Ophthalmologist and Physician-Scientist
Three Attributes to Know about Blindness

Three Attributes to Know about Blindness

There are many terms used by the United States medical community to describe people affected by blindness. Though each person’s experience is unique, all individuals affected by different forms of eye conditions leading to blindness are forced to adapt to a world developed and driven by people who are sighted.

Most of what people who are sighted believe they know about the lives of those affected by blindness comes from movies, television shows, or other sources of media and pop culture. Not all of this information is accurate. In the interest of spreading more awareness about blindness and the lives of those who live with it, listed below are three attributes about the condition.


  1. Legal blindness and total blindness are different conditions.

Many people hear the term “blindness” and think of a person who is completely unable to see. However, “legal blindness” can actually refer to people affected by a spectrum of vision disorders and capabilities of sight.

According to the US government, a person who is “legally blind” has a medically diagnosed central vision acuity score of 20/200 or less in the best-functioning eye with the aid of the best possible correction tools. Alternatively, legal blindness may consist of someone who has a visual field consisting of less than 20 degrees.

It’s important to understand some people who meet the criteria for legal blindness may actually maintain some usable form of sight, though severely limited. For context, an individual affected by legal blindness with the absolute best possible vision can only see from a maximum of 20 feet away what a person who is sighted can see from about 200 feet away.

Conversely, about 15 percent of all people who are legally blind are diagnosed with “total blindness.” This term refers to a person without any sight in either eye. In addition to legal blindness, there are a number of other vision quality classifications, such as low vision.

Low vision is considered by some federal groups to be anyone with poor sight who must rely fully on low vision devices, environmental modifications and visual strategies to navigate daily life and for whom corrective lenses do not work sufficiently.




  1. Approximately 36 million people around the world live with blindness.

According to the most recent research conducted by the World Health Organization, approximately 36 million people around the world qualify as blind. The Centers for Disease Control and Prevention reports more than 1 million individuals belonging to this group are from the United States. Another 12 million Americans qualify as having visual impairments, and a majority of this group is aged 65 years and older.

In spite of the life-changing experience of losing vision, it’s important to note people living with blindness in highly-developed countries such as the US have many tools at their disposal. These resources allow them a great deal of freedom and independence in spite of the condition.

Examples of these tools include robotic gloves to assist in locating doorknobs or small objects, guided auditory navigation systems and smartphone operating systems, which allow people with blindness to use every function on the phone a sighted person can use. It is clear technology is providing ways to give people without sight greater autonomy over their own lives.


  1. Blindness in the US is most commonly caused by four main diseases.

The World Health Organization reports 80 percent of all cases of blindness could be prevented or potentially be cured if people had access to regular eye examinations and prompt treatment. In the majority of cases, the cause of a person’s blindness can be equated to one of the four following diseases and conditions.

Glaucoma. This condition is caused by increased intraocular pressure in the eye eventually leading to damage of the optic nerve. When left untreated, the damage can result in permanent, total blindness.

In most instances, if a diagnosis is made early, an ophthalmologist can prescribe treatment in the form of eye drops or surgery. This limits the amount of damage to the optic nerve, preventing total loss of vision.

Cataracts. This is a condition in which the lens of the eye becomes clouded. Cataracts are caused by the buildup of proteins and often are a natural result of aging. They tend to develop over time and are common in people aged 60 years and older. Cataracts leading to serious vision loss are commonly and easily treated with surgery, in most cases.

Macular degeneration. This disease may occur as a result of the aging process. Macular degeneration is a result of the deterioration of part of the retina known as the macula. The retina is the light-sensitive part of the interior of the eye responsible for the reception and translation of light from the eye to the brain.

As in glaucoma and cataracts, there are often few symptoms of macular degeneration in the earlies stages. While there is currently no cure, the earlier the condition is diagnosed, the more effective treatment is likely to be.

Diabetic retinopathy. This disease occurs in people living with diabetes. High blood sugar levels cause the blood vessels in the eye to expand and leak, or contract and dry up, causing retinal damage.

Some surgical treatment options are available to diabetic retinopathy patients. However, experts suggest the best way to prevent this condition is to lead a healthy lifestyle to gain greater control over diabetes.