Refractive Error and Visual Impairment Among School Children: Result of a South-Eastern Nigerian Regional Survey.

PURPOSE: To determine the prevalence refractive errors and causes of visual impairment in school children in the south-eastern region of Nigeria. METHODS: School-based cross-sectional samples of children 5 to 15 of age in both urban and rural areas were profiled through cluster sampling. The main outcome measures were presenting, uncorrected, and best-corrected visual acuity using the Refractive Error in School-age Children (RESC) protocol. RESULTS: A total of 5723 children were examined during the study period comprising 2686 (46.9%) males and 3037 (53.1%) females; (M:F ratio 0.9:1) and aged 10.49±2.74SD of mean (range, 5 to 15 years). The age group 12 to <13 accounted for the highest 776 (13.6%) number of the study participants. The uncorrected visual acuity (VA) of <20/40 (6/12) was seen in 188 (3.4%) of the study participants while the presenting and best-corrected visual acuity of <20/40 (6/12) were noted in 182 (3.4%) children and 14 (0.2%) children, respectively. Refractive error was the principal cause of visual impairment. CONCLUSION: Prevalence of refractive error is low. Myopia is the principal cause of refractive error occurring more in females and in urban schools. The main cause of visual impairment is refractive error, and most children that need spectacle correction did not have them. Program to identify children with refractive error in addition to providing free or affordable optical services remains the key to preventing visual impairment from refractive error particularly in resource-poor settings.

Dry Eye Disease: Concordance Between the Diagnostic Tests in African Eyes.

OBJECTIVE: To assess the concordance between the diagnostic tests for dry eye disease (DED) in a Nigerian hospital population. METHODS: The study was a hospital-based cross-sectional survey of adults (≥18 years) presenting at the eye clinic of the University of Nigeria Teaching Hospital (UNTH), Enugu; September-December, 2011. Participants' socio-demographic data were collected. Each subject was assessed for DED using the "Ocular Surface Disease Index" (OSDI) questionnaire, tear-film breakup time (TBUT), and Schirmer test. The intertest concordance was assessed using kappa statistic, correlation, and regression coefficients. RESULTS: The participants (n=402; men: 193) were aged 50.1±19.1 standard deviation years (range: 18-94 years). Dry eye disease was diagnosed in 203 by TBUT, 170 by Schirmer test, and 295 by OSDI; the concordance between the tests were OSDI versus TBUT (Kappa, κ=-0.194); OSDI versus Schirmer (κ=-0.276); and TBUT versus Schirmer (κ=0.082). Ocular Surface Disease Index was inversely correlated with Schirmer test (Spearman ρ=-0.231, P<0.001) and TBUT (ρ=-0.237, P<0.001). In the linear regression model, OSDI was poorly predicted by TBUT (ß=-0.09; 95% confidence interval (CI): -0.26 to -0.03, P=0.14) and Schirmer test (ß=-0.35, 95% CI: -0.53 to -0.18, P=0.18). CONCLUSION: At UNTH, there is poor agreement, and almost equal correlation, between the subjective and objective tests for DED. Therefore, the selection of diagnostic test for DED should be informed by cost-effectiveness and diagnostic resource availability, not diagnostic efficiency or utility.

The performance evaluation of a urine malaria test (UMT) kit for the diagnosis of malaria in individuals with fever in south-east Nigeria: cross-sectional analytical study.

BACKGROUND: Accurate rapid diagnosis is one of the important steps in the effort to reduce morbidity and mortality of malaria. Blood-specific malaria rapid diagnostic tests (RDTs) are currently in use but other body fluid specific diagnostic test kits are being developed. The aim of the present study was to evaluate the performance characteristics of a one-step Urine Malaria Test™ (UMT) dipstick in detecting Plasmodium falciparum HRP2, a poly-histidine antigen in urine of febrile patients for malaria diagnosis. METHODS: This was an observational study in which a urine-based malaria test kit was used in malaria diagnosis in a normal field setting. Two hundred and three individuals who presented with fever (≥37.5°C) at seven outpatient clinics in Enugu State during periods of high and low transmission seasons in Southeastern Nigeria were enrolled. Matched samples of urine and blood of consecutively enrolled subjects were tested with UMT and blood smear microscopy. RESULTS: With the blood smear microscopy as standard, the disease prevalence was 41.2% and sensitivity for the UMT was 83.75% (CI: 73.81 to 91.95%, Kappa 0.665, p =0.001). The UMT had an LLD of 120 parasites/µl but the sensitivity at parasite density less than ≤200 parasites/µl was 50% and 89.71% at density ≥201 parasites/µl with specificity of 83.48%. The positive and negative predictive values were 77.91% and 88.07%, respectively. CONCLUSION: The UMT showed moderate level of sensitivity compared with blood smear microscopy. The test kit requires further improvement on its sensitivity in order to be deployable for field use in malaria endemic regions.

Prevalence of presbyopia in a rural African community.

