Anterior chamber paracentesis in patients with acute elevation of intraocular pressure

Abstract

Dear Editors, We read with interest on your article by Arnavielle et al. [1] on the potential benefits of anterior chamber (AC) paracentesis in patients with acute angle-closure glaucoma. Lam et al. [2, 3] first proposed this technique in treating patients with acute angle-closure glaucoma. His pilot study recruited ten eyes in eight patients, and IOP was maintained at normal range 2 hours after paracentesis. The effect of paracentesis was found to be temporary, with subsequent rise of IOP at 30 minutes, and therefore medications were still needed for breaking the pupil block and to substantiate the IOP-lowering effects. However in your study, IOP was only measured at 10 minutes, 1 day, 7 days, 30 days and 1 year after the paracentesis. In addition, most of your cases received additional surgical interventions such as laser iridotomy and cataract extraction subsequently. Hence, we believed that your study only reflected the overall management of the cases, and the IOP measurements had little relevance on the true effect of the AC paracentesis. The potential long-term complications could be increased risks of peripheral anterior synechiae, and further loss of endothelial cells counts caused by the shallow anterior chamber from the paracentesis. It would be useful to know the angle status in long term in such cases with AC paracentesis performed compared to those without. However, your study did not provide information in this regard. We believe a prospective randomized controlled trial with larger sample size, post-operative gonioscopic findings and endothelial counts in the long term is necessary. The pathogenesis of secondary angle-closure glaucoma is widely varied and they are notoriously difficult in management. Inclusions of secondary angle-closure glaucoma in your study could confound the results, and have to be interpreted with caution. In fact, AC paracentesis was not found to be useful in secondary angle-closure cases in your study. With paracentesis, additional risks of hyphema from neovascular irides and even tumour seeding (in the case of choroidal melanoma) could occur if not managed correctly. We therefore do not recommend AC paracentesis in cases with secondary angle-closure glaucoma. From the limited studies in the literature, AC paracentesis provides a methodology which is quick and effective in lowering IOP in the immediate stage of acute angle-closure glaucoma, and the effect seems to be maintained with the help of the topical and oral glaucoma medications. The complications reported so far in the limited literature are trivial. However, it is important to note that AC paracentesis is not a treatment that alleviates the true cause of the acute angle closure, which is mainly because of pupillary block with increased posterior chamber pressure. The possible side effects of ocular tissue injury, decompression retinopathy [4], suprachoroidal haemorrhage, aqueous misdirection and infection could be drastic and equally vision-threatening. Long-term risks of peripheral anterior synechiae and corneal endothelial cell loss are also not clear. We believe that it has a place in cases where IOP control is not readily effective or contraindicated due to systemic diseases, or in situations where laser such as ALPI or PI is not readily available or not possible to perform due to corneal oedema, AC paracentesis can be a treatment of choice [2, 3]. Graefes Arch Clin Exp Ophthalmol (2008) 246:463–464 DOI 10.1007/s00417-007-0675-5