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Contact Lense Basics

Hordes of people new to contacts have a lot of questions. What are the steps I should take first? How do I review my prescription? How can I tell if my contact lens is inside out? Are all contacts basically interchangeable? And so on. Read this article for facts on these and other new wearer topics, then go on to the articles in the rest of the Contact Lenses section for further in-depth review.

The first step you take is to see an eye doctor. If you need to get into contact lenses, you have got to 1st see an eye doctor optometrist, or in a select few states, a lense maker. This is the case even if you do not commonly put on glasses, and just want contacts to vary your eye hue. The reason you need to make sure and take this measure is contact lenses are medical hardware that require to be properly fitted by an eye care practitioner. In the United Sates of America, contact lenses can be legitimately bought just with a valid written prescription.

The ophthalmologist will check your eyes to guarantee it is OK for you to wear; nowadays nearly everybody could, but there are a uncommon couple who cannot. In that case, they will determine your prescription.

How to understand your Contact Lens Prescription?

Eye doctors all use pretty much interchangeable shorthand to compose contact lens prescriptions. Often, this shorthand can look like a secret code to the uninitiated, but it is actually quite simple to decrypt. Take a look at an example. As well as to the above principles, your prescription could note how typically your contact lenses must be replaced. Your doctor may require you to replace them monthly, bimonthly, weekly, or daily. You may be instructed verbally, during your exam. Commonly the lens brand name includes this data , but the actual judge is your eye care practitioner, who understands which replacement option is ideal for your eyes and lifestyle.

How do I apply my contact lenses?

The difference can be subtle, but warranty the lens looks more like a taco than a soup bowl. A enquiry many first-time wearers use is, How will I tell if my contact lens is wrong side out? The trick is to set the lens on your finger so it is looking like a cup, then hold it up directly in front of your eyes so you are searching the side of the cup. If it is making a u shape with the top bounds flared out, the lense if the lense is forming a u shape it is right.

A minimal number of contact lenses also have a laser marker, like the brand name, on the edge to assist you. If you can understand it properly, the lens is not inside out. Do not worry if you put a contact lens in your eye inside out. It will likely feel uncomfortable, but it cannot create any harm.

Fashion industry is brimming with new trends one of them is the use of contact lenses. Youngsters today prefer varied eye colors for different appearances. This has created a strong demand for disposable contact lenses or soft lenses in the market. Disposable lenses come in variety of replacement options. Replacement refers to how frequently the contact lenses could be changed. Daily disposable lenses are to be changed daily. Disposable (daily wear) have a replacement duration of 14 days or two weeks. Seven day extended wear lenses are to be replaced after a week . Planned or frequent replacement lenses are to be changed after one or more months depending upon the brand. The conventional contact lenses are replaced after an year. These replacement durations are very general n nature and vary according to the amount of lipid; the proteins; produced by the eyes.

Earlier cleaning of lens was a tedious job with various solutions. With passage of time lens manufacturers developed better quality lenses and lens solutions that are easier to use. Lenses protect eyes from UV rays of sun. UV rays from the sun are associated with formation of cataracts. Excessive exposure to UV rays leads to photokeratitis. It is a condition in which the sun burn is caused to cornea of eye leading to temporary vision blindness known as “snow blindness”. It is easy to find whether a lens is UV blocker or not. UV protection layer is clearly visible on a lens. Also, the packaging of the lens clearly states if the lens is UV protected or not. However, these lenses only cover the cornea of the eye for protecting the other parts of eye from sun it is essential to make use of sunglasses.

Also, the 30 day continuous wear lenses are back in market. They are made up of better material than they were earlier. They allow a lot more amount of oxygen to reach the eye even when you are wearing the lenses. Thereby making them much safer and convenient to use. A few manufacturers are also making bifocal & toric lenses in disposable styles in addition to the conventional styles that last from one to several years.

The replacement schedule of a lens depends on whether i can be worn during sleep or not. There are lenses that have the caliber of correcting vision. This is known as corneal refractive therapy. Under this therapy special contact lenses are worn during night when you sleep. These lenses reshape the eyes in order to improve your vision. As a result you can see even when you are not wearing them.

The concept of lenses made from silicone hydrogel was first proposed over 20 years ago. The potential benefits were clear but the technological challenge was as difficult as needing to combine oil and water to produce an optically clear product. Researcher organizations have to date invested considerable academic and financial resources to achieve the high performance soft lenses of today. They have done this quite simply because they see this material as the way forward and the ultimate standard of the future.

