Prevalence and causes of severe visual impairment and blindness in children in Mongolia

A 12-year follow up survey of childhood blindness at schools for the blind in Cambodia

BACKGROUND

Cambodia is a low-income country in South East Asia with a population of 15.5 million people of whom 4.9 million (38%) are under the age of 16. The causes of childhood blindness in Cambodia have not been investigated since the first survey of schools for the blind done in 2009 by our group. Given the large demographic and economic shifts in Cambodia since 2009 it is important to determine if these causes have changed in order to ensure intervention programmes are appropriately targeted. The purpose of the present study is to investigate the prevalence of causes of childhood blindness at schools for the blind in Cambodia.

METHODS

Students between the ages of 5 and 16 years who were attending schools for the blind in Cambodia were examined by a consultant paediatric ophthalmologist and had clinical photographs taken. Distance visual acuity was measured using a logMAR tumbling E chart and the WHO definitions of blindness and severe visual impairment were used. The examining ophthalmologist recorded the anatomical site and aetiology of vision loss using the WHO Prevention of Blindness eye examination record for children. Collected data were compared to a previous survey from 2009.

RESULTS

Data from 73 students were included for analysis. The most common anatomical location of abnormality causing vision loss was the cornea (n = 20, 33.9%) followed by the lens and retina (n = 11, 18.64% each). Hereditary factors (n = 29, 49.15%) and childhood diseases (n = 27, 45.76%) were the most common aetiological causes of childhood blindness. The majority (71.19%) of childhood blindness was avoidable. The present study did not demonstrate 0a significant difference in the causes of childhood blindness compared to 2009.

CONCLUSIONS

Corneal pathologies continue to represent the most common cause of vision loss amongst the surveyed population and the majority of causes of childhood blindness continue to be avoidable. These findings will facilitate the development of evidence-based targeted interventional programmes in Cambodia.

A survey of visual impairment and blindness in children attending eight schools for the blind in Myanmar: An update

Purpose:

To determine the causes of visual impairment (VI) and blindness among children in schools for the blind in Myanmar; to identify the avoidable causes of VI and blindness; to provide spectacles, low-vision aids, and ophthalmic treatment where indicated; to provide an update of the 2007 survey performed and identify any major epidemiological changes.

Methods:

Two hundred and ninety children under 16 years of age from all eight schools for the blind in Myanmar were examined and the data entered into the World Health Organization Prevention of Blindness Examination Record for Childhood Blindness.

Results:

In total, 271 children (93.4%) were blind (visual acuity [VA] <3/60 in the better eye) and 15 (5.17%) had severe visual impairment (SVI = VA <6/60 to 3/60 in the better eye). Most children had whole globe as the major anatomical site of SVI or blindness (105, 36.6%). The cause was unknown in the majority of these (155, 54.0%). One hundred and twelve children had avoidable causes of blindness and SVI (39.0%). Forty children (13.9%) required an optical device and 10.1% required surgical or medical attention, with a potential for visual improvement through intervention in 3.48%.

Conclusion:

In all, 39.0% of children had potentially avoidable causes of SVI and blindness with cataracts and measles being the commonest causes. This follow-up survey performed after the first one completed in Myanmar in 2007 demonstrates a change in the major site of abnormality from the cornea to whole globe and a reduction in avoidable blindness but highlights the ongoing burden of measles.

Development of Screening Criteria for Retinopathy of Prematurity in Ulaanbaatar, Mongolia, Using a Web-based Data Management System

PURPOSE

To describe a process for identifying birth weight (BW) and gestational age (GA) screening guidelines in Mongolia.

METHODS

This was a prospective cohort study in a tertiary care hospital in Ulaanbataar, Mongolia, of 193 premature infants with GA of 36 weeks or younger and/or BW of 2,000 g or less) with regression analysis to determine associations between BW and GA and the development of retinopathy of prematurity (ROP).

RESULTS

As BW and GA decreased, the relative risk of developing ROP increased. The relative risk of developing any stage of ROP in infants born at 29 weeks or younger was 2.91 (95% CI: 1.55 to 5.44; P < .001] compared to older infants. The relative risk of developing any type of ROP in infants with BW of less than 1,200 g was 2.41 (95% CI: 1.35 to 4.29; P = .003] and developing type 2 or worse ROP was 2.05 (95% CI: 0.99 to 4.25; P = .05).

