Purpose: The aim of this study was to compare the efficacy of 0.5% apraclonidine with that of 4% cocaine and to evaluate its safety in the diagnosis of Horner syndrome in pediatric patients.
Methods: This was a randomized, crossover study, wherein 10 patients with a probable diagnosis of Horner syndrome were assigned to undergo pharmacological testing with 4% cocaine and 0.5% apaconidine. The difference in the pupil diameters of each eye was recorded under dim light before and 1 h after 0.5% apraclonidine or 4% cocaine was instilled. Any adverse effects were noted during examination or reported by the patients' parents were recorded.
Results: The mean differences in pupil diameter before and after 4% cocaine testing were -2.08 and -2.97 mm, respectively (P = 0.0047). All patients had an anisocoria greater than 1 mm after 4% cocaine testing. The mean difference in pupil diameter before and after 0.5% apraclonidine was instilled were -2.04 and +1.08 mm, respectively (P = 0.005). All patients showed a reversal of anisocoria after 0.5% apraclonidine testing. Conjunctival hyperemia was noted in 2 patients, but systemic adverse effects were not noted during examination nor reported by the patients' parents.
Conclusions: The application of 0.5% apraclonidine in pediatric patients is safe and effective in the diagnosis of Horner syndrome.