Hyperopia

The course rays with farsightedness
Fig. 1. The course rays with farsightedness. Parallel light rays entering the eye behind the retina.

Fig. 2. The course rays in the correction of presbyopia convex glass. Parallel rays entering the eye converge on the net shell.

Farsightedness (hyperopia) - one of the types of clinical refraction of the eye (see), which is characterized by the fact that the focus of parallel rays after refraction them in the eye lies behind the retina (Fig. 1). Hyperopia occurs in 50% of adults. The reasons hyperopia: weakness refractive eye device (refractive farsightedness), short anterior-posterior axis of the eye (axial farsightedness); in normal length of the axis and the refractive power of their disproportionate combination (Raman farsightedness).
Clear vision at far-sighted as in the vision, and all the more in the near vision is possible only at a voltage of accommodation of the eye (see).
Diagnosis farsightedness can be supplied in the process of visual acuity in the study of glasses. The degree of farsightedness is determined by the most powerful of the collective lens, which best vision. Visual acuity at near-sightedness weak and medium degrees may be normal; high hyperopia (5,0-10,0 D and higher) visual acuity decreased, despite the correction with glasses.
Correction of presbyopia is convex glasses, reinforcing refraction (Fig. 2). In the absence of the correction points at farsighted easily occurs astenopia (see) and often develop convergent strabismus (see).
Cm. also Presbyopia.
For farsightedness characterized by weak refractive power of optical media or reduced in size of the eyeball, causing the light rays reflected from remote and from near objects, after the refraction of the cornea and the lens is focused not on the retina, and behind her. In such cases, projected on the retina is not the point, and the circle of light scattering. And images of items blur.
Some believe that if a man is wise, he must see into the distance. Indeed, with farsightedness low severity (to 1.5 DPT) children and youths have good vision. With farsightedness in 2-4 dealtree the vision, as a rule, quite satisfactory, and when working at close range considered small objects such as letters when reading, merge, pain in the eyes and forehead. And finally, with farsightedness high extent (over 5 diopters) there is a significant weakening of view as far and near.
With farsightedness DC voltage often becomes familiar to the eye, and even bothering comes complete relaxation of the ciliary muscle. Therefore, in children and adolescents is often discovered only explicit hyperopia, and hidden is revealed only with medication paralysis, which is achieved by Voskanian into conjunctival cavity 1-2 drops of 0.5-1 %solution of atropine.
Thus, hyperopia is not a disease but an optical defect of the eye. Only sometimes she can be a consequence of different disease processes. If time does not fit eyeglasses or not to wear them, especially in childhood, with farsightedness of high to medium may develop strabismus and eyesight worsened significantly.
If you come, reduced vision, which has not corrected with glasses, it is necessary to carry out treatment on special machines, properly organize the working place and mode of visual loadings.