Very often, in forums and blogs, there are the questions "how to determine the focusing of vision?", "What should I do if I have defocusing my eyesight?". Therefore, it is worth looking carefully at this topic.
The ability to clearly perceive and see the eye at different distances is accommodation. In this process, there are three elements involved: cilia or ciliary muscle, lens and ciliated ligament.
Vision in focus
In normal condition, the job of accommodation is following a simple scheme:
- Accommodation in the distance provides relaxation of the muscles - this is disaccoded vision;
- For the close examination of objects, we need to reduce the ciliated muscle, relax the price ties, as a result, the elastic lens becomes convex. At the same time, its optical power increases, and the light rays enter the focus on the retina, the image becomes clear;
- In the absence of the accommodation stimulus, the ciliated muscle relaxes again, and the refracting force decreases, defocusing to infinity, or accommodation in the distance.
Influence of age on accommodation
The elasticity of the lens is one of the most important conditions of accommodation. However, it varies with age. The accommodation properties of the lens with age are diminished, and the vision is gradually deteriorating nearby. After 45 years, prebiotics, or age-old farsightedness begins to develop. Up to 70 years, the ability to accommodation is completely lost.
At night, and simply in the dark, accommodation, which provides the vision to the distant, deteriorates and gradually disappears. This is one of the reasons for uncomfortable vision at night and night time.
Focus Off Focus. Reasons
The stimulation of the occurrence of the reflex of accommodation is the defocusing of the picture on the retina of the eye with optimal illumination. In this case, the light rays from the image are not focused on the retina. This defocusing of vision is perceived by the brain as a signal of the inclusion of the accommodation mechanism. The nerve impulse, moving along the eye's nerve, signals the contraction of the ciliated muscle, which tightens the zinc bundle and changes the curvature of the lens. This results in the focus of the image on the retina.
When you translate the look away, there are reciprocal actions - the lens becomes flat.
The development of spasm of accommodation promotes several factors:
- Excessive load on the visual apparatus;
- Bad illumination of a workplace or a training place;
- Discrepancy between the writing table or the chair of the user's growth;
- Weakness of the cervical and dorsal muscles;
- Failure to observe distance to a book or monitor;
- Non-compliance with the diet;
- Insufficient physical activity.
Defocusing at the manifestation of spasms, the consequences of poor vision:
- Fast fatigue at work;
- Redness of the eyes and burning sensation;
- Impairment of image clarity and the emergence of dichotomy;
- The appearance of headaches.
It is important to note that such a state can last for several months or even years and only then grow into a serious violation such as myopia.
Focusing of vision is seen as a serious symptom of the disruption of the eye apparatus. Therefore, only a comprehensive approach to diagnosis and adequate treatment by a specialist can help to avoid more serious consequences.