The<unk> is a transparent, biconvex (lentil-shaped) structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. The<unk>  by changing shape, functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing a sharp image of the object of interest to be formed on the retina. This adjustment of the<unk> is known as accommodation (see also Accomodation, below). It is similar to the focusing of a photographic camera via movement of its<unk> s.
The<unk> is also known as the aquula (Latin, a little stream, dim. of aqua, water) or crystalline<unk>  In humans, the refractive power of the<unk> in its natural environment is approximately 18 dioptres, roughly one-third of the eye's total power.
Lens 
Olea
Fundic glands
Eyelid
Optic tract
Iris 
Lacrimal bone
Atlas 