|Year : 2017 | Volume
| Issue : 2 | Page : 44-49
Prevalence and Causes of Childhood Blindness and Visual Impairment in Quranic Boarding Schools in Al-Gazira State of Sudan
Zoelfigar Dafalla Mohamed1, Kamal Hashim Binnawi2, Mustafa Abdu3
1 Department of Optometry, Hussam Optical Company, Riyadh, Saudi Arabia
2 Department of Ophthalmology, Faculty of Medicine, Al-Neelain University, Khartoum, Sudan
3 Department of Contact Lens, Faculty of Optometry and Visual Sciences, Al-Neelain University, Khartoum, Sudan
|Date of Web Publication||26-Feb-2018|
Zoelfigar Dafalla Mohamed
Department of Optometry, Hussam Holding Company, P.O. Box 40851, Riyadh
Aim: This study aimed to determine the prevalence and causes of childhood blindness and visual impairment among Quranic boarding schools children in Al-Gazira state of Sudan. Materials and Methods: A total of 822 children were screened, and they distributed in 8 traditional Quranic schools. The study divided into two phases, the first one was designed to detect the visually impaired children, and in the second one, the affected children were investigated deeply through inner eye, refraction, and cover test examinations. Results: The findings indicated that the prevalence of childhood visual impairment (6/12 and worse binocularly) with the best correction was 12 (1.5%) in children of traditional Quranic boarding schools in Al-Gazira state of Sudan. The prevalence of visual impairment among children was increased with the age of children (P ≤ 0.001). The uncorrected refractive errors was the main cause of visual impairment which represented (36%) of impaired children followed by cataract (21.5%), corneal opacities (21%), optic nerve lesion (10.7%), retinitis pigmentosa (3.6%), glaucoma (3.6%), and squint (3.6%). Conclusion: The study concluded that the most causes of childhood visual impairment in traditional Quranic boarding schools in Al-Gazira state of Sudan were avoidable. Uncorrected refractive errors was a major cause of visual impairment among children; this pointed out the need for urgent a comprehensive childhood eye care plan to deliver eye care services for them, through cooperation between governmental, community stakeholders, and nongovernmental organization working in the prevention of childhood blindness.
Keywords: Blindness, childhood, prevalence, refractive errors, traditional Quranic boarding schools
|How to cite this article:|
Mohamed ZD, Binnawi KH, Abdu M. Prevalence and Causes of Childhood Blindness and Visual Impairment in Quranic Boarding Schools in Al-Gazira State of Sudan. Sudanese J Ophthalmol 2017;9:44-9
|How to cite this URL:|
Mohamed ZD, Binnawi KH, Abdu M. Prevalence and Causes of Childhood Blindness and Visual Impairment in Quranic Boarding Schools in Al-Gazira State of Sudan. Sudanese J Ophthalmol [serial online] 2017 [cited 2018 Sep 25];9:44-9. Available from: http://www.sjopthal.net/text.asp?2017/9/2/44/226143
| Introduction|| |
The childhood visual impairment was defined as presenting visual acuity <6/12 in the better eye  World Health Organization (WHO) estimated 19 million children are visually impaired. There were 12 million of them due to refractive errors. Around 1.4 million are irreversibly blind for the rest of their lives and need visual rehabilitation interventions for a full psychological and personal development. Visual impairment in childhood obstructs the child's development, education, professionals, forms the child future life, affecting employment, and social prospects. Khandekar in 2008 reported that 40% of childhood blindness results from avoidable causes. The prevalence of visual impairment in African children in South Africa was 0.32% according to a study conducted by Naidoo et al. In Ethiopia, Demissie and Solomon documented the prevalence of 0.62%. The prevalence among displaced children in the Khartoum state of Sudan was 0.14%, and Alrasheed et al. documented the prevalence of 1.2% in South Darfur of Sudan.
The major causes of childhood visual impairment include Vitamin A deficiency, measles, conjunctivitis, ophthalmia neonatorum, congenital cataract, and retinopathy of prematurity. Keeffe suggests that there is wide regional variation is the causes of vision loss and blindness. In both developed and developing countries, the majority of vision loss was either preventable or treatable. Cataract, retinal diseases, and congenital abnormalities are found in all region, in developing or low-income countries where much of the vision loss is due to infection or nutrition, corneal scarring is the most common cause of blindness, therefore, prevention of these conditions is largely at primary care level. In Malaysian children, the cataract represented 17.2% of children, while Alrasheed et al. in South Darfur of Sudan reported 3.7%. The uncorrected refractive error was one of the most common causes of visual impairment in South Darfur of Sudan 57%.
