Sedimentology and paleoenvironmental studies on the Chad formation of Bornu basin, north-eastern Nigeria

This study deals with sedimentology and Paleoenvironmental studies of the Chad Formation in the Bornu Basin. The sandstones which build up this formation are fine, medium to coarse grained sands which are dominantlypoorly sorted. The skewness ranges from positive to very positive while the kurtosis varies from very platykurtic to very leptokurtic. The bivariate plots of standard deviation vs. mean, standard deviation vs. skewness, standarddeviation vs. first percentile, mean vs. first percentile and log probability plots have conclusively define the depositional environment of the arenaceous samples of the Chad Formation as fluvial in origin. The paleocurrent analysis indicates a trend in the northwestern direction which implies that the sediments forming the Chad Formation were derived from the southwest

Couching in Nigeria: prevalence, risk factors and visual acuity outcomes.

PURPOSE: Couching is an ancient treatment for cataract which is still practiced in some of the poorer developing countries, particularly in sub-Saharan Africa. The purpose of this study is to describe risk factors for couching and visual acuity outcomes in a nationally representative sample of adults aged 40 years and above in Nigeria. METHODS: Probability in proportion size methods were used to identify a representative sample. Of the 15,375 adults enumerated, 13,582 were interviewed and examined. Examination included logMar acuities, slit lamp examination and dilated fundoscopy with digital fundus imaging. RESULTS: Almost half of the 583 eyes undergoing a procedure for cataract had been couched (249 eyes, 42.7%). Individuals living in rural areas (P = 0.033) and in the two underserved northern administrative zones (P = 0.33; P = 0.002) were more likely to have been couched. Visual outcomes were poor according to World Health Organization categories, with 55.8% of people and 73.1% of eyes having a presenting visual acuity of less than 3/60 and only 9.7% and 2.4% of people and eyes respectively having a good outcome (6/18 or better). None were wearing an aphakic correction, and with correction acuities improved but 42.6% of eyes were still blind (< 3/60). CONCLUSIONS: Couching is still widely practiced in Nigeria and visual outcomes are very poor. The population needs to be made aware of the risks associated with the procedure, and services for high quality, affordable cataract surgery need to be expanded, particularly in rural areas and in the north of the country

Evidence for improving services for glaucoma in Nigeria: Epidemiology, ophthalmologists' practice pattern, patients' access to care and community experiences of glaucoma.

Glaucoma is the second leading cause of blindness worldwide. Africa region has the highest burden of glaucoma and glaucoma blindness.When diagnosed early and appropriate treatment sustained, blindness from glaucoma is avoidable. The Nigeria national blindness and visual impairment survey (NBS), with >13,500 people aged≥ 40 years examined, estimated the prevalence of blindness as 4.2% (95%CI 3.8-4.6%).16.7% was due to glaucoma, the leading cause of irreversible blindness and functional low vision. There are insufficient population-based glaucoma studies in Africa;!and the NBS provided the largest dataset in Africa from which data on glaucoma could be derived. In this study, analysis of the NBS data using established criteria from the International Society of Geographical and Epidemiological Ophthalmology showed high prevalence of glaucoma (5.02%; 95%CI 4.60-5.47%): undiagnosed in 94%; and open-angle glaucoma (OAG) in 86%. One -in -five persons with glaucoma were blind. Increasing age and higher intraocular pressure were independent risk factors for OAG; and some ethnic groups were more at risk. Glaucoma blindness was associated with socioeconomic deprivation, reflecting poor access to care. These findings underscored the high level of need for optimal glaucoma services. Information about glaucoma management obtained from 153 practising Ophthalmologists in Nigeria highlighted patient-related challenges of late presentation with advanced disease and poor compliance to treatment; and additional constraints due to inadequate access to equipment for diagnosis and treatment. In the qualitative study, we sought to understand access to glaucoma care and determine why people with glaucoma are presenting late for treatment. We found barriers of access to care which could be explained as evidence of structural inequalities associated with coping mechanisms and distinct social suffering. This study provided data required to develop evidence-based strategy for control of glaucoma blindness by improving glaucoma services in Nigeria. These data could also have implications to other Sub Saharan African countries with similar socioeconomic and ecological characteristics

How to adapt your eye service in the time of COVID-19

Eye services must adapt to prevent the transmission of SARS-CoV-2, the virus responsible for COVID-19

The concentration and biomagnification of trace metals and metalloids across four trophic levels in a marine food web

To be able to assess progress towards “Good Environmental Status” adopted across European Member States, and by the United Kingdom through its 3-stage Marine Strategy, contaminant concentrations and their biological effects need to be assessed in environmental samples by comparison to assessment criteria. This study examines the variability of concentrations (inter- and intra- species variation) of three priority heavy metals (Hg, Cd and Pb) and six additional trace metals and metalloids (As, Ni, Se, Zn, Cu and Cr) in twenty-three species across four trophic levels from different locations around Scotland. Trophic magnification factors (TMFs) were calculated using two methods for metals/metalloids possessing a significant trophic relationship (Hg, Cd, Cu, Ni and Zn) to refine and improve the application of TMFs to assess and predict biomagnification risk of metals/metalloids to biota in the environment. It was concluded that a reasonable balance in sample numbers of lower- versus higher-trophic level organisms is highly recommended when calculating TMFs and appropriate species selection is vital to ensure TMFs accurately represent the selected ecosystem

