The human eye is an organ that responds to light for a number of purposes. As a conscious sense body organ, a person’s eye allows vision. Rod and cone cells within the retina enable conscious light perception as well as vision which includes color differentiation and the perception of depth. A person’s eye can distinguish about ten million colors.
In common with the eyes of other mammals, the human eye’s non-image-forming photosensitive ganglion cells within the retina get the light signals that affect adjustment of the dimensions of the pupil, regulation as well as suppression of the hormone melatonin and entrainment of the body time clock.
The eye isn’t accurately a sphere, instead it is a merged two-piece unit. The smaller frontal unit, much more curved, known as the cornea is linked to the larger unit referred to as sclera. The corneal section is usually about 8 mm (0.3 in) in radius. The sclera makes up the rest of the five-sixths; its radius is usually about 12 mm. The cornea as well as the sclera are connected by a ring known as the limbus. The iris – the color of your eye – and its black center, the pupil, are noticed instead of the cornea because of the cornea’s transparency. To see within the eye, an ophthalmoscope is required, since light isn’t reflected out. The fundus (region opposite the pupil) reveals the characteristic pale optic disk (papilla), in which vessels arriving into the eye move across and optic nerve fibers get away from the globe.
