Bridging the gap to evidence-based eye care.

In the first article in this series, I touched on the enormous challenge to make access to information equal for those who need it at the time and place when they need it. Only if this is achieved can we successfully promote an evidence-based approach to health care. The move towards open access publishing is taking us some way to achieving this. However, there are further gaps to be bridged if we are to turn eye care workers into evidence-based practitioners. We can define an evidence-based practitioner as one who combines their individual knowledge and expertise with the best available external clinical evidence from systematic research

Setting standards for glaucoma care.

The UK National Institute for Health and Clinical Excellence (NICE) published guidelines on the diagnosis and management of open-angle glaucoma in 2009 (www.nice.org.uk/CG85). These are intended to set standards for practice in the UK's National Health Service (NHS)As these guidelines are the only strictly evidence-based glaucoma guidelines available, however, they are a resource that can be accessed and used globally

Clinical auditing to improve patient outcomes

Clinical audit is about measuring the quality of care we provide against relevant standards. If we are failing to meet these standards, the audit should help us understand the factors that are causing us to fail, so that we can set priorities and make improvements

Ivermectin for onchocercal eye disease (river blindness).

BACKGROUND: It is believed that ivermectin (a microfilaricide) could prevent blindness due to onchocerciasis. However, when given to everyone in communities where onchocerciasis is common, the effects of ivermectin on lesions affecting the eye are uncertain and data on whether the drug prevents visual loss are unclear. OBJECTIVES: The aim of this review was to assess the effectiveness of ivermectin in preventing visual impairment and visual field loss in onchocercal eye disease. The secondary aim was to assess the effects of ivermectin on lesions affecting the eye in onchocerciasis. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 3), MEDLINE (January 1950 to April 2012), EMBASE (January 1980 to April 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 2 April 2012. SELECTION CRITERIA: We included randomised controlled trials with at least one year of follow-up comparing ivermectin with placebo or no treatment. Participants in the trials were people normally resident in endemic onchocercal communities with or without one or more characteristic signs of ocular onchocerciasis. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed trial quality. We contacted study authors for additional information. As trials varied in design and setting, we were unable to perform a meta-analysis. MAIN RESULTS: The review included four trials: two small studies (n = 398) in which people with onchocercal infection were given one dose of ivermectin or placebo and followed up for one year; and two larger community-based studies (n = 4941) whereby all individuals in selected communities were treated every six or 12 months with ivermectin or placebo, whether or not they were infected, and followed for two to three years. The studies provide evidence that treating people who have onchocerciasis with ivermectin reduces the number of microfilariae in their skin and eye(s) and reduces the number of punctate opacities. There was weaker evidence that ivermectin reduced the risk of chorioretinitis. The studies were too small and of too short a duration to provide evidence for an effect on sclerosing keratitis, iridocyclitis, optic nerve disease or visual loss. One community-based study in communities mesoendemic for the savannah strain of O.volvulus provided evidence that annual mass treatment with ivermectin reduces the risk of new cases of optic nerve disease and visual field loss. The other community-based study of mass biannual treatment of ivermectin in communities affected by the forest strain of O.volvulus demonstrated reductions in microfilarial load, punctate keratitis and iridocyclitis but not sclerosing keratitis, chorioretinitis, optic atrophy or visual impairment. The study was underpowered to estimate the effect of ivermectin on visual impairment and other less frequent clinical signs. The studies included in this review reported some adverse effects, in particular an increased risk of postural hypotension in people treated with ivermectin. AUTHORS' CONCLUSIONS: The lack of evidence for prevention of visual impairment and blindness should not be interpreted to mean that ivermectin is not effective, however, clearly this is a key question that remains unanswered. The main evidence for a protective effect of mass treatment with ivermectin on visual field loss and optic nerve disease comes from communities mesoendemic for the savannah strain of O.volvulus. Whether these findings can be applied to communities with different endemicity and affected by the forest strain is unclear. Serious adverse effects were rarely reported. None of the studies, however, were conducted in areas where people are infected with Loa loa (loiasis)

Is there evidence that the yearly numbers of children newly certified with sight impairment in England and Wales has increased between 1999/2000 and 2014/2015? A cross-sectional study.

