Preventable Childhood Blindness Research Articles

Early light reduction for preventing retinopathy of prematurity in very low birth weight infants.

Retinopathy of prematurity (ROP) is a complex condition of the developing retinal blood vessels and is one of the leading causes of preventable childhood blindness. Several risk factors for ROP have been studied over the past 50 years. Among them, general immaturity (low birth weight and low gestational age) and prolonged oxygen therapy have been consistently related to disease onset. However, it is understood that the progression of the disease is multifactorial and may be associated with others risk factors, such as multiple gestation, apnoea, intracranial haemorrhage, anaemia, sepsis, prolonged mechanical ventilation, multiple transfusions and light exposure. Furthermore, the precise role of these individual factors in the development of the disease has not yet been well established. To determine whether the reduction of early environmental light exposure reduces the incidence of retinopathy of prematurity (ROP) or poor ROP outcomes among very low birth weight infants. We searched the following databases: the Cochrane Neonatal Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE, EMBASE, CINAHL, HealthSTAR, Science Citation Index Database, CANCERLIT, the Oxford Database of Perinatal Trials and www.clinicaltrials.gov. We also searched previous reviews including cross-references, abstracts, conference and symposia proceedings, and contacted expert informants. This search was updated in October 2012. Randomised or quasi-randomised controlled trials that reduced light exposure to premature infants within the first seven days following birth were considered for this review. We also considered cluster-randomised controlled trials. Data on clinical outcomes including any acute ROP and poor ROP outcome were extracted by both review authors independently and consensus reached. We conducted data analysis according to the standards of the Cochrane Neonatal Review Group. Data from four randomised trials with a total of 897 participants failed to show any reduction in acute ROP or poor ROP outcome with the reduction of ambient light to premature infants' retinas. The overall methodological quality of the included studies was about evenly split between those in which the classification was unclear and those in which the studies were categorised as low risk of bias. There was no report on the secondary outcomes considered in this review: quality of life measures; and time of exposure to oxygen. The evidence shows that bright light is not the cause of retinopathy of prematurity and that the reduction of exposure of the retinas of premature infants to light has no effect on the incidence of the disease.

Treatment of retinopathy of prematurity: a review of conventional and promising new therapeutic options.

Retinopathy of prematurity (ROP), a retinal vascular disease of premature infants, continues to be a major cause of preventable childhood blindness all over the world. The incidence of ROP varies among countries, being influenced by the quality of the level of neonatal intensive care. Here, we discuss the potential treatments that are now available or will soon or probably be available for ROP. Although ablation of the avascular retina with laser photocoagulation remains the current gold standard and well established therapy for ROP, some new therapeutic options including angiostatic therapies are being explored based on our knowledge of the pathophysiology of the ROP and complications and efficacy of laser treatment. However, prevention of the development of severe ROP and screening for ROP seem to be the best strategy in avoiding visual impairment caused by ROP in premature infants. New therapeutic interventions including vascular endothelial growth factor antibody administration, gene therapy and supplemental therapies should be supported with evidence-based data for the treatment of ROP.

Epidemiological Survey of Paediatric Ocular Morbidity in North Central Nigeria

This study was aimed at determining the spectrum of childhood ocular problems presenting to the Eye Unit of Federal Medical Centre Makurdi, Benue State over a 6-year period. This data is highly needed for effective planning of pediatric eye care services for the prevention of childhood blindness. The study was a retrospective study in which the case notes of all consecutive patients that were 16 years old and below were reviewed. Demographic data, clinical diagnosis, visual acuity where feasible and modality of treatment received were retrieved and analyzed using SPSS version 15. Eight hundred and sixty-five (865) cases constituting 22.4% of the total number 3862 of both adults and children that attended the Hospital in the study period were obtained. Age ranged from five days to 15 years eight months. Mean age 8.6 ± 1.6 years. A total of 519 (60.0%) were males and 346 (40.0%) females. Vernal disease was the commonest ocular morbidity seen constituting 349 cases (40.3%), ocular trauma 152 (17.6%), infective conjunctivitis 106 (12.3%) and refractive errors 89 (10.2%). The location of industries (rice mills, sawmills, cement factory) away from residential areas, availability of antiallergic drugs must be ensured; strategy to prevent ocular trauma must be put in place. Health education to discourage usage of traditional eye medication in trivial ocular trauma and mild infection must be discouraged and school screening for early detection / correction of refractive errors should be embarked on. Key words: pediatric, vernal disease, ocular trauma, conjunctivitis

