According to the World Health Organization, there are over 39 million people in the world who live with blindness, and another 246 million who suffer from low vision.
The WHO defines blindness as a visual field of less than ten degrees, or less than 20/500 vision in one’s better eye. The American Medical Association’s definition is “Central visual acuity of 20/200 or less in the better eye with corrective glasses.”
Apart from the medical definitions described above, there are legal definitions of blindness that differ from one country to another. Within the US, different states also define blindness differently, and these definitions determine eligibility for financial and medical assistance, and whether you’re allowed to obtain a driver license.
The AMA’s definition of blindness was adopted in 1934, and a year later Congress incorporated it into the Social Security Act as part of a program designed to aid the blind.
Why Am I Going Blind?
There are many causes of blindness, which can sometimes accompany seemingly unrelated conditions such as cerebral palsy or epilepsy. Some other possible causes of blindness include:
- Age—nearly 2 million Americans are blind, and over half of them are over the age of 65. Age-related macular degeneration is a particularly common cause of blindness among the elderly.
- Eye Injury
- Optic Neuritis
- Cytomegalovirus (CMV) retinitis is fairly harmless in healthy people, but can threaten the sight of people whose immune systems are compromised.
- Macular dystrophy, a rage genetic condition.
- Cataracts account for nearly half of all cases of blindness.
- Glaucoma is a distant second place behind cataracts, accounting for just over 12 percent of cases.
- Retinoblastoma is a type of malignancy that affects the eye.
- Diabetic retinopathy is one of many complications of diabetes that can result in blindness.
- Retinal detachment is a condition in which the retina peels away from the back of the eye like the skin of an orange.
- Trachoma and Onchocerciasis (“river blindness”) are parasitic infections that cause blindness in many parts of the developing world.
What Complications Does Blindness Cause?
Many of the challenges faced by blind people are obvious—they cannot drive or watch movies or television (although they can listen), and there are limitations to their ability to use computers. But there are additional challenges stemming from blindness that most of us do not consider.
Among the totally blind—those who cannot even perceive the presence or absence of light—it is estimated that more than 50 percent suffer from non-24-hour sleep/wake disorder, a condition in which the circadian rhythm is not aligned to the 24-hour cycle of light and darkness.
Such people have irregular sleeping and waking patterns, making it difficult for them to adapt to the schedules required in the professional and social lives.
How Will I Learn to Adapt to Blindness?
While blindness is still a considerable challenge, it is not the terrible handicap it once was. Many blind people now employ specially trained guide dogs to assist them, and these animals enable them to enjoy a degree of mobility that was once unimaginable.
The white-tipped canes carried by many blind people serve a dual purpose, assisting blind people with navigation while alerting passers-by to their impairment.
Advances in technology have enabled the blind to adapt in some surprising ways. Computers, for example, can be equipped with voice interfaces and refreshable Braille displays. These devices display online text via a row of mechanical character cells containing combinations of round-tipped pins that are raised and lowered to create Braille letters that can be read with the fingertips.
Automated Teller Machines now serve people with visual impairments by a combination of synthesized speech and Braille keypads, and many cities have installed audible traffic signals. Technology has also improved mobility for the blind; GPS devices can now be used to augment the services provided by guide dogs.
Some countries have taken measures to make it easier for blind people to use their currencies. The Euro, the British Pound, and the Indian Rupee all operate on systems in which the bills and notes increase in size according to their value.
The Canadian Dollar is adapted in another way, with a tactile feature; raised dots (similar to Braille letters) enable the user to distinguish a bill’s value by touch. In the US and other countries, some blind people develop the habit of folding bills in different ways according to their value.
Early in his career, the blind singer and pianist Ray Charles famously would take payment only in one-dollar bills in order to ensure that he was not cheated.
A List of Successful Blind People
Ray Charles is certainly not alone in having made his mark on the world despite blindness. Other notable blind people who have achieved noteworthy success include:
- Musician Stevie Wonder
- Writer John Milton
- Activist and writer Helen Keller
- Louis Braille, inventor of the Braille alphabet used by blind people all over the world.
- Guitarist Blind Lemon Jefferson, the legendary “Father of Texas Blues”
- Writer Aldous Huxley
Is There a Way to Prevent Blindness From Happening?
Recent research suggests that drinking coffee may help to prevent blindness! Raw coffee beans contain a small amount of the antioxidant chlorogenic acid, which may act to protect the retina from a variety of diseases, including diabetic neuropathy, glaucoma, and macular degeneration.