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Top-ten from the Royal Australian and New Zealand College of Ophthalmologists Scientific Congress Glaucoma Sessions
Melbourne, November 23-26, 2008

Anne Brooks

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1. The current nomenclature for describing angle closure and angle closure glaucoma that has been adopted widely in the literature as well as by major glaucoma organizations (including the World Glaucoma Association) was described. Detailed images of the anterior segment structure in angle closure using ultrasound biomicroscopy showed the large variations in iris insertion, iris thickness, amount of pupillary block, and other factors that all play a role in angle closure. The lens plays an important role in angle closure and new evidence shows that early lens extraction after acute angle-closure attacks is likely to be beneficial in many cases. (David Friedman, Baltimore, MD, USA)
2. The accuracy of seven confrontation visual field tests was prospectively compared against automatic static perimetry in 163 patients with regard to the density, location and cause of the visual field defect. Overall confrontation visual field tests are insensitive at detecting visual field loss and are therefore a poor screening test. However identified field defects are usually real and warrant further investigation. The most sensitive confrontation visual field test for the detection of glaucomatous field loss was a kinetic 5mm red target which had a sensitivity of 67.3% and specificity of 92.9%. (Nathan Kerr, Shenton Chew, Elizabeth Eady, Kent Chow, Helen Danesh-Meyer, Auckland New Zealand)
3. A novel genome-wide DNA pooling association study was used to investigate the allelic architecture of advanced open-angle glaucoma. Several putative novel loci reached suggestive significance levels yet no variant was found to be significant at the Bonferroni-correction level set for genome-wide and individual follow- up significance levels. (Alex Hewitt, Melbourne, Australia)
4. Rotenone and resveratrol are mitochondrial modifiers that reduce glutamate-induced excitotoxicity in retinal ganglion cells (RGC) in-vitro. Protection of RGC has been associated with reduced oxidative stress. We believe that modifying mitochondrial activity may provide a therapeutic target for protecting retinal ganglion cells. (Houston Li, Nicole van Bergen, Y.G. Kong, Jonathan Crowston, Melbourne, Australia)
5. Aging predisposes glaucoma, but the pathophysiology behind this is not well understood. Greater dysfunction, slower recovery and increased oxidative stress in retinal ganglion cells of 3-month old compared to 18-month old mice was demonstrated. These data indicate that the old optic nerve is more vulnerable to acute IOP elevation than optic nerves of young animals. (Jonathan Crowston, Melbourne, Australia)
6. Scarring after trabeculectomy is a regulated process that is terminated by apoptosis of Tenon's fibroblasts. Mitomycin-C (MMC) kills fibroblasts by inducing apoptosis. In as many as one in three trabeculectomies there may be some degree of MMC-resistance. This may be higher in repeat MMC surgery and may lead to clinical failure. IFN-a IFN-g enhance the susceptibility of MMC-sensitive fibroblasts to MMC-induced cell death. Interferons also increase Fas expression in fibroblasts and render MMC-resistant fibroblasts sensitive to Fas mediated apoptosis. (Paul Healey, Sydney, Australia)
7. An acute pig glaucoma model was used maintaining CSF pressure at 5 mmHg, right IOP at 13 mmHg (normal pressure) and left IOP at 43 mmHg (high pressure) for 6 or 12 hours in anaesthetized pigs. Application of DAB-cytochrome oxidase (COX) for 40 minutes to cryosections through the optic nerve head, revealed no significant variation in COX stain between high and low pressure eyes at 6 hours. However, at 12 hours a significantly greater COX stain was seen in the lamina-cribrosa region of the high-pressure eyes implying greater oxidative phosphorylation activity was occurring in the lamina region without detectable changes elsewhere. This change is probably required to satisfy the increased metabolic demands of axonal transport and other molecular events occurring in the region of increased pressure gradient. (William Morgan, Chandrakumar Balaratnasingam, Louise Bass, Stephen Kringle, Dao-Yi Yu, Sydney, Australia)
8. Glaucoma comprises pathology apart from simple loss of retinal ganglion cell bodies. Glial fibrillary acidic protein is upregulated in early experimental glaucoma, indicating astrocyte and Muller cell activation. Microglial cells are evident throughout the optic nerve and the contralateral optic nerve may be involved through chiasmal spread. (Bob Casson, Adelaide, Australia)
9. Nocturnal oxygen desaturation and self-reported sleep-disordered breathing symptoms were measured in a large study comparing a glaucoma population with a normal control group. The mean oxygen desaturation index (ODI) of the glaucoma group (8.6) did not differ significantly from that of the control group (9.6) (P = 0.715). The prevalence of moderate to severe respiratory dysfunction (ODI > 20) in the glaucoma group (17%) was similar to that in the control group (12%) (P = 0.463). The severity of sleep-disordered breathing symptoms was similar between the groups (P = 0.157). This study found no statistically significant association between glaucoma and either nocturnal oxygen desaturation or sleep-disordered breathing. Whilst the possibility of either impaired optic nerve head autoregulation or hypoxic damage occurring secondary to sleep apnoea syndrome cannot be excluded, the findings do not support the routine use of pulse oximetry in the workup of individuals with glaucoma. (Tim Roberts, Sydney, Australia)
10. Central arterial blood pressure, pulse wave characteristics and markers of arterial stiffness derived from radial artery tonometry were measured in 110 glaucomas and subdivided into NTG vs POAG, and progressive vs stable. MAP and central BP was similar to historically matched controls, and in both glaucoma subgroups, but the glaucomas had lower pulse pressures. Progression was found more in cases with absent spontaneous venous pulsation at the disc. (Stuart Graham, Mark Butlin, Albert Avolio, Sydney, Australia)