Wearing contact lenses for prolonged time
Like eyeglasses, contact lenses also come in both prescription and Plano types. The latter group is mainly for aesthetical purposes and feasible products are called colored contact lenses, either enhancing natural eye color or changing it completely. Paying attention to lens materials, there are hard contact lenses, rigid gas permeable contact lenses and soft lenses. Each of them has dedicated optical properties and suit different people. Yet contact lenses can also be divided based on the frequency you replace or remove them. A jargon named replacement schedule is used to describe contacts replacement frequency and another one called wearing schedule refers to lens removal frequency. According to different wearing schedules, contact lenses have two types: daily wear and extended wear.
The definitions of daily wear and extended wear contact lenses
Daily wear contact lenses refer to contacts that must be removed before going to bed. These contact lenses are not allowed to stay in the eyes for a whole night. Contact lenses are medical devices and there are strict laws and regulations in this aspect. Putting daily wear contact lenses improperly in the eyes overnight is a quite dangerous malpractice. It will quite probably lead to an eye infection.
Extended wear requires no removal before sleeping so that they can provide a clear vision as soon as you wake up. Extended wear contacts are designed to permit more oxygen on the cornea, which should get prior approval from FDA. While most extended wear contact lenses are made for continuous seven days wearing, silicone hydrogel-made ones can last up to 30 days without removal. This type is also available in RGPs. Currently technological improvements have made extended wear contacts quite comfortable during the full time period.
Extended wear contact lenses were once restricted
Extended wear contact lenses were first approved by FDA in 1981, initially in two-week style and later in 30-day style. However, there was once reported a higher possibility of developing eye infections among extended contacts wearers. Both ECPs and the FDA took actions in response to this situation. FDA reduced the continuous wearing period to seven days and ECPs persuaded customers into removing their contacts before sleep. The infections may come from organisms from the fingers. They are lodged under extended wear contacts and thrive in the comfortable environment. These organisms may cause infections, which in turn lead to pink eyes or even blindness.
Modern improvements on extended wear contacts
Contributed by lens technological advancements, extended wear contacts are safer today. The greatest contribution comes from the invention of disposable contact lenses. After the wearer removing their contacts after a week’s wearing, they just discard them, along with the deposits accumulated during those days. This practice largely avoids long-term deposit built-up. In this ways, the old application that extended wear contact were re-used week after week is forever gone. The new created silicone hydrogel lenses also contribute to extended wear contacts by offering more oxygen to the eye, so that they are approved for 30 days continuous use. Another tricky way is to use extended wear contacts, but remove them at night.
Tips for using extended wear contacts
Extended contacts wearers should always obey the instructions from eye doctors so as to minimize underlying risks. Remember that the discussed lens improvements can never provide a 100% safety. You should discard the used contacts after a period of continuous wear, never re-use them. Some factors such as smoke exposure and previous infections may also be dangerous. For extended contacts wearers, daily observation of their eyes is important. The eyes should be looking good, feeling good, and seeing well. Red eyes, irritated eyes and reduced vision acuity are dangerous signs.
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