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Year : 2017 | Volume : 5 | Issue : 2 | Page : 55 - 59  


Original Articles
Vision Screening by School Teachers: Will it be qualitative?

AA Kameswara Rao1, TAV Narayana Raju2, B. Swaraj Laxmi3, T. Jayaraj4

1Retired Professor of Community Medicine, Malla Reddy Institute of Medical Sciences, Hyderabad

2Professor of Community Medicine, Maharaja Institute of Medical Sciences, Vijaya Nagaram

3Professor Emiratus, Andhra Medical College, Visakhapatnam

4Professor of Ophthalmology, Regional Eye Hospital, Visakhapatnam

Corresponding Author

Dr. AA Kameswara Rao

Email: avasarala46@gmail.com

ABSTRACT:

Background: National Programme for Controlling Blindness in India is encouraging Vision Screening for refractive errors among school children by teachers.

Objectives: 1. To find out whether the vision screening conducted by school teachers will be of acceptable quality or not? 2. To find out whether the school environment will influence the eye-health of the school children or not?

Methods: Settings and Design: School setting, Cross -sectional descriptive study. Eighty Teachers were trained by the ophthalmologists to test for refractive errors and to detect other eye diseases. These teachers screened 5193 schoolchildren. Screening was repeated by an ophthalmologist assisted by two ophthalmic assistants, to assess the quality of teachers screening. Statistical techniques: Cluster sampling, Proportions, X2 test, Confidence intervals; Cohens Kappa statistic.

Results: The vision screening done by the school teachers was found to be of acceptable quality. (Excellent inter -rater agreement with specialists screening. Kappa statistic 0.993 for defective Vision and 0.867 for other eye diseases). Refractive errors and other eye diseases were significantly more seen in the schools with poor Sanitation 62 (1.19%), 214 (4.13%) respectively. Overall prevalence of Refractive errors was 85 (1.63%): Myopic 59(1.14) Hypermetropic 12 (0.23%) Astigmatic 11 (0.21 %) and Amblyopic 3 (0.05%) Overall Prevalence of other Eye diseases was 375 (7.23%). Xerophthalmia 156(3%), Conjunctivitis 148(2.8%), Proptosis 19(0.36%) Squint 13(0.14%), Phlycten 10 (0.25%).

Conclusion: Vision screening by teachers was of acceptable quality. Poor School environment was resulting in poor eye- health of school children.

Key-words: Vision screening by teachers, Eye diseases, Refractive errors

INTRODUCTION:

Childhood blindness is considered a public health problem when its prevalence exceeds 1 %. [1] It is more than 1% in several states of India. [2, 3] Uncorrected Refractive errors are the second leading causes of blindness in India, [4] next to cataract. Approximately 6-7% of school children are suffering from refractive errors in this country. [4] Refractive errors contribute to 19% of blindness in India. [3] Indian National Programme for Control of Blindness (NPCB) strengthened the eye services, emphasizing on the detection and treatment of refractive errors in school children. [2] NPCB advises to engage teachers for preliminary vision screening of the school children as school teachers are at an advantage to observe any child suffering from defective vision at an earliest point of time, next to parents.[2,4] Doubts were expressed by medical community whether the vision screening by teachers will be of acceptable quality or not. In the present study, the vision screening done by the teachers was crosschecked and validated by specialists by repeating the screening. The study also tried to find out whether eye -health of the school children was related to the school sanitation or not.

MATERIAL & METHODS:

Period of study: The study was conducted after obtaining the necessary ethical permission from the institute.

Sampling method: There were sixty schools with their children in the Visakhapatnam city. They were natural groups or clusters. By simple random sampling, fifteen schools (clusters) were selected out of 60 schools in the city. Cluster sampling was ideal in this situation for studying as it was simplest, involves less time and less cost and convenient than any other sampling technique. Statistical validity will be also good at 95% confidence interval with just 10% variation. Even W.H.O recommended 30 cluster sampling technique for evaluating coverage of child immunization. (Biostatistics by BK Mahajan)

A population of 5554 children (27.42% sample) was selected from 15 schools existing in the 7 clusters. (Table.1). A total of 361 children were absent for screening. Finally, 5193 school children were screened. They included 2546 boys and 2647 girls in the age group of 5 – 14 years. (Table.1)

