Same as tires, toothbrushes and batteries, lenses also have an expiration date. So, how long can the lenses last? Actually, lenses can be reasonably used for 12 months to 18 months.

1. Lens freshness
During the use of optical lens, the surface will be worn to a certain extent. The resin lens can absorb ultraviolet rays, but at the same time, the lens will also age and turn yellow. These factors will affect the transmittance.

2. The prescription will change every year
With the change of age, the eye environment and the degree of use, the refractive state of the human eye has been changing, so it is necessary to re-optometry every one year or a year and a half.

Many people think that their eyesight has been set. As long as the myopia glasses are not bad, it is OK to wear them for several years. Even some elderly people have the habit of “wearing a pair of glasses for more than ten years”. In fact, this practice is incorrect. Whether it is myopia or presbyopic glasses, they need to be checked regularly and replaced in time if discomfort occurs. Ordinary myopia patients should usually change their glasses once a year.

Teenagers who are in the period of physical development, if they wear blurry glasses for a long time, the retina of the fundus will not receive the stimulation of clear objects, but will accelerate the development of myopia. Generally speaking, teenagers who wear myopia glasses should have their eyesight checked every six months. If there is a big change in the degree, such as an increase of more than 50 degrees, or the glasses are badly worn, they should also change the glasses in time.

Adults who do not use their eyes often should have their eyesight checked once a year and their glasses checked for damage. Once there is a scratch on the lens surface, it will obviously affect its optical correction performance. The presbyopic glasses of the elderly should also be replaced regularly. Presbyopia is caused by aging of lens. The aging degree of lens increases with age. Then the lens degree is increased. Old people should replace their glasses when they have trouble reading newspapers and their eyes are swollen.