OBJECTIVES: To use routine data capture from hospitals in England and Wales to identify whether there has been an increase in the annual numbers of children newly certified sight impaired in England and Wales between 1999/2000 and 2014/2015 and to examine causes of certifiable sight impairment in children certified in 2014/2015. DESIGN: A cross-sectional study including an analysis of all certificates of vision impairment completed in hospitals in England and Wales each year between 2007/2008 and 2014/2015 and all certificates completed in hospitals in England and Wales in 1999/2000. PARTICIPANTS: Certificates for all individuals aged 16 years or less at the time of certification in England and Wales for each financial year between 1 April 2007 and the 31 March 2015 and for individuals aged 15 years or less for the year ending 31 March 2000. We obtained information on the main cause of certifiable sight loss for all children certified in 2014/2015. We estimated crude and sex specific incidence estimates with 95% confidence intervals computed by Byars method. RESULTS: In 1999/2000, the estimated incidence (95 % CI) of certification was 8.2 (7.7 to 8.8) per 1 00 000. In 2007/2008, the estimated incidence was statistically significantly higher at 10.1 (9.5 to 10.7). Since then a trend of increasing incidence with time has been observed until 2014/2015 when an estimated incidence of 13.3 (12.6 to 14.0) was observed. Hereditary retinal dystrophies, cerebral visual impairment and nystagmus were the most common single causes of certifiable sight impairment in children in 2014/2015. CONCLUSION: Our findings show that in England and Wales there has been an increase in the number of children newly certified sight impaired by consultant ophthalmologists since 1999/2000. This mirrors our previous findings based on data originating within social service departments

The effect of structure directing agents on the ordering of fluoride ions in pure silica MFI zeolites

The authors would like to thank Keele University and the University of St Andrews for providing a PhD studentship for SLB. PW would like to thank the EPSRC for funding (EP/E041825/1). RJD would like to thank Prof. Colin Fyfe of the University of British Columbia for useful discussions and for providing NMR spectrometer time for initial results.The effect of different sizes of structure directing agents on the ordering of the fluoride ions in pure silica MFI zeolites has been determined using magic angle spinning solid state NMR. By synthesizing fluoride containing pure silica MFI zeolites using methyltributylammonium cations as the structure directing agent, it has been possible to change the type of ordering seen for the fluoride ions at room temperature from the previously reported dynamic to static disorder. An initial mechanism for how this fluoride ordering occurs is suggested based upon the coulombic interaction between the positive charge on the nitrogen and the negative fluoride ion, within the zeolite framework, with different sizes of tetraalkylammonium cations.Publisher PDFPeer reviewe

Improving services for glaucoma care in Nigeria: implications for policy and programmes to achieve universal health coverage.

Glaucoma in Africa is sometimes referred to as the silent thief of sight. In Nigeria, glaucoma is common, it is serious, ophthalmologists face many constraints in managing it, people do not even know they have it until it is advanced, patients do not understand or comply with treatment after they are diagnosed and the poor are more likely to be glaucoma blind. Available evidence indicates that the health system in Nigeria is failing to meet the needs of patients with glaucoma. Based on evidence, we propose future directions for improving services for glaucoma care in Nigeria, and the implications for policy and programmes to control glaucoma blindness, using a health system-oriented approach. Three complementary strategies are required: (i) strengthening clinical services for glaucoma-by developing models of glaucoma care, improving clinical treatment options, making medicines and equipment available, financing glaucoma care and training eye care workers; (ii) introducing initiatives for earlier detection of glaucoma in the clinic and approaches in the community and (iii) strengthening health system governance. Glaucoma is a complex disease to manage and addressing it as a public health problem is challenging. However, we need to change the paradigm to recognise that glaucoma is a potentially avoidable cause of blindness in Africa

