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July 2007, Volume 57, Issue 7

Original Article

Blindness in Children at the Ida Rieu School for the blind and deaf

Sadia Javed Khan  ( Aga Khan University Hospital, Karachi. )
Afshan Hassan  ( Aga Khan University Hospital, Karachi. )
Laila Khalid  ( Aga Khan University Hospital, Karachi. )
Uzma Karim  ( Aga Khan University Hospital, Karachi. )
Erurn Hashmi  ( Aga Khan University Hospital, Karachi. )
Fariha Gul  ( Aga Khan University Hospital, Karachi. )
Imtiaz Jehan   ( Aga Khan University Hospital, Karachi. )


Objective: To identify the causes of blindness at the Ida Rieu school for the blind and deaf, Karachi, Pakistan. Methods:Across sectional study was conducted at the Ida Rieu School for the blind and deaf. The data collected from medical record of students was entered into the WHO/PBLeye examination form for children with blindness and low vision. Results: Records of 144 pupils aged between 4-30 years were reviewed, including 67% males and 33%females. One third (31%) children had visual impairment (<6/18-6/60) and 69% were blind (<3/60-NPL). The commonest anatomical site was retina (41%) and whole globe (20%). The etiology was unknown in 49% cases.In 33% of cases, the data suggested here ditary cause as the etiology, 40% of cases were preventable and 13%treatable. Conclusion:Avoidable causes of blindness were seen in 53% of children, 58% of which were preventable and19 were treatable (JPMA57:334:2007).


Eye diseases which lead to blindness remain a highly prevalent and serious health problem in many developing countries. The control of blindness in children is a priority because it affects their development, education and employment opportunities. This has far-reaching impact onthe quality of not only their lives but also that of their families. Another important concept associated with childhood blindness is 'years of blindness'.1Its significanceis paramount when it comes to allocation of resources, as it can be argued that restoring the sight of one child from cataract is equivalent to restoring the sight of ten elderly adults from cataract.2 Most of these children live in theunder developed world, in Africa, Asia and Latin America,where economic deprivation is exacerbated by the added challenge of failing vision. Disabled people have lower education and income levels than the rest of the population.3 And since most disabled children will become disabled adults, the consequence is alarming. Out of the presently estimated 45 million blind people only 3% are children,these figures might seem trivial. Since without intervention,the number of individuals with blindness might reach 76million by 2020, resulting in an increased burden ofchildhood blindness. Thus highlighting the need to control blindness in children, so as to eliminate unnecessary blindness and promote good vision throughout the world.4According to a population-based survey 1987-1990,conducted by the Ministry of Health of Pakistan and theWorld Health Organization (WHO), Pakistan has 1.78% aprevalence of blindness.5In Pakistan, so far there is no reported data available on prevalent causes of childhood blindness for any future recommendations. Thus necessitating the need for study in this area. Reliableprevalence data are difficult to obtain for a variety of reasons but the available evidence suggests that the prevalence varies from 0.3/1000 children in economically developed countries to over 1.0/1000 children in underdeveloped societies.6Almost half of all blindness in children particularly those in the poor countries is due to avoidable causes that are amenable to cost effective interventions.7Vitamin A deficiency, harmful treatmentremedies, measles, congenital rubella, ophthalmianeonatorum are a few examples of avoidable blinding conditions seen in the developing world.8 This study was undertaken to identify the causes of blindness in a school for blind and deaf children in Pakistan.


Across sectional study was conducted at the IdaRieu School for the Deaf and Blind - named after IdaAugusta Rieu, wife of the then commissioner of Sindh, J.L.Rieu. It was set up in the 1920s and is presently providing education to over 700 students. Medical records of students were reviewed from February to April 2004, after obtaining consent from the school administration. The blind students at the Ida Rieu School were examined in the year 2002. Amongst these,students with on set of blindness before 15 years of age, with complete medical and ophthalmological records were included in the study. The school keeps a personal record for each child,which includes medical and ophthalmological reports. All children attending school for the visually handicapped were seen by an ophthalmologist and results for eye examination which stated visual acuity, ophthalmic findings, category of visual impairment, recommended treatment, proposed mode of education and the need for training and mobility were reported. The visual acuity was measured using anilliterate Snellen E optotype. If the visual acuity was lessthan 3/60, each eye was tested for ability to perceive light.Refraction and low vision aid assessment, if indicated was preformed by a qualified optometrist. Visual loss was classified according to WHO categories of visual impairment 9. Simple tests for functional vision were used.Anterior segment examination was performed using flashlight and magnifying lens. Posterior segment examination was performed by indirect and direct ophthalmoscopy after mydriasis.The WHO/PBLeye examination record for childrenwith blindness and low vision form10 was used to analyze the available data. These forms have sections pertaining todemographic data, visual acuity, general medical conditions, past eye surgeries, anatomical site affected,suspected causes and present usage of low vision aids orspectacles.Data collected was analyzed by the SPSS statistical software. Areport of the findings and recommendations was given to the principal of the school.


