Among the internal factors, there are two main manifestations:

1. Genetics: About 40% of myopia cases are hereditary, mainly related to high myopia (more than -6.00 diopters). High myopia is categorized into two types: physiological and pathological. If it is pathological myopia, then a child is more likely to develop myopia. If one parent has high myopia and the other has normal vision, the risk of their child developing high myopia is about 10%–15%. If one parent has high myopia and the other is a carrier of the myopia gene (without showing symptoms), the risk rises to 50%. If both parents are carriers of the myopia gene but have normal vision, the child has a 25% chance of developing high myopia. However, not all cases of myopia are inherited.

2. Development: Infants are typically farsighted due to their small eyeballs. As they grow and their eye axis lengthens, their vision generally normalizes by around age 6. However, if the eye axis continues to grow excessively, myopia can develop. These two internal causes are inherently uncontrollable.

The second major cause is external factors , including:

1. Viewing objects too closely: Studies show that many young people frequently use their eyes at very close distances. Since their eyes have strong focusing ability, they can still see clearly even when reading material is within 10 cm. However, prolonged close-up work causes eye strain, which eventually leads to myopia.

2. Excessive eye usage time: Both youths and adults often overuse their eyes due to homework, the temptation of screens (phones, TVs), and work stress. These lead to prolonged eye use without sufficient rest, preventing proper relaxation of the eyes.

3. Poor visual environment: People often use phones while in vehicles, on the street, indoors, or outdoors. These environments are not conducive to eye health—the constant body motion makes it hard for the eyes to focus, and unstable lighting increases eye strain. Over time, these conditions contribute to the onset of myopia.

To better protect vision, it is essential to focus on prevention, especially among young people. This includes:
· Developing good eye-use habits and correcting bad ones
· Ensuring a proper visual environment
· Getting enough outdoor activity
· Undergoing regular vision checkups to understand your eye health and take preventive measures early.