Astigmatism is an odd cornea shape that impairs vision, common with older people. Although most people think that only glasses will correct this problem, contacts can fix the problem as well. No matter which one of the two you decide to go with, you are sure to get the vision you need. If you aren t lucky enough to have perfect vision, contact lenses and glasses are the perfect way to correct your vision. Bifocal Contact Lenses For a majority of us, presbyopia is something we have to live with. In definition, presbyopia is the lack of focusing on things in close range. The cause for this, is the lens in our eyes becoming less and less flexible as we grow older. The bad part is, most of us will need some type of corrective lenses, such as contact lenses or glasses and possibly even bifocals at some point in our lives as this condition gets worse. This material is very rigid, and doesn t contain near as much water as soft contacts. With that in mind, taking care of and cleaning hard lenses is very different that cleaning and maintaining soft contact lenses. Before you purchase a pair of hard or rigid contacts, you should know how to take care of them and how to clean them. If you wear them too long when you start wearing them, they can harm your eyes. Your optician will tell you what he recommends, which is normally a few hours during the day then take them out. With each passing day, you can wear them for longer periods until your eyes gradually adjust. Another aspect that will take some getting used to, that you don t face with glasses, is knowing how to handle your contact lenses. The first thing you ll notice about the Acuvue advance lenses is the addition of Hydroclear, made by Johnson and Johnson. Although other types of Acuvue lenses now offer Hydroclear, the advance lenses were the first. Hydraclear is a break through in contact lens technology, perfect for those who have problems with their lenses drying out. Soft lenses are gas permeable to a certain extent, being further categorized by the amount of water they contain. Soft contacts can have either a low, which is less than 50 percent moisture, or a high moisture content, which is more than 50 percent. Rigid or hard contacts on the other hand, are much harder in material and are considered to be gas permeable.