Colour vision deficiency among students in Lagos State, Nigeria

Background: Congenital colour vision defects are x-linked inherited, non-progressive and untreatable disorders that describe poor colour discrimination.Objective: To determine the prevalence of congenital colour vision deficiency among students in Lagos, Nigeria.Methods: A school-based cross-sectional, cluster sample study was conducted to test the colour vision of 2326 primary and high school students. Inclusion criteria were Snellen VA 20/20 or better and absence of known ocular pathologies. Colour vision deficiency (CVD) was evaluated with the Richmond-HRR colour vision test plates.Results: There were 1014 (43.6%) males and 1312 (56.4%) females with a mean age of 13.40 ± 2.40 years (range = 7−22 years). The prevalence of CVD was 58 (2.5%), which was higher in males 49 (4.8%) than females 9 (0.7%). The prevalence of congenitalCVD was significantly associated with males (p = 0.00), but not with females (p = 0.22). Of the 58 cases of CVD, 17 (0.7%) had protan deficiency, 38 (1.6%) had deutan deficiency and three (0.1%) were unclassified.Conclusion: The prevalence of congenital CVD among students in Lagos is comparable to findings in other parts of Nigeria but differs from other parts of the country. These results strengthen the need to establish school vision screening.Keywords: Colour vision deficiency, Richmond-HRR, prevalence, red-green defects, Nigeria

Colour vision deficiency among students in Lagos State, Nigeria

Background: Congenital colour vision defects are x-linked inherited, non-progressive and untreatable disorders that describe poor colour discrimination. Objective: To determine the prevalence of congenital colour vision deficiency among students in Lagos, Nigeria. Methods: A school-based cross-sectional, cluster sample study was conducted to test the colour vision of 2326 primary and high school students. Inclusion criteria were Snellen VA 20/20 or better and absence of known ocular pathologies. Colour vision deficiency (CVD) was evaluated with the Richmond-HRR colour vision test plates. Results: There were 1014 (43.6%) males and 1312 (56.4%) females with a mean age of 13.40 \ub1 2.40 years (range = 7 1222 years). The prevalence of CVD was 58 (2.5%), which was higher in males 49 (4.8%) than females 9 (0.7%). The prevalence of congenital CVD was significantly associated with males (p = 0.00), but not with females (p = 0.22). Of the 58 cases of CVD, 17 (0.7%) had protan deficiency, 38 (1.6%) had deutan deficiency and three (0.1%) were unclassified. Conclusion: The prevalence of congenital CVD among students in Lagos is comparable to findings in other parts of Nigeria but differs from other parts of the country. These results strengthen the need to establish school vision screening. DOI: https://dx.doi.org/10.4314/ahs.v19i2.48 Cite as: Oduntan OA, Mashige KP, Kio FE. Colour vision deficiency among students in Lagos State, Nigeria. Afri Health Sci.2019;19(2): 2230-2236. https://dx.doi.org/10.4314/ahs.v19i2.4

Two decades of optometric education in Ghana: Update and recent developments*

Many authors have reported on the evolution and trends of optometric education in Africa. Amongst these are articles on Optometry and optometric education in Africa, West Africa, Nigeria, South Africa, Ghana, and Ethiopia. This article reports the historical perspectives of optometric education in Ghana and the developments that have been made in the last 20 years. It also attempts to relate the stride made towards legal recognition of optometry in Ghana. In presenting this historical account, it is hoped that sometime in the future, one should be able to look back at the beginning of optometry training in Ghana and be able to measure the advancement or otherwise that have been made since its inception. (S Afr Optom 2011 70(3) 136-141

Pyromellitamide gelators : exponential rate of aggregation, hierarchical assembly, and their viscoelastic response to anions

The gelation and aggregation properties of a newly synthesized structurally simplified tetrahexyl pyromellitamide 2 have been studied and compared to the previously reported tetra(cthylhcxanoate) pyromellitide 1, indicating that the ester groups in the latter significantly impede its aggregation. Morphology studies (AFM and TEM) on the aggregates formed by tetrahexyl pyromellitamide 2 in cyclohexane revealed highly uniform, aggregates with different dimensions at different starting concentrations, suggesting that this molecule aggregates in a hierarchical fashion from a one-dimensional supramolecular polymer through hollow tubes or compressed helices to a network structure and then to a gel. This hypothesis is further supported, by viscosity measurements that indicate a crossover point where individual supramolecular fibers get entangled at concentrations above ca. 3 mM in cyclohexane. Addition of 1 equiv of tetraalkylarnmonium salts of chloride or bromide, however, caused the viscosities of these pyromellitamide solutions to drop by a factor of 2-3 orders of magnitude, demonstrating the sensitivity of these aggregates to the presence of small anions. The sensiti vity to anions does depend on the solubility of the salts used as small anion salts with little solubility in cyclohexane did not show this effect. Time-dependent viscosity studies showed that the aggregation of pyromellitamide 2 follows an exponential rate law, possibly related to the columnar rearrangements that are associated with the observed 6 Å contraction in d spacing in the XRD pattern of these gels. These results, particularly on the importance of kinetics of aggregation of self-assembled pyromellitamide gels, will be useful for future development of related materials for a number of applications, including tissue engineering and drug delivery.7 page(s

Relationship between urban planning and flooding in Port Harcourt city, Nigeria; insights from planning professionals

Flooding is widely recognised as a global problem which has worsened in recent years due to climate change. In Nigeria, flooding remains the most widespread environmental disaster with the population of 200 million suffering numerous threats from perennial flooding. Port Harcourt in Southern Nigeria experiences annual flooding on a significant scale. While research has linked the flooding in Port Harcourt to poor urban planning, little research has engaged with planning professionals to investigate this relationship. This paper fills this gap. It explores how urban planning is linked to flooding in Port Harcourt and reports on qualitative research undertaken with five urban planners in Port Harcourt. The findings affirm that poor planning and/or lack of compliance with planning regulations are the main factors contributing to the flooding of Port Harcourt. The urban planners gave their expert opinions on how to control the flooding and unanimously agreed that improved planning practices could control the endemic flooding problem in the city. This implies that the government needs to work more closely with urban planners and other stakeholders to effectively control and find a lasting solution to the flooding problem in Port Harcourt city