Keratoconus gradually thins and reshapes the cornea, and early changes are easy to miss without the right instruments. Here's how we detect it early, monitor it, and find the right treatment for you.
The cornea is normally a smooth, dome-shaped window at the front of the eye, and its regular curve is what allows light to focus clearly onto the retina. Keratoconus is a progressive condition where the cornea gradually thins and loses its structural strength, causing it to bulge outward into an irregular, cone-like shape.
As the cornea's shape becomes increasingly irregular, so does the astigmatism it produces, a type that's harder to correct fully with standard glasses. Vision becomes blurred, distorted and increasingly sensitive to light, and prescriptions can change noticeably from one visit to the next as the underlying corneal shape keeps shifting.
Keratoconus most often starts in the teens or early twenties, tends to progress fastest during this period, and often stabilises by a person's thirties or forties. Catching it as early as possible gives access to the widest range of effective treatment options.
Keratoconus develops gradually, and its earliest signs are easy to mistake for a routine change in prescription. Here's what to watch for.
Vision can appear smeared, ghosted or doubled, particularly around points of light, in a way glasses don't fully resolve.
Needing a new spectacle prescription more often than expected can reflect a cornea that's still actively changing shape.
Bright lights and sunlight can become increasingly uncomfortable, with pronounced glare or streaking around light sources.
Halos, streaking and reduced contrast can make headlights and streetlights particularly troublesome after dark.
Astigmatism that keeps increasing, rather than staying stable, is one of the more telling patterns we look for.
Chronic, vigorous eye rubbing is strongly associated with keratoconus and is worth mentioning at your assessment.
A prescription that keeps changing, especially in a teenager or young adult, has more than one possible explanation. It might reflect ordinary myopia progression, the early development of keratoconus, or in some cases, both happening together. Telling these apart matters, because the right monitoring and treatment approach is quite different for each.
This is exactly where our instrumentation makes a practical difference. Axial length measurement tracks whether the eye itself is elongating, the hallmark of myopia progression, while corneal topography and Pentacam imaging track whether the cornea's shape is changing independently. Looking at both together gives a genuinely clearer picture than either measurement alone, and lets us pick up keratoconus developing alongside myopia rather than being masked by it.
Because early keratoconus produces no pain and only subtle visual change, it's easy to miss on a standard eye test that doesn't include corneal imaging. Regular comprehensive assessment, particularly for anyone with a family history or a rapidly changing prescription, is what catches it while treatment options are still at their widest.
The cornea gets its strength and shape from collagen fibres arranged in a precise, layered pattern. In keratoconus, these fibres weaken and lose some of their normal cross-linked structure, making the cornea less able to resist the eye's internal pressure. Over time, the weakened area thins and bulges outward, most commonly slightly below and to the side of the corneal centre.
What makes keratoconus challenging to catch early is that the earliest structural changes often begin on the back, or posterior, surface of the cornea, before they're visible on the front surface at all. Standard corneal topography, the equipment many optometry practices rely on, maps only the front surface. The Oculus Pentacam goes further, capturing the posterior corneal surface and a full corneal thickness map in a single scan, along with progression analysis that compares scans over time.
This matters in practice: a cornea can show early keratoconic changes on Pentacam years before it would show up on standard topography alone, which is often the difference between catching it while glasses or simple contact lenses still work well, and catching it once more involved treatment is needed.
Diagnosing keratoconus, and tracking it accurately over time, relies on imaging most standard eye tests simply don't include.
Maps the curvature of the front corneal surface, revealing the irregular, asymmetric pattern characteristic of keratoconus.
Maps both the front and back corneal surfaces and full corneal thickness, with progression analysis that compares scans over time to catch subtle change early.
Checks for physical signs associated with keratoconus, including thinning, faint stress lines and, in more advanced cases, scarring.
Tracks whether the eye is elongating, helping distinguish myopia progression from keratoconus, or identifying when both are present together.
Many optometry practices don't have a corneal topographer at all, let alone a Pentacam, and rely instead on a standard refraction and a general look at the eye. Without corneal imaging, subtle early keratoconus doesn't look like keratoconus; it just looks like a slightly stronger or more astigmatic prescription than last time. It's easy, and reasonable, for that to be treated as a routine refractive change rather than flagged as a progressive corneal condition.
That's often how keratoconus goes unnoticed for years: each visit produces a slightly different prescription, new glasses are given, and the underlying cause is never actually looked for, until the cornea has thinned and steepened enough that glasses can no longer correct vision clearly. At that point, the range of effective treatment options is considerably narrower than if it had been caught early.
We have both a corneal topographer and a Pentacam on-site, so this distinction isn't theoretical for us. The Pentacam adds posterior corneal surface mapping and progression analysis on top of standard topography, letting us tell early keratoconus apart from a routine refractive change well before it would be obvious any other way.
Glasses can work well in very early, mild keratoconus, but as the cornea's shape becomes more irregular, they generally stop providing clear enough vision on their own. Most people are fitted with a rigid lens of some kind, and following your assessment, we'll discuss which option is the most suitable for you.
Effective only while the cornea's irregularity is still mild. As astigmatism becomes more irregular, glasses increasingly can't correct it fully, and a rigid lens becomes the more effective option.
Now the most popular choice for keratoconus for many of our patients. These larger lenses vault over the entire irregular cornea and rest on the white of the eye, often giving excellent comfort and vision. Learn more about scleral lenses.
A rigid centre for sharp, stable vision surrounded by a softer skirt for comfort, combining benefits of both lens types. Learn more about SynergEyes hybrid lenses.
A smaller, firm lens that sits directly on the cornea, creating a smooth optical surface over the irregular shape beneath. A well-established, effective option for many people. Learn more about RGP lenses.
Alongside vision correction, monitoring whether keratoconus is progressing is central to deciding if and when further treatment is needed.
Corneal topography, Pentacam imaging and axial length measurement together establish a detailed baseline to track future change against.
Based on your corneal shape and lifestyle, we discuss and fit the most suitable option, whether that's glasses, scleral, hybrid or RGP lenses.
Repeat Pentacam scans are compared directly against your baseline to determine whether the cornea is stable or actively progressing.
Where progression is confirmed, we refer to a corneal specialist or ophthalmologist to discuss CXL, which aims to halt further thinning and bulging while it's still early.
For more advanced disease, options such as intrastromal corneal ring segments or a corneal transplant may be discussed with your specialist, aiming to improve corneal shape or replace significantly scarred tissue.
Whether managed with lenses alone or alongside surgical treatment, we continue monitoring your corneal health long term, working with any treating specialist.
Keratoconus is exactly the kind of condition our instrumentation was built for. Where many practices don't have a corneal topographer, let alone a Pentacam, we have both on-site as part of a standard comprehensive assessment, not as an optional extra. Between corneal mapping, axial length measurement and progression analysis, we can pick up early keratoconic change, distinguish it from myopia progression, and know with confidence when a cornea is genuinely getting worse rather than simply varying between visits.
We fit the full range of specialty lenses, scleral, SynergEyes hybrid and RGP, and talk you through the trade-offs of each for your specific cornea and lifestyle rather than defaulting to one option. Where progression is confirmed or vision needs are beyond what lenses can offer, we coordinate directly with trusted corneal specialists for cross-linking or further surgical care.
Our Kew East practice is easily accessible from across Melbourne's inner east, including Hawthorn, Camberwell, Balwyn and Box Hill.
A prescription that keeps changing deserves a closer look. Our corneal mapping and progression monitoring can tell us whether it's myopia, keratoconus, or both, and point you towards the right treatment sooner rather than later.