Keratoconus: What It Is, Causes & Treatment

What is keratoconus?

Keratoconus is a condition in which the central part of the cornea gradually becomes thinner, so that its normal spherical or oval shape is replaced by a cone shape.

Page contents

1. What is keratoconus?
2. What causes keratoconus?
3. What are the risk factors?
4. Pathophysiological findings
5. Primary prevention
6. How is keratoconus diagnosed?
7. What is the right treatment?
8. How much does treatment cost? Are prices affordable?
9. Symptoms of keratoconus
10. How someone with keratoconus sees
11. Stages of keratoconus
12. Keratoconus in teenagers: why early diagnosis is crucial
13. Eye rubbing and keratoconus
14. The tests you need
15. Corneal cross-linking: how progression is stopped
16. Contact lenses for keratoconus
17. Other surgical options
18. Acute keratoconus: a rare complication
19. Keratoconus and laser eye surgery for short-sightedness
20. Everyday life with keratoconus
21. Astigmatism or keratoconus? How to tell them apart
22. How often you need a check-up
23. Keratoconus and pregnancy
24. Keratoconus, school, work and driving
25. Questions worth asking your ophthalmologist
26. What to expect before and after cross-linking
27. Keratoconus and cataract in the future
28. Myths about keratoconus
29. Keratoconus and sport
30. Frequently Asked Questions about Keratoconus

What causes keratoconus?

The exact cause is unknown. There is evidence that hereditary factors play an important role, but the exact way it is passed on has not been found. Even so, it is more common in some families than in others. Internationally, keratoconus is thought to affect 1 in 2,000 people, although in Greece it is believed to be considerably more common, and in Cyprus even more so.

What are the risk factors?

There is a strong link between keratoconus and itching, so we see patients who rub their eyes constantly, even during sleep. We do not know whether this is the result of an immune reaction or something that contributes to the progression of the condition.

Pathophysiological findings

Histopathological studies show that the cornea of patients with keratoconus has breaks in Bowman’s membrane, disorganisation of the collagen fibres, scarring and thinning.

Primary prevention

No specific strategy has been proven effective. Some believe that eye rubbing should be avoided.

How is keratoconus diagnosed?

Keratoconus is diagnosed mainly with corneal topography, and also by examination at the slit lamp (though not in the early stages). Besides topography, pachymetry also plays a major role in diagnosis, as its epithelial maps provide very important information. Together with our extensive experience, these help us diagnose even subclinical cases of keratoconus.

What is the right treatment?

In the early stages, and if the condition is not progressing, treatment is with glasses or soft contact lenses. If it does progress, glasses may no longer give the patient satisfactory vision, and keratoconus lenses, RGP (Rigid Gas Permeable) lenses, are then needed.

If the condition is progressing, it can be stabilised with corneal collagen cross-linking (CXL). With the most advanced cross-linking system available, the Avedro KXL II, we can offer the best possible results.

Collagen cross-linking can be done on its own or combined with topography-guided laser, which smooths the surface of the cone and improves vision. This procedure, known as the “Athens Protocol”, is now internationally accepted as one of the most effective ways of treating keratoconus, and it has significantly reduced the need for a corneal transplant. With experience in this technique, Dr. Skouteris can tell you what stage your condition is at and, based on that, guide you on the treatment path that is right for you.

How much does treatment cost? Are prices affordable?

The cost of treatment depends on the individual case and how advanced it is. For more details about prices, please contact the ophthalmologist.

Symptoms of keratoconus

Keratoconus usually starts in the teenage years or early adulthood, and in the early stages it looks like ordinary astigmatism. That is why it often goes unnoticed. The symptoms that should make us think of keratoconus are:

• blurred or distorted vision that is not fully corrected with glasses
• frequent changes in the glasses prescription within a few months
• increasing astigmatism, often with a change in axis
• ghosting or “double” outlines, even when looking with one eye
• strong glare from car headlights at night, with “streaks” and haloes
• sensitivity to light and eye strain
• frequent eye rubbing because of itching or allergy

The condition almost always affects both eyes, but one is usually more advanced. So the patient may see well with the “good” eye and not notice the problem in the other.

How someone with keratoconus sees

Because the cornea becomes thinner and bulges like a cone, its surface loses its smooth curvature. Light is scattered irregularly and the image reaching the retina is blurred and distorted. Letters seem to have shadows, straight lines look wavy, and light sources at night spread out into stars or lines. This irregular astigmatism is why glasses only help in the early stages.

