How Your Eyes Work

Light is passing through the cornea, the aqueous humor, the pupil, the crystalline lens and the vitreous body before reaching the retina.

  • Sclera or “white of the eye” Outer white and opaque membrane, covering the eyeball. It protects the eyeball and muscles attached to it control the eye's movements

  • Retina Light-sensitive inner membrane, it hosts photoreceptor cells (rods* and cones*)

  • Cornea  Transparent front side circular area in the sclera where light enters the eye. It covers the iris, the pupil and the anterior chamber of the eye

  • Angle of the Anterior Chamber Area of the anterior chamber where the cornea and iris join.

  • Iris Coloured smooth muscle surrounding the pupil. The iris contracts and dilates according to the brightness of the light and to allow more or less light to enter the eye.

  • Pupil Orifice in the middle of the iris, where light enters the retina

  • Crystalline Lens Transparent, flexible and bi-convex lens that concentrates light rays on the photoreceptor cells of the retina

  • Ciliary Body Smooth muscle that modifies the curvature of the crystalline lens and in doing so allows a better accommodation of the eye

  • Zinn’s Zonule Ring of fibers connecting the ciliary body and the crystalline lens.

  • Vitreous body Gelatinous fluid filling the space between the lens and the retina. It helps to maintain the retina against the eye wall and the intraocular pressure.

  • Macula Small area at the center of the retina, highly concentrated in cones. Its diameter is around 2 mm. The center of the macula is the Fovea Centralis, exclusively composed of cones and offers the sharpest vision

  • Optic disc Part of the retina where the optic nerve fits into, as blood vessels. This area is also called the blind spot because there are no receptors in this part of the retina.

  • Central retinal vein Vein that runs through the optic nerve and drains blood.

  • Optic nerve Nerve that transmits visual information (electrical signals) to the brain.

  • Blind Spot

  • Anterior Chamber Space located between the cornea and the iris, filled with a watery fluid, the aqueous humor. This liquid helps to refract light rays.