The Maseeds are quite common all over Sudan. Children spend a considerable time at the “maseed,” away from their homes. The diet provided to the children at the “maseed” is mostly nutritionally deficient in vitamins. We had obtained information on local dietary practices at the “maseed” in a prior exploratory visit. Boys are exposed almost exclusively daily (for prolonged periods of time) to a diet that consists of a staple cereal (sorghum or millet) and “mullah” (water, scanty, dried meat, and okra).
Sudan is a tropical country with tropical diseases; poverty is widespread; therefore, the blindness threatens people, especially children. The prevalence of childhood visual impairment believed to be high. In the rural areas, there are limited health services; therefore, the problem of vision handicap is increased. Add to that the Quranic schools have a shortage of health regimen (diet, health care, and latrines). The lack of baseline information on the magnitude of health problems among maseeds's students is considered one of the factors of the unsatisfactory status of children health in Sudan. Availability of such data from Quranic Schools will help in the health promotion of this community.
| Materials and Methods|| |
This was a cross-sectional, Maseeds-based study of visual impairment among children with age ranged between 6 and 15 years; the Maseed is a place in which children learning and writing the Quran. The overall number of children enrolled in traditional Quranic boarding schools in Al-Gazira state was not registered regularly. A total of 822 Quranic boarding schools children distributed to nine Maseeds in Al-Gezira state were investigated.
The sample size for the study was calculated using the formula for estimating a single population proportion (unknown statistical population).
N = (Z/M)2× (P) × (1 × P)
N sample size
M is the margin of error P is an estimated value of the proportion
Z confidence interval
The study sample was selected according to 95% confidence interval (CI) for P with a margin of error equal to 4% because there is no estimation of this proportion.
- Used P ≤ 0.50 for a conservative estimate.
- For a 95% CI, z = 1.960
- n = (1.9600/0.04)2× (0.5)(1 − 0.5) = 600.25.
This is the minimum sample size; therefore, we should round up to 601. To construct a 95% CI with a margin of error of 4%, the study sample screened was more than the estimated sample size to give more confidence.
The clinical tests
The mechanism depended on transferring from school to another. Quranic schools teachers (Sheikhs) received definition letters from Al-Neelain University and signed the consent form in The Arabic language [Figure 1]. Examinations for all participants in this study covered taking the ABCs of patients (name, gender, age, duration of students in Maseed, and origin of students), in addition to, symptoms, family, ocular history of the patients were documented. Visual acuity was examined for all participants monocular and binocular, then outer eye checked for all subjects. Students with affected visual acuity examined deeply. In addition to clinical examinations, sheikhs (teachers) interviewed by the researcher to get information about the Maseed nutrition, health condition, and barracks condition to detect prevalence and causes of childhood blindness and visual impairment in this community [Figure 2].
|Figure 2: Procedures for testing visual acuity and diagnosing vision impairment|
Click here to view
Data analysis was carried using (SPSS) Version 22 software for Windows 10 (Armonk, NY: IBM Corp). The data were revised for data entry errors and missing values inserted before starting the data analysis. The data for each subject were analyzed descriptively using mean, standard deviation, mode, frequency, and percentages. The relationship between measures was determined using correlation, cross-tabulations which is one of the most useful analytical tools and Chi-square test with a P < 0.05 was taken as the threshold of significance.
| Results|| |
A total of 822 children who live in the boarding of Quranic schools (Maseeds) were examined. The children were distributed in eight schools in Gezira state districts as follows; Wad Albahar (34), Alsheikh Taha (113), Alsheikh Ibrahim (76), ALdweneeb (200), Wad-Alfadny (205), Alsheikh Abdel Mahmoud (Tabat) (52), Alsheikh A. Abdulaziz (81), and Alsheikh Al musharaf (Alhilaleya) (61) students.
Demographic characteristics of participants
The age of the students ranged from 5 to 15 years with a mean of 12.41 ± 1.994 years and median of 13 years. All children are male. The origin of participants distributed in 15 states of Sudan and some African countries. The presence of children in Maseeds is ranged from <1 year to 6 years. Cross-tabulation Chi-square tests revealed a significant relationship between age and duration periods (P ≥ 0.01). Results also show a significant relationship between symptoms and the period of the presence in Maseeds according to cross-tabulation Chi-square tests (P ≥ 0.02).
