Transnational review of visual standards for driving: How Australia compares with the rest of the world.

IMPORTANCE: Driving is a highly visual task and a primary mode of transportation for many people around the world. BACKGROUND: There appears to be little uniformity of vision standards across the world for driving. We reviewed the basic screening visual requirements for obtaining standard private and commercial driving licences for a total of 70 jurisdictions, and reviewed the evidence behind these standards. DESIGN: Systematic review of basic screening vision standards worldwide for driving and literature review. SAMPLES: Published online documentation on visual acuity and field requirements for driving. METHODS: Journal articles, government reports and websites obtained via a Google search were used to review the regulations for driving. This was limited by the comprehensiveness of resources, and countries were excluded if the requirements were unclear or unattainable. A literature review was performed using Medline with keywords vision, driving and visual field. MAIN OUTCOME MEASURES: Visual parameters used for driving assessment. RESULTS: The results suggest significant variations across the world. The visual acuity requirements for a private licence range from a minimum of 6/9 to 6/60. The minimum binocular horizontal field requirement ranges from 110° to 150°. In general, standards for a commercial licence are stricter compared to a private licence. A literature review could not support the current driving standards as evidence-based. CONCLUSIONS AND RELEVANCE: The disunity of driving vision requirements worldwide likely reflects the inconclusive evidence base. Accounting for individual differences and the ability to predict individual risk is important in the context of determining driving licensure.

Increase in mitochondrial DNA mutations impairs retinal function and renders the retina vulnerable to injury.

Mouse models that accumulate high levels of mitochondrial DNA (mtDNA) mutations owing to impairments in mitochondrial polymerase γ (PolG) proofreading function have been shown to develop phenotypes consistent with accelerated aging. As increase in mtDNA mutations and aging are risk factors for neurodegenerative diseases, we sought to determine whether increase in mtDNA mutations renders neurons more vulnerable to injury. We therefore examined the in vivo functional activity of retinal neurons and their ability to cope with stress in transgenic mice harboring a neural-targeted mutant PolG gene with an impaired proofreading capability (Kasahara, et al. (2006) Mol Psychiatry11(6):577-93, 523). We confirmed that the retina of these transgenic mice have increased mtDNA deletions and point mutations and decreased expression of mitochondrial oxidative phosphorylation enzymes. Associated with these changes, the PolG transgenic mice demonstrated accelerated age-related loss in retinal function as measured by dark-adapted electroretinogram, particularly in the inner and middle retina. Furthermore, the retinal ganglion cell-dominant inner retinal function in PolG transgenic mice showed greater vulnerability to injury induced by raised intraocular pressure, an insult known to produce mechanical, metabolic, and oxidative stress in the retina. These findings indicate that an accumulation of mtDNA mutations is associated with impairment in neural function and reduced capacity of neurons to resist external stress in vivo, suggesting a potential mechanism whereby aging central nervous system can become more vulnerable to neurodegeneration.

Increasing hepatitis B viral load is associated with risk of significant liver fibrosis in HBeAg-negative but not HBeAg-positive chronic hepatitis B.

BACKGROUND/AIMS: To evaluate the association between demographical features, serum ALT and HBV DNA and the prevalence of significant fibrosis and inflammation on liver biopsy in patients with chronic hepatitis B. METHODS: In this cross-sectional study of patients on St Vincent's Hospital HBV database, patients were classified into three groups on the basis of HBeAg status and HBV DNA level and the prevalence of significant (F2/3/4) fibrosis and (A2/3) inflammation in each group was established. Patients were also divided into HBeAg-positive and -negative groups and examined for the prevalence of significant fibrosis/inflammation in the strata of HBV DNA and ALT. Predictors of significant fibrosis and inflammation in HBeAg-positive and -negative patients were examined by logistic regression. RESULTS: Three hundred and ninety four patients (HBeAg positive=198; HBeAg negative=196) with liver biopsy were identified. Fifty-eight percent of HBeAg-negative patients with HBV DNA >25,000 IU/ml had F2/3/4 fibrosis. HBV DNA and F2/3/4 were positively correlated in HBeAg-negative patients [odds ratio (OR) 1.42, P=0.001] but inversely correlated in HBeAg-positive patients (OR 0.71, P=0.03). HBV DNA was an independent predictor of significant fibrosis in HBeAg negative (P=0.03) but not HBeAg-positive patients. In HBeAg-positive patients, age was the only predictor of significant fibrosis (P=0.001) and ALT the only predictor of significant inflammation (P=0.003). In the whole cohort there was a close positive association between inflammation and fibrosis. CONCLUSION: Increasing levels of HBV DNA are associated with increasing prevalence of significant fibrosis only in patients with HBeAg-negative CHB.