At the time of writing, silicone hydrogel lenses are available in the USA from four manufacturers: “Night & Day” and “O2OPTIX” from CIBA Vision, “Pure Vision” from Bausch & Lomb, and “Acuvue OASYS” and “Advance” from J&J Vision Care.

OXYGEN TRANSPORT

So what’s so special about silicone hydrogel as a lens material? Essentially, the great benefit of this material is it’s ability to transport oxygen to the eye and thus maintain proper eye health. Modern contact lens technology is all to do with oxygen permability, which is measured using the “Dk” index. And for optimal oxygen transmission, this must be as high as possible.

The Dk of traditional, non-silicone based hydrogel lenses is directly related to the amount of water that the material can hold, since oxygen dissolves into the water-component of the material and thus diffuses through the lens. The Dk in fact increases logarithmically with increasing water content. Water itself has a Dk of only 80, thus placing a ceiling on the Dk of convential materials, and the original soft contact lens material, polyHEMA, possesses a Dk of only around 10 (with a water content of about 38%).

However, in silicone hydrogels, the relationship between Dk and water content is the opposite. Here higher water content implies lower Dk. With these lenses Dk increases significantly as the silicone content – not water content – of the lens increases. The Dk values of silicone hydrogel contact lenses are much higher than those of older soft lens materials.

SLEEPING IN CONTACT LENSES

According to market data from CIBA Vision, 84% of soft contact lens wearers occasionally sleep with their lenses in, and one-third admit to doing this regularly. 25% of wearers of one to two-week disposable lenses with low oxygen transmissibility occasionally or routinely sleep in their lenses overnight. And 72% of soft contact lens wearers said they would prefer to be allowed to wear their lenses overnight provided it was safe.

Thus the demand for lenses with the capablities of silicone hydrogels is evidently very high with almost three-quarters of soft lens wearers wanting to be able to sleep in their lenses.

LENS HANDLING

Silicone hydrogel lenses are significantly more rigid than their conventional counterparts, due to the presence of silicone. This increased rigidity does possess some advantages, making the lenses markedly easier to handle and thus the ideal choice for wearers with a less delicate touch. There is a downside to this however in that the rigidity makes the lenses less prone to adopting the shape of the eye so readily, resulting in the possibility for some of reduced comfort.

REDUCED DEPOSITIONS

Historically, the deposition of proteins and lipids has been a problem with contact lenses. The amount of depositions is essentially linked to the duration of wear, the lens material and the tear composition of each individual wearer. With traditional lenses, a frequent replacement schedule greatly reduces the buildup of harmful deposits.

Silicone hydrogel contact lenses have been proven to offer major benefits in the reduction of protein and lysozyme deposition. Indeed, combined with the correct replacement schedule and appropriate care system, problems associated with protein deposition have become almost a thing of the past.

DRY EYES

A problem frequently encountered by wearers of traditional soft contact lenses is one of a feeling of discomfort and “grittiness” in the eyes towards the end of the day. It has been reported that after one week wearing silicone hydrogel lenses, the quantity of regular soft lens wearers in a particular study group who previously suffered significantly from end-of-day dryness, was reduced dramatically to only 13% of the sample.

LIFESTYLE BENEFITS

Silicone hydrogel contact lenses also provide some benefits that conventional lenses don’t. Continuous wear contact lenses can be particularly beneficial for use by members of certain professions, such as medical workers, police, the armed forces and firefighters who frequently work unpredictable and long hours.

Furthermore, an increasing numbers of contact lens wearers can now enjoy active outdoor lifestyles, enjoying pursuits such as camping and hiking where it is often difficult to handle and disinfect the lenses with the appropriate level of hygiene.

THE FUTURE FOR CONTACT LENSES

There is much evidence to suggest that, owing to their significant benefits over conventional soft lenses, silicone hydrogel lenses will ultimately, and sooner rather than later, displace other types of contact lens as the prefferred choice for both daily and overnight wear for the majority of contact lens wearers. Silicone hydrogel lenses provide a much improved physical performance, excellent handling properties and greater comfort. They might be considered as the ideal lens for general purpose use that exists today and are likely to become the new everyday standard.