Quick answer. Keratoconus is a condition where the normally round cornea thins and bulges into a cone shape, distorting vision. It often starts in the teens or twenties and tends to worsen over time, so early diagnosis and treatment can protect your sight.
Keratoconus is a progressive eye condition in which the cornea – the clear front window of the eye – gradually thins and bulges outward into an irregular cone shape. This warps the way light enters the eye, causing blurred and distorted vision that ordinary glasses often struggle to correct. It commonly appears during the teenage years or early adulthood and may progress slowly over a decade or more.
In Singapore, where short-sightedness and allergic eye conditions are very common, keratoconus is something eye specialists see regularly. The good news is that modern treatments such as corneal cross-linking can halt its progression when it is caught early, while specialised contact lenses and, in advanced cases, corneal transplant can restore useful vision. Avoiding vigorous eye rubbing is one of the simplest and most important things you can do.
At a glance
| Stage | What you may notice | Typical approach |
|---|---|---|
| Early / mild | Slightly blurred vision, frequent prescription changes | Glasses or soft contact lenses; monitor closely |
| Progressing | Worsening distortion, glare, ghosting of images | Corneal cross-linking to stabilise the cornea |
| Moderate | Glasses no longer sharp, increasing irregularity | Rigid gas-permeable or scleral contact lenses |
| Advanced | Significant thinning, scarring, poor vision | Corneal transplant considered if lenses fail |
| Any stage | Itchy eyes with a habit of rubbing | Treat allergy and stop eye rubbing to limit progression |
What is keratoconus?
Keratoconus is a disorder of the cornea, the dome-shaped clear layer at the front of the eye that focuses light. In keratoconus the cornea progressively weakens and thins, so the normal pressure inside the eye pushes it outward into a cone shape rather than a smooth dome. This irregular surface scatters light and creates blurred, distorted vision that is difficult to correct fully with standard glasses.
It usually begins around puberty or in the late teens and tends to advance through the twenties before stabilising in the thirties or forties. It typically affects both eyes, though often one is worse than the other. Because Singapore has high rates of myopia and allergic conjunctivitis, both of which are linked to eye rubbing, eye specialists here are very familiar with the condition.
Symptoms & signs
Early keratoconus can be subtle and is sometimes mistaken for ordinary short-sightedness or astigmatism. Common features include:
- Blurred or distorted vision that is not fully corrected by glasses
- Frequent changes in your spectacle or contact lens prescription
- Increasing astigmatism (vision that is smeared or stretched)
- Glare and halos around lights, especially when driving at night
- Ghosting or doubling of images in one eye
- Sensitivity to bright light and eye strain
- A feeling that vision is steadily getting harder to correct over months or years
If you find yourself needing new glasses unusually often or your optician keeps changing your astigmatism, it is worth asking about keratoconus.
Causes & risk factors
The exact cause of keratoconus is not fully understood, but it involves a weakening of the cornea’s structural fibres. Several factors raise the risk:
- Eye rubbing – vigorous, repeated rubbing is strongly linked to onset and progression and is the most important modifiable risk
- Allergic eye conditions and eczema – itchy eyes encourage rubbing, which is very relevant in Singapore’s allergy-prone climate
- Family history – keratoconus can run in families
- Age – it usually starts in the teens or twenties
- Certain conditions – such as Down syndrome and some connective-tissue disorders
Because eye rubbing is such a major factor, treating any underlying allergy and breaking the rubbing habit is a key part of protecting your sight.
How it's diagnosed
An eye specialist (ophthalmologist) diagnoses keratoconus through a detailed eye examination. Tests typically include:
- Corneal topography or tomography – a scan that maps the shape and curvature of the cornea and is the key test for detecting and tracking keratoconus
- Pachymetry – a measurement of corneal thickness
- Slit-lamp examination – a microscope examination of the cornea to look for thinning and characteristic signs
- Refraction – measuring how light focuses, which often shows high or irregular astigmatism
Repeat scans over time help the specialist judge whether the condition is stable or progressing, which guides treatment decisions.
Treatment options
Treatment depends on the stage and whether the condition is progressing. The aim is to stabilise the cornea and provide the clearest possible vision:
- Glasses and soft contact lenses – adequate in early, mild cases
- Corneal cross-linking – a procedure using vitamin B2 (riboflavin) drops and ultraviolet light to strengthen the corneal fibres and halt progression; most effective when done early
- Rigid gas-permeable or scleral contact lenses – specialised lenses that create a smooth optical surface over the irregular cornea, often giving much sharper vision than glasses
- Intracorneal ring segments – small implants that can help reshape the cornea in selected cases
- Corneal transplant – reserved for advanced disease with significant scarring or thinning when lenses no longer help
Crucially, treating allergy and stopping eye rubbing supports every other treatment. Your specialist will tailor the plan to your eyes; this guide does not quote prices, as costs vary by procedure and provider.
When to see a doctor & which specialist
See an eye specialist if your vision is becoming blurred or distorted, if your glasses prescription keeps changing, or if you have been told you have high or worsening astigmatism. Early assessment matters because cross-linking works best before the cornea has changed too much. Children and teenagers with itchy eyes who rub frequently should be checked, as their disease can progress quickly.
While keratoconus is not usually an emergency, you should seek prompt eye care if you develop sudden severe eye pain, a sudden marked drop in vision, or a very red, watery eye, as advanced keratoconus can rarely cause sudden corneal swelling (called hydrops) that needs review. For any sudden loss of vision, do not wait – attend an eye emergency service.
The right specialist for keratoconus is an ophthalmologist (eye specialist), ideally one with a corneal interest. You can find one through our directory of eye specialists in Singapore.
Related guides
- Best Eye Clinics in Singapore — our editorial shortlist
- eye clinics directory
- Ptosis (droopy eyelid)
- Mitral valve prolapse
- Sarcoidosis
- Pulmonary fibrosis
- Essential tremor
Sources
- NHS – Keratoconus and corneal conditions
- Mayo Clinic – Keratoconus
- SingHealth – Eye conditions
- HealthHub Singapore – Eye health
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