EFFECTS OF VALSALVAS MANEUVER ON INTRAOCULAR-PRESSURE

We examined the effects of breath holding against a closed glottis (Va lsalva's manoeuvre) on intraocular pressure (IOP) in four groups of vo lunteer subjects: 37 healthy young control subjects, 10 patients with chronic open-angle glaucoma, 11 age-matched control subjects and 8 gla ucoma suspects. IOP was recorded by one person using a Digilab 30R/T P neuma-Tonometer. Chart recordings of the IOP were measured independent ly by a second investigator. Recordings were taken before, during and 5 minutes after the seated subject exhaled into an aneroid manometer t o a pressure of 25 to 35 cm H2O. There was marked variability in the i ndividual responses to Valsalva's manoeuvre in all four groups, with s ubstantial increases (to +9.5 mm Hg) and decreases (to -4.0 mm Hg) in IOP seen. The mean change in IOP during Valsalva's manoeuvre was a sma ll, statistically insignificant decrease in all four groups. The mean change in IOP following Valsalva's manoeuvre was a larger, but still c linically small, decrease. The clinician should be aware of the indivi dual variability in IOP changes with Valsalva's manoeuvre.