Progress in blindness prevention in North Sudan (2003-2010)

Objectives: (1) To review progress in the prevention of blindness in Sudan compared to Vision 2020 targets. (2) To show gaps and shortfalls. Materials and Methods: Reports of national Vision 2020 program covering the period 2003-2010 are reviewed, including data generated from six RAAB surveys conducted in 2009-2010. Results: Prevalence of blindness is 1% compared to 1.5% in 2003. Cataract surgical out-put, cataract surgical rate (CSR), and IOL implantation rate increased steadily. It is estimated that 70% of the population are covered with refractive errors services. Low vision services are provided by four centers. Trachoma mapping completed for Northern Sudan except Darfur. SAFE strategy is implemented. Prevalence of childhood blindness is not known. Two centers provide specialized pediatric eye services. There is community-directed treatment with Ivermectin (CDTI) in 3 out the 4 onchocerciasis foci. Ophthalmologists tripled in number. Optometists exceeded 1000, compared to less than 500 in 2003. Secondary and tertiary level facilities increased in major cities. There is no primary eye-care program. Conclusion: Northern Sudan shows good progress in most of the components of Vision 2020, namely cataract, trachoma, onchocerciasis, refractive errors, and low vision. However, scaling up and attention to diabetic retinopathy and glaucoma are still needed to reach all the targets by the year 2020.

Maternal risk factors for neonatal conjunctivitis in Aminu Kano Teaching Hospital, Kano, Nigeria

Background: Neonatal conjunctivitis remains a major cause of preventable childhood blindness in developing countries. There are maternal risk factors, which if identified can assist in its prevention. Objective: This study attempts to determine the maternal risk factors for the development of neonatal conjunctivitis among babies seen in a tertiary health facility in Kano, Nigeria. Materials and Methods: This was a cross-sectional study. Neonates from special care baby unit, postnatal ward, paediatric out-patient unit and labour room who had bilateral or unilateral eye discharge were enrolled in the study. Those neonates whose parents refused consent were excluded from the study. The questionnaire sorted for information including patients' biodata, place and mode of delivery, age at onset of eye discharge, mothers' biodata, antenatal care attendance, educational and socioeconomic status and obstetrics history. Samples were collected and Gram staining was conducted using standard technique. Chlamydial antigens were detected using a rapid immunochromatographic technique (ICT). The data were analysed using EPI INFO version 3.5.1 2002. Proportions were compared using Chi-square test of significance. A probability ( P - value) of less than 0.05 was considered statistically significant. Results: A total of 175 neonates were studied. The mean age was 5.7 ± 4.6 days with a male:female ratio of 1.1:1. Low level of maternal education, lack of antenatal care attendance, prolonged rupture of amniotic membranes and low socioeconomic status were significantly associated with isolate positive neonatal conjunctivitis. Conclusion: Maternal factors including lack of antenatal care attendance and poor socioeconomic conditions are significantly associated with isolate positive neonatal conjunctivitis.

Validation of the effects of molecular marker polymorphisms in LcyE and CrtRB1 on provitamin A concentrations for 26 tropical maize populations

