The aim of this review is to evaluate the prevalence of and factors associated with keratoconus in Africa. Method: A systematic online literature search was conducted for articles on keratoconus in Africa. Meta-analysis was performed to estimate the prevalence of keratoconus in Africa. The Freeman-Tukey double arcsine transformation was used to minimize the effects of studies with extremely high or low prevalence estimates on the overall pooled estimates. Leave-one-out sensitivity analysis was used to assess the robustness of the pooled effects and potential outliers. Meta-regression was performed to explore associations between keratoconus, gender and age. Results: Twelve studies were included in the review; 5 from Egypt, 2 from South Africa, 2 from Kenya, 1 from Sudan, 1 from Ghana and 1 from Nigeria. Two studies were conducted in allergic conjunctivitis patients, 4 in keratoconus patients, 1 in contact lens service seekers, 1 in pre-LASIK patients, 1 in refractive patients and 1 in a student population. Eight studies were included in the meta-analysis. The overall prevalence estimate of keratoconus in Africa was 7.9% (95% CI: 2.5%-16.0%). The prevalence of keratoconus among males and females in Africa was estimated to be 9.3% (95% CI: 2.5%-19.5%) and 5.8% (95% CI: 1.5%-12.7%) respectively. The estimated prevalence of unilateral and bilateral keratoconus was 2.6% (95% CI: 0.4%-6.5%) and 5.8% (95% CI: 1.6%-12.3%), respectively. The estimated prevalence of mild keratoconus was 2.2% (95% CI: 0.7%-4.7%), moderate keratoconus was 3.5% (95% CI: 0.0%-11.8%) and severe keratoconus was 4.0% (95% CI: 0.0%-19.6%). There was no significant association between gender and the prevalence of keratoconus in Africa (p = 0.63), and age and the prevalence of keratoconus in Africa (p = 0.78). Conclusion:The estimated prevalence of keratoconus reported here is higher than prevalence values reported in other meta-analyses or different geographical locations. This is mainly because studies included in this meta-analysis were either conducted on a cohort at high risk of keratoconus or a population with high possibility of finding keratoconus patients. There is a dearth of well-designed population-based studies on keratoconus in Africa, resulting in a lack of epidemiological information. This highlights the urgent need for research on keratoconus in Africa.

We tested the hypothesis that five daily sessions of visual cortex transcranial random noise stimulation would improve contrast sensitivity, crowded and uncrowded visual acuity in adults with amblyopia. Nineteen adults with amblyopia (44.2 ± 14.9 years, 10 female) were randomly allocated to active or sham tRNS of the visual cortex (active, n = 9; sham, n = 10). Sixteen participants completed the study (n = 8 per group). tRNS was delivered for 25 min across five consecutive days. Monocular contrast sensitivity, uncrowded and crowded visual acuity were measured before, during, 5 min and 30 min post stimulation on each day. Active tRNS significantly improved contrast sensitivity and uncrowded visual acuity for both amblyopic and fellow eyes whereas sham stimulation had no effect. An analysis of the day by day effects revealed large within session improvements on day 1 for the active group that waned across subsequent days. No long-lasting (multi-day) improvements were observed for contrast sensitivity, however a long-lasting improvement in amblyopic eye uncrowded visual acuity was observed for the active group. This improvement remained at 28 day follow up. However, between-group differences in baseline uncrowded visual acuity complicate the interpretation of this effect. No effect of tRNS was observed for amblyopic eye crowded visual acuity. In agreement with previous non-invasive brain stimulation studies using different techniques, tRNS induced short-term contrast sensitivity improvements in adult amblyopic eyes, however, repeated sessions of tRNS did not lead to enhanced or long-lasting effects for the majority of outcome measures.

Presence is seen to be important in the Virtual Reality (VR) domain, as there is often a close link between an individual’s experience of a virtual environment and their subsequent performance/behaviour. Unfortunately, the generic presence questionnaires available in the VR literature have been developed considering tasks not necessarily relevant to the driving situation - for instance, relating to the participant’s ability to move objects, use touch, smell items, etc. This paper describes the evolution of a driving simulator experience questionnaire, designed specifically to enable researchers and practitioners to understand how study participants perceive the driving simulation environment in relation to real-world equivalent situations. The final questionnaire has been informed by 20 interviews and focus sessions, 5 expert reviews, and simulator studies involving 225 people across different fidelity simulators and research institutions. Specifically, 41 items are currently included, believed to be of importance for natural driving. Examples of questions relate to strategic - “I felt as if I had been on a journey”, tactical -“I was compelled to obey the displayed road signs…”, and control – “I had a strong sense of physically controlling the vehicle” elements of the driving task. Items are also included relating to social aspects of driving, e.g. “I was aware that other people were driving cars around me”. In next steps, we intend to evaluate the questionnaire by comparing ratings made by individuals with their subsequent driving behaviour/performance in a simulator.

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Precis: Dry eye disease (DED) observed in this study is associated with ocular surface abnormalities as shown by specific dry eye tests. Changes in tear quality may be responsible for dry eye symptoms among the participants. Purpose: This study sought to evaluate DED in glaucoma patients in Ghana. Materials and Methods: This was a hospital-based descriptive cross-sectional study involving glaucoma patients on topical glaucoma treatment for at least 6 months. The medical records of participants were thoroughly reviewed for information on demographics, ocular history, medical history, number of topical antiglaucoma medications used within the last 6 months, and any other ophthalmic medications used by the participants. An Ocular Surface Disease Index (OSDI) questionnaire was administered to each participant, after which Schirmer test and tear break-up time (TBUT) were performed on each participant in a controlled environment. Results: A total of 100 individuals participated in the study. The mean±SD age of participants was 60.44±14.05 years. The majority (60.0%) of the participants were females and 55.0% of participants used 2 or more topical antiglaucoma medication. Of the participants, 81.0% reported subjective dry eye symptoms. Schirmer test and TBUT showed that 55.0% and 87.0% of the participants had decreased tear production and abnormal tear quality, respectively. Multiple logistic regression showed a significant association between age and abnormal OSDI (P=0.037), Schirmer test (P=0.003), and TBUT (P=0.042); the number of topical glaucoma medications and OSDI (P=0.016) and Schirmer test (P=0.009). The prevalence of DED was 23.0%. Increasing age was associated with an ∼7 times higher odds of having DED (P=0.0019), using >2 glaucoma medications with ∼4.5 times higher odds of having DED (P=0.001), 5 or more years of glaucoma medication use with ∼4 times higher odds of DED (P=0.009), and both benzalkonium chloride and sodium chlorite as preservative was associated with ∼3.5 times higher odds of DED (P=0.047). Conclusion: DED is prevalent among glaucoma patients in Ghana and is associated with age, duration of glaucoma medication, type of preservatives, and number of topical glaucoma medications.