There is no single "bad vision" level, as vision is a complex sense with multiple aspects. Instead, vision is measured on a scale, and different levels of impairment affect individuals differently.
Understanding Vision Measurement
Vision is typically measured using a Snellen eye chart, which displays letters of varying sizes at a specific distance. The result is expressed as a fraction, such as 20/20, where the top number represents the distance at which the person is standing from the chart, and the bottom number represents the distance at which a person with normal vision can read the same line.
- 20/20 Vision: This is considered normal vision.
- 20/40 Vision: This means that a person can see at 20 feet what a person with normal vision can see at 40 feet.
- 20/100 Vision: This indicates a more significant impairment, meaning the person can see at 20 feet what a person with normal vision can see at 100 feet.
Impact of Vision Impairment
The impact of vision impairment varies depending on the level of impairment and the individual. Some people with mild vision impairment may only need corrective lenses, while others with more severe vision loss may require assistive devices or specialized training.
Levels of Vision Impairment
- Low Vision: This refers to vision loss that cannot be corrected with eyeglasses or contact lenses, but which can be improved with assistive devices.
- Legal Blindness: This is defined by the US Social Security Administration as a visual acuity of 20/200 or worse in the better eye with correction, or a field of vision of 20 degrees or less.
- Total Blindness: This refers to the complete absence of light perception.
It's important to note that these are just general guidelines. The specific impact of vision impairment can vary greatly depending on the individual and their unique circumstances.
