Cerebrospinal fluid pressure in ocular hypertension

Background: To assess the lumbar cerebrospinal fluid pressure (CSF-P) in ocular hypertensive subjects with elevated intraocular pressure (IOP) but without development of glaucomatous optic nerve damage.

Methods: The prospective interventional study included 17 patients with ocular hypertension and 71 subjects of a nonglaucomatous control group. All patients underwent a standardized ophthalmologic and neurological examination including measurement of lumbar CSF-P. In the ocular hypertensive group, the IOP was corrected for its dependence on central corneal thickness (IOP(corrected) ). The trans-lamina cribrosa pressure difference (Trans-LCPD) was calculated as IOP(corrected) - CSF-P.

Results: CSF-P was significantly (p < 0.001) higher in the ocular hypertensive group (16.0 ± 2.5 mmHg) than in the control group (12.9 ± 1.9 mmHg). CSF-P was significantly associated with IOP(corrected) (p < 0.001; r = 0.82). In multivariate analysis, CSF-P was significantly correlated with IOP(corrected) (p < 0.001) and marginally significantly with mean blood pressure (p = 0.05). Trans-LCPD was not associated significantly with blood pressure (p = 0.69).

Conclusion: Some ocular hypertensive subjects with increased intraocular pressure measurements (after correction for their dependence on central corneal thickness) had an abnormally high lumbar cerebrospinal fluid pressure. Assuming that lumbar cerebrospinal fluid pressure correlated with orbital cerebrospinal fluid pressure, one may postulate that the elevated retro-lamina cribrosa pressure compensated for an increased intraocular pressure. The elevated retro-lamina cribrosa pressure may have led to a normal trans-laminar pressure difference in the eyes with elevated intraocular pressure, so that glaucomatous optic nerve damage did not develop. Intraocular pressure, cerebrospinal fluid pressure and arterial blood pressure were correlated with each other.