DAKSHA PATEL: Good morning, Professor Murthy. Thank you very much for joining us today on Skype from Hyderabad. We appreciate you taking time to speak to us. You’ve been involved in the development of school screening programmes in India for a long time. Could you give us a brief background to this whole development?
GVS MURTHY: Right. It’s a pleasure to give you a brief idea about how this tool was developed, and how this process of schools training has been conducted in India. India actually had a school health programme right from the 1960s. But then the school health programme did not look at looking at the vision of schoolchildren. It was more of a health examination. So way back in 1989, when we had the Danish International Development Agency-supported programme for the control of blindness in India, they were working in five pilot districts. And they felt that in addition to cataract services, it was important to look at school-going children and try and provide services for refractive errors in school-going children.
And that is how this idea first worked out. Five pilot districts spread across the country where they went and tried out a number of tools using and different vision cut-offs, before finally settling on a particular vision cut-off. The same methodology has been used, now, since 1989 till date. But it is now run, rather than by DANIDA, by the National Programme for Control of Blindness. And over these years, 25 million children who go to school and are in grade six to nine have been covered under the programme. And about 0.2 million children have received free spectacles under the programme. It is a uniform methodology adopted right across the programme. But some states do better than the others.
But otherwise, the methodology is exactly the same.
DAKSHA PATEL: Professor Murthy, could you tell us how was the cutoff for the screening test established between 6/9 and 6/12?
GVS MURTHY: Yeah. So there were a couple of issues which were considered when, one, the cut-off tool was identified, and two, specific age groups were identified. So this programme looked at children aged 10 to 14 years who were in school, because nearly 17% of the Indian population is aged 10 to 14 years, and about 70% to 75% of them are enrolled in secondary school, which covers grades six to nine. So that was the reason why these schoolchildren were taken up. The operational feasibility, because school teachers were used for the screening exercise. And therefore, they just had a one-day training, and this they had to go and pick up.
When they had a one-day training, it was important that they were able to pick up as many children as possible among schools who are being screened. So an experiment was done in two of the districts which were being covered in 1989 by the DANIDA programme. And they tried out two different vision acuity charts. One, they used a 6/9 optotype, and another, they used a 6/12 optotype. The validation, both of using teachers and both the cut-off points. So that was one validation. The second validation was of the optotype. So when they looked at the validation of teachers versus an optometrist, the sensitivity of the teacher to pick up individuals of schoolchildren was about 86% and the specificity was 98%.
When they looked at the vision card and they looked at the 6/9 optotype, it was about 71% sensitivity and 94% specificity. Then, they looked at the 6/12 optotype. The sensitivity improved, or increased further. The specificity, there was not much of a change. When they looked at the teachers and spoke to the teachers, the teachers were very unhappy when they picked up only, say, one child per school when they used 6 by 12 optotype, compared to about five or six children per school when they used a 6 by 9 any eye optotype. So to look at the operation of a programme which would involve the teachers and keep their interest going, so there was this toss-up between using 6/12 or 6/9.
Looking at the high sensitivity and specificity rates with 6/9 any eye, it was decided to use the 6/9 optotype in the national programme in India.
I’d also like to share the tool that is used for the schools’ training in India. This is a laminated card, a cardboard cut-out, it has an E in front, which is in the vernacular language. And if you reverse this card, you find that there are four optotypes, which are equivalent to the 6 by 9 optotype. So what the teacher does is that she or he holds the card at a distance of six metres, and the child is asked to read each of the optotypes which is pointed out. If the child can read three out of the four, then the child is passed the screening test.
And if the child cannot read at least three, then the child is referred on to the ophthalmic assistant. Once one eye is completed, the teacher just rotates the card, so the child can then read it again. So rotating the card for each of the eyes then protects the children in that group from memorising the order of the Es that are on the card. So it’s a very simple tool. Very easy for the teacher. And on the inside of the card are the instructions, which become a ready reckoner for the schoolteacher. So after the training, they could refer to these points, which are in the vernacular, for them to actually conduct the screening.
DAKSHA PATEL: Professor Murthy, thank you very much for joining us today and for sharing your experiences with the National School Vision Testing Programme in India.