contact lens
February 22nd, 2011
contact lenses
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Contact lens - Wikipedia, the free encyclopedia
February 1st, 2011
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Contact Lenses
A contact lens (also known simply as a contact) is a corrective, cosmetic, or therapeutic lens usually placed on the cornea of the eye. Leonardo da Vinci is credited with describing and sketching the first ideas for contact lenses in 1508, but it was more than 300 years later before contact lenses were actually fabricated and worn on the eye. Rigid ones were produced and marketed first. Modern soft contact lenses were invented by the Czech chemist Otto Wichterle and his assistant Drahoslav Lím, who also invented the first gel used for their production.
Some soft contact lenses are tinted a faint blue to make them more visible when immersed in cleaning and storage solutions. Some cosmetic lenses are deliberately colored to alter the appearance of the eye. Some lenses now have a UV protection surface treatment to reduce UV damage to the eye’s natural lens.
It has been estimated that 125 million people use contact lenses worldwide (2%), including 28 to 38 million in the United States and 13 million in Japan. The types of lenses used and prescribed vary markedly between countries, with rigid lenses accounting for over 20% of currently-prescribed lenses in Japan, the Netherlands and Germany but less than 5% in Scandinavia
People choose to wear contact lenses for many reasons, often due to their appearance and practicality. When compared with spectacles, contact lenses are less affected by wet weather, do not steam up, and provide a wider field of vision. They are more suitable for a number of sporting activities. Additionally, ophthalmological conditions such as keratoconus and aniseikonia may not be accurately corrected with glasses.
Source :- http://en.wikipedia.org
History of Contact Lenses
January 15th, 2011
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| LATE 1400S
Leonardo da Vinci is cited as the first individual to develop the concept of a contact lens based on certain sketches. It is suggested, however, that the sketches dealt with the concept of image reversal and not the concept of a contact lens. |
| LATE 1880S
Adolf E. Fick, Eugene Kalt, and August Müller all produced glass scleral shells. Fick called them “Contactbrille” or contact spectacles, while Müller called them “Hornhautlinsen” or Corneal Lenses. Kalt was later the first to treat keratoconus by utilizing a glass shell approximating the radius of the normal cornea. |
| 1886
Xavier Galezowski introduced using “plaquettes” to cover the corneal surface. These were gelatin squares soaked in mercury chloride and designed to reduce the possibility of infection after cataract surgery. This was considered the first use of a “therapeutic” contact lens. |
| EARLY 1900S
German companies Carl Zeiss and Müller led the optical industry in advanced usage of scleral contact lenses. In 1931, Joseph Dallos determined that tear flow beneath the contact lens was important and published the results of his study of 120 fittings. He later added fenestrations at the corneoscleral junction of the lens, which provided the flow of oxygenated tears to the underlying cornea. |
| 1934 – 1960 S
In 1934, Polymethylmethacrylate (PMMA) was the first plastic used for corneoscleral lenses. In 1948, Kevin Touhy was granted a patent for a corneal contact lens using PMMA that fit only on the cornea and not on the sclera, and became the contact lenses of choice throughout the 1950s and 1960s. |
| 1954 – 1971
The first synthesis of a “soft” contact lens material, hydroxyethylmethacrylate (HEMA), by O. Wichterle and D. Lim (Czechoslovakian scientists) occurred in 1954. This was followed by the development of spin-casting of HEMA by Otto Wichterle, (Christmas night in 1961 using his son’s erector set). Spin-casting became an ideal way to manufacture soft contact lenses. Soft contact lenses were first introduced in the United States in 1971 by Bausch and Lomb who acquired the rights to spin-casting and HEMA in 1966 from the National Patent Development Corporation. |
| 1971
20/20 Optical Group estimates that the wholesale contact lens market was approximately $800,000. |
| 1979
20/20 Optical Group estimates that the wholesale contact lens market was approximately $480 million. |
| 1981
First contact lenses for overnight wear were introduced. |
| 1982
The first bifocal soft contact lenses were introduced (BiSoft® by CibaVision). |
| 1984
Enhancement tinted soft contact lenses were released (SoftColors® by CibaVision). Introduction of hydrogen peroxide care systems also occurred. |
| 1987
A major development occurred with the introduction of disposable soft contact lenses (Acuvue® by Vistakon). |
| LATE 1980S
A formulation of fluorosilicone acrylate material for rigid gas permeable (RGP) lenses became available; disposable soft contact lenses were introduced, along with soft contact lenses to change eye color. |
| 1990S
Direct contact lens distribution to patients through companies or eye care practitioners who provided this option as a value-added service increased significantly. Daily disposable lenses were introduced along with RGP lenses with low silicone content and high Dk fluorosilicone acrylates. |
| 2001
A new concept in extended wear (continuous wear up to 30 nights) was first approved by the FDA in the United States |
What are contact lenses?