Vitamin A deficiency (VAD) compromises immune function and is the leading cause of preventable blindness in children in many developing countries. Biofortification, or breeding staple food crops that are rich in micronutrients, provides a sustainable way to fight VAD and other micronutrient malnutrition problems. Polymorphisms, with associated molecular markers, have recently been identified for two loci, LcyE (lycopene epsilon cyclase) and CrtRB1 (β-carotene hydroxylase 1) that govern critical steps in the carotenoid biosynthetic pathway in maize endosperm, thereby enabling the opportunity to integrate marker-assisted selection (MAS) into carotenoid breeding programs. We validated the effects of 3 polymorphisms (LcyE5′TE, LcyE3′Indel and CrtRB1-3′TE) in 26 diverse tropical genetic backgrounds. CrtRB1-3′TE had a two-ten fold effect on enhancing beta-carotene (BC) and total provitamin A (proA) content. Reduced-function, favorable polymorphisms within LcyE resulted in 0–30 % reduction in the ratio of alpha- to beta-branch carotenoids, and increase in proA content (sometimes statistically significant). CrtRB1-3′TE had large, significant effect on enhancing BC and total ProA content, irrespective of genetic constitution for LcyE5′TE. Genotypes with homozygous favorable CrtRB1-3′TE alleles had much less zeaxanthin and an average of 25 % less total carotenoid than other genotypes, suggesting that feedback inhibition may be reducing the total flux into the carotenoid pathway. Because this feedback inhibition was most pronounced in the homozygous favorable LcyE (reduced-function) genotypes, and because maximum total proA concentrations were achieved in genotypes with homozygous unfavorable or heterozygous LcyE, we recommend not selecting for both reduced-function genes in breeding programs. LcyE exhibited significant segregation distortion (SD) in all the eight, while CrtRB1 in five of eight digenic populations studied, with favorable alleles of both the genes frequently under-represented. MAS using markers reported herein can efficiently increase proA carotenoid concentration in maize.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-012-1987-3) contains supplementary material, which is available to authorized users.

A study on awareness about eye health care and eye donation among secondary level students of North Kolkata, India

Corneal blindness is one of the important types of blindness that can be prevented by proper health care education and conventionally cured by corneal transplantation for which awareness regarding eye donation is essential. The aim of the study is to assess the awareness of eye health care and eye donation among secondary level school students of North Kolkata. It was a cross-sectional study. Eight Government aided schools of North Kolkata, West Bengal, India. A total of 1525 students of standard VIII, IX and X of Government aided schools of North Kolkata participated in this study. A pre-tested, semi-structured questionnaire was administered on eye health care and eye donation. 1284 (84.2%) participants opined that awareness on eye health care can prevent most of the blindness and 1206 (79.1%) students knew that Vitamin A has important role in prevention of childhood blindness. Majority, 1235 (81.0%) students were aware of eye donation after death while only 489 (32.1%) participants knew that the ideal time for eye donation is within 6 hours of death. 802 (52.6%) participants mentioned printed and electronic media (like newspaper and television) as the major source of information on eye donation. Media publicity to increase awareness of eye donation and eye health care is not enough. Strategies have to be developed to educate the students, so that they can act as motivators for enhancing eye donation and increasing eye health care awareness in the community.

Pattern of Ocular Problems in School going Children of District Lasbela, Balochistan

Purpose: To find out the pattern of eye problems in children of age 6 to 15 years, attending schools and madaris (religious schools) and also to determine the difference in prevalence of ocular disease in students attending these different types of institutions. Material and Methods: The study was conducted in Madaris of district Lasbela were screened from February 2008 to September 2009. All students of schools / madaris of district Lasbela were included in the study. The visual acuity (VA) was measured using standard Snellen’s chart; external examination was carried out with the help of magnifying loop and direct ophthalmoscope. The children with VA < 6/12 were refracted to the best correction. The study team included a community ophthalmologist, an ophthalmologist, an ophthalmic technician and a community social worker. A structured questionnaire was prepared and operational methods were field tested and refined by piloting at the outpatient of Isra Postgraduate Institute of Ophthalmology, Al-Ibrahim Eye Hospital (AIEH), Karachi. An ophthalmic technician with community social worker checked vision of all the students and an Ophthalmologist examined the children for any abnormality and referred them to the base hospital (AIEH). All children with VA < 6/12 were refracted. Every school and madarsa of the target area was visited. Results: Out of 25,437 examined school going children, 19,629 (77.16%) were found to be normal while 5,808 (22.84%) had ocular problems. The ocular conditions in order of frequency were conjunctivitis in 2,826 (11.10%) children, vitamin A deficiency disorders in 839 (3.29%) children, refractive error in 740 (2.90%) children, vernal conjunctivitis in 484 (1.90%) children, blepheritis in 373 (1.46%) children, strabismus in 119 (0.46%) children, cataract in 45 (0.17%) children, ptosis in 33 (0.12) children, nystagmus in 26 (0.10%) children, glaucoma in 2 (0.007%) children and non-specific ocular changes were found in 259 (1.01%) children. The prevalence of ocular problems occurred in 20.68% of children in main stream schools compared to 34.33% in children studying in madaris. The main difference in prevalence was of conjunctivitis noticed in 10.03% of school children, compared to 17% of madaris students and of refractive error present in 2.14% of school children, compared to 7% of students in madaris. Conclusion: Almost 23% of school going children in Lasbela district needed treatment for their ocular problems. The prevalence of conjunctivitis and refractive error was more in madaris compared to schools. School screening could play an important role in the promotion of eye health and the prevention of childhood blindness.

