Keratoconus is the most common degenerative change of the cornea, characterized by the fact that there is no progressive thinning of the cornea, which takes a conical shape. It affects about one person in two thousand people, more often men than women. The disease occurs in all populations around the world, although it is more common in some ethnic groups.
The keratoconus is manifested by its thinning and conical projection. As a consequence of this projection, the light irregularly breaks when it enters the eye, causing the image to distort.
Reasons for occurrence
The cause is a mutation in the genes responsible for the formation of the cornea, making it inherently weak and prone to deformities. Such a cornea can receive a keratoconus if exposed to certain environmental factors that would trigger it (triggers). Stimulating factors are severe itching (mechanical corneal abrasion), frequent allergies, inflammation, environmental irritations.
New research has given particular importance to hormones in the development of the keratoconus. Thus, cortisol (stress hormone) is considered one of the major triggers in modern living. Also, the balance of estrogen and progesterone during pregnancy can cause rapid progression of the disease.
Initial symptoms are difficulty focusing at night, scattering light around a light source in the form of haloes or stars. In daylight, however, photosensitivity or hypersensitivity to light occur. Ophthalmologist examinations may show rapid growth of the diopter and cylinder or change of axis of the cylinder. Those who wear contact lenses become hypersensitive to the lenses, and still do not achieve good vision with any aids (glasses or lenses).
In the very advanced stage of the disease, when the cornea becomes excessively thinner, small cracks can appear, causing eye pain and blurred vision.
Methods of treatment
Treatment of mild to moderate cases of keratoconus consists of wearing glasses and semi-rigid or hard contact lenses and regularly monitoring the progress of the disease. For the progressive forms of the disease, the method of crosslinking is recommended . Well-tolerated patients are often satisfied with their eyesight, whereas those with advanced keratoconus stage who cannot wear lenses and have visual acuity below 30%, with pronounced corneal elevation, are candidates for surgery. corneal grip. If corneal decompensation occurs and if it irreversibly loses its transparency, then perforative corneal transplantation is the only method of choice for these patients. The best techniques used to diagnose and monitor the course of the disease are OCT – optical coherence tomography of the front of the eye and Pentacam – computerized corneal topography. Лекувањето благи и умерени случаи на кератоконус се состои од носење очила и полутврди или тврди контактни леќи и редовно следење на прогресот на болеста. За прогресивните облици на болеста се препорачува методот crosslinking. .
The corneal collagen cross-linking (CXL) is an eye intervention that is performed to stop or slow the progression of the disease. In young people under 30 it is done immediately!
The method is as follows:
- Remove the epithelium (the outer protective layer of the cornea);
- Riboflavin (vitamin B2) is drip on the cornea until it is full (like a sponge);
- Ultraviolet radiation irradiates the cornea until riboflavin is activated.
The method itself lasts from 60 to 90 minutes, followed by a precisely defined protocol (Dresden protocol) for best results.
The method itself is not dangerous to the eyes or the eye, it can be performed multiple times, but usually only requires one cross-linking in life as its effects last about 20 years.
Those recommended for crosslinking are patients with keratoconus, whose corneal thickness is not less than 390 microns, patients whose cornea is clear and scarred, whose values of corneal meridians have a maximum of 58 diopters, and their visual acuity is 0,9 or lower.
After the intervention, patients wear soft contact lenses for several days while the surface layer of the eye (epithelium) is restored. They use topical antibiotic and anti-inflammatory drops for approximately 6 weeks as treatment. Checks are performed every two weeks to measure intraocular pressure and check for cornea, healing, and riboflavin. For a few days after the surgery, they can return to their usual work and life responsibilities.
The effects of crosslinking on the hardening and flattening of the cornea appear gradually, from the day of intervention, in the next 6-8 months, and even one year after surgery. On the day of the intervention only riboflavin (a phototactic substance) is activated, which then for months forms chemical solid bonds in the corneal structure itself. That is why control pentacams are made several months after surgery.
What interests keratoconus patients the most is whether they can and when they can see well. Keratoconus treatment is slow and requires patience. Finally, after we have achieved a firm and leveled cornea by the crosslinking method and after establishing the stability of the disease, we can proceed to correction.
Always correct the type with glasses first. Depending on the diopter and the height of the cylinder, the patient may be offered contact lenses: soft or GGP (gas-permeable semiconductor). ROSE K are special lenses for keratoconus cornea. With them we can achieve excellent visual acuity in people with keratoconus, so that the disease itself is not an obstacle even in performing certain specific professions that require accurate eyesight (driver, factory worker or web designer).