Contacts are the appealing alternative to glasses. Many young adults favor contacts over glasses because of many factors. Some believe glasses make you unattractive, and others argue that contacts are just too much of a hassle to clean.
What are they?
Contacts are thin, plastic lenses that correct your vision just improve your vision just like glasses, but without the handles and frames. They restore your true vision, meaning there is no loss in peripheral vision like there is wearing glasses. Each lens is custom fitted to each person's cornea surface. If it was not, contacts would feel like an eyelash all the time, and we all know how irritable that can become! Contacts, however, hover above the cornea with a layer of tears in between. They do not feel like anything in your eye. Only a few small percentage of people cannot adapt to contacts. What keeps contacts sticking to your eye, especially the soft contacts, is surface tension.
What different types of contacts are there?
In this day and age, there are many different types of contacts to choose from. All of them fall in a category of either hard contacts or soft contacts, the latter of which is much more used.
Hard Contacts - this type is harder to adapt to and are smaller than soft contacts. You do not have to clean this kind as often as soft lens, but sometimes, they can get lost in the back of your eye or fall out. In ways they can stop the progression of nearsightedness because these contacts are solid hard. Hard contacts also correct vision better than the soft kinds, and because of their nature, sharper vision.
Soft Contacts - these contacts are bigger in shape, and as its name suggests, softer to allow better fit and comfort. They require more cleaning, but can be worn longer than hard lenses. Below is a list of the different types of soft contacts available.
*do not think that you can save money by using the lens longer than prescribed fordoing so can damage your eyes because of the protein deposits that build up after a certain amount of time
Early contact lenses were made of blown glass. Would you want to insert fragile glass into your eyes that were not meant for comfort? Probably not. Neither did people back then, but this is how the beginnings of contact lenses began.
Hard lenses made of PMMA (polymethal methacrylate) were the first contact lenses to be used. These types of lenses, however, did not permit the flow of oxygen through the glass, and because the cornea does not have any blood vessels, it became damaged.
Soft lenses then popped up during the 70's and 80's, and so did gas permeable lenses.
In 1979, contacts that allowed more oxygen to seep through made its debut. These were called extended-wear soft lenses. Regular soft lenses could only transfer enough oxygen to the cornea to last a typical day. On the other hand, extended-wear took it a step further through its material engineering, allowed enough oxygen to transfer to last about a month. Unfortunately, wearing contacts this long without cleaning them caused protein deposit to build up underneath the lenses.
The solution to this was to develop a disposable soft lenses that can be kept in the eye and thrown away each week. They were called disposable soft lenses, which were make in 1987.
Since then, astigmatism, bifocal, colored, and tinted lenses have been invented.
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