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The visual system of the eye

The visual system of the eyeball is similar to the system of a photo camera. The ray of light passes through a transparent lens and focuses on the film. The cornea (the transparent lens through which the iris and pupil is visible) and the lens (placed underneath the iris, responsible for the clear vision of near objects) play the role of the camera lens. The image is projected on the retina, which plays the role of “film”, and is subsequently sent for analysis to the visual area of the brain.

Normally, if a person’s acuity is 1,0 or 100%, all the light passes through the iris and is focused on the retina.

When the eyeball is too short, it causes hyperopia (far-sightedness). Because of this, light is focused behind, instead of on, the retina. In such cases, the image appears blurry. It is necessary to mention that all children are farsighted at birth, the refractive error being 2-3 diopters. When children grow up, the size of the eyeball grows larger and the light focuses on the retina.

For different reasons, some children are farsighted in the range of 3 diopters. In order to distinguish objects, they have to force their eyes. In many cases, the body cannot fight hyperopia (presbyopia). Frequently, these dysfunctions lead to a decrease in the cellular function of the brain’s visual cortex, because the clear image doesn’t reach the brain, therefore it lacks the necessary stimuli for the correct development of the neurons. As a result, the visual acuity decreases and amblyopia is developed.

Amblyopia – weakening of the vision associated with changes of the cerebral cortex. In cases of amblyopia, not even eyeglasses can offer a clear image. This pathology is developed exclusively in children, because early childhood the visual system is sensitive and any negative influences can lead to developmental disturbances. Therefore, amblyopia must be treated during childhood.

The treatment for vision correction is performed with the help of eyeglasses. In cases of far-sightedness or amblyopia, eyeglasses are prescribed to be used on a regular basis. Usually, the glasses are of a smaller dioptre than the degree of hyperopia. This solution can be used only during childhood, as it stimulates the growth of the eyeball and helps in decreasing the level of hyperopia. Also, different treatment procedures are used, including methods for vision stimulation. The modern conservative treatment methods with the help of different devises allow the treatment of amblyopia in children, thus eliminating the need for glasses.

Another danger threatening a child with far-sightedness is strabismus (crossed eyes). Strabismus occurs in children before the age of 2-3 years old, when the eye is more actively solicited in order to visualize objects that are near. Farsighted children with strabismus must wear glasses on a regular basis. In some cases, strabismus is treated with the help of correcting glasses.

But it is not enough to wear glasses. In cases of strabismus, a conservative treatment with the help of devices is prescribed. Thus, the reconstruction of the “bridge” between the eyes is performed and the child learns to merge the image seen in the left eye with the one in the right. The conservative treatment procedures are performed a few times per year.

In cases of astigmatism, the curvature of the cornea is irregular and the eye focuses the light in two different parts of the retina. Usually, the focus is not placed on the retina. Just like far-sightedness, astigmatism is an innate disease. Sometimes, astigmatism is hereditary. Children with astigmatism often develop amblyopia as well, but in these cases there are some particularities which have to be taken into consideration when prescribing glasses and treatment. The treatment methods for visual dysfunctions like astigmatism are conservative. It is necessary to perform 3 to 4 procedures per year, which result in a better vision with glasses and without. These special procedures can significantly improve the visual functions in children with astigmatism, thus providing the possibility to reduce the dioptre and, subsequently, eliminate the necessity for correcting the vision with eyeglasses.

Unlike the pathologies described above, myopia (near-sightedness) is an acquired dysfunction. Frequently, it develops during school years and is associated with the eyeball’s gradual growth in length. The human eye stops growing at the age of 5-6 years old. Therefore, any growth of the eyeball after this age is considered pathological.

The growth in length also occurs as a result of excessive use of visual functions, weakness and flexibility of the eyeball’s outer shell. A major role in myopia is played by the hereditary factor. Because of the eyeball’s growth in length, the image on the retina is unfocused, and the child says that he doesn’t see the far objects quite clearly. In order to see the far objects, the child stresses his eyes. Eyelids play the role of the diaphragm, and the image on the retina becomes clearer. Myopia in children is not only an optical dysfunction which can be easily corrected with the help of glasses. When the eyeball grows in length, the internal structure of the eye also modifies, especially the retina. As a result, different anomalies can occur in the back of the eye and, if they progress, can lead to the worsening of the vision. This is the reason why the treatment of children with myopia must be very complex, directed towards slowing the vision regression, as well as improving the blood flow to the eyeball and its internal structures. All these actions have a common purpose – to stop the process of eyeball growth and the progression of myopia.

In 75% of cases, adequate modern treatment of myopia, without any surgical intervention, is successful. If the treatment is correctly selected and the plan of 3-4 procedures per year is respected, in the majority of cases stopping the myopia in children is successful, as well as stopping the progression of the changes in the back of the eye.

Till now, different devises were used for developing muscular reserves of the eyeball, such as: biostimulation, magnetotherapy, electrophoresis, laser stimulation, electroacupuncture. Now, thanks to Corneal Refractive Therapy (night lenses) there is a more efficient method for developing the accommodation reflexes, ensuring the stabilization of myopia.

Corneal Refractive Therapy (CRT) or Orthokeratology

Corneal Refractive Therapy is the most modern method in myopia correction. For this purpose, special night lenses with reversed geometry are used, which reshape the cornea in a reversible manner. While being worn only for 6-8 hours per night, the special structure of these lenses ensures 100% correction of the vision for a long time (a period of 24 hours and longer), during which it is not necessary to wear glasses, contact lenses or conduct additional procedures.

Indications for refractive therapy:

· Myopia of -0,5 to -6,5 D;

· Progression of myopia, because it slows the progression considerably or even stops it;

· Professions where wearing glasses or contact lenses is not possible (pilots, climbers, divers, etc.);

· People practicing contact sports, nautical sports and speed racing;

· People who are not able to get LASIK intervention for various reasons.

Specific indications for refractive therapy:

· Progression of myopia, because it causes the myopia to stop developing;

· Elimination of the need to wear eyeglasses and contact lenses for the entire day.

How is the effect achieved?

The patient is applying the contact lenses before going to bed and sleeps with them the entire night.

When waking up in the morning, the patient removes the lenses and has a perfect vision. The good vision is maintained without contact lenses or eyeglasses during 24 hours and longer.

How can the amazing effect of these lenses be explained?

The lenses have two different surfaces, selected individually for each patient by experienced specialists in the field.

The exterior surface is optic – it actively refracts the light (similar to common lenses) and it offers the possibility to get 100% vision. The interior surface is much more complex – it acts on the interior layer of the cornea and forces the cells to migrate from the surface of the cornea. Thus, the refractive optical power of the cornea changes according to the required size.

When the patient removes the lenses, the effect maintains and the image is focused on the retina. Therefore, the patient can see more clearly.

In 2002, after long clinical research and trials, the Corneal Refractive Therapy with the help of Paragon CTR lenses was certified in the USA (with the FDA approval) and in the European Union as an efficient and safe method for correcting the vision, without any restrictions, starting with the age of 6 years old.

By using the night lenses, nearsighted people can solve two problems simultaneously: optic correction of up to 100% and healing – stabilization of the refraction and stopping progressive myopia, elimination of the accommodative spasms and development of accommodation reserves (the system responsible for focusing).

Therefore, when using refractive therapy, you maintain 100% effect during 24 hours without needing laser correction treatment.