The Hull Anterior Vitrectomy Simulation System (HAVSS): a validated novel simulation for training in the management of intra-operative vitreous loss.

OBJECTIVES: To design and validate a feasible simulation to address an identified training gap in the management of intraoperative vitreous loss. METHODS: Our simulation consists of a two-part non-toxic mixture that polymerises upon contact within a silicone training eye, to resemble the appearance of vitreous after staining with triamcinolone. This gel can be cut and aspirated with an anterior vitrectomy probe. Experienced consultant ophthalmic surgeons were invited to assess the simulation and anonymously complete validity questionnaires. RESULTS: Seven senior surgeons participated. Four (57%) strongly agreed and three (43%) agreed that the tissue behaved like vitreous. Six (86%) strongly agreed and one (14%) agreed that instrument handling was realistic. Three (43%) strongly agreed and four (57%) agreed that simulated triamcinolone staining was realistic. Four (57%) strongly agreed and three (43%) agreed that the simulation was visually convincing. Six (86%) strongly agreed and one (14%) agreed that this simulation is useful for training. No participants disagreed with any validity statements. CONCLUSIONS: This novel simulation of anterior vitrectomy has good face and content validity, with unanimous agreement among experienced surgeons of its utility for training in the management of intraoperative vitreous loss.

A hairy affair: tarantula setae-induced panuveitis requiring pars plana vitrectomy.

Cases of ocular inflammation following penetration by urticating hairs from caterpillars and tarantulas have been previously reported and although rare, the condition is increasingly being recognised as a cause of chronic panuveitis. The long-term outcomes and prognosis of this condition are not well known. This article describes a case of chronic panuveitis as a result of ocular penetration by tarantula setae, and its challenging management that ultimately required pars plana vitrectomy. Interventional case report: A 29-year-old male presented with chronic panuveitis secondary to tarantula-hair penetration. Initial management with mechanical removal of hairs from the cornea and intensive topical steroid therapy for 18 months did not adequately control his symptoms. Pars plana vitrectomy was carried out and at 6-month follow-up the patient was symptom-free without any pharmacological therapy. We propose early pars plana vitrectomy as a management option for treatment-resistant panuveitis in cases of ophthalmia nodosa secondary to setae-related injury.

Cation transport by a redox-active synthetic ion channel.

The synthesis, cation binding and transmembrane conductive properties of a novel group of synthetic ion channels containing a redox-active centre are described. Experiments using a black lipid membrane preparation revealed that these compounds function effectively as ion channels. Subsequent 23Na NMR spectroscopy studies focused on a synthesized ion channel with a ferrocene centre. When incorporated in vesicular bilayers, this channel was demonstrated to support a Na+ flux that was at least six times faster than ion transport by monensin. Since oxidation of the ferrocene moiety completely inhibited the Na+ transport, the redox-active centre provides a potential mechanism for controlling ion flux.