What is the function of annular ring in eye?

The annular ring, also known as the ciliary body, is a structure in the eye that plays several important functions related to vision and eye movement. Here are some key functions of the annular ring:

1. Accommodation: The annular ring is responsible for adjusting the focusing ability of the eye, a process known as accommodation. It contains small muscles called the ciliary muscles that contract and relax to change the shape of the lens. By altering the curvature of the lens, the annular ring helps the eye focus on objects at different distances.

2. Production of Aqueous Humor: The annular ring is also involved in the production of aqueous humor, a clear fluid that fills the anterior chamber of the eye and provides nourishment to the cornea and lens. The ciliary processes, which are finger-like projections on the annular ring, contain cells that secrete aqueous humor.

3. Regulation of Intraocular Pressure: The production and drainage of aqueous humor help regulate the intraocular pressure (IOP) of the eye. The annular ring plays a role in maintaining a healthy IOP by controlling the rate of aqueous humor production and drainage.

4. Blood-Aqueous Barrier: The annular ring contributes to the formation of the blood-aqueous barrier, a specialized structure that helps maintain the appropriate composition of aqueous humor and prevents potentially harmful substances from entering the eye.

5. Pupillary Constriction: The annular ring contains sphincter muscles that control the size of the pupil. These muscles can contract to constrict the pupil, reducing the amount of light entering the eye. This response is known as the pupillary reflex and helps protect the retina from excessive light.

6. Role in Eye Movement: The annular ring also plays a role in eye movement by coordinating with the extraocular muscles that control the position and movement of the eyeball.

Overall, the annular ring, or ciliary body, serves multiple crucial functions in the eye, including accommodation, aqueous humor production, intraocular pressure regulation, blood-aqueous barrier formation, pupillary constriction, and eye movement.