Causes of Severe Visual Impairment and Blindness

Farmer, Lachlan; Ng, Soo Khai; Rudkin, Adam K; Craig, Jamie E; Wangmo, Dechen; Tsang, Hughie; Southisombath, Khamphoua; Griffiths, Andrew; Muecke, James

doi:10.1097/apo.0000000000000152

Cited by 10 publications

(5 citation statements)

References 21 publications

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“…Additionally, the number of children blind due to lenticular (17 vs 11 students) and retinal causes (13 vs 11 students) was not signi cantly different between 2009 and 2021, respectively. Compared to neighbouring countries, the distribution of causes of eye disease in Cambodian children appears to be similar to those reported in Laos (11) and provincial towns in the Philippines (12) while there is a greater proportion of corneal causes of blindness than that seen in Malaysia (13), Mongolia (14) or Sri Lanka (15).…”

Section: Discussionsupporting

confidence: 67%

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

Rogerson

Ath

Ning

et al. 2023

Preprint

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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 prevalences of the causes of childhood blindness at schools for the blind in Cambodia. Methods: Students between the ages of 5 and 16years 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 76 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% for both). 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 a 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.

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Section: Discussionsupporting

confidence: 67%

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

Rogerson

Ath

Ning

et al. 2023

Preprint

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“…We found the highest rate of causative mutations in Bhutan (two of five probands). The audit also reported no cases of measles/ rubella induced vision loss in the Bhutanese school children (Farmer et al, 2015). It remains to be determined how many of the probands with no detected mutations in this panel of genes have genetic forms of cataract and how many may be accounted for by environmental causes.…”

Section: Discussionmentioning

confidence: 97%

“…Children under 16 years of age attending blind schools in Bhutan (Farmer et al, 2015), Cambodia (Sia et al, 2010), and Sri Lanka (Gao et al, 2011) underwent an ocular examination and review of records as part of audits of the causes of childhood blindness in each community as described previously (Farmer et al, 2015;Gao et al, 2011;Sia et al, 2010). While all children were examined at the time of recruitment, it was not possible to access historical medical records to determine age of onset, or to interview the family for a detailed history.…”

Section: Participant Selectionmentioning

confidence: 99%

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Identification of novel mutations causing pediatric cataract in Bhutan, Cambodia, and Sri Lanka

Javadiyan

Lucas

Wangmo

et al. 2018

Molec Gen & Gen Med

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BackgroundPediatric cataract is an important cause of blindness and visual impairment in children. A large proportion of pediatric cataracts are inherited, and many genes have been described for this heterogeneous Mendelian disease. Surveys of schools for the blind in Bhutan, Cambodia, and Sri Lanka have identified many children with this condition and we aimed to identify the genetic causes of inherited cataract in these populations.MethodsWe screened, in parallel, 51 causative genes for inherited cataracts in 33 probands by Ampliseq enrichment and sequencing on an Ion Torrent PGM. Rare novel protein coding variants were assessed for segregation in family members, where possible, by Sanger sequencing.ResultsWe identified 24 rare (frequency <1% in public databases) or novel protein coding variants in 12 probands and confirmed segregation of variants with disease in the extended family where possible. Of these, six are predicted to be the cause of disease in the patient, with four other variants also highly likely to be pathogenic.ConclusionThis study found that 20%–30% of patients in these countries have a mutation in a known cataract causing gene, which is considerably lower than the 60%–70% reported in Caucasian cohorts. This suggests that additional cataract genes remain to be discovered in this cohort of Asian pediatric cataract patients.

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“…Other recent childhood blindness studies performed in Asia have also found whole globe anomalies to be the main cause of blindness including India (25%),[ 9 ] Lao (30.4%),[ 10 ] and Bhutan (20%). [ 10 ] Corneal opacities, however, still remains the most common site of abnormality in sub-Saharan Africa and areas of extreme deprivation. [ 2 11 12 13 ]…”

Section: Discussionmentioning

confidence: 99%

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

Huang

Sun

Mallipatna

et al. 2021

Indian Journal of Ophthalmology

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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.

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Causes of Severe Visual Impairment and Blindness

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

Cited by 10 publications

References 21 publications

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

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

Identification of novel mutations causing pediatric cataract in Bhutan, Cambodia, and Sri Lanka

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

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