Prevention of Childhood Blindness through the Integration with Maternal Eye Care Programmes

Objective: The prevention of childhood blindness through the provision of preventive services at the community level, specialized surgical services in ophthalmic units and the provision of devices to correct low and services to children with established visual loss. Materials and methods: A series of free surgical cataract eye camps which focused on only women were conducted throughout Delta State in which children with eye problems were incidentally identified and treated. Of the 4239 women seen, 1006 (24%) brought their children along with them. Out of the 1006 children that accompanied their mothers, 840 (83%) of the children were seen based on their the request of their mothers for their ocular examination. Of these children, 28 (3%) had ocular morbidity. There were 19 boys and 9 girls. The majority of the children were between 2 to 5 years of age. The commonest causes of ocular morbidity were congenital and developmental cataract (24%), vernal conjunctivitis (28%), congenital glaucoma (14%) and corneal opacity from measles, harmful traditional eye practises and severe vernal keratoconjunctivitis. Others were refractive error, strabismus and optic atrophy. Results: A total of 10 children underwent surgery. Surgical procedures included 4 lensectomy and 3 lensectomy with intraocular lens implantation, 2 trabeculectomy and 1 optical iridectomy. One patient was given spectacles for juvenile onset myopia. Conclusion: there is a potential for a female gender focused eye programme, to promote child eye health and prevent childhood blindness.Key words: childhood blindness; community; cataract; glaucoma

Braille use among Norwegian children from 1967 to 2007: trends in the underlying causes

The aim of the study was to estimate the occurrence, diagnoses and time trends among Norwegian children that have received education in braille from 1967 to 2007. We used a retrospective population-based study design. The health care system is free for all inhabitants in Norway. We included all children that had received braille education the last four decades. From each student's record, we abstracted year born, country of birth, gender, year diagnosed, diagnosis, classification of visual impairment and type of reading media. We identified 287 children (137 girls and 150 boys) that had received braille education over the last 40 years. Of these, 262 (91.3%) children were born in Norway, 145 (53.7%) were diagnosed within the first year of life and 59 (20.6%) from age of one to five. The most frequent diagnoses were Retinopathy of Prematurity (ROP), Juvenile Ceroid Lipofuscinoses (JNCL), Lebers Congenital Amaurosis (LCA) and Retinitis Pigmentosa (RP). Among the children, 63% (N = 170) used braille only, 9% (N = 25) braille and print, but priority braille, and 27% (N = 73) braille and print, priority print. The number of children with ROP using braille had a peak in 1977, then the number declined. The number diagnosed with LCA increased from 1987 to 1992. The number of braille users among children diagnosed with JNCL tended to increase substantially after 1992. Braille education seemed to be dependent of trends in diagnoses as well as trends in recommendations from professional educators.

