Keratoconus: Symptoms, Causes and Treatment — Brisbane

What Is Keratoconus?

Keratoconus is a progressive inflammatory eye disorder that affects the shape of the cornea, the clear front surface of the eye. A healthy cornea is round like a soccer ball; in keratoconus it gradually thins and bulges outward into a cone-like shape. That irregular shape distorts vision in a way standard glasses often cannot fully correct, making everyday tasks such as reading or driving harder. Symptoms usually begin in the late teens or early twenties, and the condition can worsen over time if left untreated. Keratoconus was once considered rare, quoted at about 1 in 2,000 people, but modern corneal imaging suggests it is far more common, with some studies estimating closer to 1 in 375. It is not the only condition that changes the cornea's shape: see how it differs from keratoglobus and pellucid marginal degeneration.

Keratoconus Symptoms

Symptoms vary from person to person, and in the earliest stages there may be none at all, which is why corneal mapping matters. The common signs are:

• Blurred or distorted vision that glasses never quite seem to fix
• Glasses or contact lens prescriptions that keep changing, with steadily increasing astigmatism
• Ghosting, shadowing or doubled letters, often in one eye
• Flaring, halos and glare around lights at night, especially oncoming headlights
• Increased sensitivity to light
• Itchy eyes and a strong urge to rub them

In established keratoconus the distortion becomes harder to correct with glasses, and rigid or scleral contact lenses are often needed to see well. If any of this sounds familiar, a corneal map will give you a definitive answer.

What Causes Keratoconus?

Keratoconus is driven by inflammation that weakens the collagen framework of the cornea. Eye rubbing is the single biggest modifiable risk factor: the mechanical trauma of vigorous, repeated rubbing both triggers and accelerates the disease, and it is usually driven by the itch of allergy. Genetics load the dice, with about 1 in 10 patients having an affected family member, which is why we recommend screening children of keratoconus patients from around age 10. Allergic conditions such as hay fever, eczema and asthma travel with keratoconus, and it is also more common in people with Down syndrome, sleep apnoea and some connective tissue disorders. For the full picture, read what causes keratoconus, and if you are planning a family, see keratoconus and pregnancy.

How Keratoconus Is Diagnosed

Early keratoconus cannot be picked up from a reading chart alone. The diagnosis is made by mapping the cornea: corneal topography maps the surface shape, and tomography (Pentacam) maps the full thickness profile, picking up the earliest thinning and steepening long before vision changes. At the Queensland Eye Institute we also measure corneal biomechanics, which can reveal a weak cornea before its shape has visibly changed. Read more about how topography and tomography detect keratoconus.

How Quickly Does Keratoconus Progress?

Keratoconus progresses fastest in teenagers and young adults, which is why a new diagnosis in a young person should be acted on quickly; our guide for parents of teenagers with keratoconus covers this in detail. Progression typically slows through the thirties and forties, but no individual's course can be assumed, so stability is tracked with corneal scans every three to twelve months. In advanced disease, a sudden painful swelling of the cornea called hydrops can occur, which is one more reason to stop progression early. The goal of modern care is simple: catch it early, stabilise it, and keep the vision you have.

Stages of keratoconus

Keratoconus is commonly described as mild (vision still corrects well with glasses), moderate (distortion needs rigid or scleral contact lenses) and advanced (significant thinning, steepening or scarring, where surgery is usually discussed). The stage guides which treatments make sense, but the more important question at any stage is whether the cornea is still changing.

Keratoconus Treatment Options

Treatment has two jobs: stopping the disease and restoring vision. Which combination is right for you depends on how advanced the keratoconus is and whether it is still progressing. At a glance:

• Glasses and contact lenses correct vision in earlier disease but do not treat it; see are contact lenses the only treatment?
• Corneal cross-linking strengthens the cornea and halts progression, the cornerstone of modern keratoconus care
• Topography-guided laser (Athens protocol) combined with cross-linking can smooth corneal irregularity in selected corneas; see laser eye surgery with keratoconus
• CAIRS reshapes the cone with donor tissue ring segments to improve vision, often combined with cross-linking
• Corneal transplantation remains the answer for the small number of eyes with advanced scarring

Each option is covered in more detail below.

Why Patients Choose Dr Cronin for Keratoconus

If you are looking for a keratoconus specialist in Brisbane, it is worth knowing what sits behind the title. Dr Cronin:

• Is a Fellow of the Royal Australian and New Zealand College of Ophthalmologists and a Founding Fellow of the World College of Refractive Surgery and Visual Sciences
• Teaches CAIRS keratoplasty to surgeons internationally, co-authored the Brisbane Nomogram for CAIRS surgical planning, and co-developed cairsplan.com, the planning platform used by CAIRS surgeons worldwide
• Was Australia's first surgeon to offer Glaukos Epioxa epi-on cross-linking, and one of only 14 surgeons worldwide given early access to the Mosaic topography-guided cross-linking system
• Co-authored the 2024 Journal of Cataract and Refractive Surgery study of topography-guided cross-linking in which 60% of patients improved their best corrected vision
• Is the Director of Education at the Queensland Eye Institute and leads international research studies on keratoconus treatment

You can read more about Dr Cronin, or about the procedures themselves on the cross-linking and CAIRS pages.

Keratoconus Treatment Costs

If your health fund covers cross-linking (Medicare item number 42652), you can have your procedure performed while lightly sedated or asleep at the South Brisbane Day Hospital with NO GAP for the anaesthetist.

Cross-linking for progressive keratoconus attracts a Medicare rebate, and CAIRS is recognised by Medicare as a keratoplasty under item 42653, following a campaign Dr Cronin led. For patients without private health insurance, cross-linking can be performed in the outpatient procedure room at the Queensland Eye Institute, which makes the most of the Medicare Safety Net. The cross-linking cost guide explains the fees, rebates and what is included.

Choosing the Right Treatment

Not every treatment is appropriate for every eye. The right plan depends on how advanced the keratoconus is, whether it is still progressing, your vision in each eye and what you need your eyes to do. Dr Cronin will map your corneas, explain exactly where you stand, and set out which treatments will genuinely help, and in what order, at your consultation.