Article Text

Original research
Is an integrated model of school eye health delivery more cost-effective than a vertical model? An implementation research in Zanzibar
  1. Ving Fai Chan1,2,3,
  2. Fatma Omar4,
  3. Elodie Yard5,6,
  4. Eden Mashayo3,
  5. Damaris Mulewa5,
  6. Lesley Drake5,
  7. Mary Wepo3,
  8. Hasan Minto7,8
  1. 1Centre for Public Health, Queen's University Belfast, Faculty of Medicine Health and Life Sciences, Belfast, UK
  2. 2College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
  3. 3Brien Holden Vision Institute Foundation Africa Trust, Durban, South Africa
  4. 4Zanzibar Ministry of Health, Zanzibar, United Republic of Tanzania
  5. 5Partnership for Child Development, Imperial College London, London, UK
  6. 6Oriole Global Health, Nairobi, Kenya
  7. 7Brien Holden Vision Institute, Sydney, New South Wales, Australia
  8. 8Berkeley School of Optometry, University of California, Berkeley, California, USA
  1. Correspondence to Dr Ving Fai Chan; v.chan{at}


Objective To review and compare the cost-effectiveness of the integrated model (IM) and vertical model (VM) of school eye health programme in Zanzibar.

Methods and analysis This 6-month implementation research was conducted in four districts in Zanzibar. Nine and ten schools were recruited into the IM and VM, respectively. In the VM, teachers conducted eye health screening and education only while these eye health components were added to the existing school feeding programme (IM). The number of children aged 6–13 years old screened and identified was collected monthly. A review of project account records was conducted with 19 key informants. The actual costs were calculated for each cost categories, and costs per child screened and cost per child identified were compared between the two models.

Results Screening coverage was 96% and 90% in the IM and VM with 297 children (69.5%) from the IM and 130 children (30.5%) from VM failed eye health screening. The 6-month eye health screening cost for VM and IM was US$6 728 and US$7 355. The cost per child screened for IM and VM was US$1.23 and US$1.31, and the cost per child identified was US$24.76 and US$51.75, respectively.

Conclusion Both models achieved high coverage of eye health screening with the IM being a more cost-effective school eye health delivery screening compared with VM with great opportunities for cost savings.

  • child health (paediatrics)
  • epidemiology
  • public health

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Key messages

What is already known about this subject?

  • There is a dearth of information on the actual cost of school eye health (SEH) delivery. This was the first implementation research to review and compare cost-effectiveness of the integrated model (IM) versus the vertical model (VM) SEH delivery in Africa.

What are the new findings?

  • VM used 1.2 times more resources per child screened compared with the IM and the cost per child identified in the VM is two times that of the IM, thus the IM is highly cost-effective.

How might these results change the focus of research or clinical practice?

  • Stakeholders in low-income and middle-income settings will be better able to plan for a cost-effective SEH delivery model that suits their contexts and needs using these findings.


Even though refractive errors can be easily corrected with a pair of inexpensive glasses, worldwide, there are still 12 million children living with vision impairment due to uncorrected refractive errors.1 Left untreated, refractive error can negatively impact a child’s quality of life,2 education and future employment3 4 and can cause significant distress.5 The common barriers to the uptake of eye services in low and middle-income countries are lack of knowledge and access to available services, lack of trust and understanding of the treatment outcomes, cultural and social factors and parents unaware of the problem if their child does not complain.6 To address refractive error challenges, many countries conduct school eye health screening programmes because they are simple to conduct, not resource intensive and benefit children with refractive errors.7

While there is no formal estimate of refractive errors in Zanzibari children, a case study from the school health integrated programme reported that about 42% of the children in rural Zanzibar communities who needed a pair of glasses did not have them.8 It was also reported that 90% of vision impairment among Tanzanian children was due to refractive error.9 Recognising the need to improve public health practices and access to disability-related services,10 the Ministry of Health in Zanzibar endorsed free spectacle provision for children. Historically, school eye health screening programmes in Zanzibar were implemented in a vertical manner. While these vertical programmes bore the advantages of strong technical and financial control and focused objectives achievable in a limited time frame,11 these were often led by non-governmental organisations and ended abruptly with the cessation of funding as they were not part of the National Health Plan. Hence, in collaboration with a non-governmental eyecare organisation, the Ministry of Health of Zanzibar proposed integrating the school eye health programme with its existing school feeding programme (SFP). This provided a valuable opportunity to conduct implementation research to compare the cost-effectiveness of an integrated versus a vertical school eye health programme, conducted in both Unguja and Pemba Islands, which are unique in their geographical features, culture and access to eye health services. We hypothesised that the integrated approach would maximise the limited health resources by using teachers’ time to target both eye health and nutrition within one programme.


