Plan helps you to have everything sorted out before going into theatre,” said Dr Gunn.
To encourage new surgeons to perform CAIRS, Drs Cronin and Gunn have produced YouTube videos that demonstrate how to use the CAIRS Plan website and perform the procedure itself.
Additionally, they have developed new surgical instruments to facilitate the surgery.
“Instruments for CAIRS were a challenge – there weren’t any. But, as they say, ‘invention is the mother of necessity’. To get around the lack of instruments, I was manipulating existing instruments – bending them into the shapes I needed and, in the process, getting myself in trouble with the nurses for ‘destroying instruments’.
“One day the Director of Nursing told me that if I bent one more instrument, she’d bend me into the same shape, so I decided I’d better do something about it. I worked with a manufacturer to design the instruments needed – to get the angles and curvature right and to offset the handle for better visualisation. We’re now having them manufactured for purchase by surgeons.
ACCESSIBILITY TOP OF MIND
Dr Cronin said access to CAIRSPlan.com will aways be entirely free and the instruments are available at a fraction of the price often charged for surgical instruments.
“This isn’t about profit, it’s about making an amazing technique more accessible for surgeons worldwide so that keratoconus patients in need gain the benefit,” Dr Cronin told mivision.
Dr Gunn added, “So many patients go through invasive full corneal transplants with all the problems associated with them over the years after the first surgery. CAIRS can avoid so many of these issues. Our aim is to promote CAIRS to reduce unnecessary invasive transplants from happening. CAIRS is about repairing patients’ own corneas in a minimally invasive way rather than replacing them.”
Their efforts were applauded at the recent European Society for Cataract and Refractive Surgeon’s conference. “We were walking through the tradeshow and device companies were making comments like, ‘you’re the CAIRS guys, we want to talk to you about integrating CAIRSPlan.com with our devices”.
“Then we looked at our web stats – I’d never thought to do that – and we found that within a couple of days of launching the website, we’d attracted hundreds of visitors from 33 countries around the world. It’s exciting to see change happening so fast.’
At the time of going to print in early October, this had increased to just under 1,000 visitors from 55 countries. With so much interest, Drs Cronin and Gunn said we can expect to see a number of iterations for CAIRSPlan.com released in the coming months. “CAIRS is a gamechanger and we’re keen for all corneal surgeons to get on board”.
