Refractive errorsClose-ups, hyperopic and astigmatism are defined as refractive errors. In the past not so long ago, the only way to correct these defects was to use glasses, and then contact lenses. Today, however, various surgical procedures for fixing refractive errors have been developed, which, by changing the shape of the cornea, lead to vision correction.
To create normal vision, the cornea (transparent tissue covering the iris in the front of the eye) and the lens of the eye should receive light waves and focus on the retina to send the image of the object to the brain by the optic nerve. If the image of the object is not formed on the retina, your vision will be blurred, and the most important reason for this is refractive errors. (Look at the image to the right, not focusing at one point.
What types of refractive errors?
Near-Mind (Myopia): In this disorder, objects far away are not as transparent as the near objects, due to the longer the horizontal axis of the eyelid than the normal state, which causes the image of the object to form in front of the retina.
Hyperopia: A person with a camera is disturbed by the observation of objects near the distal objects, due to which the image of objects behind the retina is formed. In these people, the horizontal axis of the eyeball is shorter than normal.
Astigmatism: In this case, there is a disturbance in the observation of objects, both at distances and distances, due to the asymmetry of the corneal surface or the lens of the eye.
Gentiles: In this case, the person is disturbed in the close eyes of the objects, while it is not difficult to see distant objects. This disorder usually occurs at the age of 40 years and is due to the rigidity and rigidity of the lens of the eye.