History of Bifocal Glasses
Glass lenses used as magnifiers date back to about 300 BC but the first eyeglasses to aid vision were invented in Italy by Alessandro Della Spina and Alvino Degli Armati. Convex lenses were prescribed for far sightedness whereas concave lenses were used to aid near sightedness.
Bifocals are eyeglasses having two corrective lenses on each side of glasses with two distinct optical powers. Bifocals are usually prescribed for presbyopia. It is also suitable for people who develop a combination of far sightedness and nearsightedness. The lenses in the lower half are for nearsightedness and lenses in the upper part are for farsightedness correction. They can also be used to correct astigmatism present in combination with any other refractive defects.
The story of invention of bifocal glasses or lens dates back to 1784 when sight of Sir Benjamin Franklin was deteriorated. He was tired switching between lenses for far and near sightedness. So he created the bifocal lens. At the beginning two lenses were combined directly resulting in a sharp switch between upper and lower lenses. At the end of 19th century Louis de Wecker resolved this problem by fusing the sections of lenses together. Peter Williams who invented trifocal lenses coined the term bifocals and credited Benjamin Franklin in 1824.
Every coin has two sides. Having the advantage and ease of using two lenses at the same time, bifocal lenses also has some problems associated with them. They can cause headache and dizziness due to sharp vision switch from upper to lower lenses. Adjustment to the small area of view offered by the reading portion of lenses may take time and user learns with time to move the head or book rather than the eyes. Users may also have problems while using computers as monitors are placed directly in front which can lead to unusual angle and regular movement of head resulting in muscle fatigue. This problem can be resolved by monofocal lenses while using computer.
Bifocals glasses were invented for the elders to help them in reading and people started thinking that they are only for elders but this is a misconception. It can help anyone of any age. If you don’t want to have an elderly look just because of using lenses, here is the advice. Select a more youthful frame or a professional looking one. Go for a different color other than insipid black frames. Choices have increased nowadays ranging from aluminum lenses to titanium ones.
Many online optical stores are providing prescription glasses with quality. www.glassespeople.com is one of them and specialized in bifocal glasses. It has an enormous collection of bifocal glasses and stylish frames with excellent customer service and lowest prices and also offers bifocal lenses with UV400 and scratch resistant coating free of charge.