The healthy eye works very much like a camera.  Light passes through a a series of lenses in the front of the camera, and is focused upon the film in the back of the camera.  In the eye, the light passes through the cornea, lens, and vitreous gel, and is then focused on the retina.  The retina works like the film in the camera.  The information gathered by the retina is then sent to the brain via the optic nerve.

The Retina

The retina is the nerve layer that lines the inside back wall of the eye.  Blood is supplied to the retina by the retinal artery.  The retinal artery enters the eye through the optic nerve, before branching into smaller blood vessels and eventually into microscopic capillaries.  Blood is collected by retinal veins which exit the eye through the optic nerve.  Retinal veins are thicker and darker than retinal arteries.  Located in the center of the retina is the sensitive macula.  The macula provides us with our central vision.  When we look directly at an object, the macula allows us to see the fine detail.  This sharp straight ahead vision is necessary for driving, reading, recognizing faces, and doing detailed works such as sewing.  The majority of the retina lies outside of the macula  The retina outside the macula provides us with our peripheral, or side vision.

The Vitreous

Many serious eye conditions are caused by problems with the vitreous.  The vitreous gell is a clear substance which fills the cavity of the eye and is attached to the retina.  It is jell-like in consistency, but also contains strong strands of protein.  With age the vitreous gel slowly liquefies, allowing protein strands to clump together, and often creating liquid filled pockets.  As a result, many patients recognize “floaters” which are particles in the vitreous gel.  These often become more noticeable with age.