Contact lenses are divided by their period of wear. Daily contact lenses, it's the kind that dress up only once and is calculated on the day of operation. In the evening they are removed and no longer used in the morning, if necessary, wear new. Of the minuses for the application – high cost, as the price daily lenses, not cheaper lenses reusable. There are advantages - they are hygienic and require no special care. They are suitable for those people who do not wear the lens constantly, and wear them occasionally.
Lenses frequent planned replacement. Wear them during the day, and the night shoot in a special container for a lens cleaning solution. These lenses change their life, typically every two to three weeks or a month, or several months. Service life you will tell in optics, where you make the purchase. One of the advantages of replacement lenses, compared with daily lenses is the fact that one pair of lenses will last for a month or more, this means that the cost is less. If we talk about the cons, for these lenses you will also need a container, and a special liquid for storage. The liquid in the container should be changed frequently and therefore it needs to periodically buy more. Another disadvantage can be that sometimes the actual life of such lenses is less than planned. Lenses daily and routine replacement is not provided to wear during sleep.
Extended wear lenses. These lenses can be worn for several days. As a rule, they can be worn for 7 days and 6 nights. Then throw them away. It is not interchangeable option for people who frequently travel on business. No need to bring a container and liquid storage. Do not worry about that when withdrawing the lens can be lost, and you are in a strange city, and there's an extra pair for replacement. The downside is that these lenses often, can irritate the cornea of the eye. Better if you have a will special drops.
Don't forget to change the lens in time. If the lifetime of the lens ends, and you continue to wear them, they can harm your eyes. If you wear lenses continually, get a calendar or organizer to replace the lenses. Follow the correct storage, the container must be clean and the liquid to store frequently changing. This is necessary in order not to get infected. If the lifetime of your lenses has not ended, and when equipped you feel discomfort, these lenses need to change as quickly as possible. Maybe due to improper operation or storage, they have undergone deformation, then they should not be worn.