A Survey of Severe Visual Impairment and Blindness in Children Attending Thirteen Schools for the Blind in Sri Lanka

Causes of Moderate to Severe Visual Impairment and Blindness Among Children in Integrated Schools for the Blind and Visiting a Tertiary Eye Hospital in Nepal: The Nepal Pediatric Visual Impairment (NPVI) Study

Purpose

To study the causes of moderate and severe visual impairment (VI) and blindness and its changing trends in Nepalese children.

Patients and Methods

A cross-sectional descriptive study was conducted. Participants, aged 7 to 17 years were recruited from integrated schools for the blind and the outpatient department of a tertiary eye hospital in Kathmandu. VI and blindness were categorized according to World Health Organization (WHO) categories and its protocol for eye examination of children with blindness and VI was followed. Findings were compared to former studies from Nepal.

Results

A total of 200 children were included, of whom 45% had moderate VI, 5% had severe VI, and 50% were blind. Mean age of children with VI and blindness was 11.1 (SD = 3.3) and 12.9 (SD = 3) years, respectively. Forty percent of children with VI and 38% of blind children were female. In our study, retina (39%) and whole globe (32%) were the most common anatomical site of involvement in children with VI and blindness, respectively, while cornea was the most common anatomical site of involvement in former studies. Heredity (43%) was the most common etiological factor although in 24.5% of all children, etiology was unknown. In 43.5% of children, blindness and VI was due to avoidable causes.

Conclusion

In relatively many children, the etiology of VI and blindness could be either prevented or treated. Compared to former studies from Nepal, there is a changing trend in the etiology of severe VI and blindness.

Causes of low vision in children: A systematic review

OBJECTIVE

To identify the ocular pathologies that are reported as causes of low vision in children.

MATERIAL AND METHODS

The systematic search was carried out in Medline (PubMed), Embase and Lilacs. Observational studies with populations between 0-18 years of age, reporting visual acuity data between 20/60-20/400 and reporting the frequency of ocular pathologies were selected. Studies in which the diagnosis of the condition had not been verified by a professional, or which covered only cases of blindness, uncorrected refractive errors, or amblyopia, were excluded. The methodological quality of the articles was evaluated using the Joanna Briggs Institute instrument for prevalence studies.

RESULTS

27 studies conducted in Asia (13 publications), Africa (6 studies), Oceania (4 studies), Europe and South America (2 studies each) were included. The most reported causes of low vision were: cataract, with prevalence between 0.8% and 27.2%; albinism with from 1.1% to 47%; nystagmus, with prevalence between 1.3% and 22%; retinal dystrophies between 3.5% and 50%; retinopathy of prematurity (ROP) with prevalence between 1.1% and 65.8%, optic atrophy between 0.2% and 17.6%, and glaucoma from 2.4% to 18.1%.

CONCLUSIONS

Cataract, albinism and nystagmus are the ocular pathologies most mentioned by studies as a cause of low vision in children, as well as retinal diseases such as ROP and optic nerve diseases such as atrophy. However, there are numerous eye conditions that can result in low vision in the pediatric population.

Inherited retinal diseases are the most common cause of blindness in the working-age population in Australia

Background: This study examined the frequency of inherited retinal diseases (IRDs) as the reason for blindness registrations over the last two decades and the demographic and clinical phenotypes of inherited retinal disease (IRD)-related registrations.

Materials and methods: Retrospective, observational study of individuals registered with a state-wide blind and vision-impaired registry. Low-vision or blindness-only (≤20/200 or ≤20°) certificates issued to children (0-15 years), working-age (16-64 years) and older-age (65 and older) adults were assessed. Sex and age distributions were examined for the top 20 reasons for certification. Demographic and clinical features of specific phenotypes of IRDs listed in the registry were examined.

Results: Amongst 11824 low-vision certificates issued between July 1995 and January 2017, 679 (5.7%) listed an IRD as the reason for registration. In individuals with blindness-only certification (N=4919), IRDs was the second most common diagnosis (8.3%), overtaking glaucoma (8.1%) and diabetic retinopathy (5.4%). IRD was the second most common reason for low-vision certification amongst children (11.6%) and the most common reason amongst working-age population (23.3%). The mean±SD age for IRD-related blindness-only certification was 46±20 years. The top three phenotypes of IRD-related low-vision certification were non-syndromic retinitis pigmentosa (54%), Stargardt disease (12%) and macular dystrophy (8%).

Conclusion: Our findings of IRDs as a common cause of blindness in all ages justify continued funding for providing low-vision services and developing treatments for these conditions.

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

BACKGROUND

Pediatric 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.

METHODS

We 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.

RESULTS

We 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.

CONCLUSION

This 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.

Magnitude and Temporal Trends in Avoidable Blindness in Children (ABC) in India

The World Health Organization estimates that 19 million children are visually impaired, among whom, 1.4 million are blind. Childhood blindness is an excellent indicator of the state of child health and primary care services in a country. Childhood blindness is important not just due to the number of children blind but also because the number of years that the surviving child has to live with blindness (blind years lived). Childhood blindness is next only to adult cataract in terms of the number of blind person years lived. Under-five mortality rates have been used as a proxy measure to compute the prevalence of childhood blindness in low and middle income countries due to limitations of other methods of data collection. In India, it is estimated that there are 0.8 blind for 1000 children. Whole globe lesions, corneal scarring, retinal pathology and afflictions of the lens are important anatomical sites in children. Causes operating in childhood and hereditary causes are important in etiology of childhood blindness. In 38.2%-68.4% cases across the region, a specific cause of blindness could not be identified in South Asia. The proportion of blindness that can be prevented or treated (avoidable) in children is less than 50%. Therefore a comprehensive eye care system needs to be in place to cater to the needs of children with avoidable and those with incurable blindness. Early detection and prompt management are critical for success of programs targeting avoidable blindness in children.

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.

Perspective on ophthalmic support in countries of the developing world

There are over 300 million people living in the world today who are visually impaired and a further 45 million who are blind. The large majority (90%) of these people live in developing countries, and up to 75% of blindness are avoidable. With cataracts being the major cause of blindness and visual impairment, many ophthalmic aid programmes are aimed at alleviating the enormous burden caused by this readily treatable disease. Having said that, caution should be exercised that short surgical visits to remote rural areas that are not coordinated with local national eye care managers should be discouraged because they do little for the development of sustainable eye care programmes. With this in view, it has become imperative to design blindness prevention and ophthalmic support programmes that are workable, comprehensive, economical and sustainable.

The trend of retinopathy of prematurity in Malaysia from 1992 to 2001 based on a nationwide blind schools study

Retinopathy of prematurity (ROP) is one of the most important causes of childhood blindness worldwide. The trend of ROP in Malaysia was unclear because there was no national registry before 2002. The purpose of this study is to analyze ROP students of different ages in the schools for the blind in Malaysia in order to evaluate the trend of ROP from 1992 to 2001. Data were obtained from a previous survey of 24 blind schools. It was found that 78 students or 17.4% were blind/severely visual impaired as a result of ROP. There was a significant surge in the number of ROP students who were born in 1994 when the use of synthetic surfactants was first introduced in Malaysia; otherwise there was no increasing trend in the number of students with ROP. However, the percentage of ROP in total was increasing, which indicates that ROP is becoming a more important cause of childhood blindness in this country.