CONCLUSIONS

Infants in Mongolia with heavier BW and older GA who fall outside of current United States screening guidelines of GA of 30 weeks or younger and/or BW of 1,500 g or less developed clinically relevant ROP. [J Pediatr Ophthalmol Strabismus. 2020;57(5):333-339.].

Prevalence and causes of childhood blindness in Huidong County, South China, primary ascertained by the key informants

Purpose

The aim of this study is to ascertain the prevalence and causes of childhood blindness and severe visual impairment (BL/SVI) in Huidong, South China.

Methods

This cross-sectional study was conducted in early 2017 in areas of 139 816 children at the age of 0–15 as the study subjects. We used the trained key informants (KIs) to do preliminary visual test in the communities and refer those children suspected with blindness or unable to count fingers with both eyes at 5 m to hospital for further examination by paediatric ophthalmologist for causes. The WHO’s definition of BL/SVI was used, as blindness is best-corrected visual acuity worse than 0.05 in better eye and SVI is equal to or better than 0.05 but worse than 0.1 in better eye.

Results

Three hundred and fourteen KIs were trained. In total, 42 children with BL/SVI were found, and among them over half (22, 52.4%) were due to posterior segment disorders by anatomic site and 18 (42.9%) children were potentially preventable; these included BL/SVI caused by factors at children’s development in intrauterine and after birth. This established the prevalence of BL/SVI was at 0.31/1000 (95% CI 0.28 to 0.34/1000).

Conclusion

A low prevalence of childhood blindness was documented in this study. Establishment of surveillance system for disabled children including those with BL/SVI and better health education on eye care to the public according to the surveillance outcomes would help to reduce avoidable children’s BL/SVI further in China.

Burden of neurodevelopmental disorders in low and middle-income countries: A systematic review and meta-analysis

Background: Childhood mortality from infectious diseases has declined steadily in many low and middle-income (LAMIC) countries, with increased recognition of non-communicable diseases such as neurodevelopmental disorders (NDD). There is lack of data on the burden of NDD in LAMIC. Current global burden of these disorders are largely extrapolated from high-income countries. The main objective of the study was therefore to estimate the burden of NDD in LAMIC using meta-analytic techniques. Methods: We systematically searched online databases including Medline/PubMed, PsychoInfo, and Embase for studies that reported prevalence or incidence of NDD. Pooled prevalence, heterogeneity and risk factors for prevalence were determined using meta-analytic techniques.   Results: We identified 4,802 records, but only 51 studies met the eligibility criteria. Most studies were from Asia-Pacific (52.2%) and most were on neurological disorders (63.1%). The median pooled prevalence per 1,000 for any NDD was 7.6 (95%CI 7.5-7.7), being 11.3 (11.7-12.0) for neurological disorders and 3.2 (95%CI 3.1-3.3) for mental conditions such as attention-deficit hyperactivity disorder (ADHD). The type of NDD was significantly associated with the greatest prevalence ratio in the multivariable model (PR=2.6(95%CI 0.6-11.6) (P>0.05). Incidence was only reported for epilepsy (mean of 447.7 (95%CI 415.3-481.9) per 100,000). Perinatal complications were the commonest risk factor for NDD. Conclusion: The burden of NDD in LAMIC is considerable. Epidemiological surveys on NDD should screen all types of NDD to provide reliable estimates.

Etiology of Childhood Blindness in Izmir, Turkey

PURPOSE

To identify the anatomic sites and the etiology of childhood blindness and to discern treatable and preventable causes.

METHODS

The records of 998 patients seen in the authors' pediatric ophthalmology unit between June 1998 and May 2002 were examined retrospectively. A total of 148 patients who had visual impairment and blindness according to World Health Organization criteria were included in the study. They are classified according to the etiology based on time of insult and the anatomic site of visual loss.

RESULTS

The most common anatomic site of visual loss was retina, with a rate of 25.0%. The etiology according to the time of insult was unknown in 45.2% of the patients, of whom 20.2% had cataract. Genetic disorders were responsible in 25.0% of the patients. In 69.6% of the patients, the causes of visual impairment were considered either preventable or treatable, including cataract, retinopathy of prematurity, genetic disorders, and refractive errors.

