If you wear glasses and are thinking about trying contact lenses, there are many things to consider. Surely you're aware of some of the benefits of wearing contacts, such as freedom from bulky glasses as well as better peripheral vision. You may be a bit nervous about inserting contact lenses or even about care and maintenance. Before you worry about those details, you should learn a bit about the different types of contact lens options available to you. Educating yourself about the different lenses that are currently in the marketplace will put you one step ahead. Below is an overview about some of the different lenses that your optician may prescribe for you. Arm yourself with the following information before going to your eye doctor and you'll be in a much better position to come out with what's best for you. Toric Lenses Toric lenses are designed to have the effect of a cylindrical lens, usually in combination with the effect of a spherical lens. Toric lenses are typically used by nearsighted and farsighted people who also have astigmatism. Usually, these people have been told they are not suitable for regular contact lenses, but may be able to use toric lenses. If one of your eyes has astigmatism and the other does not, you may be told to use a spherical lens in one eye and a toric lens in the other. Toric lenses are made from the same materials as regular contact lenses but have a few notable differences. Some of these differences include: - They are not symmetrical and may contain a specific 'top' and 'bottom' - They must be designed to maintain their orientation - They correct for both cylindrical aberration and spherical aberration - They may be a bit more expensive and are generally intended for extended wear Rigid Gas Permeable Lenses Rigid gas permeable contact lenses were introduced in the late 1970's. While rigid gas permeable lenses (or RGP's) are more rigid or firm than soft contact lenses, they mustn't be confused with the old style of 'hard' contact lenses, which are no longer used. Most rigid gas permeable lenses incorporate silicone, which is oxygen permeable. Essentially, what this means is that oxygen can physically pass through the lenses and reach your eyes. Rigid gas permeable lenses typically last longer than soft contact lenses. They may also provide better vision, durability and deposit resistance. RGP's can be easier to clean and due to their long-lasting quality may prove to be cheaper in the long run. Vial Lenses Vial contact lenses are basically rigid gas permeable lens that are designed to be worn for up to a year. Vial lenses must be removed, cleaned and sterilized on a nightly basis. Vial lenses can be both soft or rigid. The main difference between vial lenses and other types of contact lenses lies in the amount of time that one pair of lenses will last. Though daily wear contact lenses and disposable lenses have grown in popularity, may people still prefer the durability of rigid gas permeable vial lenses. Vial lenses last a long time and are said to provide excellent vision correction. On the other hand, they tend to be thicker than disposable lenses and can take a while to get used to. The Choice is Yours Now that you know a bit more about some of the different types of available contact lenses, you'll be better equipped to make decisions about your vision care. Make sure to consult with your doctor about your lifestyle and specific vision problems to further help you determine which lenses are best for you.Click to read more info about contact lenses. External Links :- YolaSite Tumbler Weebly WordPress Penzu
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The invention of spectacles has greatly influenced progress in the arts and sciences, yet it is not very clear who invented this instrument. In 1270, Marco Polo saw elderly Chinese using this device, which they claim to have originated in Arabia in the 11th century. The spectacles evolved in the western world from the late 1200s onwards, with riveted spectacles used by monks and scholars, who held the lenses in front of there eyes, or balanced them on their noses. The invention of the printing press in 1452 encouraged the mass production of spectacles, along with the growing popularity of books. For the lower and middle classes, there were spectacles mounted in wood, horn, bone, etc, whereas the upper classes used hand held spectacles in gold or silver frames. The significant advancement in frame design occurred in the 1600s, with rigid bridges that allowed the spectacles to remain in place. In the present times, there has been a tremendous progress in frames and lens acuity, with the spectacles, whether plain or prescription, becoming a fashion statement. The Short History Of Contact Lenses If you are of the view that contact lenses are a new invention, you are way off the mark. Leonardo Da Vinci first described and sketched his ideas of contact lenses way back in 1508! However, it took more than 300 years to fabricate and wear them. Swiss physician A.E. Fick and Paris optician Edouard Kalt are credited with fitting the first contact lenses, in the late 1800s, for myopia and hyperopia. These heavy glass lenses could be used for a few hours of wear only. Plastic came into use in 1936, when William Feinbloom, an optometrist in New York, made contact lenses with the central portion of glass surrounded by plastic in the periphery that covered the sclera. 1948 saw a Californian optometrist, Kevin Tuohy produce contact lenses completely made of plastic. The same year, George Butterfield, an optometrist from Oregon, improved upon Kevin Tuohy's design with lenses that matched the shape of the cornea, and would not easily pop off. These lenses have evolved to the present soft contact lenses, which are worn by more than 90% of the contact lens wearers in the United States. Contact Lenses vs. Glasses Contact lenses offer functional advantages over glasses in areas, such as sports, work - in humid environment, and in occupations where spectacles are inconvenient and not compatible with the equipment used, such as special headgears. Let us look at some of the advantages that contact lenses offer over glasses:
Glasses, at times do not work, and contact lenses are certainly superior to them:
There was a time when contact lenses used to pop out, and this was during the time when contact lenses were hard lenses. Today, there is no 'popping' out with the introduction of soft contact lenses. These soft contact lenses conform to the shape of the eye, and do not move or pop out. |
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