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Year : 2020  |  Volume : 13  |  Issue : 1  |  Page : 24-28  

Pattern of ocular morbidity among students in a school for visually impaired children in North India

1 Institute of Ophthalmology, J N Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
2 Department of Orbit, Oculoplasty, Reconstructive and Aesthetic Services, Aditya Birla Sankara Nethralaya, Kolkata, West Bengal, India

Date of Submission04-Sep-2018
Date of Decision08-May-2019
Date of Acceptance15-May-2019
Date of Web Publication17-Feb-2020

Correspondence Address:
Dr. Md Shahid Alam
Orbit Oculoplasty Reconstructive and Aesthetic Services, Aditya Birla Sankara Nethralaya, Mukundapur, E M Bypass, Kolkata - 700 099, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ojo.OJO_194_2018

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AIMS: The aim of this study was to identify the ocular morbidity pattern among children attending a blind school in North India and comparing the data with similar studies conducted across India and abroad.
STUDY DESIGN: This was a cross-sectional observational study.
MATERIALS AND METHODS: A cross-sectional study was performed during September 2017 where 94 students attending a blind school were interviewed, and a detailed ocular examination was performed by an ophthalmologist.
RESULTS: Sixty-three (67%) children were blind since birth and 29 (30.9%) had absolute blindness. Anatomical site of blindness included retinal disorders in 38 (40.42%), whole globe pathology in 20 (21.40%), optic nerve disorders in 17 (18.09%), corneal diseases in eight (8.51%), and congenital cataract in four (4.26%). A history of consanguinity among parents was reported by 12 (12.8%) students. Blindness was potentially avoidable in 22 (23.4%) children.
CONCLUSION: Retinal pathologies were the most common cause for blindness in the present study. The proportion of corneal scarring and congenital cataract is decreasing and majority of cases had unavoidable or incurable blindness. Health education about consanguineous marriages, establishment of pediatric ophthalmology units across the country is essential to eliminate or minimize avoidable blindness among children.

Keywords: Avoidable blindness, blind school survey, childhood blindness, retinal dystrophies

How to cite this article:
Zakir SM, Alam MS, Askari SN, Imran M. Pattern of ocular morbidity among students in a school for visually impaired children in North India. Oman J Ophthalmol 2020;13:24-8

How to cite this URL:
Zakir SM, Alam MS, Askari SN, Imran M. Pattern of ocular morbidity among students in a school for visually impaired children in North India. Oman J Ophthalmol [serial online] 2020 [cited 2023 Mar 27];13:24-8. Available from: https://www.ojoonline.org/text.asp?2020/13/1/24/278550

   Introduction Top

For a child who is born blind or becomes blind, the total number of years of disability is greater than for a person who becomes blind later in life.[1] Globally, there are around 1.5 million blind children (BLC) (4% of total blind population),[2] of whom one million live in Asia.[3] With a population of 1.2 billion,[4] India has the largest number of BLC estimated around 320,000.[5] The prevalence of childhood blindness (CB) ranges from ~ 0.3/1000 (of total population) in affluent countries to 1.5/1000 in the poorest. India stands inbetween with 0.8–1.06/1000 children.[6],[7] The causes of CB, its prevalence, modalities of prevention, outcome of treatment, cost of rehabilitation and its impact on the life of such children and their society are very much different from blindness developing in later part of life. The impact of various health-care programs implemented by the government has brought a paradigm shift in diseases causing CB; and reciprocally, repeated assessment for morbidity patterns of CB from different parts of the country reflects the utilization of health-care facilities. Effective implementation of health programs aiming CB brings a change in the morbidity pattern over 10–15 years and reduces the number of children becoming blind due to avoidable causes; and because of this reason, CB has received special priority in VISION 2020 program of the World Health Organization (WHO).

With high socioeconomic impact despite a low prevalence of CB, setting priorities for health programs requires recent epidemiological data of large population samples across the country. Since such data are not available in India, blind school surveys are conducted time and again across the country keeping in mind the amount of bias that would inadvertently creep in. The present study was conducted during September 2017 at Ahmadi School for the Visually Challenged, Aligarh Muslim University, Aligarh (Uttar Pradesh) in North India. The aim was to assess the morbidity patterns among children at this school that has students from various densely populated North Indian States like Uttar Pradesh, Bihar, etc.

   Materials and Methods Top

A cross-sectional observational study was conducted during September 2017 in a school for blind students in Aligarh, Uttar Pradesh. The team visited the school after a written permission for examination of the students was granted from the school principal. Informed consent was obtained from students and guardians at the time of examination. Parents/guardians/caretakers/teachers of the children were present at the time of examination. Ethical clearance from the institutional committee was obtained and the study was conducted following the tenets of the Declaration of Helsinki.