CONCLUSIONS

A high percentage of our patients had avoidable causes of childhood blindness. Genetic counseling services, as well as national screening programs for amblyopia, red fundus reflex, and retinopathy of prematurity, should be established.

Burden of neurodevelopmental disorders in low and middle-income countries: A systematic review and meta-analysis

Background: Childhood mortality from infectious diseases has declined steadily in many low and middle-income (LAMIC) countries, with increased recognition of non-communicable diseases such as neurodevelopmental disorders (NDD). There is lack of data on the burden of NDD in LAMIC. Current global burden of these disorders are largely extrapolated from high-income countries. The main objective of the study was therefore to estimate the burden of NDD in LAMIC using meta-analytic techniques. Methods: We systematically searched online databases including Medline/PubMed, PsychoInfo, and Embase for studies that reported prevalence or incidence of NDD. Pooled prevalence, heterogeneity and risk factors for prevalence were determined using meta-analytic techniques.   Results: We identified 4,802 records, but only 51 studies met the eligibility criteria. Most studies were from Asia (52.2%) and most were on neurological disorders (63.1%). The median pooled prevalence per 1,000 for all NDD was 7.6 (95%CI 7.5-7.7), being 11.3 (11.7-12.0) for neurological disorders and 3.2 (95%CI 3.1-3.3) for mental conditions such as attention-deficit hyperactivity disorder (ADHD). The type of NDD was significantly associated with the greatest prevalence ratio in the multivariable model (PR=2.6(95%CI 0.6-11.6) (P>0.05). Incidence was only reported for epilepsy (mean of 447.7 (95%CI 415.3-481.9) per 100,000). Perinatal complications were the commonest risk factor for NDD. Conclusion: The burden of NDD in LAMIC is considerable. Epidemiological surveys on NDD should screen all types of NDD to provide reliable estimates.

Parents' awareness and perception of children's eye diseases in Nigeria

PURPOSE

Most causes of childhood blindness are treatable or preventable. Knowledge of parents' awareness and perception of eye problems is important in helping to understand parents' eye care seeking behavior. This understanding becomes necessary as early detection and intervention can be effective when done at an early age.

METHOD

Study was carried out in Benin City, Nigeria. Thirty-five parents aged 38-54 years with a mean age of 43(±2) years were recruited. Twenty six were females and nine males. Ten eye care practitioners aged 30-45 years with a mean age of 40 (±2) were included. Seven were males and three were females. Data was analyzed qualitatively and in percentages.

RESULTS

Majority of parents were aware of common eye problems: Blurry vision (85.7%), measles in eye (48.5%), cataract (74.3%), conjunctivitis (48.5%), itching and redness (74.3%), crossed eyes (34.3%), strabismus (57.1%), short sightedness (48.5%) and stye or hordeolum (57.1%). Too much carbohydrate, night reading and too much TV were some of the reasons given for bad eyesight. Self medication and use of local remedies for treatment of conjunctivitis was common practice (94.3%). Chloramphenicol eyedrop was the most common drug used for any eye problem before visiting a doctor (80.0%).

CONCLUSION

Parents are aware of common eye diseases in children but have wrong perception of their causes. Programs to increase public awareness of causes of eye problems and harmful effects of self medication are advocated for to expose inherent dangers.

The Use of Key Informant Method for Identifying Children with Blindness and Severe Visual Impairment in Developing Countries

PURPOSE

An estimated 19 million children are visually impaired; of these, 1.4 million are irreversibly blind. A key challenge is to identify them early in life to benefit maximally from visual rehabilitation, and/or treatment. This aggregative review and structured literature analysis summarizes evidence of what it is about the key informant (KI) approach that works to identify children with blindness or severe visual impairment (B/SVI) in the community (for whom, to what extent, in what circumstances, in what respect, how and why).

METHODS

Peer-reviewed (PubMed, hand search) and grey literature (Google, World Health Organization website, academic theses, direct requests) were included, and methods and criteria used for identification, productivity (number of children referred per KI), accuracy of referrals (positive predictive value, PPV), age of children with B/SVI, KI definition, sex, information about cost and comparisons aggregated.

RESULTS

We included 31 documents describing 22 unique KI programs. Mostly KIs identified children with B/SVI in 1-3 weeks, i.e. "campaign mode." In 60%, KIs were community volunteers, others formal health sector workers (FHSW). Around 0.02-1.56 children per KI (median = 0.25) were successfully recruited. PPV ranged from 12 to 66%. In two studies comparing FHSWs and community KIs, the latter were 8 and 10 times more productive.

