title: Intraocular pressure responses to systemic autonomic stimulation.
abstract: The intraocular pressure (IOP) responses to two standard tests of autonomic nerve function were studied in 15 healthy subjects, mean age 33 years (range: 20-64). Both tests are based on cardiovascular reflexes: (1) The rise in diastolic blood pressure provoked by sustained isometric muscle contraction, a response mediated by the sympathetic nervous system and (2) The heart-rate responses to the Valsalva manoeuvre, a response mediated by the parasympathetic nervous system. During sustained isometric exercise, the mean IOP decreased significantly from baseline values of 12.60 mmHg (SEM 0.55) to 11.26 mmHg (SEM 0.32, p less than 0.05) while mean diastolic blood pressure increased by 20.80 mmHg (range: +12 to +53 mmHg). However there was no direct correlation between them (r = -0.05). Post exercise the mean IOP remained significantly lower than baseline values for five minutes (p less than 0.01). During the Valsalva manoeuvre, there was a significant increase in IOP of 7.20 mmHg from a baseline of 12.80 mmHg (SEM 0.45) to 20.00 mmHg (SEM 0.78, p less than 0.001); during the recovery period, mean IOP was significantly lower than baseline values at 12.13 mmHg (SEM 0.39, p less than 0.05). The mean Valsalva ratio was normal at 1.68 (range: 1.2-2.6). The possible mechanisms involved in these responses are discussed.
authors.affiliation: Moorfields Eye Hospital, London.
authors.forename: L P
authors.initials: LP
authors.lastname: Lanigan
authors.forename: C V
authors.initials: CV
authors.lastname: Clark
authors.forename: D W
authors.initials: DW
authors.lastname: Hill
mesh_terms: D000328:Adult; D001794:Blood Pressure; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D007537:Isometric Contraction / Q000502:physiology; D008875:Middle Aged; D013997:Time Factors; D014636:Valsalva Maneuver / Q000502:physiology