Medical records of 162 students at the blind school were reviewed, out of which 144 were analyzed as they had complete information. There were 96 male (66.6%) and 48 female (33.3%)children. The mean age was 12.94 years with a range of 4-30 years; 12 students (8.3%) were under 5 yrs of age, 28(19.4%) were aged 5-10 years, 70 students (48.6%) wereaged 10-15 years while 33 (22.9%) were older than 15years.There was a positive family history of another member in the family being affected in 62 cases (43.1%),and 57 of these blind children (39.6%) were born to parents with a consanguineous marriage.The age at onset of visual loss was known for 111students (77.1%) and 75 students (52.1% of the total) were

Table 1. Anatomical site

Anatomical Site

for blindness



and visual impairment

Whole globe















Optic nerve






Table 2. Reported causes of visual loss in the study population (n=144).

Causes of Visual Loss



Hereditary Disease



Intrauterine Factor



Perinatal/Neonatal Factor



Postnatal/Infancy/Childhood Factor



Cannot Determine (unknown aetiology)



Aetiology Not Documented



Table 3. Avoidable causes of blindness and visual




Preventable (n=58)


Vitamin A def/measles






Trauma/harmful traditional remedies


Treatable (n=19)










known to be blind by birth. Amongst these 144 students, 5children had mild visual impairment (3.4%), 13 had moderate visual impairment (9%), 27 had severe visualimpairment (18.8%) and 99 were completely blind (68.8%). For all the students examined, 29 (20.1%) had whole globe lesions. Corneal lesions accounted for visual loss in 9students (6.3%); 6 (66.6%) in children under 15 years and 3(33.3%) in those over 15 years (Table 1). Cataract (13, 9.0%) was a common cause of visual impairment/blindness - 9(69.2%) in children under 15 and 4(30.8%) in children over 15. Uncorrected aphakiaaccounted for a further 9 (6.3% of all the students). In 2cases of cataract, there was associated bilateralmicrophthalmos, 7students with cataract (53.8%) had visualacuity of less than 3/60.

Retinal dystrophy (45, 31.3%) was the single commonest cause of visual impairment/blindness; 25(55.5%) in under 15 years and 20 (44.5%) in children above15 years. Other retinal causes included albinism (1, 0.7%),retinopathy of prematurity (2, 1.4%) and retinoblastoma (1,0.7%). Twelve students (8.3%) had optic atrophy, 7 (58.3%)were children below 15 years and 5 (41.7%) were older than15 years.Hereditary factors (32.6%) constituted the majoraetiology of blindness, 25 of these children (17.4%) had theabnormality since birth with the exact aetiology unknown whereas in 23 records (15.9%) the aetiology was not documented at all (Table 2).Avoidable causes of belindness were identified in 77cases, 58 of which were preventable while 19 were treatable(Table 3). However, mild degree of overlapping was presentamongst these preventable and treatable causes. Regardingneed for therapeutic interventions, spectacles for refractiveerrors were recommended for 25 students (17.4%) andprovision of low vision aid (LVA) (telescope or magnifier orboth) for 36 (25%) students.


This study aimed at identifying the causes ofblindness in a selected population of school-going children.On the one hand, children in schools for the blind may notbe representative of the blind in the whole population11as itis believed that in most developing countries only about10% of the children are in blind schools.12However, on the other hand, population-based surveys, although exhaustive,identify only a very small number of blind children, in whom it might be difficult to highlight the pattern of causesof blindness. Furthermore, in the poor countries it isestimated that 60-80% of blind children die within 1-2 years of becoming blind.13 Blind schools have the advantage of ease ofexamining a large number of children within a relatively short period of time by one examiner using standard methods; however, they are potentially biased.11Blindschools can be very expensive because of the services they offer, however, in our setting; Ida Rieu is a welfare school.Other biases include limited accessibility of services and knowledge of the existence of blind schools. Furthermore,cultural and social barriers, such as co-education, refrains parents from sending their children to these schools. The results of the study showed that the number ofmale students examined were twice the number of female students (66.7% vs. 33.3%). This proportion may be representative of practices inherent in the society which encourage education in boys rather than in girls.Coming to the results of the study, the retina was found to be the main anatomical site followed by the whole globe and the lens. Within the retinal group, retinaldystrophy was the leading cause of blindness. Such a pattern was also observed in a school-based study done inChina.14 Unfortunately in 49.3% of the children the etiology of visual loss could not be determined. This reflects limited scope for investigation, and lack of examination of family members in many cases. In the remaining children hereditary diseases came out as the predominant cause. Thisresult is consistent with studies from other Asian countriessuch as Malaysia15, Srilanka16and China14, which show a mixed pattern between hereditary and unknown etiologies(a pattern similar to that in industrialized countries). Surprisingly, only 4.9% of the children had vitamin A deficiency. This can be attributed to the location of theschool in a relatively affluent area of the largest city of Pakistan. Thus causes of blindness associated with povertyand a high mortality are likely therefore to be underrepresented in this study. Otherwise Pakistan has been classified by the WHO as a country with severe sub-clinicalvitamin Adeficiency in parts or whole of the country17, and studies conducted in different areas of Pakistan show that32-43% children under 5 have deficient serum vitamin Alevels.18-19In Africa, corneal scarring from vitamin A deficiency, measles, and harmful traditional eye medicine spredominate.20In India also the major cause of SVI/BL in children in blind schools is vitamin A deficiency.21ROP was identified in only 3 children (2.1%). The lower incidence of ROP found in our study is probably there sult of the much higher mortality of premature children in Pakistan, in particular in rural areas compared to developed countries. In the future ROP is likely to become a much bigger problem in Pakistan as neonatal services are bound to expand particularly in urban areas.Thus, to effectively prevent childhood blindness, in Pakistan, in addition to mass vaccinations, vitamin A supplementation, we stress the need for screening for earlydetection. This will not only pick up diseases which aretreatable if referred early but will also improve the prognosis after surgery. Genetic counseling has an important role to play in the prevention of blindness.Efforts can only be fruitful if the people in the community are aware about possible screening. The limitations of this study are that the findingsneed to be interpreted with great caution, as the data is not population based. The information does provide anindication of the relative importance of the different causesof childhood blindness.  However they are subject to certaininherent biases. For e.g. children with multiple disabilities,preschool age children those who have died, those from lower socioeconomic groups or from rural communities arelikely to be underrepresented.


