When prism is used to treat double vision, headache, or imbalances called
"phorias", a few prism diopters can make you much more comfortable.

In those cases, people complain that they "get dependent." But usually, it's
because they forget how hard they were working before prism. Does phoria or
diplopia increase after using prism? Not significantly, in adults.

If there is no headache, phoria, or loss of fusion, then prism isn't usually
prescribed. With no symptoms, some doctors will still prescribe prism based
on measurements and "criteria." Those wearers usually say the prism made no
difference.

-MT