Purchase this article with an account.
Cindy Lam, Laura Beltran-Agullo, Jason Cheng, Graham Eric Trope, Yvonne M Buys; Effect of Obesity on Postural Intraocular Pressure Changes. Invest. Ophthalmol. Vis. Sci. 2014;55(13):113.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The etiology of IOP increase in dependent body positions may be a shift in body fluid under gravity, causing increased episcleral venous pressure and choroidal vascular congestion. We hypothesized that this response is exaggerated in obesity.
This was a prospective, case control study enrolling 25 morbidly obese patients and 25 healthy, age- and gender-matched controls. Subjects had tonometry performed in 2 sets of positions, sitting and supine, with the order randomized. In the sitting position, IOP was measured with the neck in neutral position, flexion at 30°, and extension at 30°. In the supine position, IOP was measured in supine, right and left lateral decubitus, and with the head and upper body elevated at 30°. The order of measurements within each set was also randomized.
Mean IOP in the obese group was significantly higher than the control group across each position (P<0.02), with a mean difference of 2.5±0.4 mmHg (P<0.0001). There was no difference in the magnitude of postural IOP change in the obese group compared to controls. There was no difference in mean IOP between the three neck positions while sitting within each group. There was a significant increase in IOP in supine, right and left lateral decubitus compared to sitting with head straight in both groups (P<0.05). Elevating the head 30° in the supine position led to a significant decrease in IOP in the right eye only at 0 and 5 minutes in the obese group, and in both eyes at 5 minutes in the control group compared to the flat position. In the obese group, the dependent eye in right lateral decubitus had higher IOP at 0 minutes (P=0.02), but not at 5 minutes (P=0.14). This difference was not found in left lateral decubitus, or in either eye of the control group.
Postural IOP change was a significant phenomenon in both our obese and normal weight subjects. While weight does not play a significant role in the magnitude of postural IOP change, higher IOP was demonstrated across all positions in the obese group. The results support epidemiological data showing an association between obesity and ocular hypertension. Future steps include measuring postural IOP in the same group following bariatric surgery to characterize the effect of weight loss on IOP.
This PDF is available to Subscribers Only