PRISSM (Perfecting Refraction in India With Superior Service Models): A Cluster-randomized Controlled Trial of Three Models of School-based Spectacle Service Delivery in India
Phase: NA
Conditions: Refractive Error
Sponsor: Sun Yat-sen University

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Study Identification 
Official Title of the study: PRISSM (Perfecting Refraction in India with Superior Service Models): A 
Cluster-randomized Controlled Trial of Three Models of School-based Spectacle Service Delivery in 
India 
Date of the document: 18 June 2019 
NCT number:  NCT03983278 
Unique Protocol ID: 
PRISSM (19.09v3) 
Brief Title: 
Perfecting Refraction in India with Superior Service Models (PRISSM)   
 
Study Status 
Record Verification: 
June 2019   
Study Start: 
July 2019   [Anticipated] 
Primary Completion: 
March 2020   [Anticipated] 
Study Completion: 
June 2020   [Anticipated] 
 
Sponsor/Collaborators 
Sponsor: 
Sun Yat-sen University   
Responsible Party: 
Principal Investigator 
Principal Investigators: Prof Nathan Congdon and Ms Priya Adhisesha Reddy 
Affiliation: Queen's University Belfast 
Collaborators:  
1. Aravind Eye Hospital, Madurai 
2. PBMA’s H.V. Desai Eye Hospital, Pune 
3. Sadguru Netra Chikitsalaya, Chitrakoot 
4. Orbis International 
5. Dr. D.Y. Patil Medical College, Hospital & Research Centre, Pune 
 
 

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Study Description 
Brief Summary: 
Some programs do the screening, refraction testing and provision of spectacles to children entirely 
in the school setting ("School Model"). One strength of such programs are that most children at 
school who need spectacles get them. However, sustainability is poor, because spectacles cannot be 
sold in many schools and there may be too few refractionists to cover all schools in most countries. 
Other programs provide vision screening at schools, but refer children who fail vision screening to 
nearby facilities for refraction and distribution/sale of spectacles ("Referral Model"). This model's 
strengths include lower demand on refractionists and opportunities for the spectacles to be sold. 
However, a disadvantage is that most of the referred children do not attend the specialist facility. 
One way to improve this might be to enhance the Referral Model and a recent USAID review by Priya 
Reddy and Ken Bassett showed that involving teachers in vision screening and family counseling 
significantly increases children’s use of spectacles. Therefore, at 141 schools in India, involving over 
42,300 children (assuming a minimum of 300 children/school), the investigators will study an 
"Improved Referral Model," with strong teacher involvement, to investigate the potential benefits of 
combining the lower costs of the "Referral Model" with the high uptake of the "School Model". The 
investogators will also assess the effects of allowing parents to purchase enhanced spectacles, rather 
than having their child use the free spectacles. Children will be randomized by school to the “School 
Model,” “(Improved) Referral Model” or the “(Improved) Referral Model + Cost Recovery (sale of 
“upgrade spectacles” alongside ofering free spectacles. The main study outcome will be program 
cost-effectiveness, defined as the program cost per child identified with correctable refractive error, 
who receives spectacles, and wears them at an un-announced visit 3 month after distribution. Profit 
on spectacles sold in the "Referral + Cost Recovery" group will be subtracted from the program costs 
in this study group. The groups will be compared, with and without adjustment for baseline 
characteristics. 
 
Detailed Description: 
 
Background 
Need: The leading cause of vision impairment among children in India, and in the world more widely, 
is an uncorrected refractive error (URE). For example, the population-based Refractive Error Studies 
in Children (RESC) studies found that 61% of vision impairment in rural children[1] and 89% in urban 
children[2] in India was due to URE, and that as few as 10% of rural and 35% of urban children who 
need spectacles actually had them.[1,2,3] The impact of this shortfall in service delivery is 
highlighted by recent randomized trials in Asia showing that provision of spectacles significantly 
improves children's educational outcomes,[4] and the shortcoming in India is particularly important 
because India has the highest number children of any other country.[5] 
Potential impact: This trial has the potential to impact on at least two of the Sustainable 
Development Goals (SDG) of the United Nations. Although interventions to prevent myopia, such as 
topical anti-muscarinic therapy[6] and increased time outdoors[7], show much promise, they are not 
yet ready for large-scale use. Until then, school vision programs remain the principle tool to address 
the problem of URE in India and elsewhere, and thereby improving children's access to high-quality 
education (SDG #4) and helping to address unequal access of girls to healthcare services affecting 
vision (SDG #5).[8] In fact, the Indian government and many private entities are already taking a very 
active role in school vision screening. Since the onset of the Sarva Shiksha Abhiyan (Education for All) 