Emerging Treatments for Retinopathy of Prematurity

Retinopathy or prematurity (ROP) is a leading cause of potentially preventable blindness in children. With increased survival of infants born at earlier gestational ages the number of infants at risk from vision loss from ROP has increased. Current treatments consist of close monitoring of oxygen saturation levels, peripheral retinal ablation by cryotherapy or laser photocoagulation, and vitreoretinal surgery. Research in the area of angiogenesis has lead to numerous breakthroughs. Emerging treatments for ROP are targeting the Vascular Endothelial Growth Factor (VEGF) and Insulin-Like Growth Factor 1 (IGF-1) pathways, as well as dietary supplementation with omega-3-polyunsaturated fatty acids.

Development of a Scale to Determine Barriers to Paediatric Eye Care

Childhood blindness has huge socio-economic costs. India's commitment to the goal of vision 2020 has put priority to elimination of preventable blindness in children. Although adult blindness has been extensively studied, the literature is seen to be generally lacking in providing in-depth understanding of childhood blindness, especially about barriers that impede access to eye care. The present study attempts to fill this gap. This article explains the procedure adopted in developing a scale to determine the barriers to paediatric eye care. A 22-item barrier to paediatric eye care scale was specifically developed. The scale, along with the full-length questionnaire, was pre-tested and later administered to 207 parent-respondents at Sadguru Netra Chikitshalaya (SNC), Chitrakoot, in the state of Madhya Pradesh (India). A fiveround factor analysis variable deletion process resulted in a three factor structure. Although this procedure reduced the number of items in the scale from 22 to 9, the variance explained by the factors increased from 61 to 78 per cent. The three factors were labelled as economic, logistic and perception of service. Regression analyses of the three factors/barriers, economic, logistic and belief, showed significant results. Further analysis showed that parents’ demographic profile and health seeking behaviour significantly explained the economic barrier. Health seeking behaviour was a significant predictor of logistic barrier.

Automatic Tortuosity-Based Retinopathy of Prematurity Screening System

Retinopathy of Prematurity (ROP) is an infant disease characterized by increased dilation and tortuosity of the retinal blood vessels. Automatic tortuosity evaluation from retinal digital images is very useful to facilitate an ophthalmologist in the ROP screening and to prevent childhood blindness. This paper proposes a method to automatically classify the image into tortuous and non-tortuous. The process imitates expert ophthalmologists' screening by searching for clearly tortuous vessel segments. First, a skeleton of the retinal blood vessels is extracted from the original infant retinal image using a series of morphological operators. Next, we propose to partition the blood vessels recursively using an adaptive linear interpolation scheme. Finally, the tortuosity is calculated based on the curvature of the resulting vessel segments. The retinal images are then classified into two classes using segments characterized by the highest tortuosity. For an optimal set of training parameters the prediction is as high as 100%.

Prevalence and causes of blindness and Low Vision in Ethiopia

Background: Ethiopia lacked accurate recent national estimates of blindness and low vision. Therefore, prevention and control programs face serious problem of lack of recognition of the problem and challenges in tracking achievements towards program goals. Objective: To determine the prevalence of blindness and low vision at the national and regional levels in Ethiopia. Method: A national survey was conducted on a representative population in all nine regional states and two city administrations of the country. The LogMar chart was used to determine the presenting visual acuity and ophthalmologists determined the primary cause of low vision and blindness. Results: Based on the assessment of the presenting visual acuity, the national prevalence of blindness is 1.6% (1.1% for urban and 1.6% for rural populations) and that of low vision is 3.7% (2.6% for urban and 3.8% for rural populations). Blindness and Low vision are more prevalent among females. The major causes of blindness are cataract and trachomatous corneal opacity. The major causes of low vision are cataract and refractive error. Prevalence of childhood blindness is 0.1% and accounts for over 6% of the total blindness burden in Ethiopia. The national prevalence of Bitot\'s spots is 0.7%. Conclusion: Blindness and low vision are major public health problems in Ethiopia. The large proportion of low vision (91.2%) and blindness (87.4%) are due to avoidable (either preventable or treatable) causes. Females and rural residents carry greater risk for eye problems. Adequate emphasis needs to be given to prevent blindness among children and avert millions of years of unnecessary blindness. Recognizing the severity of the magnitude of eye problems (blindness and low vision) and enhancing the government commitment to improve the situation is critical.Ethiopian Journal of Health Development Vol. 21 (3) 2007: pp. 204-210

