The effects of alpha sympathetic drugs on positive accommodation (accommodation for near vision) were studied in 15 vervet monkeys. Levarterenol 5%, a predominantly alpha stimulating drug, when applied topically in one eye produced a depression in accommodation in that eye. This response appeared to be mediated through beta receptor sites, since it was inhibited by propranolol, a beta sympathetic antagonist, rather than phentolamine, an alpha inhibitor. Larger topical doses (10%) or subconjunctival administration of 5 mg or more, when given unilaterally, depressed accommodation bilaterally without dilating the contralateral pupil. These effects appeared to be indirectly induced. It would seem from our studies that stimulation of alpha sympathetic receptors served no important function in antagonizing positive accommodation.
Hurwitz BS, Davidowitz J, Pachter BR, Breinin GM. The Effects of the Sympathetic Nervous System on AccommodationII. Alpha Sympathetic Nervous System. Arch Ophthalmol. 1972;87(6):675-678. doi:10.1001/archopht.1972.01000020677012