CONCLUSION

KIs working in campaign mode may provide an effective approach to identifying children with B/SVI in communities. Including identification of ocular problems and/or other impairments has been recommended. Research on factors that influence effectiveness and on whether KIs continue to contribute could inform programs.

Burden of neurodevelopmental disorders in low and middle-income countries: A systematic review and meta-analysis

Background: Childhood mortality from infectious diseases has declined steadily in many low and middle-income (LAMIC) countries, with increased recognition of non-communicable diseases such as neurodevelopmental disorders (NDD). There is lack of data on the burden of NDD in LAMIC. Current global burden of these disorders are largely extrapolated from high-income countries. The main objective of the study was therefore to estimate the burden of NDD in LAMIC using meta-analytic techniques. Methods: We systematically searched online databases including Medline/PubMed, PsychoInfo, and Embase for studies that reported prevalence or incidence of NDD. Pooled prevalence, heterogeneity and risk factors for prevalence were determined using meta-analytic techniques.   Results: We identified 4,802 records, but only 51 studies met the eligibility criteria. Most studies were from Asia (52.2%) and most were on neurological disorders (63.1%). The median pooled prevalence per 1,000 for all NDD was 7.6 (95%CI 7.5-7.7), being 11.3 (11.7-12.0) for neurological disorders and 3.2 (95%CI 3.1-3.3) for mental conditions such as attention-deficit hyperactivity disorder (ADHD). The type of NDD was significantly associated with the greatest prevalence ratio in the multivariable model (PR=2.6(95%CI 0.6-11.6) (P>0.05). Incidence was only reported for epilepsy (mean of 447.7 (95%CI 415.3-481.9) per 100,000). Perinatal complications were the commonest risk factor for NDD. Conclusion: The burden of NDD in LAMIC is considerable. Epidemiological surveys on NDD should screen all types of NDD to provide reliable estimates.

Causes of Severe Visual Impairment and Blindness: Comparative Data From Bhutanese and Laotian Schools for the Blind

PURPOSE

To determine and compare the major causes of childhood blindness and severe visual impairment in Bhutan and Laos.

DESIGN

Independent cross-sectional surveys.

METHODS

This survey consists of 2 cross-sectional observational studies. The Bhutanese component was undertaken at the National Institute for Vision Impairment, the only dedicated school for the blind in Bhutan. The Laotian study was conducted at the National Ophthalmology Centre and Vientiane School for the Blind. Children younger than age 16 were invited to participate. A detailed history and examination were performed consistent with the World Health Organization Prevention of Blindness Eye Examination Record.

RESULTS

Of the 53 children examined in both studies, 30 were from Bhutan and 23 were from Laos. Forty percent of Bhutanese and 87.1% of Laotian children assessed were blind, with 26.7% and 4.3%, respectively, being severely visually impaired. Congenital causes of blindness were the most common, representing 45% and 43.5% of the Bhutanese and Laotian children, respectively. Anatomically, the primary site of blinding pathology differed between the cohorts. In Bhutan, the lens comprised 25%, with whole globe at 20% and retina at 15%, but in Laos, whole globe and cornea equally contributed at 30.4%, followed by retina at 17.4%. There was an observable difference in the rates of blindness/severe visual impairment due to measles, with no cases observed in the Bhutanese children but 20.7% of the total pathologies in the Laotian children attributable to congenital measles infection.

CONCLUSIONS

Consistent with other studies, there is a high rate of blinding disease, which may be prevented, treated, or ameliorated.

Causes of visual impairment in children seen at a university-based hospital low vision service in Brazil

PURPOSE

To evaluate the epidemiologic characteristics of patients 0-7 years of age with visual impairment registered at a university hospital low vision service in Brazil.

METHODS

The medical records of visually impaired patients were retrospectively reviewed for sociodemographic characteristics and ocular and associated deficiencies. In addition to biographical information, the following data were collected: ocular disorders, diagnosis, affected anatomic region, etiology, and avoidable or unavoidable causes.