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program in 2002, many millions of children have undergone school vision screening, but refraction 
and spectacles distribution has been limited and much more could be done to help. To sustain and 
expand these efforts, more cost-effective approaches are needed. 
Problems with current models: Many non-governmental organization (NGO) and government 
spectacle distribution programs in India and elsewhere use school-based vision screening, refraction 
and provision of spectacles. This is particularly true in poorer, rural or other under-served areas. The 
greatest strength of such programs is that they deliver refractive services and spectacles to a large 
proportion of children requiring them when school attendance rates are high. However, 
sustainability is problematic: these programs usually deliver spectacles for free, because their sale is 
not permitted in many schools. Further, this model is very demanding on resources, because 
refractionists must travel to numerous schools in their catchment area. Finally, it has been suggested 
that long-term compliance with spectacle wear may be higher when families make at least some 
contribution to spectacle costs, although evidence for this assertion is lacking.[9] 
Alternatively, other programs, particularly those in urban or better-served areas, may provide vision 
screening at schools, but then refer children and families failing to screen to a nearby facility for 
refraction and distribution or sale of spectacles. The strength of this model is that it is less 
demanding of resources (refractionists remain at their base facility rather than being directly 
involved in outreach screening) and spectacle sales at medical facilities are often more acceptable 
than sales in schools. Therefore, this model may be more sustainable. However, program experience 
and research [10] have shown up to two-third of the referred children/families do not attend the 
facility that they are referred to. 
Potential superiority of optimized Referral Models and improvements for vulnerable children: 
Recent evidence from a review by Reddy and Bassett[11,12] and trials by Congdon[13] suggest that 
various strategies which increase involvement of teachers in the screening process (parent-teacher 
meetings; short message service (SMS), phone call, or handwritten notes in the students diary from 
teachers to families who do not complete referrals) can significantly increase the proportion of 
families following up for care at an outside eye care facility. Therefore, this cluster randomized trial 
will test an "optimized" model of distribution of spectacles, maximizing teacher involvement, to 
determine whether this approach can achieve comparable service uptake to fully school-based 
models at a greater level of cost-effectiveness. High-quality, trial-based evidence that showed that 
optimized Referral models are both low-cost and high-coverage may provide a strong stimulus to 
scale up refractive service programs in India and other low-middle income countries (LMICs). These 
programs can benefit millions of low-income children not currently receiving refractive services, thus 
improving their access to classroom learning. 
This trial will compare two general screening methods: 1. School model and 2. Referral Model. A 
"Cost model", which is builds on the Referral model but includes the sale of spectacles, will also be 
included, as a third randomized group. In the School model, refraction occurs at the school and 
spectacles are given to children at the school, which may yield a higher rate of compliance, but is 
more expensive and may not be sustainable. On the other hand, the Referral model, where the 
children are referred to be screened at the vision center or service center may have lower 
compliance but be less expensive and more likely to be sustainable. This study examines the 
hypothesis that greater teacher involvement in screening and follow up can improve the compliance 
of children and families with the examination at the service center in the Referral model. For this 
reason, the main outcome of the trial is cost-effectiveness (amount spent per child who receives 
spectacles that improve his/her vision, and which are worn at an un-announced examination three 
months after distribution). If the teacher intervention can improve compliance in the Referral model, 

