The eye lens lies behind the iris and the vitreous and is cradled by the fibres of an attachment apparatus, which is clamped amongst the projections of the ciliary body. The lens is elastic, sealed in its case, and its shape is changed by muscular stimulation from the suspension apparatus.
While looking at different distances, the lens more or less curves, and thus changes its fragility. Looking at close distance, it curves more; looking into the distance it curves only a little or not at all. With age, it changes its shape and its transparency decreases.