Xerophthalmia and anterior-segment blindness among preschool-age children in El Salvador

Update on Pediatric Corneal Diseases and Keratoplasty

Managing pediatric corneal disorders is challenging as the prognosis of pediatric keratoplasty depends on several factors. Advancements in the genetic basis of congenital corneal diseases and investigations in congenital corneal conditions provide a better understanding of pediatric corneal conditions. Surgeons performing keratoplasty in children now have a choice of various techniques. Evolving surgical techniques of anterior lamellar and endothelial keratoplasties has expanded the management interventions in these pediatric corneal morbidity conditions; however, considerable concerns still exist in association with corneal transplantation in infants and children. Outcomes in pediatric keratoplasty depend upon the preoperative indications, the timing of surgical intervention, intraoperative and postoperative factors including the patient/care givers' compliance. Factors such as low scleral rigidity, higher rate of graft failure, need for frequent examinations under anesthesia, and difficulty in optimal visual acuity assessment still remain a considerable challenge in pediatric scenarios. In children, deprivation amblyopia as a result of the corneal opacification can adversely affect visual development, causing dense amblyopia. Outcomes to surgical interventions for management of corneal opacification in children is further compromised by the pre-existing amblyopia apart from the concerns of refractive outcome of the graft. Graft rejection, graft infection, amblyopia, and glaucoma continue to be serious concerns. In recent years both anterior and posterior lamellar keratoplasty techniques are being increasingly performed in pediatric eyes, which offer advantages in the form of lower risk of graft rejection. The timing of surgery, careful case selection, cautious intraoperative approach, and optimal postoperative management can improve the anatomical and functional outcome in difficult cases.

An Accidental Nutritionist

My career as an accidental nutritionist began with my immersion in cholera control, a cyclone disaster, a smallpox epidemic, and formal training in ophthalmology and epidemiology. Interest in blindness prevention inexplicably led me to (re)pioneer the effects, treatment, and prevention of vitamin A deficiency, while faced with intense criticism by many leading scientists in the nutrition community. The resulting efforts by the World Health Organization and UNICEF in support of programs for the global control of vitamin A deficiency still face vocal opposition by some senior scientists, despite having been estimated to have saved tens of millions of children from unnecessary death and blindness. This entire journey was largely an accident!

Measles blindness

Measles remains a major problem in developing countries, where it affects an estimated 30 million children a year and causes up to one million deaths annually. Measles blindness is the single leading cause of blindness among children in low income countries, accounting for an estimated 15,000 to 60,000 cases of blindness per year. There is a close synergism between measles and vitamin A deficiency that can result in xerophthalmia, with corneal ulceration, keratomalacia, and subsequent corneal scarring or phthisis bulbi. High-dose oral vitamin A supplementation is recommended for all children with measles in developing countries. Higher measles immunization coverage to interrupt measles transmission and interventions aimed at improving vitamin A nutriture of children are the main strategies to prevent measles blindness.

Keratoplasty for keratomalacia in preschool children

AIM

To study the results of surgical management of keratomalacia in children.

METHODS

A clinical case series of all children with keratomalacia, admitted to an Indian centre during the period from June 2000 to June 2001 is presented. The parameters evaluated were demographic data, systemic associations, and results of medical and surgical intervention.

RESULTS

29 children with keratomalacia ranging from 2 months to 5 years of age (mean 1.8 (SD 1.4) years) were included in the study. All children belonged to families of lower socioeconomic status. 27 patients (93.1%) had not been immunised at all. The systemic diseases precipitating the onset of keratomalacia included measles (41.37%), pneumonia (31.03%), and acute diarrhoea (37.93%). 36 eyes (66.7%) had total corneal melting and 11 (20.3%) eyes had paracentral corneal melting. In 15 eyes (27.8%) an emergency tectonic penetrating keratoplasty was performed of which only five grafts (33.3%) remained clear at a mean follow up of 7.3 (6.8) months (range 3-24 months). Seven eyes underwent optical penetrating keratoplasty, of which four grafts (57.14%) remained clear at a mean follow up of 6.4 (3.6) months (range 3-12 months). None of these could achieve a visual acuity better than 6/60.