RESULTS

A total of 229 patients were included, 65% of whom were referred from rural health centers. The mean age at first appointment was 39.4 months. Associated nonophthalmic disorders were present in 47% of patients. The most prevalent disorders were congenital cataract (14%), toxoplasmosis (14%), and congenital glaucoma (13%). The most commonly affected anatomic regions were the retina (18%) and lens (15%); 33% had a normal-appearing globe. Using World Health Organization classifications, the most prevalent underlying etiologies were undetermined (43%), perinatal/neonatal factors (22%), and intrauterine factors (20%). Avoidable causes were found in 64% of the children.

CONCLUSIONS

The three leading causes of infant blindness in our patient cohort were congenital cataract, toxoplasmosis, and congenital glaucoma. The most commonly affected anatomic regions were retina, lens, and normal-appearing globe. The percentage of avoidable causes of impairment was high and the mean age at first appointment was late.

An update on progress and the changing epidemiology of causes of childhood blindness worldwide

PURPOSE

To summarize the available data on pediatric blinding disease worldwide and to present current information on childhood blindness in the United States.

METHODS

A systematic search of world literature published since 1999 was conducted. Data also were solicited from each state school for the blind in the United States.

RESULTS

In developing countries, 7% to 31% of childhood blindness and visual impairment is avoidable, 10% to 58% is treatable, and 3% to 28% is preventable. Corneal opacification is the leading cause of blindness in Africa, but the rate has decreased significantly from 56% in 1999 to 28% in 2012. There is no national registry of the blind in the United States, and most schools for the blind do not maintain data regarding the cause of blindness in their students. From those schools that do have such information, the top three causes are cortical visual impairment, optic nerve hypoplasia, and retinopathy of prematurity, which have not changed in past 10 years.

CONCLUSIONS

There are marked regional differences in the causes of blindness in children, apparently based on socioeconomic factors that limit prevention and treatment schemes. In the United States, the 3 leading causes of childhood blindness appear to be cortical visual impairment, optic nerve hypoplasia, and retinopathy of prematurity; a national registry of the blind would allow accumulation of more complete and reliable data for accurate determination of the prevalence of each.

A survey of severe visual impairment in children attending schools for the blind in a coastal district of Andhra Pradesh in South India

PURPOSE

To identify the major causes of severe childhood visual impairment and blindness among students attending schools for the blind in a coastal district of Andhra Pradesh (AP) in South India.

METHODS

Children ≤ 16 years of age attending six schools for the blind in the study area were interviewed and examined in the year 2009, and causes were classified according to the World Health Organization Program for Prevention of Blindness (WHO/PBL) childhood blindness proforma. A total of 113 children underwent a detailed eye examination by an experienced ophthalmologist.

RESULTS

The major causes of blindness were congenital eye anomalies in 46 children (41.4; 95% confidence interval (CI): 32.3-50.6), followed by retinal disorders in 21 children (18.9%; 95% CI: 11.6-26.2), cataract in 9 children (9.7%; 95% CI: 2.9-12.9), and corneal conditions (scar and Staphyloma) in 8 children (7.1%; 95% CI: 2.4-11.8). More than half the children (56.6%) were blind due to conditions that could have been treated or prevented.

DISCUSSION

Congenital anomalies were found to be the most common cause of blindness. The majority of the cases were due to avoidable causes of blindness. Therefore, robust screening measures may help reduce the burden of visual impairment in children.

Prevalence and causes of blindness in children in Vietnam

OBJECTIVE

To estimate the prevalence of blindness in children in Vietnam and to assess the major causes.

DESIGN

A population-based study sampled children from 16 provinces across Vietnam. The second study examined children attending all blind schools in Vietnam.

PARTICIPANTS

In 16 provinces, 28 800 children aged 0-15 were sampled. In 28 blind schools, 569 children aged 0-15 were examined.

INTERVENTION

In children not seeing well according to the parents, presenting visual acuity (PVA) was assessed. If PVA was <3/60 in one or both eyes, the child was examined by an ophthalmologist. All children in blind schools were examined by a pediatric ophthalmologist.

MAIN OUTCOME MEASURES

Blindness was defined as PVA <3/60 in the better eye. Causes of visual loss were classified using the World Health Organization classification.

