Spectacle frames obscure or block sideways, upward and downward sight whereas contact lens cause no obstruction to all round vision.
When you look outside the perimeter of the spectacle frame objects will appear blurred or distorted, as you are not looking through the corrective lens.
The distance between the eye and the spectacle lens can make objects seem bigger or smaller depending on whether the wearer is long or short sighted.
Contact lenses are located in contact with and covering the cornea. The ophthalmologist will take precise measurements of the eye surface in order for the contact lens to fit comfortably and provide the necessary vision correction.
Unlike spectacles, contact lenses do not get scratched, mist up or cause vision problems when out in the rain so are ideal for active outdoor types and sportspeople.
Although many people quickly adapt to wearing contact lenses there are some who experience considerable discomfort. Most ophthalmologists will provide a pair of contact lens for a trial period and will advise if the wearer is unlikely to adapt to them.
Both main types can be used to correct most kind of vision defects. Soft lens are the most popular with the majority of wearers as they are quicker and easier to get used to with RGP lens more suitable for continuous use over a long period.
It is hard to believe that the extraordinary artist, scientist and visionary, Leonardo da Vinci is credited with the concept of contact lens for sight correction five hundred years ago.
It is a matter of record that various scientists came up with ideas to advance the notion of a contact lens for sight correction until three hundred years later a renowned British astronomer, chemist and pioneer in photography, Sir John Hershel, advanced the idea of making a mold of the cornea and applying a “spherical capsule filled with animal jelly”
In 1887, FE Muller, a German glass blower, successfully produced the first contact that we would recognise today.
A transparent covering that rested on the eye surface that could be tolerated. In the following year another German, AE Fick, developed the first contact lens that was successful in improving vision.
Over the next one hundred and twenty years contact lens have been steadily improved to the point where only isolated cases of sufferers from visual impairment are unable to enjoy the benefits of contacts.
But time moves on and now affordable laser treatment is widely available to improve vision to 20/20 levels to sufferers of short or long sight. The big bonus is no more reliance on either contacts or eyeglasses.
Also available, but at a cost, are lens transplants where the defective lens is replaced with a man made substitute to provide perfect vision. Even some US fighter pilots have had the lens replacement procedure to give them extraordinary eyesight.
Over two thousand five hundred years ago there are records of cataract surgery where the defective cloudy lens was removed. In the last fifty years this operation and the substitution of a corrective artificial lens has saved the sight of many millions.
Now the transplant procedure has been developed to such accuracy that the majority of sufferers from short, long or other lens defects can enjoy perfect vision by undertaking a day to day, virtually pain and risk free operation