What is the expiration date of contact lenses and how to find it out? There are two different types of them – until what date can the sealed package be stored and how long can they be used after opening it.
- The date is printed on the foil lid of the original container in year/month format. The standard shelf life is a period of four years from the date of manufacture. This is maximum; in fact, it ends at the moment you open the package.
- The time of use after opening the original packaging depends on which wear mode is indicated. Once opened, lenses should not be stored in their original container because the saline solution they were in is no longer sterile after opening. From now on, they can only be stored in a special multipurpose solution for storage and cleaning. It is sold separately and poured into a special container, which also must be bought. It has two compartments – for a pair of lenses, the right and left eyes. They may have different vision parameters and therefore they must be distinguished. The solution is changed every day.
On the foil cover, the characteristics are indicated:
Name of the manufacturer and trade mark;
Other characteristics (axis and angle for toric lenses, etc.).
With the help of this information, it is worth checking whether the expiration date has expired and whether the characteristics correspond to your recipe.
There are concepts of "wearing mode" and "wearing period".
This is the maximum amount of time the lenses can be worn.
Wearing modes are:
DW – daytime. Should be taken off at night.
- FW is flexible. Sometimes you can stay in them at night.
EW – prolonged. Can be worn without removing from eyes up to 7 days.
CW - long continuous. Can be worn without removing from eyes up to 30 days.
This is the period after opening and first use, after which the lenses must be replaced with new ones.
Daily replacement (one-day, disposable). Not stored, discarded at the end of the day.
Frequent scheduled replacement (every 1 – 2 weeks).
Scheduled replacement (in 1 – 3 months).
Traditional (after 6 months or more).
Often brands for lenses differ precisely in this parameter, so remembering the name of the brand once, it will be easier to navigate further.
Why is it important to respect the wearing period
When calculating the replacement period, the manufacturer takes into account the resistance of the material to protein deposits and contamination. If you use lenses for a long time, it can lead to inflammation and other eye diseases.