Struggling with double vision and sudden sensitivity to bright lights? While it's normal to experience blurred vision every now and then, if your symptoms persist it's possible you could have an eye condition. Keratoconus is an eye disorder in which the cornea progressively thins causing a cone-like bulge to develop, and problems with vision often slowly occur.
Dr Roger Henderson looks at the most common causes and treatment options for keratoconus, plus when to seek medical attention:
What is keratoconus?
Keratoconus (pronounced keh-rah-toe-cone-us) is a condition affecting the front clear window of the eye, known as the cornea. This should normally be a smooth, round and even shape but in keratoconus it becomes thinner and bulges outwards in the shape of a cone.
Keratoconus progressively worsens over time but the speed at which this occurs and its severity varies from person to person. The condition causes blurred and altered vision, and one or both eyes may be affected. In general, the later in life it starts, the more slowly it progresses.
What causes keratoconus?
The exact cause of keratoconus is unclear, but about 10 per cent of people with it have a parent who has the condition. It is more common in people who have asthma or eczema, and it may also be more common in people who rub their eyes very frequently and vigorously.
It affects about 1 in 450 people and is more common in non-Caucasians, typically being diagnosed between the ages of 12 and 25.
Keratoconus can affect your vision in a number of ways:
Because the front of the eye becomes cone-shaped rather than smooth and round, the focusing of the eye is affected. The vision becomes blurred and there is short-sightedness and astigmatism, where light passing through the eye forms a distorted image at the back of the eye.
• Sensitivity to bright lights
There may also be increased sensitivity to glare and bright light, which can cause difficulty when driving at night.
• Cloudy vision
The vision may suddenly worsen or become hazy or cloudy, and you may notice the need for frequent changes in eyeglass prescriptions.
• Severe blurring of vision
Some people with severe keratoconus can experience scarring of the front of the eye which causes severe blurring of their vision.
• Corneal hydrops
A small number of people with it suddenly lose their sight in the effected eye which is painful and frightening, and is due to fluid in the eye entering the very thin cornea. This is called hydrops, and fortunately for most people affected by it, it will gradually settle over time although some residual scarring may be left.
When should I see a doctor?
If you develop worsening vision, with or without blurring then make an appointment to see an optician who can check if your cornea is the correct shape.
They will examine your eyes with a slit-lamp (a type of microscope) and may do a photograph of the cornea called a corneal topography scan. If keratoconus is present, they may refer you to an eye specialist for further assessment and treatment.
Most people with keratoconus do not have a family history of the condition and so screening for it is not routine.
There is currently no cure for keratoconus, and it cannot be treated with tablets or eye drops. However the following can help:
🔷 Contact lenses
In the early stages of the condition, reading glasses may be all that is needed to deal with any eyesight difficulties, but contact lenses may then be needed after some time to help improve the vision. These are usually of the hard (rigid gas permeable) type of lens but some people may need to use the soft (hydrogel) type as they find them more comfortable. Special contact lenses can also be made specifically for keratoconus- shaped eyes.
🔷 Corneal collagen cross-linking
In younger patients particularly, a new treatment called Corneal collagen cross-linking (CXL) can now help stop keratoconus from worsening but is only suitable for some people with progressive keratoconus. This treatment uses a combination of ultraviolet light and vitamin B2 drops to help strengthen and stiffen the cornea, and is effective in over 90 per cent of patients. Given as a single 30-minute treatment as an outpatient procedure, it is also sometimes known as a C3R procedure and appears to be very well tolerated although in a small number of people there is the chance their vision may worsen rather than improve.
Can you go blind if you have keratoconus? Fortunately, keratoconus does not cause complete blindness and most people with it do not require surgery. Although glasses or contact lenses do not alter the progression of the disease, most people are able to continue with their lives almost as normal when using them.
Last updated: 18-03-2021
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