How to choose glasses for a child?

 

In the first year of life, the main indications for correction are aphakia and high myopia. In children under the age of three leading indications for correction of hyperopia is for esotropia. Preschool children (3-7 years) to correct aphakia, congenital myopia and hyperopia are added early acquired myopia and astigmatism. At school age, the leading indication for the correction of myopia is acquired.

 

Lens Material

Abroad, the material of choice for children is polycarbonate lenses because it is characterized by very high resistance to shock loads, and glasses with polycarbonate lenses most recessed. In the U.S., if by reason of the higher cost of polycarbonate lenses parents refuse to buy them, they necessarily give the sign a special document "Duty to warn" ("Prevention of responsibility"), stating that they received all the information about the properties of lenses and warned about the benefits of polycarbonate lenses. In Russia, in most cases, children's sunglasses are still manufactured with lenses of mineral glass. Of course, lenses based on polymeric materials is several times more expensive than mineral.

First, the lenses of plastic are 2-3 times lighter minerals. Points are made on the basis of heavy mineral lenses, may cause your child tick, disrupt the normal growth of the nasal septum, cause irritation and infection of the skin, slipping points and, therefore, inadequate correction, as well as the discomfort and reduce the motivation of the child to wear glasses .

Second, most importantly, the advantage of lenses made of plastic - high Traumatic. Children are more sedentary life, engaged in active sports and games with the use of potentially hazardous to the eyes of subjects, so the eyeglasses on the basis of mineral elements may themselves be a source of additional risk. Consequences of injuries eyes shards of broken glass lenses are very sad, so many ophthalmologists insist on the prohibition of the use of mineral elements in the manufacture of children's glasses, considering them as an additional risk factor. The use of plastic lenses contributes to the child's health, in particular organ of vision.

For high-refraction lens is preferable to plastic lenses with high refractive index. This allows a 30 per cent to reduce the thickness and weight of lenses and make points on the basis of their aesthetic appeal.

 

Protection from UV radiation

The body of the child requires greater protection from UV radiation, because:

- Children spend more time outdoors than adults;
- The lens to the retina of the child misses more UV and short visible radiation;
- Damage caused by UV radiation in the retina, are cumulative. With age, this may lead to the development of cataracts and other diseases and, consequently, to loss of vision.

Timely protect the body of a young age helps to prevent the development of diseases. Most lenses based on polymeric materials are composed of original songs of special UV-absorbers, which provide the absorption of ultraviolet component of up to 350-380 nanometers. Quality of children's sunglasses should be given special attention. Typically, parents do not want to spend large sums on sunglasses for children and, without thinking about quality, willing to acquire them at random traders.

 

Special coatings

A man wearing glasses, can experience negative feelings due to reflection of light from the outer and inner surface of the lens. The child has these feelings are compounded when working indoors classes, illuminated by fluorescent lamps, the light which has a frequency of blinking. Application of anti-reflex coating on the surface of the lens helps to reduce the sensitivity to reflections and make the glasses more aesthetically appealing.

Anti-reflex coating, applied by vacuum deposition, reduce the coefficient of light reflection from the surface of the lens and increases the light transmission. Some companies recommend the use of lenses with antireflection coatings at work at the computer, since these coatings reduce the sensitivity to flicker and the most luminous characters display.

It may be recommended to use for children's glasses plastic lens hardening coatings, which increase their resistance to the appearance of random scratches and increase lifespan. Currently, the majority of the world's leading manufacturers manufactures plastic lenses multipokrytiyami (number of layers can be up to ten), bringing them to abrasion to the mineral glass.

 

Design elements

Selection of the optimal design elements can make glasses for a child maximum light. Increasingly, for the manufacture of spectacles with lenses of high refraction, experts recommend aspherical lenses. In conjunction with vysokoindeksnym material aspheric lens may be 40 per cent to reduce the thickness of lenses - and thus their weight.

For a variety of indications doctors prescribe small patients bifocal lenses. This occurs most often in cases where a child's myopia and he needs glasses to see well blackboard, but there is no need for correction for near vision (or vice versa). Of course, bifocal lenses are a convenient alternative to the two points.

Some children do not want to have glasses, like grandmothers, "so both abroad and in Russia for the manufacture of children's glasses are beginning to use progressive lenses - with large areas near vision and minimal distortion at the edges. If parents can not afford to buy these expensive facing the lens, they are encouraged to bifocal lenses.