What is intrinsic eye muscle?

Answer 1

There are many muscles in the eye that control it. The four major muscles are the superior and inferior rectus (control up and down movement) and the lateral and medial rectus (control outer and inner movement). There are also two minor muscles, namely the inferior oblique (controls motion up and out or "extorsion") and superior oblique (controls motion down and in or "intorsion").

In additional to muscle which control movement, the lens of the eye is attached to a muscle called the ciliary body which controls anatomic movements and shape/focusing power of the lens. As we get older, this process of focusing, or accommodation gets weaker and most adults over 40 require reading glasses (magnifiers).

Finally, the iris or colored part of the eye is a muscle which can contract and expand and control the amount of light which enters the eye in various illuminated environments.

Adam D Koenigsberg MD FACS

www.eyemusclesurgery.com

Answer 2

Extrinsic muscles are voluntary muscles,external to the eye, that control the direction the eye moves in e.g looking left or right. Intrinsic muscles are within the eye, such as those that control the size of the pupil. Intrinsic muscle is not under voluntary control.

Answer 3

There are three intraocular muscles; the ciliary muscle, the iris dilator and the iris sphincter. The ciliary muscle is responsible for the accommodation reflex, which is used for focusing on near and far objects. If you know your Latin, you will probably be able to guess the functions of the next two muscles. If you don't, the iris dilator is responsible for widening the diameter of the iris (dilating the iris, hence 'dilator') and the iris sphincter is responsible for narrowing the diameter of the iris (Ancient Greek word for 'I bind tight' is sphingō).

Answer 4

They are the muscles that move the in quick and precise ways.