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it will most likely be the more cost-effective model. If the teacher's intervention doesn't increase 
compliance in the Referral model, then the School model is likely to be the most cost-effective. 
Because money invested in school screening is wasted when families do not comply with referral to 
the Vision Centre in the Referral model, compliance with a referral will be the most important 
determinant of our main cost-effectiveness outcome. 
Experimental plan Population: School children in the 6th to 10th grades (11-15 years of age) at 
public and private, rural and urban schools with a minimum of 300 students and covered by the 
Orbis India REACH (Refractive Error Among CHildren) program, including those located nearer and 
further from Vision Centers, which will serve as the principle eye care facilities in the study. 
Eligibility: Enrolment criteria: Children in randomly-selected 6th to 10th grades in selected schools 
with presenting visual acuity (that is, wearing spectacles if spectacles are owned at baseline) <= 
6/9.6 (0.2 LogMAR) in either eye. Children who already own spectacles will be requested to bring 
their spectacles on the day of screening, and children whose vision with existing spectacles meets 
study criteria will be eligible. Exclusion criteria: Parents returning the form indicating they do not 
wish their child to participate; no Vision Center within 50 km of the child's home (a rare occurrence 
in the REACH network). If the child is incapable of completing visual acuity screening in both eyes for 
any reason. 
Sample size: At a refractive error prevalence of 3%, with minimum of 300 children/school, 95% of 
children receiving spectacles in the School Model, 40% of children wearing them in both the School 
Model and Referral Model groups at un-announced 3 month visits, a cost of US$1.30 per child 
screened in the School Model and US$0.80 in the Referral Model (all assumptions based on REACH 
Program data), if 58.5% of families accept referral to receive refraction and spectacles in the Referral 
Model, this would reach the same cost-effectiveness as the School Model. A total of 141 schools (47 
in each of three groups) across three participating hospitals would be sufficient to detect 
significantly better cost-effectiveness of the Referral Model if 65% of families accept referral for 
refraction/spectacles, which is the target in our hypothesis; with a power of 90%, an alpha-error of 
0.05, and an intracluster correlation coefficient (ICC) (a measure of how similar children are to one 
another within schools: "clustering") of 0.20. 
Randomization: An independent statistician having no contact with participants will generate the 
randomization sequence using a computer system that is inaccessible until after the school has 
agreed to join the trial. Schools will be stratified into two groups as Public and private. The schools in 
each stratified group will be randomly assigned to either the intervention (referral models) or 
control group (school model) in a 1:1:1 ratio with a block size of three to ensure balance. After 
randomization, the schools and the children in them will not be masked to their allocated 
intervention but staff assessing data for the main outcome will not know a child's group assignment. 
Data to be acquired at baseline: Child: Age, gender, spectacles ownership, presenting and best 
corrected visual acuity in both eyes; refractive error in both eyes; distance of child's home from 
nearest Vision Center; brief spectacle attitude questionnaire; brief family Socio-Economic Status 
(SES) questionnaire[15]. Teacher: Brief questionnaire on attitudes and knowledge towards 
spectacles. Program: Survey of all program costs for screening and distribution for each model. Our 
cost-effectiveness analysis will be from the Program rather than the societal perspective, but the 
investigators will capture  travel cost info from a 1%  sample of randomly-selected children/families 
and capture information about teacher time spent in meeting with parents, sending notes to parents  
and encouraging children to wear spectacles in a 1 % random sample of Referral group teachers, in 
order to perform a sensitivity analysis of the impact of including these costs. Regarding programs 
costs, in the School model, where the optometrist team does the screening at school, the program 

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cost will be calculated by taking the cost of the primary and secondary screening, cost of the 
spectacles, and cost of delivering them. In the Referral model, the investigators will include the cost 
of primary screening, secondary sreening at the vision centres and the cost of spectacles. In the Cost 
recovery model, the cost recovered by selling the spectacles (difference between retail price and 
cost of spectacles to the hospital) will be subtracted from the program cost. School: Urban versus 
rural, public versus private, size of the school, SES of community, and distance of the school from 
nearest Vision Center. 
 
Follow-up schedule and follow-up data: Self-reported and observed spectacle wear to be 
ascertained at an un-announced follow-up at school 3 months after distribution of spectacles. 
Additionally, the following the data for the Referral groups will be collected from the referral centre 
and verified from the children in a random sample of 10% of children: Did they visit the referral 
centre? Did they receive free spectacles? Did they elect to purchase upgrade spectacles? (in the Cost 
Recovery group).  Children in the Referral groups not having received spectacles at the referral 
centres will receive them now, and so their visual acuity with spectacles and refractive power in 
each eye will be measured and recorded. 
Data collection: An experienced project coordinator will be responsible for data collection and 
follow-up. The project coordinator will be thoroughly trained on the completion of the data 
collection forms. 
Data Management Plan: The baseline data will be entered and stored in the database (“Reachsoft”), 
which is password protected. Other data for the study will be collected and entered by an external 
data entry operator and sent to the project manager to store it in a password-protected system. The 
collected data will be analyzed in de-identified fashion by the study statistician in India. 
A copy of the final study data will be shared with Queen's University Belfast (QUB)  under the data 
sharing and protection outlined in a Memorandum of Understanding. The final dataset will be stored 
in the QUB database under QUB custody. The study team will have access to the data for research 
and analyses purposes only. Data will be stored for 5 years after the end of the study. 
 
