DEFINITION

Contact lenses are very thin pieces of plastic or glass which float on the tear film on the surface of the cornea. They are shaped to fit the person's eye and are used to correct refractive errors such as myopia (nearsightedness), hypermetropia (far sightedness), strabismus (squint), astigmatism (unequal curvature of the cornea) and presbyopia (the natural loss of elasticity of the eye that comes to all people).

DESCRIPTION

Always show care when inserting contact lenses. There are several important steps to follow with an emphasis on absolute cleanliness.

Step 1 Make sure that the hands are clean by washing with a noncosmetic soap such as rolled oats porridge or simple soap and then rinse thoroughly so that any soap residue is washed off. Dry the hands using a lint-free towel. Using lint-free material means that there is less chance of any material such as threads of lint left on the fingers.

Step 2 Carefully open the lens container and remove the lens for the right eye. Rinse it with saline solution. This will dilute any residual preservative solution which may be left on the lens.

Step 3 Pick up the lens by placing it on the top of a finger usually the index finger and look closely to make sure that it is not inside out. This can be done by using the 'taco test' named after a taco shell which is a popular Mexican food. Gently fold the lens at the apex (not the edges) between the thumb and forefinger. The edges should look like a taco shell with the edges pointed inward. If the edges appear to roll out the lens is inverted and must be reversed. When examining the contact lens make sure that there are no signs of damage such as cracks or chips.

Step 4 Before inserting the lens make a final inspection to make sure that the lens is clean and free of any foreign matter. Clean and rinse with saline again if necessary.

Step 5 Insert the lens on the right eye as was shown to you by your optical adviser. This usually entails pulling down the lower lid with the right middle finger. Use a finger of the left hand to raise the upper eyelid and then place the lens on the eye.

Step 6 Release the lids and blink a few times. Check the vision immediately to make sure that the contact lens is in the correct position.

It is easy to tell if there is a problem as after a three or four blinks and the vision is still blurred, the lens may be off centre, on the wrong eye or dirty. If this happens instil one to three drops of rewetting or reconditioning drops into the eye.

If there is no improvement remove the lens and place several drops of wetting/conditioning solution onto both surfaces of the contact lens and reinsert.

Step 7 Repeat the process for the left eye.

REMOVAL Before removing a contact lens fill the lens container with soaking/conditioning solution. Place a hand or a towel under the eye so that the contact lens will not be lost if it falls out suddenly. Once again cleanliness is all important so that the eye does not become infected or irritated. There are two methods which can be used.

Method 1.

Step 1 Wash the hands thoroughly using a plain soap. A plain soap has less chance of causing any allergic reaction to the eye. Make sure that you rinse the hands with water thoroughly to remove any soap residue. Step 2 Dry the hands using a lint-free towel. Remember a lint-free towel will leave no threads of material on the hands. Step 3 To remove the lens in the right eye place the right forefinger in the middle of the eyelid by the lashes. Place the forefinger of the left hand on the middle lower eyelid margin. Push the eyelids inward and then together. The contact lens should pop out. If it only becomes decentred onto the white of the eye, recentre and try again. Step 4 Place the lens in the lens container with soaking/conditioning solution. Step 5 Repeat the procedure for the left eye.

Method 2

Step 1 Make sure that the hands have been washed and rinsed with water. Step 2 Place an index finger on the outside or temporal edge of the right eye where the upper and lower eyelids meet. Widen the eyelids at first. Step 3 Stretch the skin outwards and slightly upwards without allowing the eyelid to slide over the lens. Step 4 Blink quickly. The contact lens should pop out because of the pressure of the eyelids at the top and bottom of the lens. The blinking helps to remove the contact lens after pressure has been applied by stretching the skin. Step 5 Place the lens in the lens container with soaking/conditioning solution. Step 5 Repeat the procedure for the left eye.