The study included four phases: Preparatory phase, Training for the teachers phase, Vision screening by teachers phase and Vision screening by Specialists phase. In the first phase, the District officers of Education, the Head teachers of the 15 schools were briefed about the project and its objectives and their consent was obtained. A preliminary meeting was arranged at the health centre for discussions and planning. Eighty teachers were identified for the screening. The class- wise lists of the children were secured from 15 schools. Survey formats, teaching material, E – Charts (Snellens charts) and pamphlets were prepared. In the second phase, two ophthalmologists assisted by faculty members from community medicine department trained 80 teachers in vision screening for two days. The teachers were briefed regarding the structure and functions of the eye and how to test for defective vision using Snellens E chart. The standard WHO Vision Screening Training Manual by Claire Mackenzie was used for training the teachers. [5] Teachers were provided with necessary E charts. Printed material regarding the use of E chart and function of eye was supplied in local vernacular language. During the training, each teacher practiced the vision screening on his/her colleague. School teachers were made confident that they could carry on the screening program individually. Teachers were given one weeks time to practice the vision screening on school children using E chart so that children will be well-versed with E chart by the time actual screening was commenced. School teachers were particularly trained to train their children correctly in showing the direction of limbs of E in E chart.

In the third phase, the children were screened by teachers for defective vision and other eye disorders. The Snellens charts printed in black and white were kept in adequate light. They were placed at average eye level of children being screened at 6 meters distance. Teachers demonstrated the children how to show their fingers by looking at E-Chart. The smaller children were asked to show the direction of the three limbs of E in the chart with their fingers. During actual screening, the directions of the limbs of E in the charts were changed very often by changing the position of chart to avoid bias due to previous memorizing. Older children were asked to tell the direction: up, down, right or left. Teachers used pointing stick to show the symbol of E. Care was taken to keep the stick below the symbol without obstructing E from childs vision. Children wearing eye glasses were screened with glasses. Visual acuity less than 6/6 was considered as cut off value for defective vision in this study. [6]

A pretested proforma was used in all 15 schools for screening the other eye disorders. Charts and figures showing conjunctivitis, Bitots spots, trachoma etc were shown to teachers. A few patients were also demonstrated to the teachers. Uniform case definitions were taken into consideration during clinical examination for the diagnosis of eye disorders as shown below

  1. a) Case definition used for conjunctivitis was conjunctival injection (redness) with stickiness of eye lids with pus in the eye. Case definition for prominent eye (Proptosis and exophthalmos) was based on measurement of the exophthalmos scale – The distance between the outer canthus of the eye to the top of cornea was measured. A measurement more than 15mm was considered as Proptosis. Those children with prominent eyes were subjected to serum protein bound iodine (PBI) test to exclude exophthalmos due to hyperthyroidism (Normal range is 4 – 8 ug/dl). Case definition for Xerophthalmia – WHO XIB (Bitots spots with conjunctival xerosis) was considered. For Squint detection – Covering test was used. In the fourth phase, all the children found with defective vision or other diseases by teachers were again screened by an Ophthalmologist assisted by ophthalmic assistants. The children found to be having defective vision during second screening were subjected to investigations like refraction, fundus examination. Parents were motivated to bring their children for the screening, treatment and surgical correction. All the children with eye disorders were treated with free medicines, local antibiotics, vitamin A&D capsules etc by the ophthalmologist. A few medicines were left with the teachers for further use. Referral services were arranged for surgical corrections of leukomas, keratoconus and squint etc. One non governmental organization was approached for providing spectacles free of cost to the children with defective vision.