RESULTS

In the population-based study, 22 children had a PVA <3/60 in the better eye, a prevalence of 7.6/10 000 children (95% confidence interval [CI], 4.9-11.8/10 000). Fourteen children had a pinhole visual acuity <3/60 in the better eye, a prevalence of 4.9/10 000 (95% CI, 2.8-8.4/10 000). An estimated 16 400 (95% CI, 10 500-25 300), children were blind from all causes, with 36.4% from uncorrected refractive errors. In the blind schools, 411 children had a PVA <3/60 in the better eye and 55.5% were male. Conditions of the retina (24.6%) and cornea (24.0%) predominated. Retinopathy of prematurity (ROP) caused blindness in 32.6% of children younger than 10 years, but in only 6% of older children. The converse was true for corneal scarring and phthisis (14.0% and 27.3%, respectively). All other causes were similar between age groups (53.5% and 66.7%, respectively). More than half of all causes were avoidable.

CONCLUSIONS

Vietnam is developing very rapidly, and this is impacting health indices. The mortality rate of those younger than 5 years declined from 65/100 live births in 1980 to 14/100 in 2008. The findings of this study show these changes, because the childhood blindness prevalence was relatively low, and the causes show improved control of measles and vitamin A deficiency, as well as increased services for premature babies. Eye care services for children should now focus on refractive errors, cataract, and control of ROP.

Prevalence and causes of blindness at a tertiary hospital in Douala, Cameroon

PURPOSE

The aim of this study was to determine the prevalence and causes of bilateral and unilateral blindness in the town of Douala and its environs based on data from the ophthalmic unit of a tertiary hospital in Douala.

METHODS

We conducted a retrospective epidemiological survey of consultations at the eye unit of the Douala General Hospital over the last 20 years (from January 1, 1990 to December 31, 2009).

RESULTS

Out of the 1927 cases of blindness, 1000 were unilateral, corresponding to a hospital prevalence of 1.84% and 927 cases were bilateral, corresponding to a hospital prevalence of 1.71%. No statistically significant difference was noted between the two (P = 0.14). The leading causes of bilateral blindness were cataract (50.1%), glaucoma (19.7%), and diabetic retinopathy (7.8%) while the leading causes of unilateral blindness were cataract (40.4%), glaucoma (14.1%), and retinal detachment (9.1%). Cataract (51.2%), cortical blindness (16.3%), and congenital glaucoma (10%) were the leading causes of bilateral blindness in children aged less than 10 years.

CONCLUSION

Blindness remains a public health problem in the Douala region with a hospital prevalence which is relatively higher than the national estimate given by the National Blindness Control Program.

A survey of visual impairment and blindness in children attending four schools for the blind in Cambodia

PURPOSE

To identify the causes of blindness and severe visual impairment (BL/SVI) in children attending four schools for the blind in Cambodia and to provide spectacles, low vision aids, orientation and mobility training and ophthalmic treatment.

METHODS

Children < 16 years of age were recruited from all 4 schools for the blind in Cambodia. Causes of visual impairment and blindness were determined and categorized using World Health Organization methods.

RESULTS

Of the 95 children examined, 54.7% were blind (BL) and 10.5% were severely visually impaired (SVI). The major anatomical site of BL/SVI was the lens in 27.4%, cornea in 25.8%, retina in 21% and whole globe in 17.7%. The major underlying etiologies of BL/SVI were hereditary factors (mainly cataract and retinal dystrophies) in 45.2%, undetermined/unknown (mainly microphthalmia and anterior segment dysgenesis) in 38.7% and childhood factors in 11.3%. Avoidable causes of BL/SVI accounted for 50% of the cases; 12.9% of the total were preventable with measles being the commonest cause (8.1% of the total); 37.1% were treatable with cataracts and glaucoma being the commonest causes (22.6% and 4.8% respectively). More than 35% of children required an optical device and 27.4% had potential for visual improvement with intervention.

CONCLUSION

Half of the BL/SVI causes were potentially avoidable. The data support the need for increased coverage of measles immunization. There is also a need to develop specialized pediatric ophthalmic services for the management of surgically remediable conditions, to provide optometric, low vision and orientation and mobility services. Genetic risk counseling services also may be considered.

A population-based study of visual impairment among pre-school children in Beijing: the Beijing study of visual impairment in children

PURPOSE

To evaluate the prevalence and causes of visual impairment among Chinese children aged 3 to 6 years in Beijing.

DESIGN

Population-based prevalence survey.

