Ocular globe is a very complex organ consisting of many tissues which protect optic nerve and photoreceptor cells. It sits in the skull cavity and is surrounded by fibrous muscle and lipoidal tissues. The eye is protected from external environment, infection and bright light by eyelids and eyelashes. Moreover, continuous tear production removes foreign objects from the eye. The anterior segment consists of a refractive system while the posterior segment consists of a visual light perceptive mechanism. Light rays entering the eye are focused onto the retina producing continuous images that are spontaneously transmitted to the brain. In this chapter, we discuss the anatomy and physiology of various ocular structures commencing from the anterior segment. Most of the aspects mentioned in this chapter describe the human eye unless otherwise specified.