What is ADD?

"ADD" is short for "Reading Addition"—an extra correction needed for near-vision tasks like reading. It’s used to create reading glasses, bifocals, or progressive lenses. If you choose progressive lenses, your prescription should include an ADD value. This number indicates how much additional optical power is required for clear near or intermediate vision, beyond your distance prescription. The ADD power is the same for both eyes and may appear only once on your prescription, but it applies to both eyes unless otherwise specified. It’s measured in diopters, typically ranging from +0.75 to +3.50 in 0.25 increments. The ADD value is only necessary if your glasses will be used for reading or close-up work. If your glasses are intended solely for distance vision, no ADD is needed. Note: if you have an ADD in your prescription but order distance-only lenses, those glasses will correct far vision only—not reading. Sometimes, your optician may label this as “Add,” “Near,” or “Addition.” Even if listed once, it generally applies equally to both eyes (e.g., “Add +2.50” means +2.50 for each eye).