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Optic disc movement with variations in intraocular and cerebrospinal fluid pressure
William H Morgan1, Balwantray C Chauhan, Dao-Yi Yu
1Lions Eye Institute, University of Western Australia, Perth, Australia. whmorgan@cyllen.uwa.edu.au
Investigative Ophthalmology & Visual Science
|October 3, 2002
Summary
Intraocular pressure (IOP) and cerebrospinal fluid pressure (CSFP) affect optic disc movement. Most optic disc displacement occurs at low translaminar pressure differences, consistent with collagen
Area of Science:
- Ophthalmology
- Biomechanics
- Neuroscience
Background:
- Optic disc movement and lamina cribrosa displacement are influenced by pressure gradients.
- Understanding these mechanics is crucial for diagnosing and managing optic neuropathies.
Purpose of the Study:
- To quantify the effects of intraocular pressure (IOP) and cerebrospinal fluid pressure (CSFP) on optic disc movement and lamina cribrosa displacement.
- To analyze these effects in relation to translaminar pressure difference (TLPD).
Main Methods:
- Confocal scanning laser tomography (CSLT) was used in dogs to measure optic disc topography.
- IOP and CSFP were modulated and controlled, with measurements taken at varying pressure levels.
- Data were analyzed using a probabilistic method and global parameters as a function of TLPD (IOP - CSFP).
Main Results:
- Increased IOP caused posterior optic disc displacement; increased CSFP caused anterior displacement.
- CSFP changes induced larger displacements than equivalent IOP changes.
- Optic disc displacement and lamina cribrosa volume changes showed nonlinear relationships with TLPD, primarily occurring at low TLPD (<15 mm Hg).
Conclusions:
- Optic disc movement is most sensitive to pressure changes within the low translaminar pressure difference range.
- These findings align with the known mechanical properties of collagenous tissues in the optic nerve head.