1. Three experiments were conducted to examine whether mydriatic or miotic drugs instilled into one eye have any effect on the diameter of the pupil of the untreated fellow eye, in healthy volunteers. 2. In Experiment 1, the effects of four subjects, using photography in an illuminated room to assess pupil diameter. The drug evoked a dose‐ dependent mydriasis in the index eye which was accompanied by a simultaneous dose‐dependent miosis in the fellow eye. 3. In Experiment 2, the same method was used to assess pupil diameter as in Experiment 1. The effects of mydriatic (methoxamine and tyramine) and of miotic (pilocarpine) drugs instilled into the fellow eye, were studied on the sizes of pupillary responses to the same drugs instilled into the index eye. The presence of a mydriatic drug in the fellow eye resulted in a decrease in the size of the mydriatic responses in the index eye. 4. In Experiment 3, the effects of three concentrations of phenylephrine hydrochloride (0.15‐0.60 M) and of three concentrations of pilocarpine hydrochloride (0.002‐0.008 M), were studied in darkness using an infra‐ red binocular television pupillometer, in seven subjects. Phenylephrine evoked dose‐dependent mydriasis and pilocarpine evoked dose‐dependent miosis. The pupillary responses of the index eye were not accompanied by any changes in the diameter of the pupil of the fellow eye. 5. It is concluded that drug‐induced mydriasis in the index eye is accompanied by a consensual miosis in the fellow eye.(ABSTRACT TRUNCATED AT 250 WORDS)
Twenty‐nine healthy volunteers participated in an experiment lasting for 8 weeks: Phase I (2 weeks)‐pre‐treatment control period; Phase II (4 weeks)‐medication with either ciclazindol hydrochloride (50 mg twice daily), or desipramine hydrochloride (50 mg twice daily) or lactose placebo (twice daily) administered in a single‐blind fashion; Phase II (2 weeks)‐recovery. Experimental sessions took place twice weekly for the photographic assessment of resting pupil diameter, and for the assessment of one of the following pupillary responses: mydriatic response to methoxamine, mydriatic response to tyramine, miotic response to pilocarpine. Resting pupil diameter increased during medication with either ciclazindol or desipramine. Methoxamine‐evoked mydriasis and tyramine‐evoked mydriasis were antagonized by both ciclazindol and desipramine. Pilocarpine‐evoked miosis was potentiated by both ciclazindol and desipramine. The steady‐state plasma levels (mean +/‐ s.e. mean) of the antidepressants were: ciclazindol: 5.90 +/‐ 0.74 microM; desipramine: 0.60 +/‐ 0.17 microM. The antagonism of methoxamine‐evoked mydriasis is likely to reflect the blockade of postsynaptic alpha 1‐adrenoceptors in the iris by the antidepressants, whereas the antagonism of tyramine‐evoked mydriasis may reflect both the blockade of uptake of tyramine into presynaptic adrenergic terminals and the blockade of postsynaptic alpha‐adrenoceptors. There is no immediate explanation for the potentiation of pilocarpine‐evoked miosis by the two antidepressants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.