Contact Lenses Usage

Before touching the contact lens or one's eyes, it is important to thoroughly wash & rinse hands with a soap that does not contain moisturizers or allergens such as fragrances. The soap should not be antibacterial due to risk of improper hand washing and the possibility of destroying the natural bacteria found on the eye. These bacteria keep pathogenic bacteria from colonizing the cornea. The technique for removing or inserting a contact lens varies slightly depending upon whether the lens is soft or rigid.

Contact Lenses 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. The other hand may be employed to keep the eye open. Problems may arise particularly with disposable soft lenses; if the surface tension between the lens and the finger is too great the lens may turn itself inside out; alternatively it may fold itself in half. When the lens first contacts the eye, a brief period of irritation may ensue as the eye acclimatises to the lens and also (if a multi-use lens is not correctly cleansed) as dirt on the lens irritates the eye. Irrigation may help during this period, which generally should not exceed one minute.

Contact Lenses Removal
A soft lens may be removed by holding the eyelids open and grasping the lens with opposing digits. This method can cause irritation, could risk damage to the eye and may in many cases be difficult, in part due to the blink reflex. If the lens is pushed off the cornea it will buckle up (due to the difference in curvature), making it easier to grasp.

Rigid contact lenses may be removed by pulling with one finger on the outer or lateral canthus, then blinking to cause the lens to lose adhesion. 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.


Contact Lenses Care (cleaning and disinfection)
Lens cover to store contact lensWhile 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 various microorganisms including bacteria, fungi, and Acanthamoeba, that form a biofilm on the lens surface. There are a number of products that can be used to perform these tasks:

Multipurpose solution - The most popular cleaning solution for contact lenses. Used for rinsing, disinfecting, cleaning and storing the lenses. Using this product eliminates the need for protein removal enzyme tablets in most cases. Multipurpose solutions are not effective at disinfecting Acanthamoeba from the lens. In May 2007, one brand of multipurpose solution was recalled due to a cluster of Acanthamoeba infections.
Saline solution - Used for rinsing the lens after cleaning and preparing it for insertion. Saline solutions do not disinfect the lenses.
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, then the lens is rubbed for about 20 seconds with a fingertip (check the cleaner's directions) on each side. Long fingernails can damage the lens, so care should be taken.

Hydrogen peroxide solution - Used for disinfecting the lenses, and available as 'two-step' or 'one-step' systems. If using a 'two-step' product, one must ensure that the lens taken out of the hydrogen peroxide is neutralized before it is worn, or else wear will be extremely painful. Saline must not be used to rinse away the peroxide. Some peroxide solutions, such as CIBA Vision's Clear Care, come with a special storage case that contains a catalyzing disk. If soaked in the solution with the disk for at least six hours, the hydrogen peroxide decomposes and the remaining solution is a saline that will not harm the eye. People with extremely sensitive, irritable eyes often use these types of cleaning solutions. Peroxide solutions are the only commonly used disinfectant effective against Acanthamoeba, although the two-step solutions are more effective than the one-step, which neutralize too quickly to kill the amoeba's cysts. If you get this solution in your eyes, it is highly recommended that you go to the Emergency Room and get your eye(s) irrigated.

Enzymatic cleaner - Used for cleaning protein deposits off lenses, usually weekly, if the daily cleaner is not sufficient. Typically, this cleaner is in tablet form. Protein deposits make use of contact lenses uncomfortable, and may lead to various eye problems.

Some products must only be used with certain types of contact lenses: it is important to check the product label to make sure that it can be used for a given type of lens. It is also important to follow the product's directions carefully to reduce risk of eye infection or eye irritation. In addition, one should remember to wash the contact cases or lens covers thoroughly with water and multipurpose solution or hydrogen peroxide to avoid formation of biofilms on its surfaces.

It is important to ensure that the product does not become contaminated with microorganisms: the tips of the containers for these solutions should never touch any surface, and the container should be kept closed when not in use. To counteract minor contamination of the product and kill microorganisms on the contact lens, some products may contain preservatives such as thimerosal, benzalkonium chloride, benzyl alcohol, and other compounds. In 1989, thimerosal was responsible for about 10% of problems related to contact lenses: because of this, many products no longer contain thimerosal. Preservative-free products usually have shorter shelf life. For example, non-aerosol preservative-free saline solutions can typically be used for only two weeks once opened. The introduction of silicone-hydrogel soft contact lens materials in 1999 made selection of the proper disinfecting solution more important. One study has noted several incompatibilities between these new lens materials and some solutions resulting in corneal staining.