 

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• Study Flow: 
 
 
 
Referral Model 
(n=47 schools) 
Referral Model + 
Cost Recovery 
(n=47 schools) 
School Model 
(n=47 schools) 
Enrollment (n=141) 
Primary Screening 
done by vision 
screener 
Fail 
P
a
s
s 
Back to class 
Screened by 
optometrist 
Fail 
P
a
s
s 
Back to class 
Glass 
prescription 
Other 
referrals 
Compliance 
and Follow-up 
Primary Screening 
done by vision 
screener 
Fail 
P
a
s
s 
Back to class 
Referred to 
VC or nearby 
facility 
Primary Screening 
done by vision 
screener 
Fail 
P
a
s
s 
Back to class 
Referred to 
VC or nearby 
facility 
Refraction 
and free 
Compliance 
and follow-up 
Reached 
Follow-up 
screening and 
free spectacles 
after 3 months 
Not 
Reac
hed 
Refraction and 
free and  or 
upgraded  
spectacles 
Compliance 
and follow-up 
Reached 
Follow-up 
screening and 
free spectacles 
after 3 months 
Not 
Reac
hed 

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Data Analytic Plan: Data will be analysed using STATA 15. The primary and secondary outcomes will 
be compared between the three randomized groups using an intention to treat approach with and 
without adjustment for the baseline child, school and teacher factors listed above. Our primary 
outcome is cost-effectiveness (cost per child identified needing spectacles, who gets and is still 
wearing them 3 months later). The investigators have two hypotheses about this primary outcome: 
Primary hypothesis: The improved Referral model which involves teachers contacting families will 
sufficiently improve uptake that this Referral model will be more cost-effective than the School 
model. 
Proposed analysis: Cost per child identified needing spectacles (program perspective, as above), who 
gets and is still wearing them 3 months later, compared between School and Referral model. 
Secondary hypothesis: Cost recovery from the Referral + Cost Recovery Model will make this more 
cost-effective than either of the other models. 
Proposed analysis: Cost per child identified needing spectacles, who gets and is still wearing them 3 
months later, compared between the Referral + Cost Recovery and other groups.   
The investigators will also do a stratified analysis comparing the main outcome between groups at 
each of the  3 participating hospitals.  Additional stratified analyses / balancing of the main outcome 
between groups wil be done for  public versus private schools and rural versus urban schools. 
The investigators will be using Latent class regression analysis and Finite mixture models to analyze 
the main outcome.  
Monitoring: A dedicated Project Manager, Ms. Priya Reddy, will be responsible for the overall 
planning, implementation, coordination, and monitoring and evaluation in the project. She will 
recruit a local project assistant at each site to coordinate all activities at the community level and at 
the base hospital and Vision Centers; ensure that appropriate planning is done for organizing and 
implementing screening activities; and coordinate availability of trained manpower, equipment, and 
facilities. Ms. Reddy will interact with Orbis India Project Managers for the REACH program. 
Research advisors Congdon, Gogate, and Bassett each has decades of familiarity with refractive error 
research in children, and all have engaged in multiple research projects in India. Additionally, 
Congdon has worked with Orbis since 2009 and is now its Director of Research. 
 
Ethical considerations: Ethical approval has been received from two of the partners in India and 
Queen's University Belfast and will be sought from the additional partner. In the two Referral model 
groups, children who need to go to the facility to get spectacles but do not do so within the three-
month period will receive free spectacles at closeout, so that no child requiring treatment will be left 
untreated. 
  
