Influence of soft contact lenses to the VIsual analyzers

Amansheyeva A.B., Nazarbayeva A.S.

West Kazakhstan Marat Ospanov State Medical University

Department of normal physiology
Supervisor of studies – Akkozhina A.M.
Aktobe city, the Republic of Kazakhstan

Relevance. Vision is the greatest value for any of us. Vision gives us 80% of information about the world. The ability to see, perhaps, the most important of all perceptions of the world. The eye is a living optical instrument. The muscles of the eye pupil for one school day is under the same load, some feel the muscles of his arms and torso, if he was trying to lift and hold overhead barbell weights is designed for the average professional athlete. Nowadays in the vast number of people poor vision. This is due to many factors, people that can boast of 100% vision, unfortunately, a little bit. The accelerated pace of modern life, daily work at the computer, stay in front of the TV - all this has a very negative impact on vision and each person with low vision once the question arises "what is the influence of contact lenses to the visual analyzers?" Today suffering from various eye diseases among the people considerably enlarges the number of contact lenses consumers as an equivalent to other optical devices. It is known that during wearing the soft contact lenses (SCL) it can influence on the properties of visual analyzers and visual acuity. Visual acuity is ability of an eye to perceive separately two points which are at a certain distance from each other. Modern methods of research provide a possibility of profound studying and a full-fledged assessment of expression of these changes.
The aim of the study.To study the effect of contact lenses on structure and properties of the visual analyzers.
Materials and methods.100 people (200 eyes) are examined with various degree of myopia. Then the soft contact lenses for correction of vision were prescribed for them. The age of patients varied from 18 to 22 years. The control group was made by 50 patients (100 eyes) which didn't wear contact lenses. Monitoring of a condition of the visual analyzer carried out by means of Sitsev's table and the perimeter of Foster device, which allow to estimate visual acuity during the investigation. Research was conducted within half a year, and check of vision in the first day every month.

Sitsev's table — the most common table used to test visual acuity in the Soviet Union. Table named after D. A. Sivtsev, the Soviet ophthalmologist (1875-1940).

This table contains rows of printed letters (only 12 lines), the size of the letters decreases from row to row from top to bottom. To the left of each line indicates the distance D (in meters) from which they saw a person with normal vision (50,0 meters for the top row; 2.5 meters for the lower). To the right of each line indicate the value of V (in arbitrary units) is the visual acuity when reading letters at a distance of 5 meters (0,1 if the eye sees only the top row; the 2.0 — if you can see the bottom row). Normal vision (1,0) — when a person sees every eye at a distance of 5 metres the tenth row.

To calculate the size of the letters on a specific line (with a tolerance of approximately 1 millimeter), it is 7 millimeters divided by the magnitude of V (the value on this line). Thus, the size of the letters on the top row (V = 0,1) is 70 mm; the lower (V = 2,0) — letter size 3.5 mm.

In the study of visual acuity different distances (less than 0.1 — if the person with 5 meters does not recognize the letters of the top row), check the bring to the table, and every 0.5 meter to ask until it's the right name letters of the top row. Value is calculated according to the formula:

V = d / d where

V — visual acuity;

d — the distance from which the investigation;

D — the distance at which a normal eye sees this several

The field of view is determined by the perimeter of Forster. The perimeter consists of a semicircle divided into degrees. The semi-circle can be rotated around its axis. Against the middle of a semicircle there is a special stand for the chin, it can move up and down. On the inner side of the semicircle is a well-moving frame in which to insert a desired color mark. Perimeter to put against the light, set horizontally in a semicircle and its frame insert white brand. Test put back to the light; in the study of the field of vision of the right eye to put the chin in the left recess of the stand to the edge of the reticle plate against the lower edge of the orbit; fix right eye on the white circle in the center of the semicircle, and the left eyes closed with his hand. The experimenter slowly moving white mark on the outside to the center and asks the subject, he sees a stamp or not. If the answer is positive mark (for control) to move back and repeat the question. Having matching data, mark this point on the corresponding meridian of the print. Then measure the field of view from the other side of the arc. After that, arc perimeter, rotate 90°, and similarly to determine the field of view above and below, and in oblique directions.Replacing white brand color, to determine the field of view for both green and red. The test must accurately name the color of the brand, not only the direction of its movement. Then make a similar definition for the left eye (the chin put the right notch in the stand). The data obtained correlate with the data on the perimeter of the impression in the atlas on normal physiology.
Results and discussion.It was found that contact lenses cause the change of eyesight to 30% research of acuity and field of vision. The obtained data shows that the daily using of contact lenses has an influence to the deterioration of visual acuity.

Recommendations: The final choice suitable for you contact lenses depends on many factors, but if your doctor thinks you may be suitable any type, it is better first to try soft lenses. After the selection of lenses the doctor will explain exactly how to wear them, care for them and provide a special memo, which you can use at home. However, it is important to seize the moment when it begins to happen, something serious.

No matter what your lens, check the symptoms after which is to consult with your doctor:

- Hard to open eyes;

- When wearing or after removing the lenses, there is a feeling of pain;

- Hard to bear sensitivity to light;

- Decreased vision and/or the presence of a color halo around the light source;

- Burning sensation or irritation;

- Severe redness of the eye;

Conclusion.Using of contact lenses can cause a series of complications, especially at ФФ