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Top-Five of the Annual Meeting of the Australian and New Zealand Glaucoma Interest Group Fremantle
Western Australia, February 6-7, 2014
Anne Brooks
- Normal-tension glaucoma (NTG), cerebrospinal fluid and optic
nerve sheath compartmentalization
The optic nerve is a white matter tract of the central nervous system (CNS) that is surrounded by cerebrospinal fluid, just as the brain is. All CSF spaces in the CNS are covered by menigothelial cells (MEC) including the subarachnoid space (SAS) of the optic nerve. The CSF has been considered to be homogeneous in pressure and composition. Due to the plasticity and mechanosensitivity of MECs that line all CSF spaces, the SAS of the optic nerve, however, can be become compartmentalized. Such compartmentalization has been demonstrated with cisternography. The typical finding is a drastically reduced influx of contrast loaded cerebrospinal fluid from the intracranial CSF into the SAS of the optic nerves in NTG. This lack of CSF influx leads to stasis of CSF due to reduced CSF turnover with possible accumulation of toxic metabolites from some of the 20 000 peptides in the CSF. A second finding in NTG is a distension of the subarachnoid space. This distension may represent either a higher local pressure or a weakening of the dural sheath structures due to substances, such as metalloproteinases.
Further CSF studies in patients with NTG are needed to evaluate the role of CSF content and pressure. (Hanspeter E. Killer, Aarau, Switzerland) - Fun in the space around glaucoma
Recent work summarizing the role of cerebrospinal fluid pressure in glaucoma aetiology was described, with strong suggestions that low CSF pressure contributes to glaucoma aetiology. Curiously, CSF pressure pulse wave form has been shown to be responsible for retinal venous pulsation timing. Our group has been at the forefront of exploring the linkage between glaucoma severity and elevated venous pulsation pressure. More recently we and others have begun to explore the possibility of using retinal venous pulsation properties to estimate optic nerve CSF pressure. (Bill Morgan, Perth, Australia) - Cataract and quality of life in patients with glaucoma
This cross-sectional study evaluated the impact of cataract on quality of life (QoL) in patients with glaucoma (n = 192) and controls (n = 50). Using the Rasch-analysed Glaucoma Activity Limitation-9 (GAL-9) questionnaire individuals with cataract (n = 56) had poorer QoL than those without cataract, when sub-stratified by binocular glaucoma severity. Cataract was an independent predictor of GAL-9 score on regression analysis. (Simon E. Skalicky, Sydney and Cambridge) et al.) - Alterations to vascular endothelium in the optic nerve head in patients
with risk factors for retinal vascular occlusion
Arterial-like appearance of venous endothelium and increased venous endothelial stress fibre expression was found in the posterior lamina cribrosa, where pressure gradient forces are predicted to be greatest and CRV luminal diameter is known to be narrowest. It may reflect altered hemodynamic properties and coagulation cascades, implicating the posterior lamina as an important site for thrombus formation in CRVO. (Min H. Kang et al., Perth, Australia) - Determinants of rim-disc area ratio in a multi-ethnic
Asian population Heidelberg Retinal Tomography-3 imaging was performed for 4940 non-glaucomatous Asians (1214 Chinese, 1847 Malay and 1879 Indian) in Singapore. The mean disc area and rim-disc area ratio (RDAR) were 1.99 ± 0.43 mm2 and 0.73 ± 0.14 respectively. Larger RDAR was associated with Indian ethnicity, lower intraocular pressure, longer axial length, female gender, thicker cornea and higher body mass index. ( Victor Koh, Singapore)
