Medical Illustrations

Picture of Eye

Illustration of the eye

The eye is the organ that reacts to light, allowing us to see. The eye is composed of various parts, all of which work together to allow sight to occur. These parts include the cornea, iris, pupil, lens, retina, retinal blood vessels, and the vitreous body.

  • Cornea: The cornea makes up the front-center part of the eye's outer wall. The cornea bends light, focusing it on the retina. People who wear contact lenses place their lenses on the cornea.
  • Iris: The iris is the colored part of the eye. It works with the pupil to regulate how much light enters the back of the eye.
  • Pupil: The pupil is the dark circle in the center of the iris. The amount of light entering the eye is determined by the degree of pupil constriction.
  • Lens: The lens is the area immediately behind the pupil. The lens bends light entering into the eye and focuses it on the retina. The lens changes shape to focus on objects that are near.
  • Retina: The retina is the thin, transparent tissue that lines the interior of the inner wall of the eye. The retina is analogous to film inside a camera where images are first projected before being transmitted to the brain via the optic nerve. The retina is very complex. It has 10 distinct layers with specialized cells, including rods and cones.
  • Retinal blood vessels: The blood vessels that nourish the retina are located in the choroid. The choroid is a layer of tissue located between the retina and the sclera.
  • Vitreous body: The vitreous cavity is located between the lens and the retina. It comprises approximately 80 percent of the area of the back part of the eye. The jelly-like vitreous humor fills the vitreous body. This substance helps nourish the inner eye. Light enters the eye through the pupil and passes through the vitreous before it is projected onto the back of the eye (retina).
Image Source: MedicineNet, Inc.

Text Reference: American Association for Pediatric Ophthalmology and Strabismus: “Anatomy of the Eye”