About the eye
The eye is made up of multiple layers and various structures that control eye pressure, how much light comes into the eye, and how the brain can interpret what we see.
The transparent cornea in front of the eye allows light into the eye through the pupil. It continues as a protective opaque cover called the sclera or white of the eye. Light is regulated by the pigment containing iris that contacts and relaxes in response to light intensity. The conjunctiva is a mucous membrane that lines the visible part of the eye and the inner surface of the eyelids.
The lens sits behind the cornea and focuses light on to the retina at the back of the eye, and focus is controlled by ciliary muscles in the ciliary body surrounding the lens. The retina contains specialised structures, the rods and cones, that send nerve impulses to the brain via the optic nerve.
The choroid is the area between the sclera and the retina and contains many small blood vessels or capillaries.
The area between the lens and the cornea is called the anterior chamber of the eye and it is filled with a clear fluid, the aqueous humour that helps control eye pressure. Aqueous humour is produced by the ciliary bodies and drains out of the eye through the spongy tissue called the trabecular network. The balance between fluid production and drainage keeps eye pressure stable.
The inner chamber of the eye is filled with a jelly like substance called the vitreous humour that nourishes the eye and gives the eye its shape.
The lachrymal glands sit above the outer corner of each eye and these make the tears that lubricate the eye, prevent it from drying up and help keep it clean.
Eye conditions and treatments
The eye is a specialised organ and if the fine balance in the eye is disrupted conditions like glaucoma can become a problem. The eye is also prone to irritation, for example if they dry out or in the presence of irritants. Eye infection and allergic reactions can also be a problem. Treatments are available specifically for eye conditions to:
- reduce allergic reactions that cause itching redness, puffiness and inflammation, for example in response to allergens like pollen
- increase lubrication for dry eyes
- treat eye infection with topical antibiotic eye preparations
- lower intraoccular pressure and reduce risk of glaucoma
Products that enhance growth of eyelashes are also available for use in conditions where eyelash growth is abnormal or to enhance normal eyelash growth.