hypermetropia (Hypermetropi)

Definition and causes

When light rays framework eye, breaking the eye cornea and lens. Rays, then assembled into a point behind the cornea, retina and here must be to ensure that the image is crisp, and you see things clearly. By hypermetropia eye is too short, so that light beams together in a point behind the retina instead of on the retina (for further explanation, see refractive error).

Since the beams are not yet completely whole, when they hit the short eye retina, things would therefore appear dimmed and washed out. This will apply only thing that is close to the eye, while light from these things are spreading more than things seen from far away.

By hypermetropia have Monday as opposed to short-sightedness ability to compensate. This is also calledakkomodation. Both the cornea and the lens helps to break the light rays. The lenses are curious out between small wires, powered by a small muscle inside the eye. When muscle tightened by akkomodation, relax threads, and thus the lens becomes more round. This will break the light more and frameworks as the retina, although the eye is too short.

Because of this mechanism can be many long-sighted still see and read things close without problems. Long-term compensation, however, leaves pain in his eyes, headaches and fatigue, and when farsighted unit is getting worse, you can no longer compensate, and the sight gets worse.

Symptoms of hypermetropia

Symptoms of hypermetropia the line is later than the myopia because of the ability to compensate. You will find that the letters flow together when you read, you get headaches, become tired in the eye and lose concentration after reading for a long time. In children can cause hypermetropia skeløjethed.

Precautions and diagnosis

The above symptoms should be seen by an optician. Here investigated sight, and optics measures the difference in the trough in the cornea and lens (refraction measured in unitdioptres) And eye length. This difference can be found by putting lenses in front of the eye, which collects light rays in varying degrees. These are calledgather lentils. The strength of the assembly lens corresponds to the long-sighted people are. Dioptres is therefore a reflection of how strong wrestling, which will enable you look normal. It is measured as plus 1 (dpi), plus 2 (dioptres), etc. and is thus the strength of one's glasses.

Select and complications

With age, most people long-sighted (gammelmandssyn,presbyopia). This is because the lens becomes more rigid and therefore no ability to compensate as much as in adolescents. This hypermetropia must "addition to" the hypermetropia, we have as a young, and they should therefore be examined regularly inspected by opticians throughout life.

Aside from a slightly increased risk of narrow-angle glaucoma, there are no complications from hypermetropia.

Treatment of hypermetropia

There are three types of treatment of hypermetropia: glasses, contact lenses and laserbehandling / surgery.

Glasses and contact lenses

Here is the question before the assembly in front of the eye lens and worn at all times. Contact lenses have the advantage that they can compensate for greater differences in visual acuity than spectacles, but they are in turn more cumbersome and can cause infections. Many long-sighted only need correction when they read, and glasses would be best because you can take them on and off as needed during the day.

Laserbehandling / surgery

Instead of saying that the eye is too short, we could say that the cornea breaks "too little". If the cornea total of light rays more, would fit the eye length course. This takes advantage of a technique in which corneal refractive increases with laser beams. There are two types of laserbehandling. In the latest method created a small flap in the cornea, and include the laser treatment (called LASIK). When the flap then put in place, the eye will be treated. This technique has been refined through the years

Precautions

Has it been difficult to see clearly or become tired in the eye, you should let an optician or an ophthalmologist (see In opticians) check your sight. If it transpires that you are farsighted, this can be corrected with eyeglasses or contact lenses, which gathers the light (convex lenses). This increases the refractive lens capability, so visual image can focus on the retina with less effort.

Strålelegemets muscles can weaken over time, usually after 40 years of age, thus requiring stronger lenses to correct refractive error. You can also correct refractive laser field (see myopia).