Contact lenses

Hard contact lenses Soft contact lenses Cosmetic lenses Contact lens care

Contact lenses are an ideal alternative for those who, for aesthetic, professional and personal reasons, do not want to wear spectacles to correct their vision. Contact lenses are a growing market and are fast replacing spectacle frames as the main solution for vision correction. Contact lenses are worn directly in the eye over the cornea. The first experiment of a form of contact lens was done in 1827 by an English astronomer, John Frederik William Herschel who placed a piece of glass over the cornea with the aid of gelatinous substance. The evolution of contact lenses since then has been phenomenal, the latest addition to the range of contact lenses being multifocal lenses for presbyopic patients. Advantages of contact lenses over spectacles Better correction for certain eye conditions, such as keratoconus and irregular astigmatim. Thick glasses distort the peripheral vision in spectacles, while the frame reduces side vision. This problem is overcome by contact lenses. No fogging of vision from humidity and perspiration. Aesthetic solution to poor eye sight and refractive errors. Very comfortable for sportsmen. Use of optical instruments such as microscopes and cameras becomes easier. Contact lenses are divided into two main categories according to the material used: Hard Contact lenses The old type of hard contact lenses were made of hard plastic material called Polymethylmethacrylate or "PMMA". These lenses offered excellent durability and vision correction, but were difficult to get used to wearing as they were not very comfortable. Rigid contact lenses were replaced by gas permeable contact lenses, which although still being rigid, allow oxygen to reach the cornea. Gas Permeable contact lenses GP contact lenses are rigid, but are not to be confused with old-style "hard" contact lenses, which are now obsolete. Most GPs incorporate silicone, which makes them more flexible than PMMA. Furthermore, silicone is oxygen permeable, so oxygen can pass through GP lenses, resulting in greater comfort and better eye health. Gas Permeable lenses are especially good for presbyopia and high astigmatism. These lenses are usually about eight millimeters in diameter, which is smaller than the iris. Soft / Hydrophilic contact lenses Soft contact lenses are made of a soft polymer-plastic material combined with a percentage of water. Water allows oxygen to pass through the contact lens material and increases comfort. Many soft contact lenses also provide UV protection. GP lenses -  smaller than the iris. Soft lenses – cover a larger area than iris Today's soft lenses fall into various categories of usage, from the conventional pair lasting one year, to daily disposables Cosmetic lenses - Colour your look!  Cosmetic lenses are an exciting opportunity to give your eyes an allure that can be transformed according to your desire. Various colours, tones, and combinations are available to suit your personality, lifestyle, attire. Bifocal and multifocal contact lenses Contact lenses can be worn by presbyopes who need a near vision correction. Bifocal contacts lenses have two prescriptions in the same lens. Multifocal contact lenses have a range of powers (similar to progressive spectacle lenses) in each lens. These lenses are manufactured according to two principle designs: "Alternating vision" (translating) lenses are so named because your pupil alternates between the two powers, as your gaze shifts upward or downward. Simultaneous vision lenses require your eye to be looking through both distance and near powers at the same time. Although this might sound unworkable, your visual system learns to select the correct power choice depending on how close or far you are trying to see. Simultaneous vision lenses come in two types: Concentric ring designs Aspheric designs Period of use:  Conventional / traditional lenses –  A pair of conventional lenses can be worn for a period of one year, sometimes longer. They need to be cleaned daily and stored in a proper solution for contact lenses. In order to avoid deposit build-up and damage to these lenses, regular protein remover tablets and special cleaning are recommended. Disposable contact lenses – As the name suggests, these lenses can be disposed of after a certain period of use. The period of use varies with one-month disposables, two-week disposables and daily disposables.  Extended wear contact lenses – Contact lenses that can be worn overnight, continously for several days. Extended wear lenses are typically disposable. If you sleep in your lenses, not only do you remove them at least once a week, but you throw them out each week and start with a fresh pair. This avoids long-term deposit buildup and promotes eye health. Extended wear contact lenses are suitable for flexible wear. This calls for using extended wear contact lenses, but typically removing them each night. However, when you want to sleep in them — during a weekend camping trip, for example, or even for an afternoon nap — you can safely do so. The advantage of disposable contact lenses over conventional lenses Less care with disposable lenses – Since these lenses are only worn for a short period of use, they are more hygienic and require less care. Protein can build up on your lenses and make them uncomfortable. That's why the longer you wear lenses before replacing them, the more likely you are to need a protein remover. If you wear disposables, you probably will not need one, whereas if you replace your lenses about once a year, you definitely will. Less restrictions with disposable lenses – Conventional contact lenses should not be used for certain activities such as swimming, to avoid the risk of dirt and damage to the lenses. Disposable lenses, on the other hand, are ideal for such activities, since they need not be re-used afterwards. Losing a lens is less disastrous – Losing one or a pair of conventional lenses will leave you without an alternative but to purchase a new pair. With disposable lenses, you have more than one pair per pack to replace a lost lens immediately. Ideal solution for occasional contact lens wearers – If you do not wish to wear contact lenses daily, but only for special occasions, disposable lenses are safer and more cost effective.