The local effect of morphine, nalorphine, and codeine on the diameter of the pupil of the eye

Abstract

We have demonstrated that morphine (but not codeine) when applied locally to the coniunctival sac in a solution containing polysorbate produces a small but definite degree of miosis. This is apparently a local effect, since it is significantly greater in the treated than in the untreated eye. Locally applied nalorphine may also produce miosis by direct action; but this drug appears to be absorbed more readily than morphine, and its systemic effect largely masks its local effect. Locally (but not systemically) administered nalorphine, however, antagonizes the miosis produced by local application of morphine.