Do contact lenses have a shelf life?

Many people suffer from myopia in life. When myopia occurs, it will have a lot of impact on seeing things, so many people choose to wear glasses. Currently, there are framed glasses and contact lenses. Contact lenses are more convenient to use. Of course, some people do not have myopia, but they wear cosmetic contact lenses for the sake of looking good. No matter what the circumstances, the contact lenses they wear must have a shelf life, and they cannot be worn after the shelf life has expired.

Do contact lenses have a shelf life?

1. First of all, we need to know that there are two concepts of the shelf life of contact lenses. The first refers to the shelf life when the product is not unpacked after leaving the factory, that is, the shelf life before it is used. Generally, the production date and expiration date are written on the packaging of contact lenses. As long as they are opened and used before the expiration date,

Both are fine.

2. After the shelf life of contact lenses has expired, the lenses will age, become hard, discolor, reduce transparency, deform and thicken, and the amount of protein and other sediments on the lenses will increase, making it easy for microorganisms to deposit, resulting in poor oxygen permeability. If the

Continuing to wear it can easily lead to conjunctival inflammation and corneal hypoxia, and the comfort level will be much worse.

3. The second type is the shelf life of the contact lenses after they are opened, which is also the usage cycle of the contact lenses. They are mainly divided into daily disposable, monthly disposable, semi-annual disposable, annual disposable, etc. Even if you have only worn this pair of contact lenses a few times, you must discard them when the cycle is over.

4. We would like to remind everyone that the shelf life of contact lenses is calculated from the day the contact lenses are unpacked, not the number of days they are worn. The theoretical disposal cycle for annual disposable contact lenses is one year, but in reality they can be discarded after 8 to 10 months. The six-month disposal period is 6 months, but it is actually better to discard it after 4 to 5 months. It is recommended to analyze the specific situation according to your own care situation. Once the contact lenses show the above symptoms, they should be replaced in time.

The dangers of wearing expired contact lenses

Decreased vision

Wearing expired contact lenses can easily cause vision loss. Because contact lenses are worn for too long, the lens aging phenomenon will be more serious, there will be varying degrees of wear and tear, and a lot of bacteria will remain. Contact lenses are close to the cornea. If too much sediment accumulates on the lens, symptoms of corneal ulcers may appear, which will lead to decreased vision.

Corneal damage

The cornea mainly absorbs oxygen from the air. Wearing contact lenses will affect the respiration of the cornea. Expired contact lenses will have a large amount of protein deposits, which will make the oxygen permeability of the lens worse and worse, aggravate corneal hypoxia, increase the chance of infection, and even cause corneal damage.

Dry Eyes

There will be a lot of dust, mucus, protein and minerals on the lenses of expired contact lenses. These sticky substances will cause the lenses to become less itchy and make people more prone to visual fatigue, which will cause discomfort to the eyes, such as dry eyes, increased eye mucus, etc. If these conditions are not taken seriously enough, they may even cause dry eye syndrome.

Corneal hypoxia

The cornea itself has no blood vessels, and the oxygen needed for its metabolism is mainly supplied by external air. Wearing contact lenses will affect the breathing of the cornea to a certain extent. Expired contact lenses are covered with a lot of sediments. These substances will greatly reduce the oxygen permeability of the lenses, and further cause corneal hypoxia.

Eye allergy

Contact lenses will absorb proteins, lipids, collagen and other substances in tears, which will be deposited on the surface of the lens. Expired glasses will accumulate more and more deposits and breed more and more bacteria due to being worn for too long. Wearing them again will cause corneal edema, corneal neovascularization and allergic reactions.