Single vision lenses have one dioptric power throughout the entire lens. They can be used to correct vision in either near or far viewing situations, which is why single vision lenses form the basis of both distance glasses and reading glasses. As well as offering different powers, these two popular types of spectacles also differ in their appearance: single vision lenses for far-sighted wearers are slightly thicker at the center of the lens, while single vision lenses for near-sighted wearers are slightly thicker at the edges.
Once people reach the age of 40, their near vision tends to deteriorate, and reading is often challenging, as words blur on the page. This is where reading glasses help. They are made by customizing single vision lenses to the wearer’s individual distance, generally between 30 and 40 cm. This makes life easier for people who are avid book readers, as well as users of smart phones and tablets which have small text. Specially adjusted to each wearer’s visual habits and typical reading distance, they restore people’s ability to enjoy relaxed, fatigue-free vision at close distances – whatever their prescription.