In general, "bad" eyesight is defined as anything worse than 20/20 vision, meaning you need vision correction to see clearly.
Here's a breakdown:
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20/20 Vision: This is considered "normal" vision. It means that when you stand 20 feet away from an eye chart, you can read the letters that people with normal vision can also read at that distance.
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Less than 20/20: This is considered below normal. The further the second number is from 20 (e.g., 20/40, 20/100, 20/200), the worse the vision. For example:
- 20/40: You can see at 20 feet what a person with normal vision can see at 40 feet.
- 20/200: You can see at 20 feet what a person with normal vision can see at 200 feet. This is generally considered legally blind.
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Why is 20/20 Important? 20/20 vision is important for everyday tasks, such as:
- Driving safely
- Reading
- Recognizing faces
- Navigating your environment
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Vision Correction: Many options exist to correct vision, including:
- Eyeglasses: The most common and simplest solution.
- Contact Lenses: Provide a wider field of view than eyeglasses.
- Refractive Surgery (LASIK, PRK): Permanently reshapes the cornea to improve vision.
In conclusion, the degree of "bad" eyesight is measured relative to the 20/20 standard, with lower ratios indicating poorer vision and a greater need for corrective measures.
