Aim: To study the prevalence of myopia among school children in Aba, Nigeria.Methods: This cross-sectional study was conducted in public and private (primary and secondary) schools. A multi-stage random sampling technique was used for selecting participants aged between 8 and 15 years from 12 schools in Aba, Nigeria. Data were analysed for 1197 children who underwent a comprehensive eye examination. The children were divided according to the following criteria: age groups (group 1 [8–11 years] or group 2 [12–15 years]), gender (male or female), level of education (primary or secondary) and type of school (public or private). Myopia was defined as spherical equivalent refraction (SER) ≤ -0.50 D in the poorer eye.Results: The prevalence of myopia was estimated to be 2.7%. Of the 96 children with refractive error, 78.1% were uncorrected. In using logistic regression analysis, risk of developing myopia was associated with older age groups (odds ratio [OR]: 1.20; 95% confidence interval [CI], 0.16–9.11; p < 0.010) and higher level of education (OR: 1.73; 95% CI, 1.05–2.86; p < 0.030). There was no significant difference in myopia prevalence between male and female children (p = 0.89).Conclusion: Although the prevalence of myopia and overall prevalence of refractive error in school children in Aba were low, the high prevalence of uncorrected refractive error is a significant public health problem. An effective and sustainable children’s vision screening programme is needed to prevent visual impairment and blindness.

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Digital eye syndrome: COVID-19 lockdown side-effect? To the Editor: The coronavirus COVID-19 has sent humanity in doors, replacing human contact with an electronic connection. The increased use of electronic devices (e-devices) and its influence on the wellbeing of users is a concern to healthcare practitioners. Digital eye syndrome (DES) is one of these health concerns. Internal DES essentially affects the user's visual system of accommodation, convergence and refraction. Users of electronic devices will complain of blurred distance and/or near vision, difficulty re-focusing and headaches. [1] DES is caused by small font size, reduced reading distance, light emission of self-illuminating screens, and time-based exposure. [2] Moreover, the cognitive demand of reading material affects DES severity. [3] Digital blue light has a role in internal DES, and it influences circadian rhythms and sleep. The screens of modern e-devices do have built-in protective mechanisms to shield/guard us, but it is the duration of use that contributes to symptoms of DES. The other concern is digital blue light suppressing the sleep hormone, melatonin, because its wavelength stimulates the retinal photoreceptors to suppress production of melatonin from the pineal gland, thus delaying the latency of sleep onset as well as affecting the quality of sleep. [3] External DES manifests with users complaining of tired red eyes, sensitivity to light and general ocular discomfort from extended screen time. These symptoms are attributable to drying of the anterior surface of the eye, especially the cornea, due to a reduced blink rate. It is exacerbated by incomplete blinking, i.e. poor blink quality with screen time, and even air conditioning drying the eye. [1-3] Users also often complain of neck, back and shoulder pain. Prolonged sitting with poor posture and lack of movement during screen time contribute to these impairments. Users should be advised to adopt a correct posture and sit upright with the back supported, both feet supported on a surface in front, and arms, forearms and wrist (neutral) all aligned with the device at eye level or just below. Furthermore, users should change their position frequently. This open-access article is distributed under Creative Commons licence CC-BY-NC 4.0.

Introduction: Alcohol ingestion has a significant effect on speech, vision and coordination. The legal limit for driving under the influence in South Africa is 0.05% blood alcohol concentration (BAC), whilst intoxication is considered to occur at 0.10% BAC. The aim of our study was to investigate the effect of acute alcohol ingestion of 0.05% and 0.10% blood respiratory alcohol concentration (BrAC) on heterophoria.Methodology: The effect of alcohol ingestion on the oculomotor systems of 31 subjects was the basis of this quasi-experimental quantitative study. Various parameters were compared before and after the ingestion of 10% alc red wine. The Alcoscan ALP-1 breathalyser test was used as an indicator of BrAC. Heterophoric, fusional vergence and near point of convergence (NPC) measurements were measured during an experimental phase at 0.05% and 0.10% BrAC levels and a control phase at a 0% BrAC.Results: Mean changes in heterophoria for distance showed an increase of 1.13∆ ± 1.34∆ and 2.19∆ ± 1.70∆ towards esophoria at a BrAC of 0.05% and 0.10% respectively. At near, the results showed a mean increase of 0.84∆ ± 1.75∆ and 0.97∆ ± 1.70∆ towards exophoria at a BrAC of 0.05% and 0.10% respectively. There was a further mean decrease in the positive and negative fusional vergences as well as receded NPC break and recovery measurements at 0.05% and 0.10% BAC.Conclusion: It can be concluded that a BrAC of 0.05% has a minimal effect on heterophoria. However, at a BrAC of 0.1% there is a significant effect on heterophoria, fusional vergences and the NPC. This may or may not be clinically significant.