Emmetropic eyes are just the right length to allow light to reach the ideal spot on the retina to create crisp, clear vision. A person with two emmetropic eyes is considered to have “ideal vision” and does not require any sort of vision correction. Emmetropia is often given as the medical definition for 20/20 vision.

What is the power of an emmetropic eye?

In a normal, emmetropic eye, parallel rays of light from a distant object focus directly on the retina. The total refractive power of the eye is about 63 diopters. The largest part of about 43 diopters is contributed by the cornea and the smaller amount, about 23 diopters, by the lens.

What does it mean if you are emmetropic?

General Eye Examination

Emmetropia is the refractive state of an eye in which parallel rays of light entering the eye are focused on the retina, creating an image that is perceived as crisp and in focus. Myopia, hyperopia, and astigmatism are abnormalities of this desired condition (Fig. 1-4).