All children enrolled in the school were included in the study. A brief history of vision loss, including age of onset, progression, affliction of other family members, consanguinity among parents, religion, place of residence, and treatment undertaken were recorded. Medical records of students were reviewed whenever required, especially to assess additional disabilities. Visual Acuity was recorded using Snellen's chart (wherever possible) and refraction was done in case an improvement was expected. The children were distributed as per the WHO category of visual impairment.[8] Detailed anterior segment examination was done using a 3 × binocular magnifying loupe and posterior segment was evaluated by indirect ophthalmoscope (Neitz Instruments Co Ltd, Japan) after pupillary dilatation in all cases except where it was not possible (Phthisis bulbi, large corneal opacities precluding a view of fundus). All data were recorded as percentages or mean with standard deviation. The causes of visual disability were classified on the basis of primary pathology affecting the visual system. Wherever other siblings were affected, the students were told to get them examined, especially if the cause of blindness was avoidable.

   Results Top

Out of the 102 students enrolled in the school, 94 (aged ≤16 years) were present at the time of the survey. There were 59 (62.8%) males and 35 (37.2%) females (male: female ratio of 1.7:1). The mean age of the children was 13.39 ± 2.76 (range 6–16 years). Twenty nine (30.8%) students were Hindus and 65 (69.2%) were Muslims. Most of the students belonged to North Indian states of Uttar Pradesh, Bihar, Jharkhand, Jammu and Kashmir and others.

[Table 1] shows the distribution of students as per the WHO category of visual impairment. Sixty four cases (68.1%) fell in category IV, 23 (24.5%) in category V and 6 (6.4%) in category III. Only one case qualified for the WHO category II. None of the students had additional disabilities and the visual acuity could not improve from refraction. History of seeking treatment (Medical or Surgical) for visual symptoms was present in 14 (14.9%) and causes for these included corneal ulcer, developmental cataract, congenital glaucoma and retinopathy of prematurity (ROP). Major causes of blindness were various conditions of the posterior segment, affecting 58.5% of children.
Table 1: Distribution of students as per the World Health Organization category of visual impairment

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The etiological causes of blindness were classified according to the anatomical site affected [Table 2]. The most frequently affected sites were retina (40.42%), followed by whole globe (21.29%) and optic nerve (18.09%). In children with retinal pathology, 19 (20.21%) cases had retinal dystrophies, 10 (10.64%) had oculocutaneous albinism, three (3.19%) had retinochoroidal coloboma, two each (4.26%) had congenital toxoplasmosis and foveal hypoplasia, while one each (2.13%) had retinal detachment and ROP. In cases where the whole globe was affected, nine (9.58%) had anophthalmos, seven (7.45%) had microphthalmos, and four (4.26%) had phthisis bulbi. Optic nerve disorders were present in 17 (18.09%) cases, of which 13 (13.53%) had optic atrophy while four (4.26%) had congenital glaucoma. Corneal scarring was found in six (6.38%) cases, while congenital cataract was present in four (4.26%) cases. Five children (5.32%) had keratoconus with retinal dystrophy and there were three (6.38%) cases of cortical blindness.
Table 2: Anatomical classification of the causes of visual impairment

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Sixty two (66%) students reported blindness since birth, 20 (21.3%) had similarly affected siblings, but none had parents who were blind. A history of consanguinity among parents was present in 12 (12.8%) cases out of which nine (75%) were blind since birth, seven (58.3%) had other siblings affected, and more so, four out of these 12 had absolute blindness or no perception of light (Absent PL) [Table 3].
Table 3: Parental consanguinity and blindness in children

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As is evident from [Table 4], blindness could have been avoided in 22 children (23.4%). The causes for avoidable blindness included corneal scarring in six (6.38%), congenital cataract and congenital glaucoma in four (4.25%) each, congenital toxoplasmosis in two (2.13%), uveitis in two (2.12%), and posttubercular meningitis (TBM) optic atrophy in one (1.06%) case.
Table 4: Distribution of avoidable blindness among students

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   Discussion Top

In our study, diseases of retina were the most common cause of blindness (40.42%) such as retinal dystrophies (20.21%), albinism (10.64%), retinochoroidal colobomas (3.19%), congenital toxoplasmosis (2.13%), foveal hypoplasia (2.13%), and retinal detachment and ROP (both contributing 1.06%). This is in contrast with most of the studies from India[3],[9],[10],[11],[12] and other countries[1],[13],[14] that have reported whole globe pathology as the most frequent site of abnormality. Very few studies like Mirdehghan et al.[15] from Iran (51%) and Kocur et al.[16] from Czech Republic (54.2%) have reported retinal pathologies as the most common cause of CB. Another important observation was in the case of oculocutaneous albinism which accounted for 10.6% (ten children) while most of the studies have reported a small proportion of around 1%.[3],[12],[15],[17] Some important observations were noted in these cases. Eight of these ten children were Muslims, male: female ratio was 9:1, three children gave a positive history of parental consanguinity and only two had other siblings affected; in all concert with autosomal recessive conditions.