January 15th, 2011
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Contact lenses are small visual devices made with curved pieces of plastic shaped in a way to conform directly to the wearer’s eye. They provide an artificial refracting surface to the human eye and are used to correct vision problems like myopia and hypermetropia. Contact lenses aid in eye focusing in the same manner as spectacles do. Apart from these corrective measures, contact lenses can also be used for cosmetic and therapeutic reasons.
There have been many modifications and improvements to the original idea of contact lenses, conceptualized first by Leonardo Da Vinci, through centuries. About 35 million people in the U.S. wear contact lenses today.
Features of Contact Lenses
The lenses are made from different types of materials – soft and rigid – and come in a variety of designs and colors. These include disposable, colored, astigmatic, aphakic, presbyopic and keratoconic lenses. The initial fitting and follow up care are important parts of contact lens usage to give maximum benefits of vision, appearance, comfort and tissue integrity.
Advantages of Contact Lenses
Contact lenses are capable of correcting most of the problems that spectacles can as well as some additional ones that glasses cannot.
People not satisfied with their appearance using glasses can opt to use contact lenses for improved appearance. Contact lenses are not in the danger of slipping off, getting wet, or fogging up, which can easily happen with spectacles.
Extremely hypermetropiac people or those who have had cataracts removed, feel better wearing contact lenses as compared to spectacles, which in these cases produce uneven vision. Moreover, contact lenses give improved vision for people with damaged corneas due to disease or injury. Also for sportsmen, wearing contact lenses prove to be more practical as in the case of those where wearing spectacles pose a problem in their jobs. In addition to all these, contact lenses provide better side vision compared to glasses.
Uses of Contact Lens
The primary use of contact lenses is to correct myopia (short sightedness). They can also be used to rectify hyperopia, astigmatism, presbyopia and aphakia. Rigid lenses are used to correct irregular corneal trauma. Soft lenses are used as bandages for conditions like bullous keratopathy, recurring corneal erosion as well as to increase comfort, vision and postoperative wound healing.
Main Types of Contact Lenses
There are two principal types of contact lenses in use today. Soft contact lenses are those that are made of hydrophilic plastics and absorb liquid and must be kept moist for softness and easier moulding to the corneal surface. They are extremely comfortable and are used by majority of contact lens users. The other type in use is the gas permeable (RPG) or rigid contact lenses, which are composed of durable and flexible plastics, which permit oxygen to pass through to the cornea and are easier to maintain. The original hard lenses, or PMMAs, used earlier did not allow oxygen to pass to the eye and have been replaced by the RPGs.
If a person desires to use contact lenses, he or she should do so only after consultation with an ophthalmologist. He/she will advise whether contact lenses would be suitable for a person to use or which kind of lenses, soft or gas permeable, should be used in a particular case. It is imperative that a yearly examination be done after the initial use of contact lenses.
The Adverse Effects of Contact Lenses
People have difficulty in using contact lenses if they have eye irritations due to allergies or dust and chemicals. Overactive thyroid gland, severe diabetes or extreme arthritis in the hands, dry eyes related to pregnancy, contraceptives, diuretics, antihistamines and decongestants and eye disease prevents a person form using contact lenses.
