Optical Instruments

• Cornea: A dome-shaped lens that protects the iris and pupil and works with the lens to focus the light coming into your eyes.
• Iris: Controls how wide the pupil is and limits the amount of light entering the pupil, widening when darker and narrowing when brighter.
• Pupil: A black opening that lets light into your eyes.
• Lens: The main convex lens that focuses light from the pupil toward the retina of your eyes.
• Lens thickens to focus on nearby objects and thins to focus on distant objects.
• Retina: Made up of millions of cells that are sensitive to light, these cells turn the light they detect into electrical signals that are sent to the brain.
• Brain and Optic nerve: Flip and create the image formed by the retina, the brain combines the images from both eyes.
• 1. Myopia/Nearsightedness

  • light rays converge and focus on a point before the retina, causing distant objects to appear blurry.
  • cornea may be too curved or the lens may be too thick.
• Hyperopia/Farsightedness

  • light rays converge at a point further than the retina, causing nearby objects to appear blurry.
  • cornea may be too flat or the lens may be too thin.