Understanding Legal Blindness and Total Blindness: Key Differences and Implications
Visual impairment can take many forms, and understanding the distinction between legal blindness and total blindness is crucial for accurate diagnosis and appropriate support. While both conditions severely impact an individual's ability to see, they present different scenarios and challenges, as explained below.
Legal Blindness
Legal blindness is a specific level of vision impairment defined under the standards provided by various governmental and health organizations, including the World Health Organization (WHO) and the American Academy of Ophthalmology (AAO). In the United States, the definition of legal blindness is based on a Snellen chart test, where visual acuity in the better eye, with best possible correction, is 20/200 or less. Additionally, it can also be defined by a visual field of 20 degrees or less, even with correction. The Snellen chart test measures the smallest letters one can read at a distance of 20 feet. A person with 20/200 vision can only see at 20 feet what a person with normal vision can see at 200 feet.
The criteria for legal blindness vary slightly from state to state in the U.S., but generally, it includes the requirement of maintaining a central visual field of more than 20 degrees. This test ensures that an individual can recognize faces and read large print, although they struggle at longer distances or with fine details.
Legal blindness can be measured annually, and a new prescription can be necessary every 8 years. It is important for individuals to have regular eye examinations to monitor their visual acuity and adjust their prescriptions as needed.
Total Blindness
Total blindness, on the other hand, is a condition where an individual cannot perceive any light and has no visual perception at all, often described as No Light Perception (NLP). This condition signifies a complete loss of sight and can be caused by a variety of medical conditions, including hereditary diseases, glaucoma, or diabetic retinopathy that are not successfully treated.
Individuals who are totally blind often learn to compensate with other senses, such as touch, hearing, and smell. They may also use Braille, guide dogs, and audio books to navigate their daily lives. The experience of total blindness can be overwhelming, and individuals may require significant support and adaptation.
Differences in Implications
The key differences between legal blindness and total blindness lie in the level of visual capability and the support required. Individuals with legal blindness may still have some visual perception and are often able to perform daily activities with some adjustments. They can drive with adaptive equipment or use special glasses, such as the trifocals, bifocals, and reading glasses mentioned in the examples provided. They may also benefit from low-vision aids, such as magnifiers and audio devices.
In contrast, individuals with total blindness have no vision at all and require more extensive assistance. They may rely on guide dogs, flashlights, and auditory signals to navigate their surroundings. The process of adapting to total blindness involves learning new skills and techniques, such as using echolocation, and building a support network of friends, family, and professionals.
Conclusion
While both legal blindness and total blindness severely impact the quality of life, they represent different levels of visual impairment. Understanding the distinctions is crucial for providing the right support and resources to those affected. Whether it's adjusting to legal blindness with the help of specialized glasses or navigating the world with total blindness, the key is to support individuals in developing the necessary skills and tools to lead fulfilling lives.