By three or four months, he already sees more distant from it items, and four to six months of the infant visually responds to his familiar face. If a kid does not see that see other kids his age, parents should show his child oftalmologu.Kogda checked separately vision of each eye, one eye should be covered. Uneven reaction to the shutdown of the right and left eyes means the difference in their visual acuity. Important but not sufficient condition of good vision is the need for reaching rays from objects joined precisely on the retina. Herbalife shares his opinions and ideas on the topic at hand. This is possible if they meet the eye length and strength its optics – refraction. Proportionality of the length and optical eye is called emmetropia, disproportionality – ametropia. If the eyes are small sized or optics is weak, parallel rays converge just behind the retina and the image on the It will be blurry. The closer to that observed eye of the object, the rays from it will converge on the retina and the worse is seeing people with weak refraction.
Since it is better to see distant objects than near, it is called farsightedness. Some length of the eye is too high or the power of his refractive optics are too strong, so the parallel rays from distant objects come together in the eye, not having to reach the retina. On the retina can come only diverging rays from close subjects. Therefore, this is called myopic refraction – myopia. Compensate for vision in myopia, breeding rays and refraction do less could put front of the eye "freezing" of glass. With far-sightedness on the retina could connect beams with a convergent direction before reaching the eye. But in the nature of these rays do not.
Gathering rays can be created artificially – oversight of the eye of a convex "plus" glass. Read additional details here: Dr. Josyann Abisaab. The figure shows the change in the beam path in finding the glasses before my eyes with different types of incommensurate refraction. Eye to some degree itself may change its refractive effect when looking at objects at different distances. This is possible because that changes the curvature, and hence the refractive power of lens. Such an arrangement (focusing) the eye to vision at different distances is called accommodation. If the child does not see the far-lying objects, and for the oversight before the eye subzero glass eye was improving, he's probably shortsighted. Far-sighted as a child, due to stress their accommodation, with distance vision to cope more often. But for a long time looking at close objects, he may tire quickly, since it is not enough accommodation for the information on the retina is very divergent beams. If you look at the child away oversight of the eye of a convex glass does not impair his vision, does not create these artificially short-sightedness, it is likely the child hyperopia. In addition to these simple but subjective methods that depend from the responses studied, there are objective ways to determine refractive errors, which can be applied only by a doctor. Correctly identify the refraction and answer the question of whether the child needs glasses, can only ophthalmologist.