Are glass lenses with a greater “base curve” likely to give sharper vision when I look through my glasses near the edges?
There are a number of factors which reduce the sharpness of vision of glass or plastic spectacle lenses. There are five specific problems, known as aberrations, which can be present with any wavelength or color of light. The base curve of lenses are chosen to reduce the two most important of these aberrations-oblique astigmatism and curvature of field. Changing the base curve of the lenses, either steeper or flatter, away from the ideal curve (or “corrected curve”) will increase these aberrations. In order to make lenses thinner, a flatter base curve is sometimes selected, but an aspheric surface is used to control the aberrations. Back to FAQ list Q: How do I know if I need bifocals? A: The most common use of bifocals is for the treatment of presbyopia in individuals aged 40 and over. Whether or not a person has needed vision correction when younger, by the early to mid-forties, the ability to accommodate or focus the eyes has diminished. Bifocals allow the wearer to see clearly both
