Systematic review and meta-analysis of the prevalence of myopia among school-age children in the Eastern Mediterranean Region.

Background: The recent increase in myopia is a major public health concern worldwide, including in the Eastern Mediterranean Region (EMR). Aim: To provide data on the prevalence of myopia among school-age children in the EMR. Methods: This study was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol. We searched the Web of Sciences, Scopus, Index Medicus for the Eastern Mediterranean Region, ProQuest, PubMed, and Medline for studies on the prevalence of myopia in the EMR published from January 2000 to May 2022. The data were analysed using MedCalc version 19.6.1 and myopia was defined as refractive error ≥ 0.50 D. The overall pooled prevalence of myopia was estimated using a random-effects model and its associated 95% confidence intervals. Results: The meta-analysis included 27 quality-assessed studies from 13 countries among 51 111 school-age children. The overall pooled prevalence of childhood myopia from 2000 to 2022 was 5.23%, which was significantly higher among females than males (4.90% vs 3.94%). The prevalence of myopia was significantly higher among children aged 11-17 years than among those aged 5-10 years (7.50% vs 3.90%). There was a higher prevalence of myopia with cycloplegic refraction than noncycloplegic refraction (5.95% vs 3.73%). There was highly significant heterogeneity between the studies. Conclusion: Prevalence of myopia among school-age children in the EMR was high, particularly among older children, and it was more common among females. Early intervention to slow myopia progression is essential in the EMR to protect children from irreversible vision loss.

Clinical features of Sudanese patients presenting with binocular vision anomalies: A hospital-based study.

Binocular vision anomalies are major causes of asthenopia symptoms, particularly among the younger population. This study aimed to report the clinical characteristics of Sudanese patients with binocular disorders who attended the orthoptic clinic at Al-Neelain Eye Hospital. In this retrospective hospital-based study, we analyzed data from 304 patients with binocular vision anomalies who visited the orthoptic clinic between October 2020 and June 2021. We collected information on demographics, symptoms, and eye tests such as visual acuity (VA), refractive error (RE), angle of deviation, and the assessment of fusional vergence. Our findings indicated that exophoria was the most common binocular vision anomaly, affecting 79.8% of males and 71.6% of females (p=0.731). Children between 6 and 17 years old showed the highest prevalence of exophoria (75.9%) (p=0.0001). Among patients with exophoria, 100% reported itching associated with tearing during fixation, while 89.5% experienced difficulty in fixation. Refractive error varied by the type of binocular vision disorders (p=0.0001), with higher hyperopia observed in cases of unilateral esotropia and alternate esotropia (+3.571±1.238 D and +3.023±1.553 D, respectively). Positive fusional vergence (PFV) differed by types of binocular vision disorders (p=0.0001) with high PFV in esophoria (18.063±6.848∆) compared to low PFV in exophoria (12.80±5.313∆). The most common types of exophoria were convergence weakness exophoria (45.39%), followed by convergence insufficiency (20.39%). The study concluded that exophoria was the most common binocular vision anomaly among Sudanese patients, with convergence weakness and convergence insufficiency being the predominant anomalies. Headache was commonly prevalent among patients with binocular vision problems. Higher hyperopia was found in esodeviation, while low PFV was associated with exodeviation.

Morphology and thickness of corneal endothelial cells in young Sudanese individuals with myopia.

Deviations in corneal endothelium morphology and thickness may indicate corneal abnormalities and could be associated with myopia development. This study aimed to evaluate corneal endothelial cell morphology and central corneal thickness in young individuals with myopia. A prospective study was conducted at Al-Neelain University Eye Hospital between January 2019 and January 2020, including 160 patients with myopia (320 eyes). Data was gathered through clinical assessment of visual acuity, refractive error, and corneal endothelial cells. Results showed that 60% of participants with myopia were female, with a mean age of 21.99±2.8 years and a mean equivalent sphere of -3.19±2.67D. There was a significant difference in endothelial cell degeneration between myopia groups (P<0.001). Corneal guttata occurred in 9.1% of eyes with low myopia and 68.2% with moderate myopia, whereas polymegathism and polymorphism were more prevalent in high myopia. The mean central corneal thickness was 500.50±38.94 µm in low myopia, 497.02±36.23 µm in moderate myopia, and 477.87±43.625 µm in high myopia (P=0.007). The mean endothelial cell number in low myopia was 107.86±21.12, 106.0±24.03 in moderate myopia, and 101.23±18.49 in high myopia (P<0.05). The mean difference in endothelial cell density, coefficient of variation, and hexagonality in low, moderate, and high myopia was not significant (P>0.05). However, Pearson's correlation revealed a significant negative correlation between the degree of myopia and central corneal thickness (r= -0.174, P=0.002) as well as endothelial cell number (r= -0.124, P=0.026). The study concluded that central corneal thickness and endothelial cell number significantly decreased with an increase in the degree of myopia. Corneal guttata was the most common form of endothelial cell degeneration observed in cases of high myopia.

