Some customers, after undergoing a re-examination, may not experience significant or even identical changes in the degree of the new discount eyeglasses online compared to the previous ones. However, when wearing them, customers may not be able to adapt, and some may even experience lower clarity compared to the old glasses. By comparing the different states of the new and old glasses, the root cause of the problem can be identified.

The common main causes of this problem are differences in refractive power between new and old lenses, differences in optical centers, and differences in wearing positions.

During the process of optometry, it is often found that some customers have used the cheapest eyeglasses online with excessively high luminosity, and some even have a much higher luminosity. Most of these customers have the problem of excessive adjustment.

Because overcorrection can lead to imaging behind the retina, the eyes need to use adjustments to focus the object image on the retina to see clearly. The eyes are in a state of long-term tension in adjustment, and once the degree is reduced, it is equivalent to relaxing the eyes with a positive mirror, but it cannot adapt. Some customers have reported a pulling sensation in the eye muscles, while others have reported blurred vision.

The prescription principle for discount prescription glasses for nearsightedness is the minimum negative spherical lens for optimal vision, but this principle may not be suitable for overcorrected eyes. For overcorrected eyes, it is recommended to:

① If the degree of overcorrection is not significant and there are no symptoms of visual fatigue caused by overcorrection, a conservative approach can be adopted, which is to not change the original prescription;

② If the degree of over-correction is severe, it is recommended to remove half of the degree of over-correction;

③ Overcorrected customers are suitable for wearing anti-fatigue lenses.