A Surgical Technique for Difficult Glaucoma Cases: Combined Cyclectomy/Trabeculectomy

Abstract

Although glaucoma, known to be the most common cause of irreversible blindness, is characterized by progressive loss of retinal ganglion cells, it has long been perceived as a disease caused by “increased intra-ocular pressure (IOP)”. Although increased IOP has been recently removed from the definition of glaucoma and regarded as a major risk factor and glaucoma has been defined as an optical neuropathy, clinical practices are still predominantly oriented towards the reduction of IOP (Gupta & Yucel, 2007). Yet the neuroprotective strategies developed are of limited use due to both variety and receptors and ion channels and the severity of side effects. Moreover, clinical studies are not sufficient (Danesh-Meyer, 2011). Recently, we have many medical therapeutic agents that have reduced IOP via different mechanisms. When target IOP defined for particular patients cannot be reached using medical therapy, ophthalmologists still have different options. Trabeculectomy with or without antimetabolites remains the golden standard for most of the primary and secondary glaucomas when medical and laser therapy are insufficient. However, some eyes are unresponsive to this therapy as well (Coleman & Brigatti, 2001). In a study conducted on 709 eyes of 566 patients, the variability of the efficiency of standard trabeculectomy has been reported with the mean follow up of 27.9 months (Mietz et al, 1999). According to the study, success rates for complete surgical success ranged from 59% in the best group with pigmentary dispersion syndrome to 0% in the worst group with neovascular glaucoma. Success rates of patients with POAG, pseudoexfoliation, chronic angle closure, pigmentary dispersion syndrome, and dysgenetic glaucoma were similar. Failure rates ranged from 11% in the best group (pseudoexfoliation) to 80% in the worst group (neovascular glaucoma). Failure rates were high in complicated forms of glaucoma, such as traumatic (30%), buphthalmos (40%) and uveitic (50%). For repeat trabeculectomies, the failure rate was 49% (20 out of 41 eyes). The mean time until failure ranged from 2.7 months (traumatic) to 15.5 months (pigmentary dispersion syndrome) and was 4.9 months for repeat trabeculectomies.