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Report on the Annual Scientific Meeting of the Australian and New Zealand Glaucoma Club
Melbourne, Australia, February 25th-26th, 2000
Anne Brooks
The Annual Scientific Meeting of the Australian and New Zealand Glaucoma Club was held in Melbourne at the Australian Club. This was a very successful meeting attended by over 90 delegates. Robert Ritch of New York was the lead speaker. The opening session on Friday was on difficult cases and, on Saturday, on problem clinical cases which generated lively general discussion.
The papers covered a wide ranging field of interest in glaucoma, some of which are reported on here.
Angle Closure Glaucoma
The lead speaker at the Meeting was Robert Ritch, who delivered four papers, and in particular, clarified his ideas on angle closure, expounding his views on the different types of angle closure glaucoma and the anatomical and pathophysiological mechanisms by which they develop. Approximately 90% of patients with angle-closure have relative pupillary block as the underlying mechanism, and laser iridotomy provides the definitive treatment. The importance of indentation gonioscopy and of gonioscopy in the dark, even after peripheral iridotomy, was emphasized. The double hump gonioscopic appearance of the iris in plateau iris and the technique of gonioplasty was described. The role of high frequency, high resolution, anterior segment ultrasound biomicroscopy (UBM) in the study of angle closure glaucoma was highlighted.
Exfoliation Syndrome
The best presentation was Rob Ritch's final paper which addressed exfoliation syndrome (XFS). He noted that the Eskimos are the only known population without XFS. All structures of the anterior segment are affected including the conjunctiva and orbital structures. A systemic disorder is suspected. The epidemiology, clinical findings, histopathology and management of patients with XFS were reviewed. That XFS can develop in the absence of the lens was noted. It is a high pressure disease and angle closure may occur. The importance of pigment-related secondary signs of the disease, present prior to the development of clinically visible XF material was emphasized. It was noted that XFS appears to be an ischemic disease of the eye. An association with transient ischemic attacks, hypertension, myocardial infarction and stroke has been reported. He stated that any patient over 50 years of age with unilateral glaucoma has XFS until proven otherwise. Open angle glaucoma patients under 50 years of age have pigment dispersion syndrome until proven otherwise. The possibility of an infective cause for XFS was raised. Rob Ritch also proposed that pilocarpine is beneficial in XFS, increasing aqueous outflow and limiting pupil movement, whereas aqueous suppressants may make XFS worse.
In a series of 646 cases with pseudoexfoliation (PXF), Bill Gillies reported 233 uniocular cases. This demonstrated that PXF is not necessarily related to a raised intraocular pressure (IOP). Progression may be rapid or slow. There may be a previously existing ocular hypertension. An acute onset of open angle PXF glaucoma is possible and may be confusing as acute angle closure glaucoma also occurs, sometimes there is a shallow anterior chamber without glaucoma.
Neovascular glaucoma is seen following central retinal vein occlusion, but it is not clear if this is particularly common in PXF. Absolute PXF glaucoma is an entity.
Paul Mitchell reported on the Blue Mountains Eye Study and confirmed that the presence of PXF may not necessarily be associated with a rise in IOP.
The most original presentation was by Stuart Graham who delivered a paper on his progress in developing a more objective method of testing visual fields in glaucoma. He concluded that the multi-focal multi-channel visual evoked potential (VEP) can objectively detect glaucomatous visual field defects, but does need a level of patient cooperation. Asymmetry analysis has the potential to detect early defects. This technique indicates the possibility of the clinical application of objective perimetry in glaucoma.
Surgery
Surgical presentations included Tony Molteno's report on the long-term results of 40 cases of chronic uveitis with secondary glaucoma drained by Molteno implants in the years 1978-1998. The IOP was controlled with a probability of 0.87 and 0.74 at five and ten or more years after surgery. Useful vision was retained in 80% and 75% of cases after five and seven or more years, respectively. There was a high incidence of cataract formation. Corneal decompensation was much less common and where it did occur was associated with repeated intraocular procedures. There was a very low proportion of cases which showed ongoing field loss after normalisation of IOP.
Adrian Farinelli reported on pars plana tube insertion with glaucoma drainage implants. He concluded that this technique expands the use of glaucoma drainage implants for complex glaucoma management. Phillip House reported on the development of an open angle glaucoma model in the rabbit. He concluded that unusual features of the rabbits anterior segment anatomy make trabecular meshwork ablation without ciliary process damage and synechiae formation difficult to achieve. Ivan Goldberg presented data on the worldwide incidence of glaucoma.
Acute Angle Closure Glaucoma
There were several presentations from Singapore. Gus Gazzard reported that, in Asian eyes at high risk of developing acute angle closure glaucoma, sequential laser peripheral iridotomy produced a significant widening of the anterior chamber angle on ultrasound biomicroscopy; the first quantitative demonstration of changes in angle morphology after laser iridotomy.
Medical Treatment
Paul Chew confirmed that another prostaglandin, Unoprostone, was rather less effective than latanoprost. Anne Brooks confirmed that latanoprost largely maintains its effect over the longer term and has a significant add on effect with most other medication. There was participation from the pharmaceutical industry with presentations assessing brimonidine, latanoprost and betaxolol.
This was a very successful scientific meeting and the social program complemented this at the Observation Deck on the 55th Level of the Rialto overlooking Melbourne and at the Grand dining room of the Australian Club, both occasions to be remembered.
Summary
1. The main subjects were angle-closure, PXF, pigment dispersion, objective perimetry, surgical aspects of glaucoma and medications.
2. Stuart Graham's progress on objective perimetry was new and the most original presentation.
3. There was important confirmation was of the sustained effect of latanoprosts and the Blue Mountains Eye Study finding of the presence of PXF not necessarily being associated with a rise in IOP.
4. The studies presented were clinical.
5,6. Rob Ritch's presentation on angle closure will change my diagnostic approach and treatment. I will have a more flexible approach to PXF and angle closure glaucoma.
7. The lead speaker of the meeting was Rob Ritch, clarifying his views on angle closure glaucoma.
8. The most original presentation was by Stuart Graham on his development of a more objective method of testing visual fields in glaucoma.
Conclusion
Progress is being made towards developing a substantially objective method of testing the visual field. A highly flexible approach is needed to patients with XFS. Plateau iris needs different treatment from usual pupil block angle closure glaucoma.
