Abstract
Abstract: :
Purpose: To determine the effect of positional changes, heavy lifting and the performance of a valsalva maneuver on intraocular pressure. Methods: intraocular pressure was measured with a Tonopen in 15 healthy male and female subjects ages 29 to 64 (mean 43 ± 15). Pressures were measured while the subjects were sitting, standing, bending over to touch their toes, lifting a 15 kg weight and exhaling forcefully against a closed glottis. Pressure was recorded as the average of 3 sequential measurements in mmHg in each position. Results: The mean pressure while sitting was 16.4 ± 2.3, standing 15.9 ± 2.8, bending 20.4 ± 2.4, lifting 17.6 ± 4.2, and performing a valsalva 24.0 ± 4.4. Only the pressure measured while bending (p<0.001) and performing a valsalva (p<0.001) were significantly different from the pressure while sitting. Pressures were most elevated in response to performing a valsalva maneuver, but the changes measured under this condition where also the most variable. Whether this reflects actual physiologic differences in ocular response between individuals or the difficulty of standardizing the effort exerted is not clear. Conclusions: Significant elevations in intraocular pressure occur when bending over and, contrary to previous reports, when performing a valsalva maneuver, but do not when lifting a 15 kg weight. Thus, to the extent that pressure elevations can pose a risk for post-operative wound leaks, post-operative bending and straining might be discouraged, though the clinical significance of the degree of pressure changes observed remains to be established.
Keywords: intraocular pressure • outflow: trabecular meshwork • cataract