METHODS

Presenting and pinhole visual acuity were tested using picture optotypes or, in children with pinhole vision < 6/18, a Snellen tumbling E chart. Comprehensive eye examinations and cycloplegic refraction were carried out for children with pinhole vision < 6/18 in the better-seeing eye.

RESULTS

All examinations were completed on 17,699 children aged 3 to 6 years (95.3% of sample). Subjects with bilateral correctable low vision (presenting vision < 6/18 correctable to >or= 6/18) numbered 57 (0.322%; 95% confidence interval [CI], 0.237% to 0.403%), while 14 (0.079%; 95% CI, 0.038% to 0.120%) had bilateral uncorrectable low vision (best-corrected vision of < 6/18 and >or= 3/60), and 5 subjects (0.028%; 95% CI, 0.004% to 0.054%) were bilaterally blind (best-corrected acuity < 3/60). The etiology of 76 cases of visual impairment included: refractive error in 57 children (75%), hereditary factors (microphthalmos, congenital cataract, congenital motor nystagmus, albinism, and optic nerve disease) in 13 children (17.1 %), amblyopia in 3 children (3.95%), and cortical blindness in 1 child (1.3%). The cause of visual impairment could not be established in 2 (2.63%) children. The prevalence of visual impairment did not differ by gender, but correctable low vision was significantly (P < .0001) more common among urban as compared with rural children.

CONCLUSION

The leading causes of visual impairment among Chinese preschool-aged children are refractive error and hereditary eye diseases. A higher prevalence of refractive error is already present among urban as compared with rural children in this preschool population.

Babies Count: the national registry for children with visual impairments, birth to 3 years

INTRODUCTION

Information about the prevalence of visual impairment in children is not collected systematically. Further, little information is available about children under age 6. Babies Count is a national registry of children with visual impairment in the United States, aged birth to 3 years.

METHODS

Data were collected on 2,155 children at the point of entry into specialized early intervention programs. Data include patient diagnosis, functional vision, age, gender, ethnicity, and family characteristics. Concurrent visual pathology and systemic disabilities were also documented.

RESULTS

Of the sample of 2,155 children, 1,167 (54%) were boys; approximately 40% of the children were legally blind, and 68% had disabilities in addition to visual impairment. Cortical visual impairment, retinopathy of prematurity (ROP), and optic nerve hypoplasia (ONH) were the three most prevalent visual conditions. In children with these three conditions, those with ROP were diagnosed the earliest (mean, 3.4 months), and those with cortical visual impairment were diagnosed latest (mean, 7.6 months). There was on average a 4.5 month mean lag between the diagnosis of children's visual impairment and referral for services. ONH carried a poorer visual outcome when compared with other diagnoses, including CVI, ROP, and albinism.

CONCLUSIONS

Prevalent visual conditions in children in the United States differ from those found in developing countries and in adults with visual impairment. Babies Count is a comprehensive set of data that may affect our understanding of the epidemiology of visual impairment in the United States. In an era of preventive and outcome-based medicine, and with competition for health care and research funding, these data provide a valuable means for understanding the impact of these disorders on society.

The key informant method: a novel means of ascertaining blind children in Bangladesh

BACKGROUND

Most information on the causes of blindness has come from examining children in special education. To obtain a more representative population-based sample of children, a novel method was developed for ascertaining severe visually impaired (SVI) or blind (BL) children by training local volunteers to act as key informants (KIs).

OBJECTIVE

To compare the demography and cause of blindness in children recruited by KIs with other ascertainment methods.

METHOD

Children with SVI/BL were recruited in all 64 districts of Bangladesh. Three sources for case ascertainment were utilised: schools for the blind (SpEdu), community-based rehabilitation (CBR) programmes and KIs. All data were recorded using the standard WHO/PBL Eye Examination Record.

RESULTS

1935 children were recruited. Approximately 800 KIs were trained. The majority of the children were recruited by the KIs (64.3%). Children recruited by KIs were more likely to be female (odds ratio (OR) 1.6, p<0.001), of pre-school age (OR 14.1, p<0.001), from rural areas (OR 5.9, p<0.001), be multiply impaired (OR 3.1, p = 0.005) and be suffering from treatable eye diseases (OR 1.3, p = 0.005) when compared with those in SpEdu. Overall a child with an avoidable causes of SVI/BL had 40% (adjusted CI 1.1 to 1.7, p = 0.015) and 30% (CI 1.0 to 1.7, p = 0.033) higher odds of being ascertained using the KIs compared with SpEdu and CBR methods, respectively.

