Keratoconus
When cornea progressively thins and takes the shape of a cone, eyesight is blurred and distorted. Discover the laser and implants solutions to treat keratoconus.
What is keratoconus?
Keratoconus is an evolutive eye condition whereby your cornea thins and gradually bulges outward into a cone shape. This can cause blurry, distorted vision. The estimated prevalence of keratoconus in the general population is from 50 to 265 cases per 100 000. This variation is due to different diagnostic criteria, different genetic predisposition and different exposure to cofactors.
What does a keratoconus patient see?
Patients with keratoconus experience distorted, blurred or double vision, increased sensitivity to bright light and glare (problems with night driving). They need to change their glasses frequently. Keratoconus can affect one or both eyes.
What are the keratoconus causes?
Normally, the cornea has a dome shape. Sometimes, the structure made of tiny fibers of protein isn’t strong enough to hold its round shape, and it bulges outward, like a cone. This is called keratoconus. No one knows what causes keratoconus, although genetic and environmental factors are thought to be involved.
Some factors can increase the chances of developing keratoconus:
- Having a family history of keratoconus
- Rubbing eyes vigorously (eye friction would be a key element in the pathogenesis of keratoconus)
- Having certain conditions such as retinitis pigmentosa, Down syndrome, hay fever, asthma
How is keratoconus diagnosed?
To make a diagnosis of keratoconus, the doctor must measure the curvature of the cornea. Several different tests can be performed to make the diagnosis. The test that is used most often is called topography. Topography measures the curvature of the surface of the eye and creates a colored “map” of the cornea.
Keratoconus causes very distinctive changes in the appearance of these maps, which allows the doctor to make the diagnosis. During the examination, an irregular astigmatism and a loss in vision with no correction possible are found. Usually, both eyes are affected, but not necessarily simultaneously and not necessarily with the same degree.
How does keratoconus evolve?
Asymptomatic for a long time, keratoconus is usually detected in the teenage years or 20s, but it can also start in childhood. In some cases, keratoconus is diagnosed at a later age, but usually only when it is mild. The changes in the shape of the cornea occur over several years, but at a more rapid rate in younger patients. The change evolves according to an irregular trend, is unpredictable and it can end at any time, or it can continue for several years. It usually stops around 40.
What are the complications of keratoconus?
The fast and unpredictable evolution of visual acuity explains why patients with keratoconus have to change their prescription glasses or lenses. Wearing lenses or rubbing the eyes may cause corneal ulcerations and perforations. In case of acute keratoconus (less than 3%), the inner membrane of the cornea (the Descemet’s membrane) may perforate, causing a huge oedema and a drastic decrease in visual acuity.
The complications of keratoconus are extremely rare and are easily preventable with the proper interventions at the correct time.
How is keratoconus treated?
There are several methods for treating keratoconus, depending on how severe the condition is. In the early stages of the disease, vision can be corrected with normal eyeglasses or soft contact lenses. As keratoconus gets worse, vision may no longer be correctable with eyeglasses because of the amount of irregular astigmatism, and so the patient may need to be fit with a special type of hard contact lens.
For some patients, the disease may advance to a stage at which they do not have acceptable vision even with glasses or contact lenses. At this point, the doctor may recommend a cornea transplant, which is a surgical procedure to replace the cornea with a cornea from a donor. Two additional treatments for keratoconus are implantable ring segments and corneal crosslinking: - Implantable ring segments are small devices that are inserted into the cornea to improve vision or make it easier to fit a patient with contact lenses.
In this procedure, which is performed under local anaesthesia (the patient’s eye is numbed with drops), the doctor creates channels in the cornea and inserts the rings into these channels. The rings help to flatten the cornea and partially correct the cone shape caused by the keratoconus.
Corneal crosslinking (CXL) uses ultraviolet light treatment that may slow or stop the keratoconus from getting worse. In this procedure, the patient also receives local anesthesia. Drops of a drug containing riboflavin (vitamin B2) are put into the eye for up to 30 minutes. The eye is then exposed to an ultraviolet light for up to 30 minutes. The corneal crosslinking procedure is designed to strengthen the bonds between the cornea’s collagen fibers and surrounding proteins, which can help keep the cornea from steepening.
Not all patients with keratoconus are candidates for these treatments. Your doctor can help to decide which, if any, of these treatments may help you.
Cross-linking procedure at the Bellecour Vision Clinic
On the day of your procedure, you will spend an hour in the clinic. On arrival, you will receive a pre-medication and put on a sterile outfit. During your procedure It takes place in a lying position on a stryker ophthalmology chair. After following strict aseptic regulations, we perform topical anaesthesia with a few drops of eye drops. The procedure lasts around 30 minutes.
It consists of two stages:
- Putting drops of solution into the eye (vitamin B2)
- Application of UVA light to the eye
After your procedure It is necessary to be met by an accompanying person on leaving as it is advisable to rest with eyes closed during the first hours following treatment. You will start an antibiotic and anti-inflammatory treatment on the evening of the procedure, as indicated on the prescription. During the week following the operation, it is essential not to expose your eyes to hazardous situations (dust in the air, for example).
You must avoid all situations that may expose your eyes to microorganisms (e.g. bacteria, viruses, fungi). Strict hygiene rules should be observed, including washing of hands before the installation of eye drops. You should avoid shocks to your eyes and even restrain from rubbing your eyes. Doctor Donate will provide your post-operative follow-up. It will consist of a check-up visit during the days following the intervention.