Anatomy of the Eye

The eyeball is the peripheral organ of sight and is situated within the orbital cavity to protect it from injury.

Specialised nerve cells in the retina, the rods and cones, respond to changes in light and relay this information, via the optic nerve, to the brain, where the information is then processed and interpreted as vision.

All other structures within the eye serve to enhance this response, either by focusing the image e.g. the cornea and lens, or by providing nutrition and removing waste products, e.g. the choroid and ciliary body.

Aqueous humour is a clear fluid that is made in the eye to nourish the cornea and the lens.

This is produced by the ciliary body and then flows in front of the lens, through the pupil, in front of the iris, to be removed from the eye via the trabecular meshwork, sometimes referred to as the angle of the eye.

In open angle glaucoma, high pressure in the eye is generally caused when the trabecular meshwork becomes silted up so that the fluid cannot get out of the eye.

In closed angle glaucoma the iris is shaped in such a way that the space between the iris and the cornea is very narrow so as to block the fluid from reaching the trabecular meshwork again resulting in high pressure.

 

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