Noninvasive evaluation of cerebrospinal fluid pressure in ocular hypertension: a preliminary study

PurposeTo compare the orbital cerebral spinal fluid pressure (CSFP) and trans-lamina cribrosa pressure difference (TLCPD) determined noninvasively in ocular hypertensive (OH) subjects and controls. MethodsCross-sectional observational study. Magnetic resonance imaging was used to measure orbital subarachnoid space width (OSASW). The CSFP (mmHg) was estimated from a published formula as 17.54xMRI derived OSASW at 15mm behind the globe+0.47xbody mass index+0.13xmean arterial blood pressure -21.52. Estimated TLCPD was calculated as IOP- CSFP. ResultsThe orbital subarachnoid space width was significantly wider (p=0.01) in the OH group than in the control group at all three measurement locations. The MRI derived CSFP value in OH (14.92.9mmHg) was significantly higher than in the normal group (12.0 +/- 2.8mmHg; p<0.01). The estimated TLCPD value in OH (9.0 +/- 4.2mmHg) was significantly higher than in controls (3.6 +/- 3.0mmHg; p<0.01). ConclusionThe wider OSASW and higher estimated CSFP in OH subjects suggest a higher orbital CSFP. Despite a higher orbital CSFP that could be protective, the higher TLCPD in OH may play a significant role in the risk of developing glaucoma.