Loss of Pressure Control Resulting from Tube Bending during Glaucoma Drainage Tube Perforations.

PURPOSE: Tube perforations are a common method of achieving early intraocular pressure control with ligated glaucoma drainage devices (GDDs). Our purpose was to investigate how bending GDD tubes affects the performance of needle perforations. DESIGN: Experimental report. PARTICIPANTS: Twenty silicone GDD tubes attached to 27 G Rycroft cannulae tied with 7-0 Vicryl 10 mm from the cannulae tips. METHODS: Silicone GDD tubing was fitted over a 27 G Rycroft cannula and tied with a 7-0 suture 10 mm from the cannula tip. The tube was perforated 4 mm from the cannula tip with a 25 G needle (tube was kept straight). The tube was secured in a 50-mm water bath. Aqueous food dye was infused through the cannula from an adjustable height. The tube was observed under magnification while the height of the fluid column was adjusted to establish the pressure gradient at which the tube leaked dye (opening pressure) and ceased to leak (closing pressure), while the tube was held straight and bent 90 degrees. Measurements were repeated after a second perforation and a third perforation. Ten tubes were tested this way with 3 sequential slits. The entire experiment was repeated with another 10 tubes, but this time the tube was allowed to bend within the 3.5-mm open prongs of a needle holder during needle perforation. MAIN OUTCOME MEASURES: Opening and closing pressures. RESULTS: For each tube, the opening and closing pressures were similar and highly reproducible, but there was wide variation between tubes. In the tubes kept straight when perforated, the opening/closing pressure ranged from 5 to 25 cmH2O. The opening and closing pressures of slits made in the bent tube were significantly lower, frequently leaking at <1 cmH2O. Bending the tube after perforation could close a slit and prevent leakage at high perfusion pressure. The second and third successive perforations caused lower opening and closing pressures. CONCLUSIONS: Tube perforations behave like pressure-sensitive valves, opening whenever intraluminal pressure increases above a specific value. However, we found a large variation in the performance of fenestrations made with a 25-G hypodermic needle. Allowing the GDD tube to bend during needle perforation increases the risk of very low opening and closing pressures.

Association of Visual Impairment and All-Cause 10-Year Mortality Among Indigenous Australian Individuals Within Central Australia: The Central Australian Ocular Health Study.

Importance: It is well established from different population-based studies that visual impairment is associated with increased mortality rate. However, to our knowledge, the association of visual impairment with increased mortality rate has not been reported among indigenous Australian individuals. Objective: To assess the association between visual impairment and 10-year mortality risk among the remote indigenous Australian population. Design, Setting, and Participants: Prospective cohort study recruiting indigenous Australian individuals from 30 remote communities located within the central Australian statistical local area over a 36-month period between July 2005 and June 2008. The data were analyzed in January 2017. Exposures: Visual acuity, slitlamp biomicroscopy, and fundus examination were performed on all patients at recruitment. Visual impairment was defined as a visual acuity of less than 6/12 in the better eye. Main Outcomes and Measures: Mortality rate and mortality cause were obtained at 10 years, and statistical analyses were performed. Hazard ratios for 10-year mortality with 95% confidence intervals are presented. Results: One thousand three hundred forty-seven patients were recruited from a total target population number of 2014. The mean (SD) age was 56 (11) years, and 62% were women. The total all-cause mortality was found to be 29.3% at 10 years. This varied from 21.1% among those without visual impairment to 48.5% among those with visual impairment. After adjustment for age, sex, and the presence of diabetes and hypertension, those with visual impairment were 40% more likely to die (hazard ratio, 1.40; 95% CI, 1.16-1.70; P = .001) during the 10-year follow-up period compared with those with normal vision. Conclusions and Relevance: Bilateral visual impairment among remote indigenous Australian individuals was associated with 40% higher 10-year mortality risk compared with those who were not visually impaired. Resource allocation toward improving visual acuity may therefore aid in closing the gap in mortality outcomes between indigenous and nonindigenous Australian individuals.

Single-eye trial of a topical carbonic anhydrase inhibitor versus intravitreal bevacizumab for the treatment of taxane drug-induced cystoid macula oedema.

Taxanes are a class of microtubule stabilising agents used to treat a wide range of malignancies. Taxane drug-induced cystoid macula oedema (TDICMO) is a known but rare complication of therapy. First reported with Docetaxel in 2003 and Paclitaxel in 2007, there are currently less than 20 cases of TDICMO in the literature. Although most cases resolve following taxane cessation, several authors have tried using carbonic anhydrase inhibitors or intravitreal bevacizumab to accelerate resolution or when taxane therapy cannot be discontinued. We report the first published case of TDICMO treated with a single-eye trial of topical dorzolamide versus intravitreal bevacizumab.