Sanitary grading of schools was carried out to find out whether there was any influence of school environment on School eye health. Ten parameters laid down in the School Health Committee, Baroda report (1961) were considered for this sanitary grading. They are: 1) Schools away from busy place and having approach to road.2) Site of the school is 5 acres and is on high land.3) Presence of permanent structure.4) Schools having class rooms allowing not more than 40 students. 5) Colour of walls being white.6) Cross ventilation present. 7) Good natural lighting from left side 8).Independent water supply.9) Separate eating facilities for children & outside vendors are not allowed.10) Lavatories and Urinals present separately for boys and girls. Schools were graded as follows: Schools possessing only 1 – 3 positive parameters were graded as grade C schools with poor sanitation, schools having 4 – 6 positive parameters as B grade schools with average sanitation and schools having 7 positive parameters and more as grade A schools with good sanitation. According to this division, there are four A grade schools with good sanitation, 5 B grade schools with average sanitation and 6 C grade schools with poor sanitation.

Data was analyzed using proportions, and X 2 test. Kappa statistic assessed for inter-rater agreement between the two screenings using Lendis & Koch 1977 Columbia university calculator.

RESULTS:

Defective vision (DV):--

Overall prevalence of Defective vision (DV) was 85 (1.63%).

Boys 41(0.78%) Girls and Boys were almost equally affected ( boys 41, 0.8% versus girls 45, 0.9%),

Myopic 59 (1.14%) Hypermetropic 12 (0.23%) Astigmatic 11 (0.21 %) and Amblyopic 3 (0.05%).

Defective vision was more seen in 9 – 13 years 45 (0.87%) and in poor families 71(1.36%).

Other Eye Disorders (OED):-

Overall Prevalence of Other Eye diseases (OED) is 375 (7.23%):-

Xerophthalmia 156(3%), Conjunctivitis 148(2.8%) Phlyecten 10 (0.25%) Squint 13(0.14%) trachoma 1(0.01%) leukoma 1 (0.01%) proptosis19 (0.36%) [2 Tower skulls, 6 Myopic, 11 small sockets (Exophthalmoses excluded)].

Eye diseases were more seen in boys of 5-11 years of age group340 (6.54%) more in poor families 305 (5.87%)

Xerophthalmia was more in boys (93, 1.8% versus 63, 1.2% girls). Inflammatory diseases were more than Nutritional diseases (177, 3.4% versus 156, 3%). (Table.2)

Teachers found 102 children (1.96%) to be having defective vision and the specialists confirmed 85 children (1.63%). Difference was 0.33%.Kappa statistic was 0.83 for defective Vision, Agreement was 0.0993, (almost perfect agreement) at 95% CI, lower limit 0.774 upper limit 0.886, (SE0.029). Teachers also found Other Eye diseases among 395 Children (7.6. %) and specialists confirmed 375 (7.23%). Difference was 0.37%. Kappa statistic for other eye diseases= 0.945 agreement was 0.992, almost perfect agreement) excellent inter-rater agreement, almost perfect agreement at 95% CI, Lower limit 0.978 Upper limit 0.962 SE 0.009).

School sanitation and eye health: Refractive errors and other eye disorders were significantly more seen (X2df2=5.63, p< 0.05, highly significant) in schools with poor sanitation than in schools with good sanitation (Table.3)

DISCUSSION:

The vision screening done by the teachers is found to be of acceptable quality. Specialists confirmed that the teachers have correctly diagnosed defective vision and Other eye diseases in 84 % and 90% of children respectively. Only 16% and 10% of children with defective vision and eye diseases respectively have failed the gold test by specialists (full eye examination including visual acuity testing and radioscopy). There was a good agreement between the two screenings done by the teachers and specialists and only a little difference. This amount of error is tolerable when the gain of saving the specialists time is considered. But, it should be remembered that the screening done by the teachers cannot replace or substitute the specialists screening, the gold standard.

One may doubt about the biological sense of relevance of school sanitation and refractive errors and eye infections. Two of the ten parameters used for sanitary grading .i.e. colour of the walls being white causing glare on the reading materials and inadequate lighting in the class rooms where the children will be working continuously for 6-8 hours in a day can affect their visual activity. In addition, the dusty atmosphere and overcrowding in the class rooms can cause eye infections like conjunctivitis, allergic conjunctivitis etc in the children.