The usage of contact lenses may give rise to problems like eye infections, allergic reactions to lens care solutions and deposit on lenses, redness of the eyes, scratched corneas, alteration in corneal shape and structure and abnormal blood vessels growing in the apparently clear cornea. You should consult your eye specialist without delay if there is burning, extreme sensitivity or hazy vision or pain.
SoftTouchLenses dot com provides information on contact lenses and their use.
Choose The Best Colour For Your Eyes
January 14th, 2011
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Contact Lenses
People sometimes get confused about which colour lens to go for. To know the solution of this problem, go on reading.
You are again at a crossroads to decide upon the colour of your Contact lenses. Take a chill pill, as here I am to throw some light on this matter and help you out.
Mainly there are two types of colour contacts – enhancement and opaque. The first one is for people with light eyes and these lenses make the eyes brighter or add some hue e.g. a person with naturally brown eyes can wear hazel enhancement coloured contact lenses and get a cool effect. However, opaque lenses create more effect as these non-transparent lenses entirely replace the original colour of your eyes with its own colour. Therefore, first you should decide on the effect you want to achieve.
Now, there are two major scenarios. The first one is if one wants brighter eye colour without shocking people who know the person’s original eye colour:
•If you are a person with gray eyes, try hazel from Aryan 1/2/3 tone color lenses or Freshlook Dimensions and get a nice grayish-hazel colour. However, if you want to experiment more, go for green (preferable for people with fair skin). Green eyes are very rare among Indians (though Aishwarya Rai’s eyes are green), so you will make a bold fashion statement with your green contacts.
•If, brown is the colour of your eyes, then I am sorry to say that none of the enhancement colour contacts can be of any help. You may better try brown opaque lenses that will at least add some shimmer to your eyes.
But, if one is adventurous enough to try something entirely different from his/her natural colour, then following are some options:
•Go for any of the three – Acuvue 2 Colors opaques, Freshlook Colorblends or Illusions by Ciba Vision – all are best in the job.
•True Sapphire from Freshlook Colorblends collection will be the perfect choice for people with dark hair and dark eyes. These lenses makes one look extremely sophisticated and bold as the colour is quite rare.
•To look intelligent and trustworthy (a lethal combination, no doubt about that) along with a feel of warmth, try honey colour contacts. It works, believe me.
•If you just want to attract a lot of attention, go for blue or green lenses, as Indians generally have dark skin with brown eyes and it will surely create a striking appearance.
Last but not the least, change your hairstyle and wear an outfit which will complement your colour lenses. Now, if you are still not sure which colour is best for you, then visit SoftTouchLenses.com and all your doubts will be over.
No need of Glasses!! - Contact Lenses for Sports
November 24th, 2010
For the athlete, excellent vision is a must no matter what level he or she is playing at. If the vision is not as crisp and clear as it could be, the athlete not only won’t perform as well, but also risks serious harm. It’s absolutely essential to have the best vision possible. There are several options for vision correction, including glasses, contact lenses, LASIK surgery and orthokeratology (also known as ortho-k).
All of these options have their pros and cons, including costs and potential risk factors, so it’s important to have all the facts before coming to any conclusions. While not right for everyone, contact lenses are a happy medium for many people in that they’re relatively affordable, easy to use and care for and eliminate some of the drawbacks of wearing eyeglasses while avoiding both the risks of surgery and the expense of ortho-k. Even if you would prefer to stick to glasses for long term wear off the field, you should still explore the advantages of wearing contact lenses during play.
Enhanced vision with contact lenses
Contacts sit right on your eye, meaning that you can look off to the side and see as well as you do when you are looking straight ahead. With eyeglasses, you have limited peripheral vision, and the frames can cause blind spots in your visual field. This is particularly dangerous in sports where balls, pucks or other players could be coming at you from the side.
In addition, frames, even when they are fitted properly, can slide around on your face or worse, can drop off during a game. Glasses can also break during play, increasing your risk of facial and eye injuries during all types of sports, even those that are considered to be no contact. Another advantage of contacts lenses is that they fit under all of the different types of safety equipment. A hockey goalie wouldn’t exactly be comfortable with a pair of glasses under his face mask.
