Contact Lenses

Contact lenses are miraculous pieces of plastic that allow you to see without glasses. In most cases, contact lenses are used as a substitute for glasses, allowing you to dispense with them. Contact lenses may also be used to treat certain eye diseases or may be used for cosmetic purposes to change the apparent color of your eyes.

Successful contact-lens wear requires a "partnership" between the fitter, that is, anophthalmologist, an optometrist, or possibly an optician, and you, the wearer.

·                          The fitter must first decide if your eyes are healthy enough to wear contact lenses. If so, the fitter then fits the correct lenses for your eyes and your needs and teaches you how to use and care for them.

·                          The fitter should be available if problems develop; if not available, the fitter must then have system in place to address those situations.

·                          You must follow the instructions, care for, and wear the lenses correctly, and return as required for routine and emergency care.

A fitter can be an ophthalmologist, an optometrist, or possibly an optician.

·                          Ophthalmologists are doctors who have graduated from college, and a school of medicine (MD) or osteopathy (DO), after which three to five years of additional training are required and spent studying about eye examinations (including fitting of contact lenses and glasses), diagnosis and treatment of eye diseases, and performing eye surgery. Ophthalmologists perform both conventional surgery and laser surgery.

·                          Optometrists have graduated from a school of optometry (OD), where they are trained in eye examinations, fitting of contact lenses and glasses, and depending on state licensure, treatment of certain eye diseases. Optometrists do not perform conventional eye surgery or laser surgery.

·                          Opticians fit glasses based on the prescription of an ophthalmologist or an optometrist. In some states, opticians may fit contact lenses. Opticians do not perform eye examinations, do not diagnose or treat eye diseases, and do not perform surgery.

Contact lenses are mainly used to avoid having to wear glasses in conditions such as nearsightedness, farsightedness, and astigmatism or to avoid the use of bifocals (multifocal lenses)..

Types of Contact Lenses

There are two general categories of contact lenses – soft and rigid gas permeable (RGP). All contact lenses require a valid prescription.

Soft Lenses

Soft contact lenses are made of soft, flexible plastics that allow oxygen to pass through to the cornea. Soft contact lenses may be easier to adjust to and are more comfortable than rigid gas permeable lenses. Newer soft lens materials include silicone-hydrogels to provide more oxygen to your eye while you wear your lenses.

Rigid-Gas-Permeable (RGP) Contact Lenses

Rigid gas permeable contact lenses (RGPs) are more durable and resistant to deposit buildup, and generally give a clearer, crisper vision. They tend to be less expensive over the life of the lens since they last longer than soft contact lenses. They are easier to handle and less likely to tear. However, they are not as comfortable initially as soft contacts and it may take a few weeks to get used to wearing RGPs, compared to several days for soft contacts.

Extended Wear Contact Lenses

Extended wear contact lenses are available for overnight or continuous wear ranging from one to six nights or up to 30 days. Extended wear contact lenses are usually soft contact lenses. They are made of flexible plastics that allow oxygen to pass through to the cornea. There are also a very few rigid gas permeable lenses that are designed and approved for overnight wear

Disposable (Replacement Schedule) Contact Lenses

The majority of soft contact lens wearers are prescribed some type of frequent replacement schedule. "Disposable," as defined by the FDA, means used once and discarded. With a true daily wear disposable schedule, a brand new pair of lenses is used each day.

Some soft contact lenses are referred to as "disposable" by contact lens sellers, but actually, they are for frequent/planned replacement. With extended wear lenses, the lenses may be worn continuously for the prescribed wearing period (for example, 7 days to 30 days) and then thrown away. When you remove your lenses, make sure to clean and disinfect them properly before reinserting.

Usage

Before touching the contact lens or one's eyes, it is important to thoroughly wash & rinse hands with a soap that does not containmoisturizers or allergens such as fragrances. The technique for removing or inserting a contact lens varies slightly depending upon whether the lens is soft or rigid.

In all cases, the insertion and removal of lenses requires some training and practice on the part of the user, in part to overcome the instinctive hesitation against actually touching the eyeball with one's fingertip.

Insertion

Contact lenses are typically inserted into the eye by placing them on the index finger with the concave side upward and raising them to touch the cornea. When the lens first contacts the eye, a brief period of irritation may ensue as the eye acclimatizes to the lens and also (if a multi-use lens is not correctly cleansed) as dirt on the lens irritates the eye. This may be relieved by placing a drop of saline or multipurpose solution into the lens prior to insertion, this also allows the lens to conform to the eye more quickly by lubricating both contact lens and eye surfaces. It is never advisable to wear the lenses inside-out even if they feel comfortable and vision is good when doing so.

Removal

A soft lens may be removed by holding the eyelids open and grasping the lens with opposing digits. This method may cause irritation, could risk damage to the eye and may in many cases be difficult, in part due to the blink reflex. As an alternative method to grasping, once the lens is moved off the cornea to the inner corner of the eye, it can be pushed out of the eye by pressing downwards on the upper eyelid with a finger. With this method there is less risk of touching the eye with the fingers, and it may be easier for people with long fingernails.

Rigid contact lenses may be removed by pulling with one finger on the outer or lateral canthus, then blinking to cause the lens to loseadhesion. The other hand is typically cupped underneath the eye to catch the lens. There also exist small tools specifically for removing lenses, which resemble small plungers made of flexible plastic; the concave end is raised to the eye and touched to the lens, forming a seal stronger than that of the lens with the cornea and allowing the lens to be removed from the eye.

Care

While daily disposable lenses require no cleaning, other types require regular cleaning and disinfecting in order to retain clear vision and prevent discomfort and infections by variousmicroorganisms including bacteria, fungi, and Acanthamoeba, that form a biofilm on the lens surface. There are a lot of products that are used to cleans contact lenses:

§                     Multipurpose solutions – The most popular cleaning solution for contact lenses; these are suitable for rinsing, disinfecting, cleaning and storing lenses, and in most cases eliminate the need for protein removal enzyme tablets.

§                     Saline solution – Used for rinsing the lens after cleaning and preparing it for insertion. Saline solutions do not disinfect.

§                     Daily cleaner – Used to clean lenses on a daily basis. A few drops of cleaner are applied to the lens while it rests in the palm of the hand, and the lens is rubbed for about 20 seconds with a fingertip (depending on the product) on each side. Long fingernails can damage lenses.

§                     Hydrogen peroxide solution – Used for disinfecting the lenses, and available as 'two-step' or 'one-step' systems. With 'two-step' products, the peroxide must be rinsed away with saline before the lenses may be worn, because hydrogen peroxide is an irritant and strong oxidizer.^[48]

Ultraviolet, vibration or ultrasonic devices – Used to both disinfect and clean contact lenses. The lenses are inserted inside the portable device (running on batteries and/or plug-in) for 2 to 6 minutes during which both the microorganisms and protein build-up are thoroughly cleaned. Saline solution is typically used as multi-purpose solutions are not necessary.

Top Brands