What is keratoconus?
Keratoconus is an eye condition which causes the thinning and weakening of the cornea, resulting in it changing shape. A cone-shaped bulge develops in the cornea, which is typically round and dome-shaped.
The latest research shows keratoconus is much more common than previously thought although many cases are mild. It normally develops in teenagers or those in their twenties and often gradually gets worse over time. The speed of change and severity of the stages of keratoconus varies between those affected.
Keratoconus symptoms include;
- Worsening of vision causing frequent changes to prescription
- Blurring or clouding of vision
- Sensitivity and glare from bright lights
Keratoconus signs can change as the condition worsens over time. The change in shape and thinning of the cornea impairs the ability of the eye to focus properly. In advanced cases, some patients may develop scarring in the cornea. All of these corneal changes can cause poor vision.
The exact cause of keratoconus remains unknown, although it’s believed that both genetic and environmental factors can have an impact. It is estimated that around 1 in 10 people with the eye condition keratoconus will have a 1st degree family member who is also affected. However, keratoconus is not typically considered to be an inherited disease.
There are also a number of factors that may increase your chances of developing the keratoconus eye disease. It occurs more commonly in individuals with certain allergic conditions, including asthma and eczema, and is more likely to develop in non-caucasian ethnicity groups.
If you suspect you may have keratoconus, you can visit your ophthalmologist who will conduct an eye exam, as well as assessing your individual and family medical history. They may also conduct various tests, including eye refraction, a slit-lamp examination and computerised corneal mapping to give you a keratoconus diagnosis.
Urgent referral is not required, as the various stages of keratoconus can take years to develop. As a result, your ophthalmologist may invite you back for multiple assessments in the years following your initial consultation. These visits will include vision and refraction tests, as well as corneal scans to monitor your condition. Your ophthalmologist will be able to advise if they believe you require further treatment.
During the early stages of keratoconus, the condition can usually be treated with contact lenses or glasses. RGP (rigid gas permeable) keratoconus contact lenses may be required to correct vision as the cornea becomes thinner and more irregular. In rare cases, a corneal transplant may be required, but there are now multiple keratoconus treatment options available that reduce the need for keratoconus surgery.
Corneal cross-linking (also known as CXL and C3R) is a treatment that can prevent keratoconus from worsening. It uses ultraviolet light and vitamin B2 (riboflavin) drops to stiffen (and strengthen) the cornea to prevent further steepening and thinning in the future. It is effective in over 90% of patients. We offers the latest ‘accelerated CXL’ treatments which take approximately 20 minutes to perform. In general, CXL does not improve vision; the aim is to stop your vision getting worse.
Usually by your late 30s, the cornea naturally stiffens and CXL is generally not required. Below this age, the cornea is more flexible and disease progression (and worsening vision) are more likely to occur.
Laser refractive corneal cross-linking
Laser treatments can be combined with CXL to flatten and smooth the surface of the cornea. Laser refractive CXL may be suitable for you if your vision has already deteriorated. The aim of the treatment is to improve the focusing of the cornea, with sharper vision in either spectacles or soft contact lenses. The laser treatment typically takes 30 seconds at the start of the cross-linking treatment as a single, combined procedure.
Intracorneal stromal ring implants (ICRS) are placed in a laser-formed channel within the cornea. Depending on the severity of the keratoconus, one or two rings are implanted with the aim of improving the overall shape of the cornea (reducing astigmatism and irregularity). Corneal ring implants can be combined with, or precede, corneal cross-linking.
Phakic intra-ocular lens implant
Implantable contact lenses may be suitable in some keratoconus patients to improve your vision without relying on spectacles or soft contact lenses. Lens implants are generally not effective in correcting vision if you use rigid gas permeable contact lenses (RGP). Depending on the prescription, you may benefit from lens implants in one or both eyes to balance the vision in your two eyes.