Vision defects

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Vision defects

Perfect eyesight
When there are no problems with eyesight, the image of objects forms on the retina. Clear vision, which does not require any correction, is called emmetropia. This is characterized by good visual acuity and a normal field of vision.

The most common problems

The term ametropia refers to a condition when the image does not form correctly on the retina. Ametropia is blurred vision which requires optical correction. There are three kinds of eyesight problems:

  • myopia
  • hyperopia
  • astigmatism.

And nobody escapes presbyopia after the age of 40, when natural aging of the crystalline lens results in blurred near-sight.

One in five people in the world wear glasses. The problems listed above are very common, although others exist, including amblyopia, strabismus and low vision