Keratoconus happens when the cornea, the clear 'window' at the front of the eye, thins and becomes distorted in shape. Normally shaped like a dome, keratoconus causes the cornea to become cone-shaped, affecting vision.
Wearing prescription glasses or contact lenses can correct your eyesight, and for many people, the condition stabilises in their 30s.
Sometimes, it can progress and need other treatment, but it doesn't lead to blindness.
Keratoconus typically first develops in people in their teens and early 20s. It can progress over the years and usually affects both eyes, though it can develop in just one. When it affects both eyes, one is often worse affected.
The symptoms of keratoconus include:
- Irregular astigmatism – as the cornea changes shape, creating blurry or distorted vision.
- Nearsightedness (myopia) – this means objects close to you look clear, but you have difficulty seeing things further away.
- Light sensitivity – you may find bright lights uncomfortable or experience glare around lights, especially in the dark.
As the shape of the cornea becomes progressively more distorted, your vision may get worse and cause vision problems and other symptoms, including:
- More severe blurred and distorted vision
- Worsening astigmatism and myopia
- Keratoconus eye pain
- Being unable to wear contact lenses due to the shape of the cornea
- Scarring of the cornea with loss of transparency further hindering the ability to see clearly
Glasses may no longer be able to correct your vision sufficiently, meaning you might have to wear contact lenses, usually the rigid gas-permeable kind.
Sometimes, the shape of the cornea alters so much it can require specialist types of contact lenses or other treatments.
The cornea can thin so much that it results in scarring, creating cloudiness, further hampering the eye's ability to focus.
In the very early stages, keratoconus may not affect your vision enough to need treatment. You're likely to have routine eye exams or checkups to keep an eye on the condition and how it's progressing.
Can keratoconus be cured?
There's no cure for keratoconus, which is a lifelong condition. Rather than reversing keratoconus, treatments aim to manage it and slow its progression, while also correcting your vision.
What causes keratoconus?
As for the causes of keratoconus, genetics and environmental factors are both thought to play a role.
This doesn't mean keratoconus is directly inherited, but for around 10-14% of cases, there will be a family history of the condition.
Other conditions are associated with a higher risk of keratoconus, including retinitis pigmentosa, and genetic conditions including Down's syndrome, Ehlers-Danos syndrome (EDS), and Osteogenesis Imperfecta (OS).
Having allergies and excessive eye rubbing are considered risk factors that increase the chance of keratoconus, as inflammation and rubbing can break down the corneal tissue.
When to get medical advice
Living with keratoconus
If you have keratoconus, you'll have regular check-ups to monitor changes and ensure your prescription is up to date.
Keratoconus can get worse over time, though for many people, it stabilises when they reach their 30s.
Excessive eye rubbing can make keratoconus worse, exacerbating the thinning of the cornea. If you have allergies, it's a good idea to have treatment to get them under control.
Frequently asked questions
Medically reviewed by: The Royal College of Ophthalmologists on 18/10/2022
Edited by: Nick Astbury FRCS FRCOphth FRCP
Clinical Associate Professor
The Royal College of Ophthalmologists champions excellence in the practice of ophthalmology and is the only professional membership body for medically qualified ophthalmologists. The RCOphth is unable to offer direct advice to patients. If you’re concerned about the health of your eyes, you should seek medical advice from your GP, optometrist or ophthalmologist.