When selecting the cheapest eyeglasses lenses, the most important factor is the refractive index. When the refractive index of glasses remains constant, the higher the refractive index, the thinner the lens. Therefore, people with high refractive index are more suitable for wearing lenses with high refractive index.

Of course, if the refractive index is not too high, there is no need to blindly pursue a high refractive index, as the higher the refractive index, the higher the price of the lens.

Another point is that lenses with higher refractive indices generally have lower Abbe numbers (also known as dispersion coefficients; the higher the Abbe number, the more realistic the view). This is another reason why low refractive index glasses are not recommended.

The material and coating of the cheapest eyeglasses lenses endow different lenses with different properties. The biggest difference between them in practical use also lies in this.

The main reason why wearing lenses can be uncomfortable is that the thickness of the lenses is uneven, which causes the things you see through the center of the lens to be clear and undistorted. However, when you look around the lens, your line of sight cannot pass through the optical center, resulting in a distorted field of view.

So, we need to choose lenses that are scientifically designed so that we can see clearly and accurately from any angle through the lenses.

There is a cold knowledge that myopia and presbyopia cannot offset each other, even if one is handsome. Therefore, when people with myopia start to experience presbyopia with age, they need to wear progressive lenses.

Compared to adding a pair of presbyopia glasses, progressive lenses have advantages. Firstly, whether looking far or close in work and life, wearing a pair of cheap eyeglasses is enough without the hassle of frequently changing glasses.