Defective vision and other eye diseases were significantly more prevalent in schools with poor sanitation. Dim light factor, glaring colour of the walls, poor reading techniques adopted by the children and bad reading posture were probably operating in these schools to cause defective vision. The ideally, 40 children may be allowed in a room. Overcrowding present in the schools with poor sanitation predisposed to more number of eye infections in the study. In these schools, the light was falling from the front side, instead of from the left side, and causing glare in the eyes resulting in defective vision and the white coloured walls are exaggerating the effect. There is a possibility of subjective variation with regard to the space; lighting and ventilation as they are not actually measured but the eye problems are more in these schools. . Infectious and nutritional eye disorders in children were associated with bad environment of schools.

Several studies reported refractive errors in the same age group (5-13 years) of children. [2, 6, 7, 8, 9, 10] Prevalence of defective vision was low (1.63%) in this study. Such a low figures were also seen with a few other studies from Africa, [11, 12] Nepal [13] and India. [7] But the majority of the studies conducted world wide revealed higher prevalence rates ranging from 6.4% to 54%. [8, 14 to 18] This variation may be due to the difference in cut off values used for detecting defective vision. While 6/6 was used as a cut off value for the present study, the other studies used 6/12, 6/18 & 20/40 as cut off values. Refractive errors noticed in this study were myopia, Hypermetropia and astigmatism in that order. Myopia turned out as a major cause of defective vision in this study as in other studies. [7, 8, 13, 18, 19, 20] Females with myopia were more in the present study akin to the other Asian, Middle East and Latin American studies. [7, 8, 13, 18 to 21] Increase in myopia with age was found in this study as observed by Murthy et al. [19] Hypermetropia and astigmatism were the common refractive errors next noticed to myopia as seen with He M study from China. [15]

Other eye disorders noticed were Xerophthalmia, conjunctivitis, squint and trachoma in that order. Xerophthalmia was about 3% in this study, higher than the figures revealed by other Indian NPCB and Chaturvedi S studies. [4, 22] Conjunctivitis was markedly present in this study that too more in boys from bad schools. It may be due to their excessive outdoor playing in dusty playgrounds than girls. Squint and trachoma were also noticed in this study as observed by Chaturvedi from India. [22] Trachoma was less in this study, when compared to Chaturvedi study. Trachoma was seen in girls using Kaajal (black pigment prepared from oily smoke) for their eyes.

The study answered its two objectives.It utilized the teachers, a valuable human resource in the community. The study suggested a worthy strategy to save the valuable time of specialists. The school children were benefited as their teachers were taking care of them. Their parents were also happy for the same reason. Teachers were benefited with their gaining medical knowledge. However, the cluster sampling method used in this study, though convenient, was accurate about 95% only. Absence of about 361 children for the screening was another drawback. The non response was minimized to less than 10% by repeated motivation of parents. Sanitary grading was also vulnerable to subjective bias. Each environmental factor should be studied for its causal contribution by further studies. Studies of this sort, linking poor environment with eye-health are scarce and are worth conducting

CONCLUSION:

To conclude, the vision screening by the school teachers was of acceptable quality and worth practicing to prevent and control childhood blindness as recommended by NPCB. The concept of making a school teacher responsible for the child health was a welcome feature. Improvement of school environment should be given priority while planning for school eye services

REFERENCES:

