Eyeworld

5 0 10:21 EW MEETING REPORTER 62 May 2014 into acute, sub-acute, and chronic. The International Society of Geographical and Epidemiological Ophthalmology (ISGEO) further classifies the condition into primary angle closure suspect (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG). This sub-classification, she said, is important because treatment modalities and prognosis may be different for each sub-class. She also reviewed the mecha- nisms of angle closure, including pupillary block, lens status, and plateau iris. Plateau iris may be of particular significance to the Asia- Pacific region, with reports of up to 30% plateau iris in Asian eyes. Dr. Sung wondered whether it would be useful to sub-classify PACG by mechanism. Maybe, she said, par- ticularly considering that previously published papers on PACG report different mechanisms and biometric differences between cases. In their own study, a cluster analysis of 166 PAC subjects, Dr. Sung and her colleagues identified two clusters: cluster 1, consisting of eyes with deep anterior chambers and low lens vaults; and cluster 2, consisting of eyes with shallow ante- rior chambers and high lens vaults. These clusters seem to predict responsiveness to laser peripheral iridotomy (LPI): The procedure appears to have less effect in eyes with shallow anterior chambers. Going further, Clement Tham, MD, Hong Kong, said that the man- agement of the acute form of PACG comes in two stages: stage 1 aims to reduce IOP while stage 2 aims to pre- vent the recurrence of acute angle closure and progression to PACG. IOP reduction is generally achieved through medication, but can also be achieved through LPI and anterior chamber (AC) paracen- tesis. For LPI, Dr. Tham spoke specifically about argon laser PI. ALPI is the use of an argon laser to induce contraction burns in the extreme iris periphery. The argon laser is characterized by long dura- tion, low power, and large spot size; for stage 1 management, said Dr. Tham, ALPI is significantly better than IOP-lowering drugs. Only 17.6% of patients who undergo ALPI progress to chronic ACG, compared with 38.2% of pa- tients who are treated with medica- tion. In addition, ALPI has no systemic adverse effects. The effects are also faster, with IOP lowering in some cases observed just half an hour after the procedure. Wong Hon Tym, MD, Singapore, considered the use of LPI as prophylaxis for ACG. Dr. Wong recommended performing LPI in the fellow eye of an acute PAC eye—these eyes, he said, have a 50% risk of also undergoing attack. LPI can also be used in all stages of chronic angle closure glaucoma (CACG), and in primary angle closure suspects or patients with nar- row angles—although the evidence for the latter is the weakest, he said, it is still acceptable. Sequential argon-YAG lasers are recommended for thick brown iri- des. Surgeons can also consider using diode lasers. For stage 2 management, Dr. Tham discussed the role of early lens extraction. Phaco performed at the time of acute attack makes a significant difference, he said. Among patients who underwent early phaco, only 3.2% progressed to CACG after 18 months; in comparison, 46.7% of those who underwent phaco later progressed to CACG after 18 months. Once a patient develops CACG —that is, PACG with glaucomatous optic neuropathy—the management changes dramatically, said Prin Rojanapongpun, MD, Thailand. In particular, success with LPI drops to 60%. Dr. Rojanapongpun detailed the steps in the management of CACG: First, document the angle. Is the tra- becular meshwork open, closed? He cautioned that in some cases, the angle may appear closed until you tilt the eye. Once closure is documented, the ophthalmologist needs to determine the mechanism of closure. Pupillary block, said Dr. Rojanapongpun, is the most com- mon; in agreement with Dr. Sung's observation, plateau iris, he said, is also common. The mechanism, he cautioned, can be multiple. After gonioscopy and angle study, the next step is to start with medication. Medication, he said, is effective for the majority of patients. LPI can also be performed, but the eye should be reassessed after the procedure; meanwhile, laser iridoplasty may be combined with iridectomy and is helpful for some patients. Filtering surgery, he said, is a "late choice," since the outcome is quite variable and has a high risk of failure, while data is insufficient to support primary cataract surgery as an option for CACG. After treatment, patients should be followed up to monitor IOP and disc and visual field status, and un- dergo periodic gonioscopy. EW Reporting live from the 2014 World Ophthalmology Congress, Tokyo Supported by Carl Zeiss Meditec AG View it now: WOC 2014 ... EWrePlay.org Amar Agarwal, MD, gives a step-by-step description of the scleral glued IOL technique.

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