Refractive State, Accommodation, and Resolving Power of the Fish Eye
The refractive state of the eye is a measure of the difference between the focal distance of the dioptric elements and the distance at which the receptors are located. If parallel rays of light incident on the pupil, as they would be when they come from an object at long distance, are brought to a point focus in the plane of the light-sensitive outer segments of the photoreceptors, the eye is said to be emmetropic. If the rays from the distant object focus in front of the receptor layer, the eye is considered myopic, or near-sighted, and only a blur would exist at the photoreceptor level. This blurred image can be brought into sharp focus by reducing the object-to-eye distance, since the image plane of a near object lies at a longer distance from the lens than that of an object farther away.
KeywordsReceptive Field Refractive Error Refractive State Retractor Muscle Photic Stimulation
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