Paediatric cataract surgery

Bilateral congenital cataract is the most common cause of treatable childhood blindness. Nuclear cataract is usually present at birth and is non-progressive, while lamellar cataract usually develops later and is progressive. Prompt surgery has to be performed in cases with dense congenital cataract: if nystagmus has developed, the amblyopia is unfortunately irreversible. A treatment regime based on surgery within 2 months of life, combined with prompt optical correction of the aphakia and occlusion therapy with frequent follow-up, have been successful in both unilateral and bilateral cases. The surgery ought to include anterior and posterior capsulorexis in all children at the present time. Intraocular lens implantation has been safely performed below the age of 1 year and has also been successfully performed in bilateral cases. Anterior dry vitrectomy should be performed in preschool children to avoid visual axis opacification. Visual axis opacification is the most common complication found after cataract surgery in children. Secondary glaucoma is by far the most sight-threatening complication and is, unfortunately, common in the newborn so lifelong follow-up is essential in these cases.

Uniocular blindness among children in the Gambia

Background: Uniocular blindness in children though not uncommon has not been given prominence, as emphasis is placed on binocular blindness. Aim: To determine the common causes of uniocular blindness in children, and to suggest strategies for prevention. Methods: A prospective study involving children seen at the Eye Clinic of the Royal Victoria Hospital, The Gambia was undertaken; from the 1st December 1999 to 30th June 2000. All newly diagnosed cases of children who attended the clinic and were blind in one eye during the period of the study were included. A history was taken, visual acuity using age specific methods and ocular examinations were carried out. When necessary an examination under anaesthesia was performed. Results: Out of 470 children, 45(10%) had uniocular blindness, 39(86%) were aged 6-15years. The male - female ratio was 4:1. Common causes were trauma 28(62%), uveitis 4(9%), and corneal ulcer 3(7%) . Others included congenital cataract, glaucoma and retinoblastoma. Conclusion: The commonest cause of uniocular blindness was ocular trauma. Focus should be directed towards the prevention, early referral and appropriate treatment of ocular trauma in children. Strategies for the prevention of childhood blindness would also be applicable to uniocular blindness in The Gambia. Port Harcourt Medical Journal Vol. 1 (3) 2007: pp. 167-170

Production of β‐Cryptoxanthin, a Provitamin‐A Precursor, by Flavobacterium Lutescens

ABSTRACT: Vitamin A deficiency (VAD) is the leading cause of preventable blindness in children and raises the risk of disease and death from severe infections. Some plant foods contain darkly colored pigments with provitamin A activity (α‐carotene, β‐carotene, and β‐cryptoxanthin) that can be converted to vitamin A. In this work, a process is described for β‐cryptoxanthin production by Flavobacterium lutescens ITCB008 using fermentation technology. The critical process variables associated with batch fermentation production in a stirred vessel were evaluated and quantified based on experimental design strategies. An ad hoc mathematical model was constructed and used to identify the operating conditions (agitation 190 rpm, aeration 0.086 VVM [air volume/broth volume per minute], and temperature 27.6 °C, pH 7.3) that maximized β‐cryptoxanthin synthesis (770 mg of β‐cryptoxanthin/kg biomass; dry weight) in a short processing time (28 h). In addition, downstream‐processing studies were performed revealing that extraction of β‐cryptoxanthin can be achieved with a polar solvent that produces cell lysis, such as methanol or ethanol, in only 1 step. High performance liquid chromatography analysis showed that β‐cryptoxanthin represents nearly 95% of the total carotenoid content in the obtained product. The process described could be a commercial alternative for producing β‐cryptoxanthin additives, as supplement in food formulation, thus assisting VAD prevention.