Environmental Limits of Methanogenesis and Sulphate Reduction

The current proposed strategy for the disposal of intermediate-level radioactive waste (ILW) within the United Kingdom is through emplacement within a deep underground facility, termed a geological disposal facility (GDF). Anaerobic and highly alkaline (10.013) conditions are expected to prevail within the near-field of a GDF, which will result in the chemical degradation of cellulose-bearing ILW. Isosaccharinic acids (ISA) and volatile fatty acids (VFA) are the major products of alkaline cellulose hydrolysis and their generation within an ILW-GDF will result in a range of organic carbon sources being present. The potential for these carbon sources to provide the substrates for methanogenesis and sulphate reduction under near-field conditions holds importance within a GDF. The generation of biogases such as 14CH4 from 14C-bearing waste could facilitate the transfer of radionuclides to the biosphere. The production of corrosive sulphide by colonising microorganisms could impact the integrity of engineered barriers used to prevent the transfer of radioelements to the biosphere. The potential for methanogens and sulphate-reducing bacteria (SRB) to be active under ILW-GDF conditions is poorly understood. The work outlined in this thesis utilised anaerobic sediments from anthropogenic analogue sites to demonstrate the activity of methanogens and SRB under near-field conditions. The alkaline leachates generated in these sites result in high pore-water pH values equivalent with those expected to dominate an ILW-GDF (pH 11.0-13.0). In spite of these conditions, the incubation of cellulose in situ allowed a range of active microbial processes to be identified, including cellulose degradation by Fibrobacter species, sulphate-reduction by Desulfobacter and hydrogenotrophic methanogenesis by members of the order Methanomicrobiales. The formation of hydrophobic extracellular polymeric substances (EPS) and production of metabolic acids in situ facilitated microbial survival within these extreme environments. Microcosms operating under methanogenic conditions at pH 10.0-11.0 developed from these alkaline sediments demonstrated high hydrogen consumption rates and were dominated by alkaliphilic Methanobacterium and Methanoculleus genera. Acetate was unable to be utilised as substrate by the associated methanogen communities under these conditions, however high acetate consumption rates were observed in pH 7.0-8.0 microcosms where the acetoclastic lineages Methanosarcina became more important. Sub-cultures of the alkaline methanogenic microcosms demonstrated the ability to utilise precipitated calcium carbonates as the sole carbon source for hydrogenotrophic metabolism at pH 10.0. Alkaliphilic Desulfonatronum biofilms grown on stainless steel surfaces developed from the alkaline sediment communities were capable of dissimilatory sulphate reduction at pH 11.0 using the products of alkaline cellulose degradation as the sole carbon and energy source. The sulphide produced by these biofilms induced the corrosion of stainless steel at pH 11.0 within 3 months. The results outlined here suggest the colonisation of an ILW-GDF by methanogens will result in a population dependent on the hydrogenotrophic pathway, with acetate-derived methanogenesis being inhibited under these conditions. Furthermore, biofilms formed within the near-field facilitate the corrosion of steel materials by alkaliphilic SRB and enable microbial survival through the production of low pH niches. These findings can inform future safety assessments and gas generation modelling studies used to predict ILW-GDF performance

Geographical variation in certification rates of blindness and sight impairment in England, 2008-2009

To examine and interpret the variation in the incidence of blindness and sight impairment in England by PCT, as reported by the Certificate of Vision Impairment (CVI). Design: Analysis of national certification data. Setting: All Primary Care Trusts, England. Participants: 23 773 CVI certifications issued from 2008 to 2009. Main Outcome measures: Crude and Age standardised rates of CVI data for blindness and sight loss by PCT. Methods: The crude and age standardised CVI rates per 100 000 were calculated with Spearman's rank correlation used to assess whether there was any evidence of association between CVI rates with Index of Multiple Deprivation (IMD) and the Programme Spend for Vision. Results: There was high-level variation, almost 11-fold (coefficient of variation 38%) in standardised CVI blindness and sight impairment annual certification rates across PCTs. The mean rate was 43.7 and the SD 16.7. We found little evidence of an association between the rate of blindness and sight impairment with either the IMD or Programme Spend on Vision. Conclusions: The wide geographical variation we found raises questions about the quality of the data and whether there is genuine unmet need for prevention of sight loss. It is a concern for public health practitioners who will be interpreting these data locally and nationally as the CVI data will form the basis of the public health indicator ‘preventable sight loss’. Poor-quality data and inadequate interpretation will only create confusion if not addressed adequately from the outset. There is an urgent need to address the shortcomings of the current data collection system and to educate all public health practitioners