CONCLUSION

Using this innovative approach has resulted in one of the largest studies of SVI/BL children to date. The findings indicate that KIs can recruit large numbers of children quickly, and that the children they recruit are more likely to be representative of all blind children in the community.

Causes of severe visual impairment and blindness in Bangladesh: a study of 1935 children

OBJECTIVE

To identify the anatomical site and underlying aetiology of severe visual impairment and blindness (SVI/BL) in children in Bangladesh.

DESIGN

A national case series.

METHODS

Children were recruited from all 64 districts in Bangladesh through multiple sources. Causes were determined and categorised using standard World Health Organization methods.

RESULTS

1935 SVI/BL children were recruited. The median age was 132 months, and boys accounted for 63.1% of the sample. The main site of abnormality was lens (32.5%), mainly unoperated cataract, followed by corneal pathology (26.6%) and disorders of the whole eye (13.1%). Lens-related blindness was the leading cause in boys (37.0%) compared with corneal blindness in girls (29.8%). In 593 children, visual loss was due to childhood factors, over 75% being attributed to vitamin A deficiency. Overall 1338 children (69.2%) had avoidable causes. Only 2% of the country's estimated SVI/BL children have access to education and rehabilitation services.

CONCLUSIONS

This is the first large-scale study of SVI/BL children in Bangladesh over two-thirds of whom had avoidable causes. Strategies for control are discussed.

Changing pattern of childhood blindness in Maharashtra, India

AIM

To determine the causes of severe visual impairment and blindness in children in schools for the blind in Maharashtra, India.

METHODS

Children aged <16 years with a visual acuity of <6/60 in the better eye, attending 35 schools for the blind were examined between 2002 and 2005, and causes were classified using the World Health Organization's system.

RESULTS

1985 students were examined, 1778 of whom fulfilled the eligibility criteria. The major causes of visual loss were congenital anomalies (microphthalmos or anophthalmos; 735, 41.3%), corneal conditions (mainly scarring; 395, 22.2%), cataract or aphakia (n = 107, 6%), and retinal disorders (mainly dystrophies; n = 199, 11.2%). More than one third of children (34.5%) were blind from conditions which could have been prevented or treated, 139 of whom were referred for surgery. Low vision devices improved near-acuity in 79 (4.4%) children, and 72 (4%) benefited from refraction. No variation in causes by sex or region was observed.

CONCLUSIONS

Congenital anomalies accounted for 41% of blindness, which is higher than in a similar study conducted 10 years ago. Corneal scarring seems to be declining in importance, low vision and optical services need to be improved, and research is needed to determine the aetiology of congenital anomalies.

Characteristics of infants with severe retinopathy of prematurity in countries with low, moderate, and high levels of development: implications for screening programs

OBJECTIVE

Retinopathy of prematurity (ROP) is a potentially avoidable cause of blindness in children. The proportion of blindness as a result of ROP varies greatly among countries depending on their level of development, being influenced by the availability of neonatal care, neonatal outcomes, and whether effective screening and treatment programs are in place. The objective of this study was to compare characteristics of premature infants who developed severe ROP between 1996 and 2002 in highly developed countries with less developed countries.

METHODS

This was an observational study. A questionnaire was completed by ophthalmologists in countries with low, moderate, and high development rankings (3 highly developed countries and from 10 less well-developed countries) who screen for ROP in which they supplied birth weights and gestational ages (GAs) of infants who were treated for threshold ROP or identified with more advanced stages of the disease. Birth weights and GAs of infants with severe ROP were measured.

RESULTS

The mean birth weights of infants from highly developed countries ranged from 737 to 763 g compared with values ranging from 903 to 1527 g in less developed countries. Mean GAs of infants from highly developed countries ranged from 25.3 to 25.6 weeks compared with 26.3 to 33.5 weeks in less developed countries. A total of 13.0% of 1091 infants from poorly developed countries exceeded United Kingdom screening criteria; 3.6% exceeded a criteria of <34 weeks' GA and/or <1750 g birth weight.

CONCLUSIONS

These findings suggest that larger, more mature infants are developing severe ROP in countries with low/moderate levels of development compared with highly developed countries. ROP screening programs need to use criteria that are appropriate for their local population.