A normal eye can see all objects over a wide range of distances i.e., from 25 cm to infinity. But due to certain abnormalities the eye is not able see objects over such a wide range of distances and such an eye is said to be defective. Some of the defects of vision are
- Hypermetropia or long sightedness
- Myopia or short sightedness and
- Astigmatism
- Presbyopia
