Effect of the sympathetic nervous system on accommodation

The accommodative effects of alpha- and beta-adrenergic stimulation were investigated in human subjects by measuring changes in the response ACA ratio and in the response accommodative amplitude as a result of instilling hydroxyamphetamine hydrobromide and phenylephrine hydrochloride. Statistically significant increases in the ACA ratios were found to result from hydroxyamphetamine hydrobromide, but not from phenylephrine hydrochloride. The accommodative amplitude significantly decreased under the influence of each agent. It was concluded that these adrenergic effects on accommodation were mediated through the beta-receptor sites. This provides further evidence of the dual autonomic innervation of accommodation.