Keratoconus CAIRS — DR BRENDAN CRONIN OPHTHALMOLOGIST
Introduction to Keratoconus
Keratoconus is a progressive eye disorder in which the cornea—the clear, dome-shaped surface at the front of the eye—gradually thins and bulges outward into a cone-like shape. This abnormal curvature disrupts the way light enters the eye, resulting in distorted vision, irregular astigmatism, and often poor quality night vision. In the early stages, many patients can manage their symptoms with glasses or contact lenses. However, as keratoconus advances, these options may no longer provide adequate vision correction, and more specialized treatments become necessary.
For moderate to severe cases, interventions such as corneal cross-linking can help stabilize the cornea and slow disease progression. In situations where the cornea becomes too thin or misshapen, traditional corneal transplants or other surgical procedures may be considered. Corneal Allogenic Intrastromal Ring Segments (CAIRS) represent a significant advancement in the management of keratoconus and related corneal disorders. This minimally invasive technique uses allogenic intrastromal ring segments to reshape and reinforce the cornea, offering an alternative to more invasive corneal transplantation. By improving the corneal structure and reducing visual disturbances, CAIRS can help many patients achieve better vision and quality of life.
CORNEAL ALLOGENIC INTRASTROMAL RING SEGMENTS (“CAIRS”) for Keratoconus
CAIRS surgery is the next generation of cutting-edge surgical procedure for keratoconus, pellucid marginal degeneration, and post LASIK ectasia being offered at the Queensland Eye Institute. Watch a video of the procedure here.
This minimally invasive surgical procedure is performed for patients with keratoconus or weak corneas to provide more strength and to reduce the corneal distortions that occur in this condition. The procedure is tailored to the patient's unique corneal anatomy and aims to improve the shape of the cornea, meaning that you will hopefully be able to achieve better vision, improve vision, and potentially be a better candidate for further vision enhancing procedures such as topography guided laser resurfacing procedures.
CAIRS is a modern take on the older Keraring™ procedure for keratoconus – with some important differences.
CAIRS is covered by health funds – Kerarings™ are not. However, only certain levels of private health insurance, such as bronze level hospital cover or higher, typically cover eye surgery procedures like CAIRS. Basic hospital cover or extras-only policies usually do not cover eye surgery, so patients should check their insurance policy to confirm if it will cover eye surgery like CAIRS.
CAIRS segments are inserted at a depth of 50% corneal thickness meaning they can have more effect on the shape of your cornea than Kerarings™ which must be inserted much deeper.
CAIRS has a much lower risk of a severe complication called “extrusion”.
CAIRS also has significant advantages over full thickness or other partial thickness types of corneal transplants
No tissue is removed from your eye in CAIRS – it leaves your eye stronger not weaker
CAIRS is generally done without any stitches
You can still continue all contact sports with CAIRS.
You can even swim 7 days after the procedure!
You only need about 2-3 days off work for CAIRS.
You only need topical steroids drops for 4 weeks after CAIRS
There is no significant long term risk of failure or rejection with CAIRS
The procedure involves taking tissue from a corneal donor (someone who has passed away and has donated their eyes for transplantation) and cutting one or two very small ring-shaped segments of this tissue. These are known as allogenic tissue ring segments, also referred to as shaped corneal segments or allogenic intrastromal ring segments. A special laser called a femtosecond laser then cuts a small tunnel in the corneal stroma of the patient's cornea. The donor rings of tissue, which are intracorneal ring segments, are then threaded into these tunnels to reshape and stabilize your compromised cornea. These corneal ring segments help improve vision in patients with corneal conditions such as moderate keratoconus. The ring segments integrate with the host cornea, and it is important to monitor the host cornea post-surgery to ensure proper healing and implant stability. There are 2 big differences between CAIRS and other types of corneal transplants: 1. None of your cornea is removed in CAIRS. 2. Only a very small amount of donor tissue is implanted in your cornea. This tissue is “non-functioning,” meaning that failure or rejection of the graft (which is extremely rare) should not affect the visual outcome.
CAIRS leads to improved visual acuity and better visual outcomes, with corrected visual acuity assessed before and after the procedure to measure effectiveness. Most patients notice significant improvements in vision after CAIRS, especially those who previously experienced poor vision due to moderate keratoconus.
Recovery from CAIRS requires careful postoperative care, including the use of prescribed eye drops and anti inflammatory eye drops to prevent infection and promote healing. It is essential to attend scheduled follow up appointments to monitor the integration of the ring segments and the health of the host cornea.
For uninsured patients, the procedure can represent a significant expense.
Patient selection for CAIRS involves developing a personalized treatment plan, and refractive surgery may also play a role in the overall management of keratoconus.
Candidate Selection: Who is Suitable for CAIRS?
CAIRS is particularly well-suited for patients experiencing progressive keratoconus, pellucid marginal degeneration, or post-LASIK ectasia—especially when other treatments have not provided sufficient improvement. Many patients who struggle with contact lenses due to discomfort or poor fit, or who have not achieved the desired results from corneal cross-linking, may benefit from this innovative approach.
Before proceeding with CAIRS, patients undergo a comprehensive evaluation that includes detailed eye examinations and advanced corneal topography. This imaging assesses the corneal shape, thickness, and overall health, allowing corneal surgeons to tailor the treatment to each patient’s unique corneal anatomy. Visual acuity measurements and a review of previous treatments are also essential to determine candidacy.
During the CAIRS procedure, highly skilled corneal surgeons use donor corneal tissue to craft allogenic intrastromal ring segments, which are then precisely implanted into the patient’s cornea. These ring segments help to reshape and stabilize the cornea, reducing distorted vision and improving visual acuity. By customizing the placement and size of the ring segments, the procedure can address the specific needs of each patient, offering significant improvements in vision without the need for a more invasive corneal transplant. This makes CAIRS an excellent option for those seeking to restore or enhance their vision while preserving as much of their natural corneal tissue as possible.
What else does the procedure involve
This is performed as routine day surgery. The procedure is performed at the South Bank Day Hospital – the only hospital in Queensland with the femtosecond LASER that is required for the procedure.
You are sedated for the procedure, so you won't remember much at all.
You vision will often have significantly improved the next day but will fluctuate over a few weeks.
Is CAIRS still a corneal transplant?
ABSOLUTELY YES! CAIRS might sound easy but it is still an extremely delicate procedure requiring years of training, meticulous planning, hugely expensive lasers, extremely precise positioning of the tissue and regular post-operative follow up to ensure good results. Rejection can still occur with a CAIRS transplant (although the rates are very low).
Have you had CAIRS or are considering it? Please use the opportunity to discuss organ donation with your family. Giving the gift or life and / or sight can be one of the greatest gifts of all.
A video explanation of CAIRS for keratoconus.