Distribution of students according to place of origin
A total of 214 (26%) students from Al-Gezira state followed by South Darfur state 140 (17%), North Darfur 78 (9.5%), West Darfur 69 (8.4%), North Kurdofan 63 (7.7%), East Darfur 44 (5.4%), Khartoum state 43 (5.2%), Gadaref state 37 (4.5%), Middle Darfur state 36 (4.4%), and other states 18 (9.7%). A total of 18 (2.2%) students derived from other African countries.
Visual acuity of students
[Table 1] shows the visual acuity of students. The right eye results appeared a total of 773 (94%) of subject their vision was normal 6/6 (95% CI 92.6–95.4) and a total of 777 (94.5%) had normal vision 6/6 (95% CI 93.1–95.9). A total of 14 (1.7%) and 8 (1.0%) of students had a vision 6/9 (95% CI 1.0–2.4) and (95% CI 0.5–1.5) in the right and left eye, respectively. Around 35 (4.3%) (95% CI 1.5–7.5) and 37 (4.5%) (95% CI 1.9–6) of the students had affected visual acuity of <6/9 in the right and left eye, respectively. Binocular visual acuity (better eye) results showed normal vision in 789 (96%) (95% CI 94.8–97.2), while 6/9 appeared as 11 (1.3%) (95% CI 0.7–1.9), and 22 (2.7%) had affected visual acuity.
Distribution of participants according to external eye examination:
Outer examination of the participant's eyes showed a total of 566 (68.9%) and 569 (69%) of children free from ocular defects in the right and left eye, respectively, while vitamin A deficiency signs (conjunctival xerosis, Bitot's spots, and corneal xerosis) represented 175 (21.3%) and 176 (21.4%) of total students. The bacterial and allergic conjunctivitis appeared as 6 (0.7%) and 39 (4.7%) in the right eye, however, in the left eye resulted in 4 (0.5%) and 38 (4.6%) for bacterial and allergic one. Other conditions revealed as cataract (0.6%), trachoma (0.2%), corneal opacity (0.1%), pterygium (2.8%), pinguecula (0.2%), dry eye (0.1%), ptosis (0.1%), and chalazion (0.1%) in the right eye. The left eye condition showed cataract (0.2%), trachoma (0.2%), corneal opacity (0.4%), pterygium (2.7%), pinguecula (0.2%), dry eye (0.1%), and chlazion (0.4%) [Table 2]. Cross-tabulation Chi-square tests showed the closed-relationship between symptoms and outer eye finding in both eyes (P ≤ 0.01).
Distribution of subject's refractive errors
[Table 3] showed a total of 780 (94.9%) and 781 (95%) of the students were emmetrope (95% CI 93.3–96.4 and 93.6–96.5), while astigmatism represents 19 (2.3%) and 18 (2.2%)−(95% CI 1.3–3.3 and 1.2–3.2) in the right and left eye, respectively. The results appeared 13 (1.6%) and 14 (1.7%) of the children had myopia in the right and left eye (95% CI 0.9–2.6 and 1.0–2.7); however, hypermetropia represents 5 (0.6%) and 4 (0.5%) in the right and left one of students (95% CI 0.1–1.2 and 0.1–1.0), and no fundus reflex in 5 (0.6%) in both eyes (95% CI 0.1–1.1 and 0.1–1.2).
| Inner Eye Examination Results|| |
Fundus examination of children revealed that a total of 814 (99.0%) and 815 (99.1%) of the children were free from fundus defects in the right and left eye, respectively, while there was none seen fundus due to opacity in 3 (0.4%) in the right eye and 2 (0.2) in the left eye. Retinitis pigmentosa and optic nerve lesion represent 2 (0.2%) equal to the right eye. Left eye represent 3 (0.4%) for retinitis pigmentosa and 1 (0.1%) for optic nerve lesion. Glaucoma revealed in 2 (0.2%) of participants in the right eye, and only one (0.1%) in the left eye [Table 4].