Contact lens options for athletes
For the serious athlete, the rigid gas permeable contact lens is typically the recommended choice of sports vision specialists for a number of reasons.
- They hold their shape while on the eye. (Soft contacts may flatten out at times.)
- They offer better correction of astigmatism and other corneal abnormalities that might be difficult to correct with other types of contact lenses.
- They allow more oxygen to flow to the eye, which makes them more comfortable for longer wear.
- The hard surface of RGP lenses doesn’t collect debris easily, so they will stay cleaner.
- RGP lenses do not absorb the tears from the eyes, so you are less likely to have uncomfortable, dry eyes than with soft contacts.
RGP lenses do have drawbacks however. They can be harder to get used to than soft lenses, and are more likely to end up off-center or dislodged during play. You should discuss the pros and cons of each with your eye doctor before making a final decision.
Staying safe while wearing contacts
There are a number of things you have to consider about your safety when wearing contact lenses. First, no matter what type you are wearing, you must make sure that you are handling, wearing and caring for your lenses properly, to reduce your risk of complications including eye damage or infection. If you are on the road a lot, you may want to consider single-use soft contact lenses. These lenses are worn for one day only, and then thrown away, so you won’t have to bother with nightly cleaning or worry about packing solutions and cases. (Just be sure to pack some extra lenses in case of a mishap.)
Second, contact lenses do not provide adequate UV protection for the entire eye, so you’ll still have to wear UV-blocking sunglasses or goggles when you’re playing outside.
Source:www.SoftTouchLenses.com
New PET bottle for renu fresh multi-purpose solution.
June 29th, 2010
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renu fresh multi-purpose solution.
Collaboration with Amcor and R&D/Leverage creates innovative clear bottle for renu fresh multi-purpose solution.
Bausch + Lomb, the global eye health company, has unveiled a major packaging innovation into the lens care market. B+L has replaced the traditional white HDPE bottle with a clear PET container. This launch is an important paradigm shift in lens care packaging driven by consumer demand for a transparent container.
The bottle’s design and development was made possible through a partnership with Amcor Rigid Plastics, the world’s leading producer of PET packaging, and R&D/Leverage, known for its world-class packaging design capabilities.
Bausch + Lomb worked with R&D/Leverage for several years to develop the clear PET bottle with rounded shoulders. Bausch + Lomb and Amcor worked extensively on optimizing the bottle’s wall thickness and dimensions, thus providing a comfortable feel and proper squeezing capability for the user.
- The new package had to precisely communicate key product attributes — the feeling of wearing a fresh pair of lenses cushioned in moisture - says Daryl DuLong, global product manager, lens care Bausch + Lomb. “With R&D/Leverage’s and Amcor’s support, we are changing the industry, which has long been dominated by contact lens solutions packaged in that ubiquitous white bottle and white label — packaging that has grown stale.
A clear, polyolefin pressure-sensitive label replaces the previous white label and enhances the appealing see-through look. A special texture was added to the bottle design, to facilitate high-speed production and to enhance end-user ergonomics.
- This was a true collaboration - said Larry Schumacher, national account manager for R&D/Leverage. “We worked engineer-to-engineer, in our U.S. and UK facilities, with intensive communication back and forth, every step of the way, to make sure each element of the project was perfect.”
The renu fresh bottles are made of a healthcare-approved grade of PET. They are blow molded and then transported directly to a clean room where they are packed and then shipped to Bausch + Lomb.
- After extensive testing and refinement, we were able to achieve very tight wall tolerances that far exceeded the typical PET bottle - said Matt Curtis, Amcor’s Southeast regional account manager. - Through proper material distribution, we developed an optimum wall thickness that
enhanced the consumer experience.
The custom PET bottle will also be a key element of Bausch + Lomb’s new renu lens care portfolio. The PET bottle features a snap-on cap and is available in 2oz, 4oz, 8oz, 12oz, and 16oz sizes. Bausch + Lomb said it plans to use the clear PET bottle as a new platform for future lens care products.
Source: bausch.com
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