Access to Optometric Education: Challenges in Sub-Saharan Africa

Access to education was identified as a key international priority by UNESCO as far back as 1998 when it called for “equality of access”. The profession of optometry has been challenged to educate practitioners in increasing numbers in order to meet the eye care needs. The World Health Organization reported that globally, an estimated 285 million people are visually impaired and in Sub Saharan Africa (SSA) uncorrected refractive error is the main cause of visual impairment. The number of optometrists trained on the continent is currently insufficient to meet these eye care needs with limited access to education remaining a stark reality for students. A qualitative research design framed in phenomenology was used to conduct structured interviews with academic leaders in optometry across SSA. Finance for tuition andstudent maintenance, lack of knowledge of optometry and optometrists, high admission criteria, limited spaces at institutions,poor mathematics and science results, gender inequalities and geographical location were cited as barriers to optometric education. Lack of funding was the main contributing factor for the high attrition rate from university in countries where students have to pay their own fees.Where tertiary education is free, the limited number of spaces available in the programmes was the major barrier to access to optometric education for the ever-increasing number of aspiring applicants. The profession of optometry has a key role to play in eye care service delivery in Africa. Therefore educators, policymakers and health professionals must together formulate strategies to increase access to optometric education

Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050

PurposeMyopia is a common cause of vision loss, with uncorrected myopia the leading cause of distance vision impairment globally. Individual studies show variations in the prevalence of myopia and high myopia between regions and ethnic groups, and there continues to be uncertainty regarding increasing prevalence of myopia.DesignSystematic review and meta-analysis.MethodsWe performed a systematic review and meta-analysis of the prevalence of myopia and high myopia and estimated temporal trends from 2000 to 2050 using data published since 1995. The primary data were gathered into 5-year age groups from 0 to ≥100, in urban or rural populations in each country, standardized to definitions of myopia of −0.50 diopter (D) or less and of high myopia of −5.00 D or less, projected to the year 2010, then meta-analyzed within Global Burden of Disease (GBD) regions. Any urban or rural age group that lacked data in a GBD region took data from the most similar region. The prevalence data were combined with urbanization data and population data from United Nations Population Department (UNPD) to estimate the prevalence of myopia and high myopia in each country of the world. These estimates were combined with myopia change estimates over time derived from regression analysis of published evidence to project to each decade from 2000 through 2050.ResultsWe included data from 145 studies covering 2.1 million participants. We estimated 1406 million people with myopia (22.9% of the world population; 95% confidence interval [CI], 932–1932 million [15.2%–31.5%]) and 163 million people with high myopia (2.7% of the world population; 95% CI, 86–387 million [1.4%–6.3%]) in 2000. We predict by 2050 there will be 4758 million people with myopia (49.8% of the world population; 3620–6056 million [95% CI, 43.4%–55.7%]) and 938 million people with high myopia (9.8% of the world population; 479–2104 million [95% CI, 5.7%–19.4%]).ConclusionsMyopia and high myopia estimates from 2000 to 2050 suggest significant increases in prevalences globally, with implications for planning services, including managing and preventing myopia-related ocular complications and vision loss among almost 1 billion people with high myopia

In Vivo Oxygen Uptake into the Human Cornea

PURPOSE. We provide a new procedure to quantify in situ corneal oxygen uptake using the micropolarographic Clark electrode. METHODS. Traditionally, upon placing a membrane-covered Clark microelectrode onto a human cornea, the resulting polarographic signal is interpreted as the oxygen partial pressure at the anterior corneal surface. However, the Clark electrode operates at a limiting current. Hence, oxygen flux is directly detected rather than partial pressure. We corrected this misunderstanding and devised a new analysis to quantify oxygen uptake into the cornea. The proposed analysis is applied to new polarographic data for 10 human subjects during open-eye oxygen uptake. RESULTS. Average open-eye corneal oxygen uptake over 10 subjects is approximately 11 lL/(cm 2 h), approximately five times larger than the average reported by researchers who invoke the original mathematical analysis. Application of the classical interpretation scheme to our experimental data also garners uptake values that are approximately a factor of three to five times smaller than those obtained with our new procedure. CONCLUSIONS. The classical procedure originally developed by Fatt and colleagues misinterprets the behavior of the Clark microelectrode. We corrected the analysis of the in situ polarographic technique to provide a simple yet rigorous procedure for analyzing both previous data in the literature and those newly obtained. Our proposed interpretation scheme thus provides a reliable tool for in vivo assessment of corneal oxygen uptake. (Invest Ophthalmol Vis Sci. 2012;53:6331-6337

SARS-CoV-2 Omicron is an immune escape variant with an altered cell entry pathway

Vaccines based on the spike protein of SARS-CoV-2 are a cornerstone of the public health response to COVID-19. The emergence of hypermutated, increasingly transmissible variants of concern (VOCs) threaten this strategy. Omicron (B.1.1.529), the fifth VOC to be described, harbours multiple amino acid mutations in spike, half of which lie within the receptor-binding domain. Here we demonstrate substantial evasion of neutralization by Omicron BA.1 and BA.2 variants in vitro using sera from individuals vaccinated with ChAdOx1, BNT162b2 and mRNA-1273. These data were mirrored by a substantial reduction in real-world vaccine effectiveness that was partially restored by booster vaccination. The Omicron variants BA.1 and BA.2 did not induce cell syncytia in vitro and favoured a TMPRSS2-independent endosomal entry pathway, these phenotypes mapping to distinct regions of the spike protein. Impaired cell fusion was determined by the receptor-binding domain, while endosomal entry mapped to the S2 domain. Such marked changes in antigenicity and replicative biology may underlie the rapid global spread and altered pathogenicity of the Omicron variant

The Role of Optometry in VISION 2020

The global initiative, Vision 2020: The Right to Sight, established by the World Health Organization (WHO) and the International Agency for the Prevention of Blindness, has created valuable and effective collaborations of organisations involved in a wide range of eyecare and community healthcare activities aimed at the elimination of avoidable blindness and impaired vision