Stages of keratoconus

• Early stage: a mild change on topography, good vision with glasses. At this stage the diagnosis is usually made only with specialised tests.
• Moderate stage: the astigmatism increases, glasses are no longer enough and special contact lenses are needed.
• Advanced stage: marked thinning and bulging of the cornea, possibly with scarring, which significantly affect vision.

The aim of modern treatment is to diagnose keratoconus at the early stage and stop it progressing before vision is permanently affected.

Keratoconus in teenagers: why early diagnosis is crucial

In young people, keratoconus usually progresses faster than in adults. A teenager who changes glasses often, especially one with allergies, atopic dermatitis or who rubs their eyes a lot, should have corneal topography. You can read more about the signs at this age in our article on keratoconus in teenagers.

Eye rubbing and keratoconus

Hard and frequent eye rubbing is one of the most important factors that make keratoconus worse. The mechanical pressure further weakens an already vulnerable cornea. That is why treating allergies with suitable eye drops, managing dry eye and consciously avoiding rubbing are a key part of treatment, especially in children and teenagers.

The tests you need

To diagnose and monitor keratoconus we use:

• Corneal topography and tomography: these map the front and back surfaces and the thickness of the whole cornea. They are the most sensitive tests for early diagnosis.
• Pachymetry: measures the thickness of the cornea, information that is essential for choosing treatment.
• Refraction and visual acuity: to record vision with and without correction.
• Slit lamp examination: to look for characteristic signs such as thinning, stress lines or scarring.

Comparing successive measurements every few months shows whether the keratoconus is stable or progressing. This information determines whether cross-linking is needed.

Corneal cross-linking: how progression is stopped

Corneal collagen cross-linking is currently the treatment that can stop keratoconus from progressing. During the procedure, riboflavin (vitamin B2) drops are applied, and the cornea is then exposed to controlled ultraviolet light. The combination creates new bonds between the collagen fibres and makes the cornea stronger.

The procedure is done under local anaesthetic drops and takes about an hour. In the standard technique the epithelium is removed, so for the first few days there is discomfort, watering and sensitivity to light, and a bandage contact lens is placed until it heals. Vision stabilises within a few weeks to months. The aim of cross-linking is not to get rid of glasses but to protect the cornea from getting worse. That is why it is most valuable when done early.

Contact lenses for keratoconus

When glasses are not enough, special contact lenses often give excellent vision:

• Rigid gas permeable lenses: these create a new, smooth optical surface in front of the irregular cornea.
• Scleral lenses: larger lenses that rest on the white of the eye and “vault” over the cornea, with a layer of fluid underneath. They are often more comfortable in advanced keratoconus.
• Hybrid lenses: these combine a rigid centre with a soft outer edge.

Fitting requires experience and patience, and choosing the right lens makes a huge difference to everyday comfort.

Other surgical options

• Intracorneal ring segments: small semicircular segments placed inside the cornea that make it more regular, improving vision in selected patients.
• Topography-guided laser combined with cross-linking: in some cases this smooths the corneal surface while stabilising it at the same time.
• Corneal transplant: needed in a small proportion of patients with very advanced keratoconus or scarring. Today, techniques that replace only the front layers of the cornea are preferred, as they have fewer complications.

Acute keratoconus: a rare complication

In advanced keratoconus, the inner membrane of the cornea can occasionally break. Fluid then enters the cornea and the eye suddenly becomes cloudy, with pain, redness and strong sensitivity to light. This condition, called acute hydrops, needs urgent assessment by an ophthalmologist. It usually settles gradually over a few weeks with treatment, but it can leave a scar.

Keratoconus and laser eye surgery for short-sightedness

Keratoconus, even at an early stage, is a contraindication for standard laser procedures for myopia, such as LASIK, because they thin the cornea and can speed up the condition. This is one of the main reasons why, before any laser eye surgery, we carry out detailed corneal topography and tomography.

Everyday life with keratoconus

• Avoid rubbing your eyes and treat any allergies.
• Attend your scheduled check-ups, even if your vision seems stable.
• Be meticulous about contact lens hygiene.
• Wear sunglasses with UV protection, as many patients are sensitive to light.
• Encourage your siblings and children to have a check-up, as there is a family predisposition.