Prevalence of visual impairment
The results of visual impairment among 822 Quranic boarding schools children in Gezira state are shown in the [Table 5]. The prevalence of visual impairment was 12 (1.2%) distributed as 9 (1.1%) moderate visual impairment (95% CI 0.4–1.9), 1 (0.1%) severe visual impairment (95% CI 0.0–0.4), and total blindness 2 (0.2%) of participants (95% CI 0.0–0.4).
The prevalence of visual impairment in the right eye appeared in 21 (2.6%) classified as follows; moderate visual impairment 11 (1.3%) (95% CI 0.6–2.2), 1 (0.1%) severe visual impairment (95% CI 0.0–0.4), and 9 (1.1%) had blind right eye (95% CI 0.5–1.8). A total of 20 (2.4%) of participants had visual impairment in the left eye as; 14 (1.7%) moderate (95% CI 0.9–2.7), 1 (01%) severe (95% CI 0.0–0.4), and 5 (0.6%) were blind (95% CI 01–1.2). The prevalence of vision impairment increased, according to age, younger ages were associated with lower prevalence of vision impairment; there is no visual impairment among the students aged between about 10–15 years old as in (P ≥ 0.01).
Causes of visual impairment in impaired participants
The causes of visual impairment in (22) subjects who had visual impairment monocular or binocular are shown in [Figure 3]. Cataract was found in 6 (27.3%) of subjects, refractive errors 4 (18.2%), corneal opacity (xerophthalmia, infection, and keratoconus) 6 (27.3%), optic nerve lesion 3 (13.6%), retinitis pigmentosa 1 (4.5%), glaucoma 1 (4.5%), and squint in one student (4.5%). Pearson Chi-square cross-tabulation revealed significant crossing between age and causes (P ≤ 0.00).
| Discussion|| |
Prevalence of visual impairments
The prevalence of visual impairment among traditional Quranic boarding schools children in Al-Gazira state of Sudan in the present study was 1.5% which was comparable to the South Darfur state of Sudan through a study conducted to assess the prevalence of visual impairment and refractive errors among Sudanese school-aged children. The prevalence of visual impairment in the present study was higher compared to prevalence of school children of the upper-middle socioeconomic status in Kathmandu in Nepal, Sikoru District children of Ethiopia, low-middle-income school children in Sao Paulo, Brazil, African children in South Africa, and the camps of a displaced person in the Khartoum State of Sudan.
The prevalence of visual impairment was higher than other previous studies because of different community characteristics. The results were higher than the WHO estimation (2017) which was 1.2/1000 children in the developing countries. The visual impairment in this study classified according to categories mentioned as follows; the prevalence of moderate visual impairment was 1.1%, severe visual impairment 0.1%, and total blindness 0.2% of children.
The prevalence of visual impairment in the right eye documented as 2.5% and left eye 2.4% among participants (classified as blindness, severe, and moderate visual impairment). Results of this study revealed that the prevalence of visual impairment increased when the age increased that means younger ages were showed no visual impairment, while all of the impaired children situated between the ages of 10 and 15 years old same as Alrasheed et al. findings in (2016).
These results reveal that vision impairment among Quranic boarding schools students is high, thus children need direct intervention from the governmental or nongovernmental organization and more specific studies, and management plan is needed to prevent this community from blindness.
The main causes of visual impairments
The uncorrected refractive errors were the most common cause of visual impairment among students of Traditional Quran Boarding Schools in Al-Gezira state 36% which was lower than Alrasheed et al. estimation in South Darfur of Sudan. The present outcome was also lower than that estimated by Naidoo et al. in African children of South Africa.
The results of this study revealed a cataract affect 21.5% of visual impairment children which was higher than Muhit et al., in children of Bangladesh  and Alrasheed et al. in South Darfur of Sudan. The present finding was lower compared to a nationwide study conducted in Malaysia. The results showed a significant crossing between age and causes of visual impairment and blindness of participants. Majority of cataracts affected children are traumatic, that means it can be reversible by urgent intervention but is not available for them at that time.
Corneal opacity due to infections, trauma, and keratoconus in this study represents 21% which was comparable to Bangladesh study. The corneal opacity in South Darfur of Sudan was lower than present results that according to the study conducted by Alrasheed et al. in (2016).
According to this result and previous results from a different region in the third world, the corneal problems are one of the most causes of childhood, and visual impairment, the prevention of corneal blindness must be taken critically in all levels of eye care.
