This systematic review and meta-analysis compares sodium hyaluronate (HY) with non-HY based artificial tears in the treatment of dry eye syndrome. A literature search for clinical trials comparing HY against non-HY preparations was conducted across PubMed, Cochrane Central Register of Controlled Trials and Scopus databases from inception up to May 2016. Majority of the 18 studies selected for review showed superiority of HY in improving ocular staining and symptoms. Randomized controlled trials (RCTs) examining Schirmer’s I (SH) and tear breakup time (TBUT) underwent further meta-analyses with calculation of pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs). 7 RCTs including 383 eyes randomized to HY and 596 eyes to non-HY preparations underwent meta-analysis for SH. 9 RCTs including 458 eyes randomized to HY and 651 eyes to non-HY preparations underwent meta-analysis for TBUT. By fixed-effects modelling, HY demonstrated greater improvement of SH compared to non-HY preparations (SMD, 0.238; 95% CI, 0.107 to 0.369; p < 0.001). By random-effects modelling, HY demonstrated less improvement of TBUT (SMD, −0.566; 95% CI, −1.099 to −0.0336; p = 0.037). In summary, neither preparation was shown to be consistently superior across all outcome measures. The difference in effect between preparations on SH and TBUT was not clinically significant.

Background An asymptomatic SCUBA (Self-contained underwater breathing apparatus) diver was discovered to have an intralobar bronchopulmonary sequestration during routine pre-course screening. This is the first reported case of a diver who, having previously completed several recreational and military diving courses, was subsequently diagnosed with a congenital lung condition, possibly contraindicating diving. Presently, there is no available literature providing guidance on the diving fitness of patients with such a condition. Case presentation An asymptomatic 26-year-old male diver was nominated to attend an overseas naval diving course. Prior to this, he had been medically certified to participate in, and had successfully completed other military and recreational diving courses. He had also completed several hyperbaric dives up to a depth of 50 m and 45 recreational dives up to a depth of 30 m. He did not have a history of diving-related injuries or complications. He had never smoked and did not have any medical or congenital conditions, specifically recurrent respiratory infections. As part of pre-course screening requirements, a lateral Chest X-ray was performed, which revealed a left lower lobe pulmonary nodule. This was subsequently diagnosed as a cavitatory left lower lobe intralobar bronchopulmonary sequestration on Computed Tomography Thorax. The diver remains asymptomatic and well at the time of writing and has been accepted to participate in another overseas course involving only dry diving in a hyperbaric chamber, with no prerequisites for him to undergo surgery. Conclusion Although bronchopulmonary sequestrations lack communication with the tracheobronchial tree, they may still contain pockets of air, even if not radiologically visible. This can be attributed to anomalous connections which link them to other bronchi, lung parenchyma and/or pores of Kohn. As such, there is a higher theoretical risk of pulmonary barotrauma during diving, leading to pneumothorax, pneumomediastinum, or cerebral arterial gas embolism. Taking these into consideration, the current clinical consensus is that bronchopulmonary sequestrations and all other air-containing lung parenchymal lesions should be regarded as contraindications to diving. Patients who have undergone definitive and uncomplicated surgical resection may be considered fit to dive.

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