Functions of eye parts of a human being

1.sclera- it is a tough white and opaque layer and which protect inner part and maintain shape of the eye 

2.Cornea- it is a transparent and front layer of sclera which allow light into the eye and reflect light entering the eye 

3.Conjuctiva- is a thin smooth and transparent layer before the cornea which allow light to the eye and protect the cornea

4.choroid- has melanin ,ateries,veins  to provide nourishment to eye pigment and prevent reflection of light within eye bal

5. Cilliary body- contains rings of thickened tissues araising from choroid. It produce aqueous humuor to maintain the shape of the eyeball