Dual Piezoelectric Energy Investing and Harvesting Interface for High-Voltage Input.

A novel harvesting interface for multiple piezoelectric transducers (PZTs) is proposed for high-voltage energy harvesting. Pre-biasing a PZT prior to its mechanical deformation increases its damping force, resulting in higher energy extraction. Unlike the conventional harvesters where a PZT-generated output is assumed to be continuous sinusoidal and output polarity is assumed to be alternating every cycle, PZT-generated output from human motion is expected to be random. Therefore, in the proposed approach, energy is invested to the PZT only when PZT deformation is detected. Upon the motion detection, energy stored at a storage capacitor (CSTOR) from earlier energy harvesting cycle is invested to pre-bias PZT, enhancing energy extraction. The harvested energy is transferred to back CSTOR for energy investment on the next cycle and then excess energy is transferred to the battery. In addition, partial electric charge extraction (PECE) is adapted to extract a partial amount of charges from the PZT every time its voltage approaches the process limit of 40 V. Simulations with 0.35 µm BCD process show 7.61× (with PECE only) and 8.38× (with PECE and energy investment) improvement compared to the conventional rectifier-based harvesting scheme Proposed harvesting interface successfully harvests energy from excitations with open-circuit voltages up to 100 V.

Infant Oral Healthcare and Anticipatory Guidance Practices among Dentists in a Pediatric Care Shortage Area.

OBJECTIVES: To assess dentists' practices and barriers towards infant oral healthcare (IOH) and anticipatory guidance (AG) in eastern Saudi Arabia. METHODS: A regional, cross-sectional survey was distributed to 340 (323 general dentists (GPs) and 17 pediatric dentists (PDs)) working in a governmental setting in eastern Saudi Arabia. A 23 close-ended, pilot-tested questionnaire was developed. The questionnaire asked about dentists' IOH and AG practices. A five-point Likert scale question assessed barriers interfering with AG practices. Descriptive and multivariate logistic regressions were used. RESULTS: Participation rate was 98.5% (335/340). Only 18% of GPs indicated performing IOH exams, while 100% of PDs do. About 90% of GPs would see children on a first visit when they are ≥3 years old, whereas 60% of PDs reported seeing one-year-old children. Older practitioners and those performing AG were more likely to perform IOH (OR = 1.8, CI = 1.06-3.1, and OR = 3.84, CI = 1.93-7.65, resp.). The majority of respondents (94%) felt their training did not prepare them to practice AG. "Parents bringing their children for the first time for emergency or existing conditions" was cited by 99% of respondents as a barrier to performing AG. CONCLUSION: Increasing the awareness of GPs and parents about the importance of IOH and AG is crucial in improving children's oral health. Collaboration with pediatricians for early referral of children is equally important in increasing the awareness on prevention principles.

A systemic review of barriers to accessing paediatric eye care services in African countries.

Background: Global estimate reported that 1.4 million children are blind of which three-quarters live in developing countries. Childhood Visual Impairment is a major public health problem globally especially in rural areas of developing countries. Objective: To review barriers to accessing paediatric eye care services in African countries. Methods: The studies in this review were searched in online databases (PubMed, Web of Sciences, ProQuest, Scopus, Google Scholar, African Index Medicus and Medline) for studies published between January 2000 and April 2020. The articles included in this review, which was conducted in Africa to assess the barriers for accessing paediatric eye care services with regards availability, accessibility, affordability, socio cultural barriers of parents/caregivers and community. Results: Of 22 705 articles screened, the study found 29 publications from 10 African countries which met the inclusion criteria. The main barriers were non-availability, non-accessibility, and non-affordability of paediatric eye care services. The studies reviewed revealed that there are other factors affecting the utilization of paediatric eye services which include the primary health system, geographic barriers, health beliefs, perception of parents; lack of knowledge, attitudes and practices about paediatric eye care. Furthermore, environmental, demographic barriers and socio-economic status has negative impact on accessing paediatric eye care services in African counties. Conclusion: The main barriers to accessing paediatric eye care services in Africa were affordability, accessibility and availability. There is therefore a need for all relevant stakeholders to play a significant role in addressing barriers to child eye care in African countries.

Prevalence of refractive error and visual impairment among school-age children of Hargesia, Somaliland, Somalia.

