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Abstract #19187 Published in IGR 3-1
Non-penetrating glaucoma surgery: the state of play
Tan JCH; Hitchings RABritish Journal of Ophthalmology 2001; 85: 234-237
In this editorial, the authors review the present state of non-penetrating glaucoma surgery. Central to the appeal of this technique is the avoidance of ocular entry, which obviates the need for an iridectomy and theoretically limits early postoperative hypotony. This in turn minimizes the attendant sequelae of hyphema, choroidal effusions, shallow anterior chambers, and cataract. The techniques of non-penetrating surgery are briefly described. The authors continue by comparing the reported pressure control by conventional trabeculectomy and by non-penetrating glaucoma surgery. It seems that IOP control is better maintained in trabeculectomy. Therefore, when a target pressure in the low teens is deemed necessary for visual preservation, trabeculectomy is to be preferred. They further discuss the risk profile and surgical technique. It seems that the complications of non-penetrating glaucoma surgery are indeed lower than after trabeculectomy. However, there is a steep learning curve associated with this type of surgery. Inadvertent perforation of the trabecular meshwork may occur in as many as 30% of initial cases. Conversion from non-penetrating surgery to trabeculectomy may lead to an incidence of 90% postoperative hypotony and close to 70% hyphema. The risk of postoperative cataract formation is also discussed. Finally, the costs and quality of life considerations are mentioned. The authors conclude that the present research into non-penetrating surgery has set an early stage, on which these operations may be openly and rationally judged as alternatives to the gold standard trabeculectomy. The considerations for justifying new treatments in the context of lifelong disease are many and complex, requiring rigorous assessments that must prove safety and real health benefits over time. More exacting modern concepts would also embody financial and quality of life perspectives. Fundamental questions relating to the basic mechanisms of outflow need to be addressed in order to provide a sure premise for treatment, as well as to pave the way for fresh insights and improvements. Several randomized control trials comparing new and conventional approaches are under way which will, with appropriate follow-up, provide a basis for comparison. However, current trials are known to include small numbers, and this will limit the extent to which these issues can be addressed. Until a larger, possibly multinational, study with adequate power is conducted, we may not have sufficient information to justify a change in surgical practice.
Prof. R.A. Hitchings, Glaucoma Research Unit, Moorfields Eye Hospital, City Road, London EC1V 2PD, UK
Classification:
12.8.3 Non-perforating (Part of: 12 Surgical treatment > 12.8 Filtering surgery)
