Based on the provided reference, the concept of "normal" myopia is not defined; however, myopia is categorized by severity into distinct ranges based on diopter measurements.
Myopia, often referred to as nearsightedness, is a common refractive error where distant objects appear blurry. It occurs when the eye focuses light in front of the retina instead of directly on it, resulting in blurry vision for faraway things. While a small amount of blur might be considered less impactful, the reference classifies myopia into different levels of severity based on the degree of the refractive error, measured in diopters (D).
The provided reference outlines the following classifications for myopia severity:
- Mild Myopia: Ranges from 0 to -1.5 diopters.
- Moderate Myopia: Ranges from -1.5 diopters to -6.0 diopters.
- High Myopia: Ranges from -6.0 diopters or more.
Additionally, the reference mentions:
- Pathological Myopia: Characterized by more than -8.0 diopters. It's important to note that while pathological myopia involves a high degree, significant eye diseases like retinal diseases, cataracts, and glaucoma can occur even in people with moderate to high myopia.
Therefore, while the reference does not label any specific category as "normal" myopia, it provides a clear structure for understanding the different levels of severity. Mild myopia represents the least severe end of the spectrum.
Here's a breakdown of these categories:
| Myopia Classification | Diopter Range | Notes |
|---|---|---|
| Mild Myopia | 0 to -1.5 D | Least severe form. |
| Moderate Myopia | -1.5 D to -6.0 D | Mid-range severity. |
| High Myopia | -6.0 D or more | Higher risk of associated eye health issues. |
| Pathological Myopia | More than -8.0 D | Often associated with significant structural changes and eye diseases. |
It's crucial to understand that any level of myopia is a deviation from emmetropia (vision with no refractive error, which is typically considered "normal" vision). However, mild myopia is very common and often easily corrected with glasses or contact lenses, typically with less associated risk compared to higher levels of myopia, although risks can still be present with moderate to high levels.
Understanding your specific diopter measurement helps determine the severity of your myopia and guides appropriate vision correction and eye care. Regular eye exams are recommended regardless of the degree of myopia to monitor eye health.