Despite mathematical modelling suggesting that screening and correcting refractive error in school children is cost-effective in Africa,12 there is very limited information on the actual costs of school eye health programmes at country level. Furthermore, previous studies on the cost-effectiveness of school eye health programmes in Thailand,13 India14 and Germany15 gave mixed results. This makes it extremely difficult to persuade the Zanzibari government to formally integrate school eye health within the National Health Plan, as it needs careful planning and resourcing.16 Hence, our study aimed to compare the total costs, the cost per child screened and the costs per child detected of the vertical model (VM) with the integrated model (IM). We also reviewed the different cost categories to aid realistic budgeting and identify opportunities for cost saving and cost sharing.

Materials and methods

School selection

This research protocol was approved by the Zanzibar Medical Research and Ethics Committee (ZAMREC/0001/January/17). The research was implemented in 19 rural schools from 1 April 2017 to 1 October 2017 in four districts in Unguja (North A and South Districts) and Pemba Island (Micheweni and Mkoani Districts).

All nine schools (6242 children aged 6–13 years old) with an existing SFP were included in the IM. We purposefully selected 10 schools with no SFP into the VM because the remaining schools in the study area had fewer students. To ensure similar characteristics in the schools enrolled in the two models, we only included rural primary schools that had student school-going rates of approximately 75%, with a similar number of boys and girls and within 5 km of the nearest eye centres.

Patient and public involvement

Community beneficiaries (parents, teachers and children) were involved in the development of the school eye programme through four patient and public involvement meetings during the initiation and development stage. They provided input on the research questions, suggestions on timing for recruitment and implementation. Community beneficiaries were invited to the dissemination of the findings, with a breakout session to obtain their views and suggestions.

Description of intervention

Phase 1: training

In April 2017, six master trainers (n=4 for IM and n=2 for VM) were trained in vision screening, recording and referral pathways and delivering health education to children. As a result of the recommendations made by the local stakeholders, we trained four master trainers for the IM to avoid overburdening the master trainers and compromised the quality of teachers’ training. More master’s trainers were trained for the project. They subsequently trained 60 teachers (n=30 in both IM and VM) who were appointed by the school head teachers. The training for the IM and VM was a 2-day session and a 1-day session, respectively.

Phase 2: screening and referral

Following their training, teachers returned to their schools and conducted eye health screening from April to September 2017. In the VM, the schools received only the eye health intervention. Teachers conducted the screening, recorded all students screened and identified the students who required follow-up. A list of children who were identified with an eye condition was compiled from the student eye screening register. A week after the completion of the eye health screening, children received eye health education using the materials that were developed in collaboration with the Ministry of Health and approved by the Health Promotion Unit. The eye health material package provided to teachers included a handbook and training manuals on health promotion, posters for display around the school compound and an eye health education booklet for use during health education sessions.

For schools in the IM, eye health intervention was added to the SFP. As part of the screening programme, teachers also measured the children’s height and weight (anthropometry measurement). On top of the eye health component, the health education materials included additional information on nutrition, face and hand washing and deworming for children.

Phase 3: monitoring and evaluation

The research coordinator visited the schools monthly to collect the list of children who were screened (eye screening in VM and eye screening and anthropometry in IM) and those who failed screening. Children who failed the eye health screening were referred to a designated vision centre for vision management and children with weight problems were referred to the nearest health centre. The optometrists at the vision centres examined the referred children and managed their eye conditions. The free treatment provided at the vision centre included spectacles and basic eye medication (as per national health policy). The detailed vision screening protocol and referral criteria are included as online supplemental appendices.

The optometrists compiled lists of the children examined and their diagnoses. Cases that could not be managed at the vision centre were referred to Muhimbili Hospital in Dar-es-Salaam for further management. The hospital management was informed of the study so that they were prepared for the increased referrals the screening could create. The description of the IM and VM school eye screening programme is shown in table 1.

