Treatment of keratoconus
Treatment of Keratoconus
Keratoconus is an uncommon condition in which the normally round, dome-like cornea (the clear front window of the eye) becomes thin and develops a cone-like bulge. Keratoconus literally means “cone-shaped cornea.”
Onset of keratoconus can be anywhere between the ages of 8 and 45. In the majority of cases, it becomes apparent between the ages of 16 and 30 years. Keratoconus usually affects both eyes, though symptoms in each eye may differ.
Symptoms of keratoconus are usually:
– Blurring of vision
– Distortion of vision
– Increased sensitivity to light
– Mild eye irritation
How is the keratoconus treated?
Until recently, the only form of treatment for patients with keratoconus was keratoplasty, or corneal transplantation.
Since the advent of corneal cross-linking procedures, it is possible, in most patients to stop the progression of keratoconus before there is a significant disease progression and pronounced decline in vision.
Illumination with UV-A lamp then continues for 5 to 30 minutes, with continuing application of riboflavin and local anesthetic agents. When the illumination is completed and the procedure involves abrasion, a contact lens is put on the eye and will cover the eye for the next four days. The entire procedure lasts approximately 60 minutes; the illumination of the cornea with ultraviolet light takes 5 to 30 minutes.
After surgery keratoconus should be stopped at the level at which it was. Although the primary goal of this method is to stop the progression of keratoconus, lately a number of studies suggests the possibility of improving visual acuity in some degree depending on the stage of keratoconus. Postoperative treatment drops are essential and lasts for several months, with regular check ups. The patient may continue to wear contact lenses, usually one to two months after the intervention. Seven to ten days after surgery, the patient returns to the state it was before the intervention. Ultra B2 can be used with other corrective procedures such as Ferrara ring implantation.
Great importance has recently been given to the combined procedure, which involves the simultaneous use of CXL (cross linking) and PRK methods for correcting certain degree of refractive error, astigmatism primarily, alongside with the reinforcement of the cornea. This method is now largely in use to treat mild to moderate stages of keratoconus. In this way, in addition to strengthening the cornea, patients get better visual acuity. It is therefore very important to detect keratoconus as early as possible, while the cornea still has a certain thickness, which will allow us to strengthen near the cornea to some extent to correct diopter. Combined procedures are commonly applied to “forme fruste” keratoconus.
In some cases, it is recommended that the cross linking is used as prophylaxis, when the cornea is thin, and LASIK or PRK method are planned, even if keratoconus has not been diagnosed.
And of course that this method alone or in combination with other methods entails certain risks, and the results can sometimes be limited and unpredictable. However, the rate of complications is negligible compared to the performance, usefulness and significance of this method.
Except in cases of keratoconus, cross linking is used in stopping the progression of pellucid marginal degeneration, ectasia after refractive procedure, or I in the treatment of conditions that melt the cornea “melting conditions” and with infectious keratitis, where it also strengthens the cornea and UV-A radiation perform sterilization of the infectious agent.
Cross linking today represents the “gold standard” in stopping the progression of keratoconus, ectasia and pellucid marginal degeneration.
This revolutionary discovery is considered one of the greatest inventions in the field of modern ophthalmology.
When good vision is no longer possible with other treatments, a corneal transplant may be recommended. This surgery is only necessary in about 10 percent to 20 percent of patients with keratoconus. In a corneal transplant, your ophthalmologist removes the diseased cornea from your eye and replaces it with a healthy donor cornea.
Other methods of treatment
Implantation of intrastromal corneal ring segment
It is an alternative to corneal transplantation.
The method consists of the insertion of intrastromal ring segment in the middle periphery of the cornea. The central part becomes flattened and more regular, which reduces myopia, especially astigmatism, and increases the quality of vision.
Implantation takes about fifteen minutes in the local anaesthetic applied by eye drops. Special spatula creates a “corridor” in the deeper layers of the cornea in which one or two half rings are implanted.
The protective contact lens is placed on the eye rather than the eye patch until next day, and a postoperative treatment with drops countinues for several weeks after the procedure.
The most famous intrastromal rings are Intacs and Ferrara Rings.
Between 10 and 25% of untreated cases of keratoconus eventually progress to the stage where vision correction is no longer possible, where the thinning and scarring of the cornea has become too large and in these cases, corneal transplant becomes necessary.
Sick, very curved, cloudy or scar deformed cornea is replaced by this method with healthy, donated cornea. In cases of keratoconus two methods are applied: DALK method and penetrating keratoplasty PKP. In fact, regardless to localization of pathological changes in the cornea compared to the thickness of the corneal transplant can be:
– Traditional full corneal transplant (penetrating keratoplasty)
– Partial corneal transplant (lamellar keratoplasty)
Whit DALK grafts, only outer epithelium and stroma are replaced, which allows to keep the posterior of the cornea and to preserve the structural integrity and stability. Since the rejection of grafts begins in the endothelium, the chance of it is much lower in this kind of transplant. Advantages over PKP: extra ocular procedure, preserved the posterior part of the cornea, faster recovery. Disadvantages: difficult to perform, the greater number of complications during surgery.
The most important thing is not to allow the disease to progress to the stage that needs transplantation. Nowadays, we have a possibility and the way to fight and to successfully prevent significant progression and visual impairment in patients with keratoconus. Detecting diseases at an early stage, regular monitoring and timely implementation of cross linking method are crucial in achieving good results.