Soft Contact Lenses
Despite continual improvements in hard contact lens designs throughout the 1950’s and 1960’s, these lenses were generally uncomfortable for most people to wear. In the late 1950’s the Czechoslovakian chemist Otto Wichterle and his assistant Dr. Drahslov Lim began experimenting in order to create a contact lens that could be made more comfortable, using a soft water absorbing plastic called hydroxyethyl methacrylate (HEMA). This led to the launch of the first soft hydroxyl lenses in some countries in the 1960’s and the first approval of the ‘Soflens’ material by the U.S. FDA in 1971. Soft lens contact lenses were first sold commercially by Bausch & Lomb in 1971 in the U.S. Today about 90% of contact lenses used in the U.S. are soft lenses.
WHAT ARE SOFT CONTACT LENSES?
Soft contact lenses consist of hydrophilic plastic capable of liquid absorption and when they absorb liquids, they become soft and moist and can easily be molded to the eyeball comfortably. Soft lenses can rectify various vision problems and are quite different from gas permeable (RPG) hard lenses. Soft contact lenses are used to correct near sightedness, far sightedness and some forms of astigmatism, which involves the uneven curving of the corneal surface in front of the eye.
TYPES OF SOFT CONTACT LENSES
Daily wear contact lenses are those, which are not to be used overnight and must be cleaned and removed nightly. Also they can be made thick or thin as per individual requirements.
In 1999, there was an important discovery of the first silicone hydrogels, which amalgamated the benefits of the high oxygen permeability with the comfort and performance of traditional hydrogels and the newer type of soft lenses were launched for extended (overnight) use. Extended wear contact lenses are usually very thin containing a lot of water allowing oxygen to reach the eyeball even if worn for a long time sometimes even up to 6 consecutive days and nights of wear. However, the downside is that they have greater chances of causing corneal infections than daily wear soft contacts.
Disposable contact lenses are those that can be used for a set period of time be it a month, a week or a day and after the lapse of the time period they must be discarded. They must be cleaned every night unless they are of the extended wear disposable variety. The advantages of this type of soft lenses are that they have less chances of causing infection and need less cleaning than regular soft lenses. However, they are expensive compared to the daily wear soft lenses.
Soft lenses can also be made into bifocals for myopia and hypermetropia. They can also be tinted to give eyes lighter or darker colors as desired.
THE ADVANTAGES OF SOFT CONTACT LENSES
They are extremely comfortable and the comfort is an immediate one compared to hard lenses, which require a period of adaptation before full comfort is achieved. Dirt and other particles do not get caught and deposited under soft contact lenses as frequently as in the case of rigid lenses. Also they are easier to insert in the eye and have less danger of slipping off.
DISADVANTAGES OF SOFT CONTACT LENSES
It is important that soft lenses be cleaned and sterilized with extreme care failing which there arises problem to the eyes. The soft lenses are definitely more costly than gas permeable lenses. There are a variety of cleaning and storing solutions, which must be purchased to maintain the safety of soft lenses. Users of soft lenses have more chances of encountering eye infections compared to wearers of RPG’s. These infections must be identified and treated immediately before causing adverse and long lasting vision problems.
Once you decide to go in for soft lenses, you must visit the eye specialist who will advise you if your eyes are suited to contact lens wear. Also the type of lens you should use, whether soft or gas permeable is to be determined by the specialist. It is important that you go in for yearly eye check ups after you initiate lens wear.
DIRECTIONS WHILE USING SOFT CONTACTS
The break in schedule prescribed by the eye doctor must be adhered to sincerely. Washing of hands with water and soap before handling lenses is a must. The sterilizing solutions should be used properly and homemade or non sterile solutions must be avoided as it results in eye infections. Soft lenses must not be used while swimming or sleeping and even the extended wear type should ideally be removed every night. Lenses should be inserted before applying make up or hair spray and deodorants. If a person has a tendency of seizures or other medical problems the fact that soft lenses are used should be mentioned in The Medical ID card. Also the doctor should be consulted if there is any burning, redness, pain or hazy vision in the eyes.
SIDE EFFECTS ASSOCIATED WITH CONTACT LENS WEAR
Wearing contact lenses lead to eye infections, allergic reactions inflammation of the eye and scratched cornea. Also, if irritation occurs due to allergies or if one has an overactive thyroid gland, uncontrolled diabetes, severe arthritis or hand tremors or in cases of dry eye as a result of pregnancy, use of contraceptives, diuretics, antihistamines or decongestants, then one must refrain from wearing soft contact lenses.