INTRODUCTION: When presbyopia (loss of accommodation of the crystalline lens with increasing age) sets in, doing near work becomes associated with headache and eye strain. Reading and writing become a challenge. Literacy levels may be low in rural communities; nevertheless some work other than reading, like sewing, sorting stone from grain and operating mobile phones, is done with dissatisfaction. This study aims to determine the prevalence of presbyopia, the unmet presbyopia need and the presbyopia correction coverage in a rural African community. METHODS: A population-based cross-sectional study was carried out in a rural population aged 35 years and greater, selected by cluster random sampling. Information was sought on biodata of the participants and they were subsequently examined. Distance visual acuity for each participant was determined. Anterior and posterior segments of the eyes were examined. Objective refraction with subjective refinement was done on all subjects with distant visual acuity less than 6/6. Near visual acuity was assessed at 40 cm with distant correction in place if required. Presbyopia was defined as inability to read N8 at 40 cm or requiring an addition of at least +1.00DS to improve near vision to at least N8. Questionnaires were administered to those identified as presbyopic on source of procurement of spectacles (if they had one) and on reasons for non-procurement of presbyopic spectacles. They were also asked to rate their difficulty with various listed near work. Data entry and analysis were done using Statistical Package for the Social Sciences v16.0 and Program for Epidemiologist v4.01 software. RESULTS: A total of 585 subjects (participation rate 81.1%) aged 35 years and greater were interviewed and examined. The prevalence of presbyopia was 63.4% (95% confidence interval (CI) 62.6-64.2%). There was increasing prevalence with increasing age. The met presbyopia need was 17.6%, unmet need was 45.8% and presbyopic correction coverage was 27.8%. The commonest reasons for not procuring presbyopic correction were 'not a priority' (21.5%) and 'cost' (21.2%). CONCLUSIONS: The prevalence of presbyopia in this rural African community is high. Many who need presbyopic correction do not have corrective spectacles.

Dry eye disease: prevalence, distribution and determinants in a hospital-based population.

OBJECTIVES: To determine the prevalence, distribution and risk factors for dry eye disease (DED) in a tertiary ophthalmic outpatient population. METHODS: The study was a cross-sectional descriptive hospital-based survey conducted at the Eye clinic of the University of Nigeria Teaching Hospital (UNTH), Enugu, between September and December, 2011. The participants comprised adult ophthalmic outpatients aged 18 years or older. Participants' sociodemographic data were obtained. Dry eye disease was assessed subjectively with the Ocular Surface Disease Index (OSDI) questionnaire; and objectively with Schirmer's test and Tear-film Break-up Time (TBUT). An OSDI score of ≥ 50 with a TBUT of <10s or Schirmer's test reading of <10mm was considered diagnostic of DED. Descriptive and analytical statistics were performed. In all comparisons, a p<0.05 was considered statistically significant. RESULTS: The participants (n=402) comprised 193 males and 209 females who were aged 50.1 ± 19.06 SD years (range 18-94 years). The majorities of the participants were married - 74.1%, possessed formal education - 86.0% and were civil servants - 33.6%. The prevalence of DED was 19.2%. Dry eye disease was significantly associated with age>40 years (OR 1.88, 95% CI 1.06-3.35, p=0.0004), non-possession of formal education (OR 0.40, 95% CI 0.21-0.74, p=0.001) but not gender (OR 1.48, 95% CI 0.89-2.46, p=0.158). CONCLUSION: The prevalence of DED among ophthalmic outpatients at UNTH, Enugu, is comparatively high. Older age and illiteracy are predictors of DED. There is need for high index of diagnostic suspicion to prevent sight-threatening complications of DED.

Chlorproguanil-dapsone-artesunate versus artemether-lumefantrine: a randomized, double-blind phase III trial in African children and adolescents with uncomplicated Plasmodium falciparum malaria.

BACKGROUND: Chlorproguanil-dapsone-artesunate (CDA) was developed as an affordable, simple, fixed-dose artemisinin-based combination therapy for use in Africa. This trial was a randomized parallel-group, double-blind, double-dummy study to compare CDA and artemether-lumefantrine (AL) efficacy in uncomplicated Plasmodium falciparum malaria and further define the CDA safety profile, particularly its hematological safety in glucose-6-phosphate dehydrogenase (G6PD) -deficient patients. METHODS AND FINDINGS: The trial was conducted at medical centers at 11 sites in five African countries between June 2006 and August 2007. 1372 patients (> or =1 to <15 years old, median age 3 years) with acute uncomplicated P. falciparum malaria were randomized (2:1) to receive CDA 2/2.5/4 mg/kg once daily for three days (N = 914) or six-doses of AL over three days (N = 458). Non-inferiority of CDA versus AL for efficacy was evaluated in the Day 28 per-protocol (PP) population using parasitological cure (polymerase chain reaction [PCR]-corrected). Cure rates were 94.1% (703/747) for CDA and 97.4% (369/379) for AL (treatment difference -3.3%, 95%CI -5.6, -0.9). CDA was non-inferior to AL, but there was simultaneous superiority of AL (upper 95%CI limit <0). Adequate clinical and parasitological response at Day 28 (uncorrected for reinfection) was 79% (604/765) with CDA and 83% (315/381) with AL. In patients with a G6PD-deficient genotype (94/603 [16%] hemizygous males, 22/598 [4%] homozygous females), CDA had the propensity to cause severe and clinically concerning hemoglobin decreases: the mean hemoglobin nadir was 75 g/L (95%CI 71, 79) at Day 7 versus 97 g/L (95%CI 91, 102) for AL. There were three deaths, unrelated to study medication (two with CDA, one with AL). CONCLUSIONS: Although parasitologically effective at Day 28, the hemolytic potential of CDA in G6PD-deficient patients makes it unsuitable for use in a public health setting in Africa. TRIAL REGISTRATION: ClinicalTrials.Gov NCT00344006.