Clear vision occurs when light rays enter the eye and are focused by the cornea and lens directly on the retina (Emmetropia).

Presbyopia is a condition in which there is reduced reading vision first noticed around age 40.

• Cornea: the clear front window of the eye. The cornea transmits and focuses light into the eye.
• Iris: the colored part of the eye. The iris helps regulate the amount of light that enters the eye.
• Pupil:   the dark center in the middle of the iris. The pupil determines how much light is let into the eye.
• Lens: the transparent structure inside the eye that focuses light rays onto the retina.  When it becomes cloudy, it is called a cataract.
• Retina: the nerve layer that lines the back of the eye. The retina senses light and creates impulses that are sent through the optic nerve to the brain.
• Macula: a small central area in the retina that allows us to see fine details clearly.
• Optic Nerve: the nerve that connects the eye to the brain. The optic nerve carries the impulses formed by the retina to the brain, which interprets them as images.
• Vitreous:  the clear, jelly-like substance that fills the middle of the eye.