Myopia, also known as nearsightedness, affects how far someone can see clearly, with the exact distance varying depending on the severity of the condition.
Understanding Myopia and Visual Acuity
Myopia causes distant objects to appear blurry because the eye focuses light in front of the retina instead of directly on it. The severity of myopia is often described using visual acuity measurements, which compare a person’s vision to that of someone with normal vision.
Vision Measurements Explained
Visual acuity is expressed as a fraction, such as 20/20, 20/30, or 20/100. The first number (20) represents the distance in feet at which a person with normal vision can see a particular object. The second number represents the distance at which a person with myopia must stand to see the same object clearly.
| Vision Measurement | Description |
|---|---|
| 20/20 | Normal vision. A person can see at 20 feet what a person with normal vision can see at 20 feet. |
| 20/30 | Mild myopia. **A person sees at 20 feet what a person with perfect vision can see at 30 feet**. |
| 20/40 | Moderate myopia. A person sees at 20 feet what a person with normal vision can see at 40 feet. |
| 20/100 | Severe myopia. A person sees at 20 feet what a person with normal vision can see at 100 feet. |
Examples of Myopia and Viewing Distance
- Mild Myopia: A person with 20/30 vision may see at 20 feet what a person with normal 20/20 vision can see at 30 feet. This means they can see reasonably well at a short distance but may struggle with distant objects.
- Moderate Myopia: Someone with 20/40 vision would need to be twice as close to an object to see it clearly compared to someone with 20/20 vision.
- Severe Myopia: A person with 20/100 vision needs to be very close to an object to see it with the same clarity as a person with 20/20 vision at 100 feet.
Practical Implications
- People with mild myopia may only need glasses for specific tasks such as driving or watching a movie.
- Individuals with moderate or severe myopia require corrective lenses for most activities, including reading, working, and daily interactions.
Conclusion
In summary, the range of clear vision for a person with myopia varies greatly, depending on the severity. The reference explains that someone with mild myopia (20/30 vision) can see at 20 feet what a person with perfect vision can see at 30 feet, emphasizing that the further the second number is from 20, the more severe the myopia, and the shorter the distance a person can see clearly.
