An animated film details the parts of the eye. Lynn Poole compares the operation of an eye to that of a television camera. Eye prints reveal retinal detachment, glaucoma, and diseases of the body such as diabetes. A diagram traces the evolution of the eye. A history of sight-related research includes Galileo's telescope, Sir Isaac Newton's experimentation with prisms, Dr. Thomas Young's work with astigmatism, and Hermann von Helmholtz's development of the ophthalmoscope to look into the interior of the eye. Dr. Stewart Wolff, ophthalmologist at Johns Hopkins' Wilmer Eye Clinic, displays an electric ophthalmoscope, demonstrates a slit lamp, using Lynn Poole as a patient, and shows slides of cataracts. He also explains the test for tunnel vision with the tangent screen and peripheral field examination, the Snellen chart to test eyesight, and the tonometer to measure the intraocular pressure of the eye.