Vitamin Deficiencies: An Overview

Vitamins are substances that act as coenzymes (enablers) and regulators of metabolic processes. There are 13 known vitamins (vitamins A, B1, B2, niacin, pantothenic acid, B6, folic acid, B12, biotin, C, D, E, and K). Most have to be added to the body via food or supplements. Vitamins A, D, E, and K are fat-soluble while the others are water-soluble. Deficiencies in one or more of the vitamins lead to so-called vitamin deficiency syndromes. This article briefly reviews the symptoms and diseases found in such deficiencies. 1. VITAMIN A (RETINOL, CAROTENE) DEFICIENCY Vitamin A (retinol) is a fat soluble and found in fish liver oils, liver, egg yolks, butter, and cream. Another substance, β-carotene found in vegetables such as carrots, can also be converted to retinol. Vitamin A deficiency is a public health problem in over 100 countries, especially in Africa and South-East Asia. It is the leading cause in the world of preventable blindness in children and raises the risk of disease and death from severe infections. NYCTANOPIA, NYCTALOPIA, NIGHT BLINDNESS: Night blindness may be an early sign of A deficiency. Individuals suffering from night blindness not only see poorly at night, but also require some time for their eyes to adjust from bright light. In addition, contrast vision may also be affected.

Long-Term Visual Results in Congenital Cataract Surgery Associated with Preoperative Nystagmus

Background Congenital cataracts are the leading cause of preventable blindness in children. The prevalence of this disease is higher in developing countries. The incidence and visual outcome of patients who have undergone congenital cataract surgery in Mexico is not currently known. The purpose of this study is to evaluate the long-term visual results in Mexican children with bilateral congenital cataracts associated with preoperative nystagmus. Methods In a tertiary-level hospital, the long-term visual results of 13 children (26 eyes) with bilateral congenital cataracts associated with preoperative nystagmus were evaluated. All patients had at least 5 years of follow-up after surgery, and all patients were subjected to an intentional ophthalmologic examination. Three types of visual function were evaluated: visual acuity, contrast sensitivity vision, and stereoscopic vision. Age at surgery was correlated with visual outcome. Optical rehabilitation and surgical complications were also analyzed. Results Our group found five patients (38%) with acceptable visual acuity levels. Eight patients (62%) were legally blind according to World Health Organization (WHO) guidelines. Contrast sensitivity vision and stereopsis were severely affected in all patients. We also found a high correlation between timing of surgery, optical rehabilitation, and visual outcome. Conclusions Early diagnosis and treatment, in addition to adequate optical rehabilitation, are mandatory for preventing blindness secondary to congenital cataracts in developing countries. The current state of congenital cataract management in Mexico is also examined.

Toxocara canis and human health

Soil sampling shows widespread contamination of the environment, particularly parks and playgrounds, with the eggs of Toxocara canis, the dog roundworm.1,2 Human toxocariasis occurs after ingestion of infective eggs of T canis and migration of larvas, particularly to liver, lungs, muscle, and brain, It accounts for considerable preventable childhood illness and blindness and is often associated with pica and poor hygiene. Although the clinical features vary, three syndromes are recognised: toxocaral visceral larva migrans, ocular larva migrans, and covert toxocariasis. Toxocaral visceral larva migrans is characterised by fever, malaise, cough and bronchospasm, abdominal pain, and occasionally failure to thrive. Hepatosplenomegaly, lymphadenitis, and bronchopulmonary signs predominate. Severe infection may cause myocarditis or respiratory failure. Focal or generalised seizures may occur. Epilepsy is associated with positive findings on serological testing for toxocara, but pica is also commoner inpatients with epilepsy. Contradictory reports relate toxocara to long term defects in cognitive function. Visceral larva migrans is usually, but not invariably, associated with pronounced IgE hypergammaglobulinaemia, eosinophilia, and increased concentrations of blood group A and B isohaemagglutinins. The findings of antibodies to toxocaral excretory and secretory products on enzyme linked immunosorbent assay has aided diagnosis and given greater credence to studies of seroprevalence. Ocular larva migrans was described over 40 years ago after examination of 47 eyes enucleated for retinoblastoma: 23 had larval or hyaline remnants in eosinophilic …