advertisement
PURPOSE: To assess whether a Valsalva manoeuver influences intra-ocular pressure (IOP), cerebrospinal fluid pressure (CSF-P) and, by a change in the trans-laminar cribrosa pressure difference, optic nerve head morphology. METHODS: In the first part of the study, 20 neurological patients (study group 'A') underwent measurement of IOP and lumbar CSF-P measurement in a lying position before and during a Valsalva manoeuver. In the second study part, 20 healthy subjects (study group 'B') underwent ocular tonometry and confocal scanning laser tomography of the optic nerve head before and during a Valsalva manoeuver. RESULTS: During the Valsalva manoeuver in study group 'A', the increase in CSF-P by 10.5 ± 2.7 mmHg was significantly (p < 0.001) higher than the increase in IOP by 1.9 ± 2.4 mmHg. The change in CSF-P was not significantly (p = 0.61) correlated with the change in IOP. During the Valsalva manoeuver in study group 'B', IOP increased by 4.5 ± 4.2 mmHg and optic cup volume (p < 0.001), cup/disc area ratio (p = 0.02), cup/disc diameter ratio (p = 0.03) and maximum optic cup depth (p = 0.01) significantly decreased, while neuroretinal rim volume (p = 0.005) and mean retinal nerve fibre layer thickness (p = 0.02) significantly increased. CONCLUSIONS: The Valsalva manoeuver-associated short-term increase in CSF-P was significantly larger than a simultaneous short-term increase in IOP. It led to a Valsalva manoeuver-associated decrease or reversal of the trans-laminar cribrosa pressure difference, which was associated with a change in the three-dimensional optic nerve head morphology: optic cup-related parameters decreased and neuroretinal rim-related parameters enlarged. These findings may be of interest for the pathogenesis of glaucomatous optic neuropathy.
Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing, China.
Full article6.1.3 Factors affecting IOP (Part of: 6 Clinical examination methods > 6.1 Intraocular pressure measurement; factors affecting IOP)
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
2.16 Chiasma and retrochiasmal central nervous system (Part of: 2 Anatomical structures in glaucoma)