Ford produced Model Ts in this manner for three years at its new Highland Park plant before adopting the assembly line. When modern drivers think about the Ford Model Tâif they think about it at allâthey perhaps dimly perceive it as the car that changed the world.
The Cornea. The cornea represents the strongest part of the refracting power of the eye, providing about 80% of the power of the system. The index of refraction of the cornea is about 1.376. Rays pass from the cornea into the watery fluid known as the aqueous humor which has an index of refraction of about 1.336, so most of the refraction is at the cornea-air interface.
Its transparency permits light to pass into the eye, through the pupil, lens, and onto the retina at the back of the eye. The three major corneal layers are the outer layer of the cornea or epithelial layer, the middle layer termed the stroma, and finally a single layer of cells called the endothelium. The curvature of the cornea plays an important role in focusing (refracting or bending) light. The normal cornea is smooth, clear, and tough. It helps protect the eye from infection and foreign material.