 
Conditions 
Conditions: 
Childhood Refractive Error 
Keywords: 
Child, refractive error, myopia, school screening, cost effectiveness, India 
 

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Study Design: Cluster-randomised, investigator-masked trial 
Study Type: 
Interventional 
Primary Purpose: 
To determine the most cost-effective approach to school-based vision 
screening and spectacles delivery in India . 
Health Services Research 
Study Phase: 
N/A 
Interventional Study Model: 
Parallel Assignment 
 
Randomization, Interventions: This is a cluster randomized trial, with eligible children allocated to 
the intervention that their school was randomized to receive. This will be one of the following three: 
School Model (47 schools): Vision screening will be carried out by the vision screeners; refraction will 
be done at the schools by refractionists; and children who need them will be given free spectacles at 
the school within two weeks. 
Referral Model (47 schools): Vision screening carried out by the vision screeners; and children are 
referred to nearby Vision Center/ secondary center for refraction and delivery of free spectacles. 
Teachers will contact families not presenting for follow-up care and for spectacle compliance 
through SMS, phone call and notations in the school diary. 
Referral Model + Cost Recovery (47 schools): Vision screening carried out by the vision screeners; 
children referred to Vision Center for refraction and delivery of spectacles with an option to 
purchase "upgrade spectacles" (which was shown to be appealing to families in the recent PRICE 
study[14]. These spectacles have scratchproof coatings and designs selected to appeal to local 
children. Teachers will contact families not presenting for follow-up care through SMS, phone call 
and notations in school diary. 
 
Number of Arms: 
3 
Masking: 
Single (Investigator) ): Investigators assessing the components of the main study 
outcome will be masked to the study group assignment of the school. 
Staff assessing data for the main outcome will be masked to a child's group assignment. 
 
Allocation: 
Randomized 
Enrollment: 
141 schools [Anticipated] 
 
Arms and Interventions 
Experimental: School Model 
Vision screening will be carried out by the vision screeners; refraction will be done at the schools by 
refractionists; and children who need them will be given free spectacles at the school within two 
weeks. 

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Experimental: Referral Model 
Referral Model (47 schools): Vision screening carried out by the vision screeners; and children are 
referred to nearby Vision Center/ secondary center for refraction and delivery of free spectacles. 
Teachers will contact families not presenting for follow-up care and for spectacle compliance 
through SMS, phone call and notations in the school diary. 
 
Experimental: Referral Model + Cost Recovery 
Referral Model + Cost Recovery (47 schools): Vision screening carried out by the vision screeners; 
children referred to Vision Center for refraction and delivery of spectacles with an option to 
purchase "upgrade spectacles" (which was shown to be appealing to families in the recent PRICE 
study[14]. These spectacles have scratchproof coatings and designs selected to appeal to local 
children. Teachers will contact families not presenting for follow-up care and for spectacle 
compliance through SMS, phone call and notations in school diary. 
 
Outcome Measures 
Primary Outcome Measure: 
Program cost-effectiveness 
Program cost per child identified with correctable refractive error, who receives spectacles and 
wears them at an un-announced visit 3 month after distribution. Income from sales of spectacles in 
the "Referral + Cost Recovery" group will be subtracted from the program costs. The groups will be 
compared, with and without adjustment for baseline characteristics. 
[Time Frame: 13 months] 
 
Secondary Outcome Measures: 
Proportion of children receiving spectacles who are wearing them at the time of un-announced 3-
month follow-up 
Purchase rates of upgrade spectacles in the Referral + Cost Recovery Group 
Teacher and student reports of rates of teacher interventions in the two Referral groups (contact of 
parents to complete referral, encouraging children to wear spectacles) 
Baseline visual acuity with spectacles 
Refractive power of spectacles 
[Time Frame: 12 months] 
 
Eligibility 
Minimum Age: 10 Years   
Maximum Age: 15 Years   

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Sex: 
All   
Gender Based: No   
Accepts Healthy Volunteers: 
No   
Criteria: 
 
Inclusion Criteria: 
Eligibility: Enrolment criteria:  
• 
Children in randomly-selected 6th to 10th grades in selected schools with presenting visual 
acuity (that is, wearing spectacles if spectacles are owned at baseline) <= 6/9.6 (0.2 LogMAR) 
in either eye.  
• 
Children who already own spectacles will be requested to bring their spectacles on the day 
of screening, and children whose vision with existing spectacles meets study criteria will be 
eligible.  
• 
Entry into the trial only requires that a child fail vision screening, which is assessed in the 
same way for all three randomized groups.  
Exclusion Criteria: 
• 
Parents returning the form indicating they do not wish their child to participate;  
• 
no Vision Center within 50 km of the child's home (a rare occurrence in the REACH network). 
• 
If the child is incapable of completing visual acuity screening in both eyes for any reason. 
 
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