Eyeballs

Parts of the eye

• Sclera - The white of the eye
• Cornea - the clear outer surface of the eye
• Aqueous Humor - the fluid supporting the cornea
• Pupil - the hole where light enters the eye
• Iris - the muscles that control the pupil size
• Ciliary Muscle - the muscles that move the lens in the eye
• Lens - The part that changes the focus distance of the eye
• Vitreous Humor - the gel filling the eye (this is where floaters usually form)
• Rods and Cones - the sensory cells of the eye that see light intensity and color
• Retina - the tissue that supports the rods and cones.

Axial Length

The primary cause of differences in refractive state is the length of the eye, referred to as axial length. Long eyeballs are associated with myopia, as the natural lens of the eye focuses light too far forward of the retina.