RefraCard
What does ADD mean on your prescription?
ADD — the near addition — is extra plus power added on top of your distance prescription for close work. Its arrival is the reason most people who never needed glasses suddenly do, somewhere in their forties.
THE ANATOMY OF A PRESCRIPTION
| SPH | CYL | AXIS | ADD | |
|---|---|---|---|---|
| OD | −2.25 | −0.75 | 175 | +0.75 |
| OS | −2.75 | −0.50 | 12 | +0.75 |
Presbyopia, not a new eye problem
The lens inside your eye changes shape to focus up close. From childhood onwards it gradually stiffens, and around the mid-forties it can no longer flex enough to hold near text sharp. That is presbyopia — a universal ageing change, not a disease and not related to whether you were short- or long-sighted before.
The ADD is simply how much help the lens now needs to make up the difference.
It climbs, then it stops
A first reading addition is typically around +0.75 to +1.25 D. It rises over the following years and then plateaus, usually somewhere between +2.50 and +3.00 D, once the natural lens has no flexibility left to lose. An ADD that is still climbing steeply past that point is unusual enough to be worth a conversation.
- Mid-40s — +0.75 to +1.25
- 50s — +1.50 to +2.25
- 60s onwards — +2.50 to +3.00, then steady
How it becomes a lens
What the ADD is used for depends on the lens you choose. Reading glasses apply it across the whole lens. Bifocals put distance on top and near in a segment below, with a visible line. Progressives blend from distance at the top through an intermediate corridor to near at the bottom, with no line — which is why they take some getting used to and why the fitting measurements matter.
Why the history is useful here
Presbyopia is one of the few refractive changes with a predictable trajectory, so a run of prescriptions makes it easy to see whether yours is following the usual curve. It also settles the recurring question of when your near vision actually started changing — which people almost never remember accurately.