The paired eyes are a very complex sense organs that with relevant neural connections to the brain provide vision.

Learning outcomes

Your knowledge of the Eye should include the following:

• Identify all the following structures of the eye: cornea, sclera, iris, lens, ciliary body, vitreous, retina and optic nerve.
• Understand why the cornea is clear and the sclera is opaque.
• Understand why corneal transplantation is possible.
• Understand the roles of the cornea and lens in focusing light onto the retina.
• Describe the role of the ciliary muscle and the zonular fibres in accommodation of the lens.
• Recognise the iris sphincter and dilator muscles and know their functions.
• Recognise and understand the role of Schlemm’s canal (scleral venous sinus) in aqueous humor drainage and the cause of glaucoma.
• Distinguish between rod and cone photoreceptor cells and know the function of each of these cells.
• Describe the cause of presbyopia.