1.World Health Organization. Preventing Blindness in Children. Report of aWho/IAPB Scientific meeting. Who/PBL/00.77.Geneva: WHO, 2000

2.Gilbert C, Foster A. Childhood blindness in the context of Vision 2020-theright to   sight. Bull World Health Organ 2001; 79:227-32

3.Poverty & Disability: a Survey of the Literature, World Bank, 1999

4.World Health Organization. 1997. Global initiative for the elimination ofavoidable blindness. WHO/PBL/97.61. Geneva: WHO, 1997.

5.Memon MS. Prevalence and causes of blindness in Pakistan. J Pak Med Assoc1992, 42:196-8.

6.World Bank. World development report 1993: investing in health. New York,1993 Oxford University Press.

7.World Health Organization. Resolution of the World Health Assembly:Elimination of   Avoidable Blindness. Geneva, Switzerland: World HealthOrganization; 2003. Public WHA56.26

8.Ezegwui IR, Umeh RE, Ezepue UF. Causes of childhood blindness: resultsfrom    schools for the blind in south eastern Nigeria. Br J Ophthalmology2003; 87: 20-3

9.World Health organization. International statistical classification of diseaseand related Health problems 10th revision. Geneva: WHO, 1992: 456-7.

10.Gilbert C, Foster A, Negrel D, Thylefors B. Childhood blindness: a new formfor recording causes of visual loss in children. Bull World Health Organization1993; 71: 485-9.

11.Kello AB, Gilbert C. Of severe visual impairment and blindness in children inschools     for the blind Causes in Ethiopa. Br J Ophthalmol 2003; 87:526-30.

12.Gilbert C, Foster A. Blindness in children: Control priorities and researchopportunities. Br. J. Ophthalmology 2001; 85: 1025-7.

13.Lewallen S, Courtright P. Blindness in Africa: present situation and futureneeds. Br J Ophthalmol 2001;85:897-903.

14.Hornby SJ, Xiao Y, Gilbert CE, Foster A, Wang X, Liang X, et al. Causes ofchildhood blindness in the Peoples's Republic of China: results from 1131blind school students in 18 provinces. Br J Ophthalmol 1999; 83:929-932

15.Reddy SC, Tan BC. Causes of childhood blindness in Malaysia: results froma    national study of blind school students. Int Ophthalmology 2001;24:53-9.

16.Eckstein MB, Foster A, Gilbert CE. Causes of childhood blindness in SriLanka: results from children attending six schools for the blind. Br JOphthalmology  1995;79:633-6

17.WHO. Global prevalence of vitamin Adeficiency MDIS Working Paper # 2.Geneva: WHO, 1995.

18.Paracha PI, Jamil A, Northrop-Clewes CA, Thurnham DI. Interpretation ofvitamin Astatus in apparently healthy Pakistani children by using markers ofsubclinical infection. Am J Clin Nutr. 2000;72:1164-9.

19.Molla A, Badruddin SH, Khurshid M, Molla AM, Rahaman FN, Durrani S, etal. Vitamin Astatus of children in the urban slums of Karachi, Pakistan,assessed by clinical, dietary, and biochemical methods. Am J Trop Med Hyg.1993;48:89-96.

20.Foster A, Sommer A. Corneal ulceration, measles, and childhood blindness inTanzania. Br J Ophthalmol 1987;71:331-43.

21.Rahi JS, Sripathi S, Gilbert CE, Foster A. Childhood Blindness in India:Causes in 1318 blind school students in nine states. Eye 1995;9:545-50.

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