One child had sequel of ROP, an emerging cause of avoidable blindness, especially in countries like India where improving neonatal care has raised the survival rate of premature babies. There is an urgent need to expand the ROP screening by involving virtually every neonatal intensive care unit (NICU) admitting premature babies. In one study conducted in the Czech Republic during 1998, Kocur et al.[16] have reported 41.9% of ROP cases from a cohort of 229 BLC attending ten blind schools. The Karnataka Internet Assisted Diagnosis of Retinopathy of Prematurity (KIDROP)[18] model is practical and should be implemented across the country.

Conditions involving whole globe such as microphthalmos, anophthalmos and phthisis bulbi were the second most frequent and were responsible for 21.4% of cases. Similar figures have been reported from other studies,[1],[9],[12],[14] but some studies have reported a very high prevalence ranging from 35% to 55%[3],[10],[11],[14] and others have reported a prevalence of ≤10%.[15],[16],[17],[19] In any case, the etiology of these conditions is still unclear, and in all possibility, blindness is neither preventable nor treatable except for acquired phthisis bulbi where the inciting cause could have been preventable; however, we were not able to identify it because of lack of proper history.

Optic nerve disorders were responsible for blindness in 17 children (18.09%) in our study. These figures are quite high as compared to other studies from various parts of India that have reported optic nerve diseases, including congenital glaucoma as a cause of CB in 4.6% to 13.5% cases.[3],[9],[10],[11],[12] A recent study[17] from Chennai in South India has reported a very high prevalence of 35.4%. Studies from other countries have also reported slightly higher figures ranging between 9.7% and 15.3%.[14],[16] Four children in our study had congenital glaucoma, but all were blind despite surgical interventions. This reflects the need of continuous screening programs to identify such cases and referring them to tertiary care centers at appropriate time.

Bilateral large corneal opacities, bilateral congenital cataracts, and other causes of avoidable blindness which had a large share in most of the older studies from India and abroad, are now slowly decreasing down in significance because of better health-care facilities and community ophthalmology programs. There were six cases of corneal opacity and four cases of congenital cataract accounting for a mere 10.64%.

In about a quarter (23.4%), the blindness was potentially avoidable. Special note is to be given to two cases who were blind secondary to severe dry eye following Steven–Johnson syndrome. There were three cases (3.19%) of cortical blindness.

Blindness among siblings was noted in 19 students (20%; 12 males and seven females) out of which seven (37%) gave a history of consanguinity among parents. This points to a possibility of accumulation of defective genes in a family and the same is likely to be represented repeatedly. In our study, a history of consanguineous marriage was recorded from 12 (13%) students (all Muslims). Half (six) of them had retinal dystrophies, a quarter (three) had albinism, and rest were cases of optic atrophy, foveal hypoplasia, and microphthalmos. Consanguineous marriages are common in certain societies in many countries and one study from South India has reported a very high prevalence of 48.7%,[3] while others have reported various figures ranging between 0.4% and 10%.[1],[9],[10],[12],[16] The impact of such marriages on CB has been elaborated to certain extent in few studies. Our study has noted a unique finding among such families. Seven out of 20 children (35%) with blindness among siblings had parental consanguinity. In all the seven families, at least one male child was blind. Four out of these seven (57.1%) had three to four visually handicapped siblings.

The control of CB is one of the priorities of the WHO Vision 2020 program. Following successful Vitamin A prophylaxis and measles vaccination programs, there is a marked reduction in the incidence of CB due to corneal opacity.[17] The causes for CB and the priorities of prevention and management keep changing with the implementation of blindness control programs. Therefore it becomes mandatory to identify important avoidable causes in each region and assess the changes in morbidity patterns over time. Although large-sized population-based surveys would provide a better idea of these changes and the impact of control programs, but it would not be feasible to conduct them at regular intervals.

Population-based data on the causes of blindness in children are difficult to obtain in countries like India as registers of the blind do not exist and very large sample sizes would be required for formal cross-sectional surveys. Furthermore, there are great regional variations among the states due to inherent diversity. Alternatively, other sources to gather such data include the use of key informants and examination of children identified as blind in community-based rehabilitation programs wherever available. Examination of children in special education has increasingly been used to provide data on the causes of blindness in children, but sources of bias need to be borne in mind. In poorer regions, the prevalence of CB is higher and the causes are mostly avoidable. BLC from lower socioeconomic groups and those with other disabilities usually do not pursue education and therefore get excluded from such studies. The advantages of blind school studies are that many children can be thoroughly examined with ease in a standard manner by a limited number of observers over a short span of time with minimal expenditure. Medical records of these children are also available at the school.

   Conclusion Top

Following successful child health-care programs, there is a marked reduction in the incidence of CB due to corneal opacity. However, alarmingly congenital cataract and congenital glaucoma are still poorly managed and hence emphasis should be laid on establishing pediatric ophthalmology units across the country. Centers for low vision aids and vocational rehabilitation are essential to help these citizens live a dignified and independent life. Health education about hazards of consanguineous marriages might reduce another small percentage of blindness due to autosomal recessive conditions. The improvement in neonatal health-care services demands an aggressive ROP screening and timely intervention to save such children from blindness in the coming decades.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

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  [Table 1], [Table 2], [Table 3], [Table 4]

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