Myopia is generally limited to 300 degrees, and people below 300 degrees will not squint during outdoor activities. At this time, they can see clearly and without blurring, so it is not recommended to wear prescription glasses. It is only recommended to wear prescription glasses during class, watching TV, and watching computers.
However, above 300 degrees, you feel that you won't squint at things, but in fact, when you see things that are blurred, you will use greater adjustment to see things in the distance. According to the blurring theory of ophthalmology, your nearsightedness will accelerate and it is easy to form astigmatism. The principle of deepening myopia is that when you see something blurred, the ciliary muscles of the eye need to use greater regulatory power. Over time, the ciliary muscles will become tired and lose their elasticity, forming pseudomyopia. Over time, the eye axis will elongate, forming true myopia. In a relaxed state of eye regulation, when external parallel light enters the eye and its focus falls right on the retina, a clear image is formed, which is called emmetropia; If the focus cannot fall on the retina, it is called non emmetropia, which is ametropia. Low-degree true myopia is converted to moderate myopia below 600 degrees due to new fatigue and new pseudomyopia in the eyes. And then develop into high myopia. Therefore, we recommend wearing glasses all day long at temperatures above 300 degrees.
Without prescription glasses for nearsighted eyes, seeing things in a blurred state can only accelerate the development of myopia and form astigmatism more quickly. Greater astigmatism can cause headaches and is more difficult to correct than simple myopia.