Understanding marine food web dynamics using fatty acid signatures and stable isotope ratios:Improving contaminant impacts assessments across trophic levels

Scotland's marine food webs support a diversity of species and habitats. They contribute to maintaining the balance of the natural environment. Previous studies show that these ecosystems are contaminated by persistent organic pollutants and trace metals; with animals in higher trophic levels (e.g. cetaceans and pinnipeds) containing concentrations that are among the highest found in the ocean. Contaminants represent one of many pressures to which species and habitats are exposed. In assessing the contribution of contaminants to the overall pressure, measuring contaminants at a specific trophic level and then using trophic magnification factors (TMFs) to estimate concentrations at other trophic levels permits assessments across the food web, as well as allowing the adjustment of contaminant concentrations to a particular trophic level for comparison to assessment criteria. Fatty acid (FA) signatures and stable isotope (SI) ratios were used to develop a picture of Scottish marine food web ecology and reliably ascribe trophic levels to a wide range of species. Fatty acid trophic markers (FATMs) were used as trophic level indicators and with SI analysis, permitted identification of the mean trophic level of each species and determination of the feeding patterns and predator-prey relationships existing in the Scottish marine food web. Two hundred and eleven (211) samples comprising of seven fish species, one shark species, fourteen marine invertebrate species, three marine mammal species and two zooplankton species from different locations around Scotland were found to have mean trophic levels ranging from 1.47 ± 0.11 in zooplankton to 5.02 ± 0.35 in harbour seal. Fatty acid profile showed specific dietary information which differed between the eleven taxonomic classes and twenty-seven species. The organic and inorganic contaminant concentrations of the species for which trophic level has been determined, together with TMFs, will be reported in future papers

Ecological determinants of blindness in Nigeria: The Nigeria National Blindness and Visual Impairment Survey

Objective. To determine the prevalence and causes of visual loss in different ecological zones across Nigeria. Methods. A population-based survey using multi-stage, stratified, cluster random sampling with probability proportional to size comprising a nationally representative sample of adults aged &ge;40 years from six ecological zones. Outcome measures. Distance vision was measured using reduced logMAR charts. Clinical examination included basic eye examination for all respondents and a detailed examination including visual fields, gonioscopy and fundus photography for those who were visually impaired or blind (i.e. presenting vision &lt;20/40 in the better eye). A principal cause of visual loss was assigned to all respondents with presenting vision &lt;20/40 in the better eye. Results. A total of 15 122 persons aged &ge;40 years were enumerated, 13 599 (89.9%) of whom were examined. The prevalence of blindness varied according to ecological zone, being highest in the Sahel region (6.6%; 95% confidence interval (CI) 4.2 - 10.4) and lowest in the rain forest region (3.23%; 95% CI 2.6 - 3.9). Age/ gender-adjusted analyses showed that risk of blindness was highest in Sahel (odds ratio (OR) 3.4; 95% CI 2.1 - 5.8). More than 80% of blindness in all ecological regions was avoidable. Trachoma was a significant cause only in the Sudan savannah belt. The prevalence of all major blinding conditions was highest in the Sahel. Conclusions. The findings of this national survey may be applicable to other countries in West and Central Africa that share similar ecological zones. Onchocerciasis and trachoma are not major causes of blindness in Nigeria, possibly reflecting successful control efforts for both these neglected tropical diseases

Improving cataract services: better access, better outcomes, better value

Although highly effective treatment for cataract has been available around the world for several decades, it remains the leading cause of avoidable blindness. It is completely unacceptable that millions of people are deprived of their right to sight due to a condition that can be cured with a safe, fast, and cost-efficient procedur

Beliefs, Attitudes and Health-seeking behavior towards ocular cancers among adults in Abuja, Nigeria

Background: To assess the beliefs attitudes, and health seeking behaviors towards ocular cancers among adults in Abuja.Methods: A descriptive cross-sectional survey of 1,887 Nigerians between June and September 2009 using interviewer-administered questionnaire.Results: The respondents’ reported refraining from interacting with persons afflicted with ocular cancers along these lines: eating together 261/669 (39%), hugging 149/668 (22%), shaking hands 106/561 (19%), laying on the same bed 328/560 (59%), and contracting marriage 462/558 (83%) with ocular cancer patients. However, 416/486 (85.6%) respondents would support getting appropriate health interventions for ocular cancers.Level of education was associated with positive attitudes towards ocular cancers patients (P&lt;0.05). The respondents’ belief on characteristics of ocular cancers included “dangerous” 814/840 (96.6%), unknown nature 19/840 (2.3%); potential to cause blindness 849/882 (96.3%); potentially fatal 665/870 (76.4%), nonfatal 205/870 (23.6%). Also, the respondents believed treating ocular cancer is necessary 651/679 (95.9%) and unnecessary 28/679 (4.2%). About management of ocular cancers, 560/683 (82%) will consult eye doctors while 123/683 (18%) will seek other methods. Suggestions on how to improve management of ocular cancers were: improve public awareness 28.1%, train personnel 16.3%, provision of facilities 17.8%, establish national ocular cancer reference center 13.2% and free/subsidized treatment 13.2%.Conclusion:  Though significant proportion of respondents had the correct beliefs and attitudes towards ocular cancers, effective health education needs to be mounted to reinforce these positive beliefs and attitudes and also convert those with the wrong notions. This will in the long run improve health seeking behaviors.Keywords: ocular cancers, beliefs, attitudes, healthseeking behavior