Keratoconus is a disease of the cornea, which can gradually cause a significant visual impairment or even a loss of vision. This disease manifests as a gradual thinning with an increased curvature mostly of the lower half of the cornea. Gradually it causes impaired vision which mostly leads to an increase of minus dioptres and astigmatism. However, now patients with keratoconus have a chance to delay complicated corneal transplantation for many years or to avoid it altogether. Laser surgery, during which the eyes are fitted with so-called kerarings, is completely painless and takes only a few minutes.
Until very recently the only and very complicated solution to advanced keratoconus was a corneal transplant. After transplantation most patients were left with irregular high astigmatism, which could no longer be corrected by glasses or contact lenses.
However, modern medicine offers a treatment that stops the development of keratoconus and stabilizes the cornea. “At our clinic we have several options to treat keratoconus, without having to resort to a corneal transplant. In the initial stage, we advise the patient to wear appropriate corrective glasses or contact lenses and we monitor the cornea regularly. If keratoconus gets worse, we either choose an application of riboflavin and UV-A radiation, which is a method known as CCL or CxL, or the latest option—corneal rings implants—kerarings, which can be followed by CCL treatment, “explains MUDr. Věra Kalandrová, the senior consultant at the NeoVize Eye Clinic.
A keraring is a semicircular implant made of a special synthetic material (polymethylmethacrylate), which is tailor-made for each patient according to the parameters of their cornea. It is implanted into the cornea using a special channel technique. This results in the reduction of the corneal curvature and it also reshapes the unequal curvature of the upper and lower parts of the cornea. This also reduces dioptres and improves vision. A keraring can be implanted using special tools or a femtosecond laser.
As one of the few centers, the Brno NeoVize Clinic performs painless and very precise implantation of kerarings using the aforementioned femtosecond laser. The femtolaser initially creates “channels” in the cornea, into which the eye surgeon subsequently inserts one or two semicircular implants. This causes a flattening of the cornea and improves vision.
“By using the femtosecond laser there is no need for a complicated cutting of the cornea, which may be inaccurate and heals slowly. The femtolaser prepares the cornea for the implantation of a keraring exactly according to the parameters of the patient’s eye and the implantation is then much easier and more accurate,” says senior consultant Kalandrová when describing the advantages of using the laser ketarings implantation.
Implantations of kerarings using the femtosecond laser have been carried out with excellent results at Brno NeoVize already for the second year. Two NeoVize doctors have received certification for this method of treatment: senior consultant MUDr Věra Kalandrová.and MUDr Kristina Vodičková, Ph.D.
Keratoconus usually occurs between 10 to 20 years of age. It may develop very slowly, often taking 10–20 years. The eye defect is first corrected with glasses or with appropriate, often hard, contact lenses. Later, when the keratoconus is developed, it becomes difficult to use such corrective methods.
Other treatment options for keratoconus
Hard contact lenses
Hard contact lenses can, if properly applied and worn regularly, flatten the cornea slightly. However, the problem is that hard lenses put pressure on the cornea and on top of that the eye has difficulty breathing underneath. Therefore, some patients cannot tolerate these contact lenses in the long term.
New possibilities in the treatment of keratoconus are represented by Esclera contact lenses. “These are hard scleral lenses, which touch the white of the eye, but not the cornea. Between the cornea and the lens there is a space which we fill with a special solution. After some time this solution is spontaneously replaced with tears. In this way the lenses compensate for the irregular corneal surface and rays of light break regularly. It leads to a significant improvement of vision in patients. In addition, the eye can breathe better through such a lens,” says Mgr. Andrew Vlasák, the optometrist of NeoVize, when describing the innovation.
CCL (CxL) method
In indicated cases the strengthening of the cornea can be successfully achieved by the use of a riboflavin (vitamin B2) solution and subsequent ultraviolet light irradiation. “During a chemical reaction the riboflavin molecules produce connecting bridges between the collagen fibers of the corneal stroma, creating so called Corneal collagen cross linking. The cornea is then stabilized and its further increase in curvature and thinning is stopped. Within two years the dioptres may even be reduced as vision improves,” explains MUDr. Kalandrová.
The procedure is carried out under sterile conditions in an operating theater. The cornea is saturated with riboflavin for a certain amount of time and subsequently it is irradiated with a measured amount of ultraviolet light. The procedure is safe and easily handled by the patient.