Ocular instillation of naloxone increases intraocular pressure in morphine-addicted patients: a possible test for detecting misuse of morphine.

The effect of conjunctival instillation of naloxone on intraocular pressure has been examined in morphine-addicted patients as compared to non-addicted healthy volunteers. Morphine-addicted subjects showed a lower basal value of intraocular pressure as compared to the control volunteers. The instillation of naloxone caused a normalization of intraocular pressure to a level similar to that of control volunteers. This test seems to be a useful screening method for detecting morphine addiction.