Spectacles

[U-] Two gla es set in a light frame to help weak sight. They were invented by an Italian in the thirteenth century. For short-sighted eyes,spectacles with concave lenses are used, which form an image of the object nearer to the eye than the object itself. For long-sighted eyes, spectacles with convex lenses are used, which form the image at a greater dis¬ tance from the eye than the object.