Table 1

Description of the school eye screening programmes: integrated and vertical model

Phase 4: costing analysis

Project account records were reviewed to collect information on resources used by the interventions (resource types, numbers and unit costs). Primary data collection was conducted by interviewing key informants from schools, vision centres, districts ministry offices and project sites. Informed consent was obtained from key informants prior to their participation in the study. The key informants were representatives of the Ministry of Health (n=1), Ministry of Education (n=1), District Education Officers (n=4), head teachers (n=4), trained teachers (n=4), optometrists (n=2), project coordinator (n=1), project administrator (n=1) and principal investigator (n=1). The cost categories with their cost components are shown in table 2.

Table 2

Cost categories and cost components for the project

The collected information was entered, cleaned and analysed in Excel. Staff time was estimated using the recall method. Costing was done for the period of 6 months (April to September 2017), the actual time taken to implement the two models. Project start-up expenses are considered to assess the project implementation costs but are not included in the costs per child screened and costs per child identified. This rests on the hypothesis that the project start-up costs are only incurred in the first year of the project and absorbed by the relevant ministry costs hereafter. Cost-effectiveness of the models was compared in terms of cost per child screened and cost per child identified.


Children screened and identified for eye diseases

At the end of the intervention period, 11 987 children were enrolled in the schools, with 6257 children (3127 boys and 3130 girls) in the IM and 5721 children (2960 boys and 2761 girls) in the VM. A total of 11 134 (93%) children were screened from April to November 2017, with 5992 children (96%) from the IM and 5142 children (90%) from the VM. Of those who were screened, 427 (3.8%) children failed eye health screening, of which 297 (69.5%) were from the IM and 130 (30.5%) from the VM.

Breakdown of eye health costs in IM and VM

Eye health costs accounted for 60.4% of the total direct cost for the IM. While costs incurred for the training of trainers, teachers’ training and monitoring and evaluation were similar in the two components, costs incurred for teacher’s salaries, printing and screening kits were higher in the eye health component (table 3).

Table 3

Total integrated programme costs breakdown

Cost per child screened and cost per child identified in VM and IM

The eye health cost for the VM and IM was US$6 728 and US$7 355, respectively. A total of 5142 children were screened in the VM and 5992 children were screened in the IM. Thus, the cost per child screened in the VM was US$1.31 and IM, US$1.23. With 130 children identified in the VM and 297 children in the IM, the cost per child identified was US$51.75 and US$24.76, respectively (table 4).

Table 4

Eye health cost per school child in vertical model and integrated model


This study aims to compare the cost-effectiveness of delivering school eye health using an IM versus a VM. Our findings show that we were able to screen a high number of children in both models and that the IM is a more cost-effective eye health screening model compared with the VM.

Children screened and identified for eye diseases

The eye health screening coverages in both models were high (90% in VM and 93% in IM). This screening efficiency was achieved because school children are a captive audience and can be reached more easily in schools compared with the general population and there was good coordination in planning and implementing the interventions between the partners of the programme, schools and teachers. We conducted all school screening activities in the first 2 months of the school semester and before the monsoon season in June because the school attendance rate is highest in this period.

Costing analysis

Our costing analysis shows that the VM used 1.2 times more resources per child screened than the IM. The incremental cost of screening the additional 850 children in the IM was US$627 (US$0.74 per child). If we perform a projection on the cost per child screened for screening an additional 850 children in the VM, the cost per child screened decreases from US$1.31 to US$1.26, only marginally different to the IM.

Furthermore, our findings show that the cost per child identified in the IM was about half that of the VM, making the IM highly cost-effective. In the VM, there were about 2.5 in 100 children identified with an eye problem. When we factor in the 21 children identified, projected from an additional 850 children screened, the cost per child identified in the VM decreases slightly from US$51.75 to US$50.12. However, this is still two times the cost of the IM.

A previous study on the cost-effectiveness of school eye screening versus a primary eye health model to provide refractive error services for Indian children by Lester17 concluded that school eye screening in India is a highly cost-effective method of correcting visual impairment due to refractive errors in school-age children. However, the study used cost per Quality-adjusted Life Years (QALY) as their cost-effectiveness measure and did not describe in detail the difference between the two models and the cost categories of his cost calculation, making it impossible for meaningful comparison between our findings.

We also made a conservative assumption, based on Baltussen et al12 that the equipment will have a useful life of 10 years. However, equipment useful life greatly depends on the existence of a functioning maintenance and repair (M&R) service. In a resource-constrained location such as Zanzibar, where there are no existing M&R services for eye equipment, realistic equipment useful life may be less than 10 years. The Ministry of Health has plans to upskill its M&R services to routinely maintain eye equipment, but the timing of this is not yet confirmed.

