What is the purpose of the "ADD" value in a contact lens prescription?

The "ADD" value in a contact lens prescription is specifically used to address presbyopia, a condition that commonly occurs as people age, resulting in difficulty focusing on close objects. This additional power helps provide the necessary magnification for near vision tasks, such as reading or working on a computer.

In a contact lens prescription, the "ADD" value indicates how much additional power is needed for the lens to aid in clear near vision. This adjustment is essential for patients who may have a different prescription for distance vision compared to what they require for close-up tasks.

While other options refer to corrections for different vision issues, such as astigmatism, myopia, or general diopter adjustments, they do not specifically address the need for additional power for near vision that the "ADD" value represents. Thus, the focus on presbyopia underscores the specific role of the "ADD" in contact lens fitting and optics.