CONCLUSIONS

Corneal grafting surgery in keratomalacia is associated with poor visual outcome.

Pattern of childhood blindness and partial sight among Jordanians in two generations

A study of 260 Jordanians who became blind or visually impaired (according to World Health Organization standards) before the age of 15 years showed the dominant effects of genetically determined causes in two generations. Genetic causes were responsible for the visual impairment in 122 (77.7%) of 157 subjects in the group born after 1970 and for 69 (67%) of 103 in the group born before 1970. There was a statistically significant change in the overall pattern (genetic and acquired causes) of blindness between the two generations, and there was also a significant change in the pattern of acquired blindness alone. A decrease in corneal infections leading to blindness or visual disability in the younger generation was accompanied by an increase of trauma in the same age group. Parental consanguinity in those with genetically determined causes of visual impairment was high compared with those with nongenetic causes (79% vs 33.3%, P < .05). The autosomal recessive mode of inheritance was the most common pattern encountered (53.9%).

Efficacy of massive oral doses of retinyl palmitate and mango (Mangifera indica L.) consumption to correct an existing vitamin A deficiency in Senegalese children

Administration of large oral doses of retinyl palmitate has become the most widely practised vitamin A deficiency prevention strategy in developing countries. We conducted a follow-up study among 220 Senegalese children aged 2-7 years suffering from moderate undernutrition to determine the efficacy of vitamin A treatment on their vitamin A status assessed by biochemical and cytological (impression cytology with transfer) methods. The first examination (T = 0 m[onth]) was carried out during April 1989, before the mango (Mangifera indica L,) harvest. The second examination (T = 2 m) was carried out 2 months after vitamin A treatment during June 1989 when ripe mangoes become widely available. Conjunctival cells of the eyes of the children with or without ocular inflammation were responsive to vitamin A administration (P < 0.01). There was a significant increase (P < 0.001) in mean serum retinol and beta-carotene levels between T = 0 m and T = 2 m. Mean serum retinol-binding protein (RBP) and transthyretin (TTR) levels did not differ significantly (P > 0.05) at T = 0 m and T = 2 m. Despite the intake of vitamin A, 54% of the children who had abnormal cytology at T = 0 m remained abnormal at T = 2 m. This was due to inadequate levels of TTR and RBP, presumably due to the cereal diet eaten by the Senegalese population. children with abnormal eye cytology had lower serum retinol levels than those with normal eyes at T = 0 m, and beta-carotene values did not correlate with eye cytological abnormalities at T = 0 m. Children with normal cytology had higher serum retinol and also beta-carotene levels than those with abnormal cytology after massive oral doses of vitamin A and consumption of mangoes at T = 2 m. Retinyl palmitate may, therefore, only lead to partial cytological improvement due to a lack of retinol-carrier proteins but dietary beta-carotene may also be involved.

Response of Bitot's spots in preschool children to vitamin A treatment

In a double-masked, placebo-controlled, clinical trial in Indonesia, 88 preschool children between the ages of 36 and 72 months with Bitot's spots were randomly assigned to 200,000 IU of oral vitamin A or placebo and followed up for five weeks. Baseline and follow-up serum vitamin A levels were obtained. Of the 45 children receiving vitamin A, 33 (73.3%) showed complete cure and disappearance of Bitot's spots, six (13.3%) had disappearance of some but not all Bitot's spots, and six (13.3%) were unresponsive to treatment. The nonresponsive children were older, all male, and had higher initial mean serum vitamin A levels, 23.0 micrograms/dl, compared to 15.9 micrograms/dl in the cured group (P = .017). These data suggest that normal vitamin A status may be found in approximately 13% of children with Bitot's spots before vitamin A intervention and that one fourth of those who had Bitot's spots originally will not be cured of all Bitot's spots after intervention. These are important factors to consider when using Bitot's spots in prevalence surveys as a clinical sign of vitamin A deficiency.

