Cornea Of The Eye Cornea Definition 10-foods-highest-in-iron. The cornea is the unmistakable front surface of the eye. It lies straightforwardly before the iris and student, and it permits light to enter the eye. Seen from the front of the eye, the cornea shows up marginally more extensive than it is tall. This is on the grounds that the sclera (the "white" of the eye) somewhat covers the top and lower part of the front cornea. The level distance across of the cornea normally gauges around 12 millimeters (mm), and the upward breadth is 11 mm, when seen from the front. However, whenever saw from behind, the cornea seems roundabout, with a uniform measurement of around 11.7 mm. This makes the cornea around 66% the size of a dime. The middle thickness of the normal cornea is around 550 microns, or somewhat the greater part a millimeter. The cornea has five layers. From front to back, these layers are: The corneal epithelium. This external layer of the cornea is five to se...
Iris / Uvea Of The Eye Definitions of Iris and Uvea The uvea is the colored middle layer of the eyeball. It consists of three parts: the iris, the ciliary body, and the choroid. Iris. The iris of the eye is the delicate, circular structure composed of connective tissue and muscle that surrounds the pupil. The hue of our not completely fixed depends on the amount of pigment in the iris. Ciliary body. The ciliary body is the second part of the uvea. It includes the iris and should not be seen because it is located behind the opaque sclera (the white part of the eye). Choroid. The choroid, located at the back of the uvea, is positioned between the rigid outer sclera of the eyeball and the retina at the rear of the eye. Iris, Ciliary Body, and Choroid Roles Each component of the uvea serves a specific function: Iris. In addition to providing color to the eye, the iris functions like a camera's aperture, regulating the...