Future cost-saving opportunities of the IM lie mainly in more efficient use of teacher’s time, shorter training and fewer monitoring activities. The IM has a greater opportunity of further reducing resource use as many inputs can be shared with other school-level programmes such as nutrition and other health education programmes.

Training of trainers and teachers’ training in this pilot project incurred 25.3% of the total project cost. The 1-day (VM) and 2-day (IM) training sessions were needed as these were new approaches for the local implementing personnel. However, investment in intensive training will decrease in subsequent years and be replaced with less resource-intensive refresher sessions.

This pilot project required close and frequent monitoring of the teachers’ eye health screening accuracy. Retraining on site was conducted when required. We foresee both models incurring less cost as the programme continues and the teachers become more experienced. In the short term (5 years), we project that staff numbers will remain constant with salaries increasing by approximately 4% annually.

One of the long-term aims of the school health programme is to integrate health into the school curriculum, including secondary schools, hence increasing the age intervals of the children screened. Once the integration is achieved, economies of scale will further reduce programme costs. Our findings align with Baltussen et al’s12 analysis, which showed that while screening a broader-age interval is costlier than a single age-interval, cost per capita can be less because of economies of scale.

All children who required refractive correction were provided with custom-made spectacles regardless of the magnitude of the refractive error, costing between US$6.80 and US$14.60 per pair depending on their prescriptions. However, the ability to correct refractive error for many children with ready-made spectacles that are significantly cheaper than custom made spectacles could reduce programme costs and offer on-the-spot refractive corrections.18–20


The optometrists’, teachers’ and staff time spent on the activities were determined using the recall method and may have presented a certain level of recall bias. This method might have underestimated or overestimated the time spent on the activities. However, we masked the key informants from the model the schools were enrolled into and to minimise response bias.

Baltussen et al’s12 findings showed that screening of 11–15 years old is the most cost-effective in all regions of the world. However, we implemented our research among primary school children (6–13 years old) because the existing SFPs were in primary schools (IM). To make meaningful cost comparisons between the IM and VM, we implemented the VM in primary schools where the socioeconomic profiles were similar to the IM schools.

This was a 6-month pilot that limits our ability to extrapolate referral data and calculate the models’ cost-effectiveness for longer terms. Hence, these findings must be interpreted cautiously, and further research is recommended to determine the long-term cost-effectiveness of the different models.


To the authors’ knowledge, this was the first implementation research that reviewed and compared cost-effectiveness of the IM versus the VM school eye health delivery in Africa. While the total implementation cost of the IM was higher than the VM, more children were screened and identified in IM, making it the more cost-effective school eye health delivery model on a per capita basis. Compared with the VM, the IM offers greater cost-saving opportunities to achieve long-term sustainability. Using these findings, stakeholders in low-income and middle-income settings will be better able to plan a cost-effective school eye health delivery model that suits their contexts and needs.


We would like to thank Mr Kalam Abushir for his commitment in coordinating the project and Ms Happiness Saronga for data collection.


Supplementary material

  • Supplementary Data

    This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.


  • Collaborators Ministry of Health, Zanzibar, Brien Holden Vision Institute Foundation Africa Trust, Partnership for Child Development.

  • Contributors All authors have contributed substantially to the conception of the work (VFC, FO, EY, DM, EM, HM, LD, MW), the acquisition, analysis or interpretation of data (VFC, FO, EY, DM, EM), drafting the work or revising it critically for important intellectual content (VFC, FO, EY, DM, EM, HM, LD, MW) and final approval of the version published.

  • Funding The study was funded by US Agency for International Development Child Blindness Programme (grant number PGRD-15-0003-008).

  • Competing interests The study was a collaborative project between the Ministry of Health, Zanzibar, Brien Holden Vision Institute Foundation Africa Trust and Partnership for Child Development. FO and VFC were the principal investigator and coprincipal investigator of the study. VFC, EM and MW were employees at the Brien Holden Vision Institute Foundation Africa Trust; and HM was an employee at Brien Holden Vision Institute, Sydney throughout the conception, implementation and completion of the study.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article.

  • Author note Brien Holden Vision Institute Foundation Africa Trust, Durban, South Africa and Brien Holden Vision Institute, Sydney are affiliations when the study was undertaken.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.