Keratoconus

The cornea is the clear, dome-shaped window at the front of your eye. It helps focus light so you can see clearly.

In keratoconus, the cornea slowly becomes thinner and weaker, and bulges forward into a cone shape [1][2]. This bends light the wrong way, so vision becomes blurred and distorted.

• It usually affects both eyes, but often one more than the other.
• It usually starts in the teens or early twenties, and often gets worse until about the age of 30 to 40 [1][3].
• It is not infectious and does not cause total blindness, but it can seriously affect vision if not treated.

Your risk is higher if you [1][2][4]:

• rub your eyes often or hard. This is one of the most important things you can change.
• have allergies, such as itchy eyes, hay fever or asthma
• have eczema (atopic dermatitis)
• have a family member with keratoconus
• are a teenager or young adult
• have certain conditions such as Down syndrome

Stop rubbing your eyes. If your eyes are itchy, use a cold compress or anti-allergy eye drops from your doctor or pharmacist instead [4].

Changes are usually slow, over months to years [1][2]:

• Blurred or distorted vision, near and far
• Glasses prescription changing often, especially more astigmatism
• Seeing double or "ghost" images with one eye
• Glare, halos around lights, and difficulty driving at night
• Sensitivity to light

At the clinic, the eye doctor will check your vision and glasses, look at the cornea with a microscope (slit lamp), and do a corneal scan (topography or tomography). This scan maps the shape and thickness of the cornea and can pick up keratoconus early [3].

Teenagers with allergies or eczema whose vision keeps changing should have their eyes checked.

Rarely, the stretched cornea can suddenly split on the inside, letting fluid flood in. This is called acute hydrops. The eye suddenly becomes cloudy, painful, red and watery, and vision drops quickly [1][2].

A red, painful eye while wearing contact lenses also needs checking the same day, as it can be an infection.

Treatment depends on how bad it is and whether it is getting worse [1][2][3]:

1. Glasses or soft contact lenses: help in mild cases.
2. Rigid contact lenses: as the cone grows, rigid gas permeable (RGP) or larger scleral lenses give a smooth new front surface and usually give much clearer vision than glasses.
3. Corneal cross-linking (CXL): riboflavin (vitamin B2) drops and ultraviolet light are used to strengthen the cornea. It aims to stop keratoconus getting worse. It does not reverse it, so it is best done early, while vision is still good.
4. Corneal implants (ring segments): small rings placed in the cornea can flatten the cone in some people.
5. Corneal transplant: for advanced cases, when lenses no longer give good vision or the cornea is badly scarred. The damaged cornea is replaced with a donor cornea.

You will need regular check-ups and scans so your doctor can tell if it is getting worse.

Where to get help in Brunei

If your vision keeps changing, or you have been told you might have keratoconus, you can walk in to any Community Eye Clinic at your health centre. No referral is needed.