Efficacy and Safety of the Ab-interno Xen Gel Stent After Failed Trabeculectomy.

AIMS: To assess the efficacy and safety of the Xen gel stent in reducing intraocular pressure (IOP) in eyes with prior failed trabeculectomy and to determine the frequency of complications and further intervention. METHODS: Retrospective case note review of all patients with prior trabeculectomy undergoing Xen surgery across 5 centers from August 2015 to May 2017. RESULTS: In total, 17 surgeries were reviewed. IOP reduced from 21.5 (±2.4) mm Hg preoperatively to 13.6 (±3.4) mm Hg at month 12 (P<0.05). Medication usage reduced from 2.8 (±0.6) preoperatively to 1.0 (±1.3) at month 12 (P<0.05). Adverse events included: numerical hypotony (IOP<6 mm Hg) in 4 cases (23.5%) that all resolved spontaneously, IOP spike of ≥30 mm Hg in 2 (11.8%) cases and transient occlusion of the implant by iris in 1 (5.9%) case. Secondary filtration surgery (Baerveldt tube implantation) was required in 2 (11.8%) cases. Postoperative bleb intervention was required in 9 cases (52.9%), usually in the first month after surgery. CONCLUSIONS: Xen reduces IOP and number of medications in eyes with failed trabeculectomy. Detailed preoperative conjunctival assessment and targeted stent placement is required. Prospective data and follow-up beyond 12 months are required but Xen seems a viable, effective, and safe option after failed trabeculectomy.

Human organotypic retinal cultures (HORCs) as a chronic experimental model for investigation of retinal ganglion cell degeneration.

There is a growing need for models of human diseases that utilise native, donated human tissue in order to model disease processes and develop novel therapeutic strategies. In this paper we assessed the suitability of adult human retinal explants as a potential model of chronic retinal ganglion cell (RGC) degeneration. Our results confirmed that RGC markers commonly used in rodent studies (NeuN, ßIII Tubulin and Thy-1) were appropriate for labelling human RGCs and followed the expected differential expression patterns across, as well as throughout, the macular and para-macular regions of the retina. Furthermore, we showed that neither donor age nor post-mortem time (within 24 h) significantly affected the initial expression levels of RGC markers. In addition, the feasibility of using human post mortem donor tissue as a long-term model of RGC degeneration was determined with RGC protein being detectable up to 4 weeks in culture with an associated decline in RGC mRNA and significant, progressive, apoptotic labelling of NeuN(+) cells. Differences in RGC apoptosis might have been influenced by medium compositions indicating that media constituents could play a role in supporting axotomised RGCs. We propose that using ex vivo human explants may prove to be a useful model for testing the effectiveness of neuroprotective strategies.