10 little-known facts about blindness

How guide dogs know when the light turns green, and nine other surprising facts that will expand your understanding of blindness.

A girl uses a white cane to navigate while crossing a bridge.

Do you think you know everything there is to know about blindness? Think again. Did you know, for example, that the divorce rate for people who are blind is only one-third the rate for Americans in general? Or that people who are blind are more apt to have nightmares than people with sight? Here are some surprising facts and figures about the complex world of blindness.     

  1. There are different degrees of blindness. Someone can be legally blind but still see colors, shapes and varying degrees of light. In fact, only about 10-15 percent of people who are blind see nothing at all.
  2. Anne Sullivan is known worldwide as the teacher and companion to Helen Keller. However, many don’t know that Sullivan herself was visually impaired. An eye infection left her nearly blind at the age of 8, although she later regained some vision after a series of operations.
  3. You might walk by someone who is visually impaired and not know it – fewer than 2 percent of visually impaired people use a white cane to navigate. The rest use guide dogs or nothing at all.
  4. Surprisingly, 80 percent of vision problems worldwide could be avoided or even cured with prompt medical care and regular eye examinations. In particular, a leading cause of blindness among adults over 50 is cataracts, which are treatable with surgery. Organizations like the World Health Organization are working to eliminate causes of avoidable blindness in developing countries.  
  5. People who are blind are just as likely as anyone else to experience vivid dreams while sleeping. The difference is that their dreams are dominated by sounds, smells and tastes. A Danish study also suggests that people who are blind must endure significantly more nightmares than their sighted counterparts.
  6. One of the greatest ballerinas of all time relied on strategically placed spotlights to find her way around the stage. Alicia Alonso lost sight in both of her eyes at the age of 19 but continued to perform in her native Cuba and all over the world into her late 70s.  
  7. Guide dogs can’t tell whether a traffic light is green or red or if it changes color. A person who is blind or visually impaired uses audible cues like traffic noise to determine when they think it is safe to cross, and then signals their dog to move forward. If a car is coming, the dog will refuse to obey the command.
  8. As many as 70 percent of people who are blind in the United States experience non-24-hour sleep-wake disorder – a condition where a person’s circadian rhythm is out of alignment with conventional sleep schedules, causing insomnia at night or the urge to sleep during the day.
  9. People who are blind are often better at identifying aromas than their sighted peers. Studies have refuted the age-old myth that blindness sharpens other senses, but researchers believe that people who are blind pay more attention to how an object smells and devote more cognitive energy toward cataloguing that information.    
  10. People who are blind are often lucky in love – 65 percent of Americans who are blind are married or live with a partner and only 16.5 percent have divorced.