Dr. Vasileios Skouteris diagnoses and monitors patients with keratoconus at his clinic in Neo Psychiko, Athens. To book an appointment, call 210 677 0007.

Astigmatism or keratoconus? How to tell them apart

In the early stages, keratoconus looks very much like ordinary astigmatism. However, there are signs that set it apart:

• the astigmatism increases year after year, whereas simple astigmatism usually stays stable
• the axis of the astigmatism changes or is oblique
• vision does not become fully clear even with the right glasses
• there is a large difference between the two eyes
• topography shows asymmetric steepening, usually in the lower part of the cornea

The final answer always comes from corneal topography and tomography. That is why this test should not be skipped in any young person whose astigmatism is changing.

How often you need a check-up

How often you need check-ups depends on your age and how stable the condition is. In teenagers and young adults with a recent diagnosis, we usually perform topography every three to six months, so that any progression is picked up early. After cross-linking, there is a schedule of check-ups in the first year, followed by yearly monitoring. In adults over 30 to 35, when keratoconus tends to stabilise, check-ups become less frequent, but they do not stop.

Keratoconus and pregnancy

The hormonal changes of pregnancy can affect the structure of the cornea, and in some women keratoconus has been reported to worsen during this period. That is why we recommend a check-up before a planned pregnancy and monitoring after the birth. Cross-linking is usually postponed until after pregnancy and breastfeeding.

Keratoconus, school, work and driving

With the right correction, most people with keratoconus study, work and drive normally. At school it helps for the child to sit where they have a good view of the board, while for computer work regular breaks are needed, along with lubricating eye drops if there is dryness. For driving, especially at night, it is important that your vision is checked with the correction you actually use. If your contact lenses become uncomfortable after many hours, ask your ophthalmologist to reassess the fit.

Questions worth asking your ophthalmologist

• What stage is the keratoconus at in each eye?
• Are there signs of progression compared with previous measurements?
• Am I a suitable candidate for cross-linking, and when?
• Which type of contact lens would give me the best vision?
• How often should I have topography?
• Should my family members be checked too?

The answers to these questions form a clear monitoring plan, tailored to your own case.

What to expect before and after cross-linking

Before the procedure: a full assessment with topography, tomography and pachymetry is carried out to confirm that the cornea is thick enough. If you wear contact lenses, you will be asked to stop wearing them for a few days before the measurements, as they temporarily change the shape of the cornea. On the day of the procedure it is a good idea to have someone with you, as you will not be able to drive.

The first few days: it is normal to have a foreign body sensation, stinging, watering and sensitivity to light. The bandage contact lens and the prescribed eye drops help healing. Oral painkillers and sunglasses make the first few days more comfortable. Avoid rubbing your eyes, swimming and dust.

The following months: vision may fluctuate for a few weeks. The cornea continues to “stiffen” gradually for several months. Contact lenses can usually be worn again after a month, with a new fitting if needed. Success is judged by how stable the measurements are at later check-ups.

Keratoconus and cataract in the future

Patients with keratoconus can have cataract surgery as normal when they need it later in life. However, calculating the intraocular lens is more demanding, because the irregular cornea makes the measurements harder. That is why the surgery is planned with particular care, and in stable, mild keratoconus a toric intraocular lens may be chosen to reduce astigmatism.

Myths about keratoconus

• “Keratoconus always leads to a transplant.” With cross-linking and modern contact lenses, the vast majority of patients never need a transplant.
• “If I see well with glasses, I do not need monitoring.” Progression shows up on topography first and only later in vision. Monitoring is essential even when vision is good.
• “Rigid lenses make keratoconus worse.” Properly fitted lenses do not make the condition worse. A poor fit, however, can cause irritation, which is why regular checks are needed.

Keratoconus and sport

Most patients with keratoconus can play sport as normal. For contact sports and activities with a risk of a blow to the eye, protective glasses are recommended. When swimming, contact lenses should not be worn without a mask or swimming goggles, because of the risk of infection. After cross-linking, the return to sport is gradual, following your doctor’s instructions, usually within a few weeks.

One last practical point: if you have keratoconus and need to see another doctor or have any eye procedure, tell them about the diagnosis and bring your recent topography scans. Previous measurements are invaluable, because only by comparing them can we see whether the condition remains stable.

Frequently Asked Questions about Keratoconus

Medically reviewed by: Dr. Vasileios Skouteris MD, FEBO