Changing pattern of childhood blindness in Saudi Arabia

We studied 187 patients attending special educational institutions in Saudi Arabia who were blind before the age of 14. All patients underwent complete ophthalmological evaluation. The visual acuity in 31% of the patients was no light perception and in 58% light perception to counting fingers at 3 feet (1 m). 70% were blind before age 2. Prior to 1962 acquired diseases led to blindness in 75% of the patients. From 1962 onwards genetically determined diseases accounted for 84% of childhood blindness. 56% of this group were the product of consanguineous marriages. On the other hand in the group who acquired blindness only 14% were from consanguineous marriages (p less than 0.0001). We here describe guidelines for the prevention of childhood blindness in Saudi Arabia.

Clinical characteristics of vitamin A responsive and nonresponsive Bitot's spots

We examined and followed up 59 patients with conjunctival xerosis with a without classic Bitot's spots. Of these, 50 were responsive and nine were unresponsive to vitamin A. Despite a recent World Health Organization classification suggesting otherwise, all cases appeared to represent the same process. In preschool children, the presence of the Bitot's spots on both sides of the corneoscleral limbus or in association with night blindness or punctate keratopathy suggests active vitamin A deficiency. Pigmentation and wrinkling were not useful diagnostic criteria and lesions isolated to the nasal corneoscleral limbus suggested a different diagnosis. At least some cases of nonresponsive conjunctival xerosis and Bitot's spots were probably sequelae of past vitamin A deficiency.

Vitamin metabolism and therapy in ophthalmology

Vitamin deficiency states are important in the genesis of many ocular disorders. Deficiencies may be due to poor dietary intake, or to alterations in metabolism produced by some commonly prescribed medications or by certain diseases. Furthermore, some vitamins may exert important pharmacologic effects on the normal eye. The ocular effects of deficiencies and excesses of specific vitamins, and the therapeutic uses of each vitamin, are reviewed.

Xerophthalmia and anterior segment blindness

The prevalence of presumed vitamin A-related corneal scars among 5,589 preschool-age Haitian children ranged from 1.2 per 1,000 in the south, to almost 1% in the famine-afflicted north. These scars accounted for at least 45% of all corneal scars, and all bilateral corneal blindness encountered. Most lesions were acquired during the first three years of life. There was no variation by sex or ecology of the sample site. This country of 5.5 million inhabitants acquires 345 new surviving cases of vitamin A-related corneal destruction, over one fourth bilaterally blind, each year, although local ophthalmologists rarely encounter the disease and Bitot's spots were absent from our study population. Countrywide clinical prevalence surveys are the only unbiased means of determining the magnitude, severity, and geographic distribution of vitamin A-related corneal destruction, prerequisites for the design of public health prevention programs.

Mass distribution of vitamin A and the prevention of keratomalacia

A retrospective review of 3,490 adminissions to the major pediatric facility in El Salvador was undertaken to determine whether biannual administration of massive doses of vitamin A (200,000 international units) to all availabel 1- to 4-year-old children was effective in preventing keratomalacia. During the 12 months preceding and following initiation of the program, the number of children admitted with presumed vitamin-A-related corneal destruction (33 vs. 31) and proportion of all malnourished admissions with such destruction (26 vs. 25 per 1,000) were similar. The seasonal distribution of these cases remained unchanged, the usual summer peak closely following the first distribution. Unexpectedly, 48% of the children had been ineligible for participation in the program, the vast majority being under 1 year of age. Only 80% of eligible children had actually received the vitamin. Corneal destruction was invariably accompanied by severe, generalized malnutition. Mortality among girls with corneal destruction (28 per 1,000) was almost three times that of boys, or malnourished patients as a whole.