It is amazing that something as small and comfortable as a contact lens can have such a dramatic affect on our vision.
Leonardo da Vinci was the first to consider placing a lens in contact with the eye to correct vision. Leonardo placed glass spheres filled with water over his eyes and realised that the way he saw objects was changed.
We have come a long way since then. However, the principles described by Leonardo were used to develop the original contact lenses worn by pilots during the First World War and the later hard lenses that became available through hospitals and opticians.
WHAT MAKES MODERN CONTACT LENSES SO COMFORTABLE?
Today’s soft contact lenses are made from plastics that absorb liquid in the same way a sponge does. They are extremely thin and flexible, floating in the tear film that covers the surface of our eye.
They do not in fact come into contact with the eye at all. It is only the very edge of our eye lids that actually has contact with the lens, and although when lenses are first worn there may be a very slight sensation, the lid margins quickly adapt to the presence of the lens and within a few moments most people are hardly aware of the lens at all.
Of course contact lenses have to be accurately fitted; they have to mimic as accurately as possible the curvatures of the front of the cornea to enable them to float easily; they have to be the correct diameter so that they do not rub at the edge; and they have to be made in the best material to suit the type of use that the wearer requires. However, there are hundreds of permutations available from lens designers and it is fair to say that almost everybody should be able to wear contact lenses these days. Recent developments in materials and designs now make it an everyday event for clients to be fitted with contact lenses to correct even the most complicated of prescriptions.
HOW DOES A CONTACT LENS WORK?
A contact lens modifies the eyes power by becoming its new front surface.
As most of the focusing power of the eye is generated by the curvature of the cornea (at the front of the eye), we use the contact lens to produce a new front surface that has the correct curvature for the eyes length, producing the power needed to focus light accurately on the retina.
For example, if you are short sighted, the natural cornea will be too curved and so the contact lens front surface will need to be less curved.
The back surface of the contact lens will always be calculated to fit the natural corneal shape. Because both the contact lens and the cornea are almost equally transparent, as far as light is concerned, when it passes into the eye it doesn’t notice the contact lens which has, in effect, become the eyes new front surface.
Despite the fact that contact lenses are amazingly comfortable and fitted by most opticians, only about twenty percent of people whose sight needs correcting wear them.
Most believe that the reluctance by spectacle wearers to try lenses stems from concerns over how difficult it may be to insert them, and how uncomfortable they could be. However, speak to any contact lens wearer and they will tell you that wearing contact lenses is one of the best and most liberating things they have ever done. The only problem is, how do you know who is wearing contact lenses? These tiny comfortable items are almost impossible to detect, and as most contact lens wearers can’t feel their lenses, how would you know they are wearers?
If you would like to experience being able to see clearly without your glasses ask your optician about contact lenses. Most opticians are only too pleased to give you the opportunity to try them.