The effects of nerve stimulation on aqueous outflow in enucleated eyes.

The influence of ocular innervation on intraocular pressure has been the subject of much investigation. Methods of study have included: stimulation of sympathetic and parasympathetic nerve supply, section of the autonomic nerves, and stimulation of autonomic areas in the midbrain. Stimulation of the cervical sympathetic chain in animals produces a sharp rise in intraocular pressure followed by a fall due to vasoconstriction, according to the majority of workers. Sec­ tion of the sympathetic innervation has given variable results. According to Greaves and Perkins, stimulation of the third cranial nerve in rabbits has no effect on intraocular pressure after paralysis of the extraocular muscles by decamethonium, and section of the third nerve causes no acute or chronic change in tension. Schmerl and Steinberg have reported increases in intraocular pres­ sure in cats following stimulation of the ciliary ganglion and a fall in pressure after cauterization of the ganglion. A number of investigators have stimulated autonomic centers in the midbrain; the most extensive study has been that of von Sallmann and Lowenstein, who have correlated changes in intraocular pressure widi vasomotor responses, pupillary reactions, and contractions of extraocular musculature. These workers frequently noted elevations