Medical Encyclopedia

Keratoconus

What is keratoconus?

Keratoconus is a severe eye disease, manifested by progressive deformation of the cornea, which takes a conical shape. Initially, one break cell layer of the cornea, as a result, corneal rigidity is significantly reduced. Then, under the pressure of the intraocular fluid, the cornea bulges outwards, taking the form of a cone. Keratoconus leads to a significant loss of sight, but only in extremely rare cases to total blindness.

Keratoconus is not such a rare disease, as it may seem at first glance. According to statistics, keratoconus is diagnosed about 1 person in 2000. The disease is equally common in men and women and about equally distributed across the planet. The first symptoms of keratoconus usually appear already in adolescence (9-15 years), then the disease progresses slowly, complicated by astigmatism and myopia and a serious blow to the sight in 20-25 years of life. It also happens that the first symptoms of keratoconus appear later of 25-30 years. Most commonly bilateral asymmetric keratoconus is diagnosed.

Symptoms of keratoconus

  • At first, sight in one eye is reduced, then the second.
  • Symptom of monocular poliopiya - instead of a single image the patient sees more of the same. For example, the patient is instructed to consider the white point on a black sheet of paper - instead of this one point the patient sees several of these points, randomly arranged on the sheet.
  • Photophobia.
  • Distortion of letters at reading, coacervating of characters.
  • The eyes get tired quickly, sometimes there is a burning sensation in the eyes, feeling the sand or foreign body.
  • Dispersion of light around its source, for example, when looking at the burning light bulb patient sees an aura around her.
  • The correction of sight by glasses and contact lenses does not give results.

Causes of keratoconus

Keratoconus

To date, causes of keratoconus are not fully studied. There are several hypotheses about the possible causes of the disease. An immune hypothesis in obedience to which a keratoconus develops because of violations of functions of the immune system has most supporters. A disease can carry the inherited character, but a keratoconus develops, as a rule, under act of serious autoimmune diseases, and also general diseases, for example, Addison's disease, bronchial asthma, Down syndrome, hay fever, allergy, eczema and other. The row of factors, step-up the risk of origin of keratoconus is also exposed: radiation, muddy air, excessive influence of ultraviolet on a cornea, protracted reception of some drastic medicinal preparations, for example, corticosteroids.

Diagnostics of keratoconus

At the decline of sharpness of sight and distortion of visibility of surrounding objects it is necessary to appeal to the ophthalmologist. A doctor will conduct an ordinary eye test, at the exposure of some rejections will conduct one or a few additional researches – refractometer diaphanoscope, skiascopy, ophthalmoscopy. The most exact method is computer keratometry, allowing not only to diagnose a keratoconus but also to estimate its radius, asymmetry and other indexes even on the early stage of development. On the late stages the characteristic changes of cornea are noticeable at visual examination at lateral illumination

In the specialized clinics for diagnostics of keratoconus doctors apply: computer corneal topography, endothelial microscopy, optical coherent tomography of cornea and others.

For diagnostics it is necessary consult an ophthalmologist, who will examine the eye, ask about your symptoms, try to identify the cause. Additionally, the patient is sent for examination to a neurologist. When the causes of anisocoria are clear, the treatment of the underlying disease is appointed. If the cause has not been established, there shall be additional research - a blood test, CT scan of the head, EEG, eye tonometry MRI to determine the cause of the pupils of different sizes.

Treatment of keratoconus

Depending on the stage of the disease, as well as the rapidity of progression, the doctor prescribes the treatment of keratoconus conservative or surgical.

If the disease is not advanced, conservative treatment of keratoconus is used - a correction of sight by the special semi-rigid lenses, sometimes by glasses. Also immunomodulators, vitamins, eye drops injection are prescribed.

For the treatment of acute keratoconus mydriatics in the form of eye drops (medriatsil, phenylephrine) appointed. A pressing bandage is laid on an eye for prevention of further destruction of cornea.

Another method - cross-linking of the cornea. This is a relatively new technique for the treatment of keratoconus, the full name - corneal collagen crosslinking with riboflavin. The main goal - to increase the rigidity of the cornea so that it can more firmly resist deformation. During the procedure the surface of the cornea with the epithelium is removed, riboflavin solution was instilled and irradiated with ultraviolet rays. At the correctly conducted procedure probability of transition of treatment of illness in the ordinary correction of sight by contact lenses or glasses rises substantially.

Another option - use of laser keratoplasty - use of thermal energy to affect the cornea in order to make it more flat. This method is also used in farsightedness.

If a disease passed to the heavy stage or makes progress quickly, it is necessary to execute an operation. An operation at a keratoconus is two kinds:

  • Implantation of the ring segments - implantation of special corneal rings, which are constantly under pressure on the cornea, contributing to its flattening.
  • Penetrating keratoplasty - corneal transplantation, ie an own thin cornea retires, and the donor is implanted in place of it. Penetrating keratoplasty may be used at any stage of keratoconus and gives an opportunity to significantly increase the likelihood that the disease will cease to progress, then it is possible to carry out the appropriate spectacle correction of even the normal values.

Prognosis and prevention

Timely detection of the disease significantly speeds up recovery. In most cases, keratoconus develops slowly, which makes it possible in time to start treatment. The later there was a keratoconus, so much the better prognosis on convalescence.

Often, the disease leads to complications - clouding of the cornea, an acute keratoconus. Complications should be treated only by a doctor's prescription!

Some clear measures of prophylaxis of keratikonus do not exist. It is simply necessary to take to the minimum the action of harmful factors which are instrumental in the origin of illness. It is needed in good time to treat the serious diseases of general character in an organism (bronchial asthma, hay fever, Addison's disease and others), to avoid the traumas of eye, and also hit of foreign bodies.

Other articles on this topic:

Amblyopia

Anisocoria