Rittenhouse Eye Associates

Vision is tested by reading lines on the Snellen eye chart. 20/20 vision means you can read at 20 feet what a person with normal vision can read at 20 feet. 20/40 vision means you read at 20 feet what a normal person can read at 40 feet. 20/40 is generally the minimum to pass a driver’s license test. Vision of 20/200 is usually considered legal blindness.

HOW DO WE DO IT??? People can see shapes and judge distances because having two eyes set a distance apart gives us binocular vision. Instead of seeing double, however, our brain has learned to assemble images from both eyes into one image and then proceed to determine the shape of objects and how far away they are.

HERE'S LOOKING AT YOU: Eyeglasses, a necessity of life in modern days, are thought to have been first made in Italy around the year 1286. Within 20 years of that date, a guild for making them had been established in Venice. The first known attempt at sunglasses occurred even earlier in China in the form of flat... panes of smoky quartz used to shield the eyes from bright sunlight. The first bifocals were created by Benjamin Franklin. See more

When people think of an eye exam they think of a chart with black letters on a white background. The real world, however, is full of shades of gray and people with a condition known as poor contrast sensitivity can have a problem where objects seem to blend and become indistinguishable against backgrounds with similar coloring. A contrast sensitivity test, using a special chart, can determine If the condition exists.

When affected by high winds or cold weather, we may say our eyes are "watering. Actually, they’re producing tears. Besides expressing sadness, tears serve a protective purpose by keeping eyes moist and washing out dust and specks of dirt. Tears are produced by the lacrimal glands located under our upper lids and drain out through two tear ducts near the inside corner of each eye.