Other causes of visual impairment were optic nerve lesion, retinitis pigmentosa, glaucoma, and squint. The retinal disorders in this study were lower compared to most of the previous reports.,, These causes need follow-up to avoid progression of visual impairment. These causes need follow-up to avoid progression of visual impairment.
The current study had some limitations. First, there were no accurate statistics for the community of traditional Quranic boarding schools (Maseeds) in Al-Gazira state. Second, we achieved all the clinical eye examinations in the schools to improve the participation rate, however, conditions such as illumination, ventilation, and comfort were different from school to school. Third, children availability in the schools was irregular. Finally, students cooperation especially younger age and African students (language).
| Conclusion|| |
This study concluded that the prevalence of childhood blindness and visual impairment in traditional Quranic boarding schools (Maseeds) in the Gazira state of Sudan was (1.5%). The main causes of visual impairment among children was a refractive error which was (36%) followed by cataract (21.5%) and corneal opacity (21%) then optic nerve lesion, retinal disorders, glaucoma, and squints. Uncorrected refractive errors was a major cause of visual impairment among children in Al-Gazira State, this point out to need for urgently a comprehensive childhood eye care plan to deliver eye care services to those children, through cooperation between governmental, community stakeholders, and nongovernmental organization working in the prevention of avoidable childhood blindness.
We are grateful to the staff of faculty of optometry and visual sciences Al-Neelain University and teachers of Quranic schools for their help in data collection. We would also like to thank all the people who participated in this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Courtright P, Hutchinson A, Lewallen S. Visual impairment in children in middle- and lower-income countries. Arch Dis Child 2011;96:1129-34.
Maritto SP. Global data on visual impairment 2010. Geneva: World Health Organization; 2012. WHO/NMH/PBD/.
Rahi J, Severe visual impairment and blindness in children in the UK, Lancet, 2003;362:1359-65.
Khandekar R, Visual Disabilities in Children Including Childhood Blindness, Middle East Afr J Ophthalmology. 2008;15:129-34.
Naidoo KS, Raghunandan A, Mashige KP, Govender P, Holden BA, Pokharel GP, et al
. Refractive error and visual impairment in African children in South Africa. Invest Ophthalmol Vis Sci 2003;44:3764-70.
Demissie B, Solomon A. Magnitude and causes of blindness and severe visual impairment in Sikoru District, Southwest Ethiopia, Royal Society of Tropical Medicine and Hygiene, Elsevier Ltd, 2011;105:507-5011.
Zeidan Z, Hashim K, Muhit MA, Gilbert C. Prevalence and causes of childhood blindness in camps for displaced persons in Khartoum: Results of a household survey. East Mediterr Health J 2007;13:580-5.
Alrasheed SH, Naidoo KS, Clarke-Farr PC. Prevalence of visual impairment and refractive error in school-aged children in South Darfur State of Sudan. Afr Vision Eye Health. 2016;75:a355.
Khurana A. Comprehensive Ophthalmology, 4th edition, New Age International (P) Ltd, New Delhi; 2007;14:444-7.
Keeffe J, Childhood vision impairment, British Journal of Ophthalmology 2004;88:728-9.
Naidoo KS, Jaggernath J. Uncorrected refractive errors. Indian J Ophthalmol 2012;60:432-7. [Full text]
Sullivan L, Power and Sample Size Determination. Boston University School of Public Health. 2016. p. 1.
Sullivan L. Power and Sample Size Determination. Boston University School of Public Health. 2016. p. 1.
Spkota YD, Adhikari BN, Pokharel GP, Poudyal BK, Ellwein LB. The prevalence of visual impairment attributable to refractive error and other causes in school children of upper-middle socioeconomic status in Kathmandu. Ophthal Epidemiol 2008;15:17-23.
Muhit MA, Shah SP, Gilbert CE. Causes of severe visual impairment and blindness in Bangladesh: A study of 1935 children. The British Journal of Ophthalmology 2007;91:1000-4.
Patel DK, Tajunisah I, Gilbert C, Subrayan V. Childhood blindness and severe visual impairment in Malaysia: A nationwide study. Eye 2011;25:436-42.
Salomão SR, Cinoto RW, Berezovsky A, Mendieta L, Nakanami CR, Lipener C, et al
. Prevalence and causes of visual impairment in low–middle income school children in São Paulo, Brazil. Invest. Ophthalmol Vis Sci 2008;49:4308-13.
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]