  1. Brilliant LB. World Health Stat Quart 37(2) 162-185.
  2. Park K. Parks Textbook of Preventive & Social Medicine M/S Banarsidas Bhanot Publishers, Jabalpur, India, 19th edition, pp360-362.
  3. Gupta MC, Mahajan BK. Text book of Preventive& Social Medicine, Third edition,2003, Jaypee Brothers Medical Publications (P) Ltd, New Delhi, India, pp322-323.
  4. WHO National Programme for Control of Blindness Survey 1986-89(India).
  5. Claire Mackenzie. Standard Vision Screening Manual; published by Claire Mackenzie,3715,S.E. 37 TH street, Gainesville FL 32601,USA.,Revised edition 1986.
  6. May& Worth. Diseases of the eye.13th edition; T. Keith Lyle, Cross & Cook, C.B.S Publishers & Distributors, New Delhi.
  7. Dandona R, Dandona L, Srinivas M et al. Refractive error in children in a rural population in India. Invest Ophthalmol Vis Sci 2002;43(3):615-22.
  8. Zhao J, Pan X, Sui R et al. Refractive Error Study in Children: results from Shunyi District, China. Am J Ophthalmol 2000;129(4):525-7.
  9. Logan NS, Gilmartin B. School vision screening, ages 5-16 years: the evidence-base for content, provision and efficacy. Ophthalmic Physiol Opt 2004;24(6):481-92.
  10. Limburg H, Kansara HT, dSouza S. Results of school eye screening of 5.4 million children in India--a five-year follow-up study. Acta Ophthalmol Scand 1999;77(3):310-2.
  11. Wedner SH, Ross DA, Todd J et al. Myopia in secondary school students in Mwanza City, Tanzania: the need for a national screening programme. Br J Ophthalmol 2003;87(5):660.
  12. Naidoo KS, Raghunandan A, Mashige KP et al. Refractive error and visual impairment in African children in South Africa. Invest Ophthalmol Vis Sci 2003;44(9):3764-70.
  13. Pokharel GP, Negrel AD, Munoz SR et al. Refractive Error Study in Children: results from Mechi Zone, Nepal. Am J Ophthalmol 2000;129(4):525-7.
  14. Nepal BP, Koirala S, Adhikary S et al. Ocular morbidity in schoolchildren in Kathmandu. Br J Ophthalmol 2003;87(5):531-4.
  15. He M, Huang W, Zheng Y et al. Refractive error and visual impairment in school children in rural southern China. Ophthalmol 2007;114(2):374-82.
  16. Lu P, Chen X, Zhang X et al. Prevalence of ocular disease in Tibetan primary school children. Can J Ophthalmol 2008;43(1):95-9.
  17. Tananuvat N, Manassakorn A, Worapong A et al. Vision screening in schoolchildren: two years results. J Med Assoc Thai 2004;87(6):679-84.
  18. Goh PP, Abqariyah Y, Pokharel GP et al. Refractive error and visual impairment in school-age children in Gombak District, Malaysia. Ophthalmol 2005;112(4):678-85.
  19. Murthy GV, Gupta SK, Ellwein LB et al. Refractive error in children in an urban population in New Delhi. Invest Ophthalmol Vis Sci 2002;43(3):623-31.
  20. El-Bayoumy BM, Saad A, Choudhury AH. Prevalence of Refractive Error and low vision among school children in Cairo. East Mditerr Health 2007;13(3):575-9.
  21. Maul E, Barroso S, Munoz SR et al. Refractive Error Study in Children: results from La Florida, Chile. Am J Ophthalmol 2000;129(4):445-54.
  22. Chaturvedi S, Aggarwal OP. Pattern and distribution of ocular morbidity in primary school children of rural Delhi. Asia Pac J Public Health 1999;11(1):30-3.

Table 1: Age & Sex distribution of children of study population

Age in years

Boys

Examined

Girls

Examined

Total

Examined

5 – 7

704(13.55)

722(13.9)

1426(27.46)

7 – 9

948(18.25)

958(18.45)

1906(36.7)

9 – 11

786(15.13)

764(14.71)

1500(28.9)

11 – 13

154(2.96)

198(3.81)

352(6.78)

13 – 15

4(0.08)

5(0.09)

9(0.17)

Total

2546(49.03)

2647(50.97)

5193(100)

Table 2: Defective vision and other eye diseases among the study population

Disease

No.

%

Refractive errors

85

1.63

Stye

18

0.41

Proptosis

19

0.36

Conjunctivitis

148

2.84

Phlycten

10

0.25

Trachoma

1

0.01

Leukoma

1

0.01

Squint

13

0.14

Vitamin – A Deficiency

156

3.00

Congenital

5

0.09

Others

4

0.07

Total

460

8.86

Table 3: Children with Refractive errors and eye disorders according to School sanitation

School sanitation

Eye health affected (refractive errors& eye disorders) (%)

Eye health not affected (%)

�Total

Good sanitation

71(1.37)

2675(51.5)

2746 (52.8)

Average sanitation

113(2.17)

1326(25.5)

1439 (27.8)

Poor sanitation

276(5.3)

732( 14)

1008( 19.4)

Totals

460(8.85)

4733(91.1)

5193(100)

(X2df2=5.63, p< 0.05, highly significant)





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