BACKGROUND: Childhood visual impairment is a global public health problem, especially in low and middle-income countries. Its most common causes are avoidable by early diagnosis and treatment. AIMS: To assess prevalence of refractive error and visual impairment among school-aged children in Hargeisa, Somaliland, Somalia. METHODS: This was a cross-sectional study of 1204 students (aged 6-15 years) in 8 randomly selected primary schools in Hargeisa from November 2017 to January 2018. We used the modified Refractive Error Study in Children to determine prevalence of refractive error and visual impairment, including the following investigations: distance visual acuity, assessed by Snellen Tumbling E-chart; refraction, assessed by retinoscope binocular vision assessment; and examination of anterior and posterior segments. RESULTS: Prevalence of uncorrected, presenting and best-corrected visual impairment of 6/12 or worse was 13.6%, 7.6% and 0.75%, respectively. Only 16 of 91 (17.6%) children were using spectacles and the rest were unaware of the problem. Refractive error was the cause of visual impairment in 76.8% of participants, amblyopia in 22.0%, trachoma in 2.4%, and corneal opacity and cataract in 0.6%. Anterior segment abnormalities were found in 8.3%, mainly vernal keratoconjunctivitis, while posterior abnormalities were observed in 0.7%. Prevalence of myopia was 9.1%, hypermetropia 2.7% and astigmatism 3.9%. Prevalence of visual impairment because of Refractive Error was associated with increasing age, but there was no significant association with school grade or sex. CONCLUSION: Prevalence of visual impairment among school-aged children in Hargeisa was high, and the leading cause was uncorrected Refractive Error. There are barriers to care and it is critical that they are overcome.

A High-Voltage Energy-Harvesting Interface for Irregular Kinetic Energy Harvesting in IoT Systems with 1365% Improvement Using All-NMOS Power Switches and Ultra-low Quiescent Current Controller.

An energy-harvesting interface for kinetic energy harvesting from high-voltage piezoelectric and triboelectric generators is proposed in this paper. Unlike the conventional kinetic energy-harvesting interfaces optimized for continuous sinusoidal input, the proposed harvesting interface can efficiently handle irregular and random high voltage energy inputs. An N-type mosfet (NMOS)-only power stage design is introduced to simplify power switch drivers and minimize conduction loss. Controller active mode power is also reduced by introducing a new voltage peak detector. For efficient operation with potentially long intervals between random kinetic energy inputs, standby power consumption is minimized by monitoring the input with a 43 pW wake-up controller and power-gating all other circuits during the standby intervals. The proposed harvesting interface can harvest energy from a wide range of energy inputs, 10 s of nJ to 10 s of µJ energy/pulse, with an input voltage range of 5-200 V and an output range of 2.4-4 V under discontinuous as well as continuous excitation. The proposed interface is examined in two scenarios, with integrated power stage devices (maximum input 45 V) and with discrete power stage devices (maximum input 200 V), and the harvesting efficiency is improved by up to 600% and 1350%, respectively, compared to the case when harvesting is performed with a full bridge rectifier.

Origin and spread of Bos taurus: new clues from mitochondrial genomes belonging to haplogroup T1.

BACKGROUND: Most genetic studies on modern cattle have established a common origin for all taurine breeds in the Near East, during the Neolithic transition about 10 thousand years (ka) ago. Yet, the possibility of independent and/or secondary domestication events is still debated and is fostered by the finding of rare mitochondrial DNA (mtDNA) haplogroups like P, Q and R. Haplogroup T1, because of its geographic distribution, has been the subject of several investigations pointing to a possible independent domestication event in Africa and suggesting a genetic contribution of African cattle to the formation of Iberian and Creole cattle. Whole mitochondrial genome sequence analysis, with its proven effectiveness in improving the resolution of phylogeographic studies, is the most appropriate tool to investigate the origin and structure of haplogroup T1. METHODOLOGY: A survey of >2200 bovine mtDNA control regions representing 28 breeds (15 European, 10 African, 3 American) identified 281 subjects belonging to haplogroup T1. Fifty-four were selected for whole mtDNA genome sequencing, and combined with ten T1 complete sequences from previous studies into the most detailed T1 phylogenetic tree available to date. CONCLUSIONS: Phylogenetic analysis of the 64 T1 mitochondrial complete genomes revealed six distinct sub-haplogroups (T1a-T1f). Our data support the overall scenario of a Near Eastern origin of the T1 sub-haplogroups from as much as eight founding T1 haplotypes. However, the possibility that one sub-haplogroup (T1d) arose in North Africa, in domesticated stocks, shortly after their arrival from the Near East, can not be ruled out. Finally, the previously identified "African-derived American" (AA) haplotype turned out to be a sub-clade of T1c (T1c1a1). This haplotype was found here for the first time in Africa (Egypt), indicating that it probably originated in North Africa, reached the Iberian Peninsula and sailed to America, with the first European settlers.