Errors of Refraction of the Eye - An Overview
This article is a resource for the errors of refraction of the Human Eye.
The Human Eye is a delicate organ and is classified under the visual organ and highly nerve rich organ which carries the impulses created by the light falling on the retina and thus processing images in the Brain center.
Two terms denote the general conditions of the Eye and thus form the nomenclature for the errors of refraction of the eye.
1. Emmetropia
2. Ametropia
1. Emmetropia
Emmetropia is the terminology which defines the normal anatomy and physiology (Structure and Function)of the eye when parallel rays of light which may come from infinity come to a focus on the Retina of the Eye, which is known as Fovea of the Eye, and when the accomodation of the light and image processing is normal at Resting condition of the eye.
Resting condition means that there is not much movement of the eye.
2. Ametropia
Ammetropia is the terminology which defines the abnormal anatomy and abnormal physiology (Structure and Function) because of which the light rays coming in thus the person having Ametropia does not see properly as the light coming in are not processed correctly.
Based on the errors of refraction which are: -
1. Myopia or Short-sightedness
2. Hypermetropia or long-sightedness
3. Astigmatism