The structure indicated is the ciliary body.

The eyeball consists of a fibrous outer layer, a vascular layer, and an inner layer.

The vascular layer of the eyeball consists of:

• Choroid
• Ciliary body
• Iris

The ciliary body is triangular in cross-section and encircles the eyeball. It has two components:

• Ciliary muscle
• Ciliary processes

The ciliary body has three main functions:

• Accommodation of the lens
• Production and resorption of aqueous humor
• Maintenance of lens zonules