Glasses also have a “shelf life”, so be sure not to let them expire!

Do glasses have a shelf life?

On the surface, glasses seem to have no shelf life, but as the years of use increase, wear and tear, skewness, etc. are bound to occur. At this point, the glasses are very likely to have "expired".

What effect will wearing a pair of "expired" glasses have on your eyes? Perhaps dry eyes, eye fatigue, decreased vision, etc. in your daily life are quietly caused by them.

1. Symptoms of expired glasses

1. The lens turns yellow and the light transmittance decreases

As the lens changes over the usage cycle, environment and temperature, the film layer and the material itself will undergo physical changes, causing the originally transparent lens to slowly turn yellow.

Friends who wear glasses can do a simple test themselves: put the lens on a piece of white paper, compare the color difference of the white paper through the lens, to detect whether the lens is yellowing (blue light lenses may have a certain degree of yellowness, which does not fall into the category of resin aging we are discussing).

2. Scratches are severe and affect performance

When there are many scratches on the surface of glasses, it will obviously affect the optical correction performance .

When particles in the air adhere to the lenses and the glasses become dirty, many people will use paper towels or glasses cloth to wipe them. In fact, glasses cloth is only used to wrap glasses, not professional wiping materials. If you use glasses cloth contaminated with fine particles to wipe glasses for a long time, scratches will appear over time.

In addition, when the lenses come into contact with chemicals such as cosmetics, oils, etc., they may also cause scratches and peeling.

3. Frame deformation and optical center deviation

After wearing glasses for a long time, the frame may be deformed. Frame deformation not only affects the appearance, but also causes horizontal deviation of the optical center of the lens, increases the burden on the eyeball's adjustment function , and affects vision.

4. Damaged edges, breeding ground for bacteria

Wearing glasses for a long time will cause patina and bacteria to grow on the edges and nose pads, which are not easy to clean. Over time, it will not only affect the appearance, but may even cause some eye diseases due to the growth of bacteria.

2. It may increase myopia

Glasses are tailor-made based on scientific and precise calculations of the various parameters of the eyes when fitting them.

However, with long-term use, the lenses will show varying degrees of wear and tear, including scratches, aging and yellowing, which will affect the optical correction function of the lenses. Not only will it fail to improve vision, but it will also cause visual fatigue and vision loss.

You should be especially careful with children and adolescents. If you find your child squinting, tilting his or her head, or reading too close to a book, you should take your child to the hospital for examination as soon as possible.

3. How often should glasses be replaced?

1. Teenagers : It is recommended that teenagers replace their lenses every six months to one year.

Adolescents are in the peak period of eye use. At the same time, this age group is also in the period of rapid eye development, so the degree of change will be relatively fast.

2. Adults : It is recommended to replace the lenses once every year and a half .

The normal service life of ordinary resin lenses is generally about one and a half years. If they are well maintained, they can be extended appropriately, but it is recommended to have a professional eye examination every year .

3. Elderly people : It is recommended to replace them regularly .

Older people's reading glasses also need to be replaced regularly. However, because the degree of reading glasses increases slowly, there is no strict time limit, and it needs to be determined according to each person's usage.