Seeing to Learn in Sierra Leone

NCT ID: NCT06065631

Last Updated: 2026-01-20

Basic Information

• Recruitment Status: TERMINATED
• Clinical Phase: NA
• Total Enrollment: 1821 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-10-25
• Study Completion Date: 2025-01-31

Brief Summary

The main objective of the Sierra Leone Sees to Learn (SL2) trial is to assess the educational impact of providing free eyeglasses to students aged 9-20 years with uncorrected refractive error in Sierra Leone. The procedures include baseline questionnaires and educational assessments to collect data on students and schools, and then the provision of free eyeglasses to students who have uncorrected (or undercorrected) refractive error (URE). The questionnaires and student assessments will take 1-2 hours. The duration of the study timeframe is one school year. The end-line questionnaires and student assessments will be administered at the end of the school year.

Detailed Description

Objective: The main objective of the Sierra Leone Sees to Learn (SL2) trial is to assess the educational impact of providing free eyeglasses to students aged 9-20 years with uncorrected refractive error in Sierra Leone.

Sample frame: Approximately 2400 children with uncorrected (or undercorrected) refractive error (URE) at 300 randomly-selected schools in Freetown and Bo City. A similar number of children from the same schools but without vision problems will also be included, at baseline only, to compare their basic demographic characteristics and daily activities to those of the children with URE. The sample size may vary depending on the percentage of children with URE obtained from screening a total of 40,000 children. All children with URE as specified in the enrolment criteria below will be part of the study.

Design: Cluster-randomized control trial (cluster RCT), with schools as clusters.

Randomization, interventions and balancing: All eligible children will be randomized by school to receive at the start of the school year either: free ready-made or custom eyeglasses (Intervention), or an eyeglasses prescription and letter to parents, with free eyeglasses at end-line (Control). The clusters (schools) will be stratified into groups based on the prevalence of refractive error and on the score on the baseline mathematics and reading exams. The division of the sample into schools in the two cities (Bo and Freetown) will be in the same proportion as the proportion of the number of public schools in those two cities.

Power calculations (reading and math exams): Setting power = 0.8, statistical precision = 0.05, intracluster correlation = 0.2 (from 2019 Sierra Leone grade 8 learning assessment), 80 treated schools, 80 control schools, 15 students/school with uncorrected error, yields the following minimal detectable effect (MDE) sizes as a function of correlation between baseline and end-line tests:

MDE Correlation of baseline and end-line tests 0.101 0.7 0.127 0.6 0.148 0.5

A nested focus-group study will explore children's, parents' and teachers' attitudes towards vision, student learning, and wearing of eyeglasses, in order to design a locally-tailored intervention to promote wearing of eyeglasses.

Regression Framework:

The investigators will estimate the effect of the program using a single difference cross-sectional ordinary least squares regression (OLS), and a difference-in-difference (DID) OLS regression that includes observations at both end-line and baseline. The investigators will report two types of effects: the intent-to-treat (ITT) effects and local average treatment effects (LATE), using treatment assignment as an instrumental variable for participation. Analysis will use the observed baseline characteristics as control variables and account for school-level variation through a fixed effect.

Conditions

Refractive Errors

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: DOUBLE

Study Groups

Control

An eyeglasses prescription and letter to parents, with free eyeglasses at endline.

Group Type: OTHER

Prescription slip

Intervention Type: OTHER

Children with uncorrected/under-corrected refractive error will be provided with an eyeglasses prescription and letter to parents, but all of them will get eyeglasses at the end of the trial

Intervention

free ready-made or custom eyeglasses

Group Type: EXPERIMENTAL

Eyeglasses

Intervention Type: DEVICE

Children with uncorrected/under-corrected refractive error will be provided with either ready made or custom eyeglasses based on their magnitude and types of refractive errors.

Interventions

Eyeglasses

Children with uncorrected/under-corrected refractive error will be provided with either ready made or custom eyeglasses based on their magnitude and types of refractive errors.

Intervention Type: DEVICE

Prescription slip

Children with uncorrected/under-corrected refractive error will be provided with an eyeglasses prescription and letter to parents, but all of them will get eyeglasses at the end of the trial

Intervention Type: OTHER

Other Intervention Names

Glasses; Spectacle

Eligibility Criteria

Inclusion Criteria

1. Presenting (with or without glasses) distance visual acuity of 6/12 or worse in the better-seeing eye;

2. Refractive error of at least 0.75 diopters (D) of myopia, 2.00 D of hyperopia or 1.00 D of astigmatism;

3. Visual acuity is correctable to 6/7.5 or better with eyeglasses.

Exclusion Criteria

1. Other ocular problems preventing visual acuity > 6/12 in both eyes.

• Minimum Eligible Age: 9 Years
• Maximum Eligible Age: 20 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Innovations for Poverty Action

OTHER

Sponsor Role: collaborator

Peek Vision

UNKNOWN

Sponsor Role: collaborator

Vision Action

UNKNOWN

Sponsor Role: collaborator

University of Minnesota

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Nathan Congdon, MD

Role: PRINCIPAL_INVESTIGATOR

Queen's University, Belfast

Locations

Innovations for Poverty Action (IPA)

Freetown, , Sierra Leone

Countries

Sierra Leone

References

GBD 2019 Blindness and Vision Impairment Collaborators; Vision Loss Expert Group of the Global Burden of Disease Study. Trends in prevalence of blindness and distance and near vision impairment over 30 years: an analysis for the Global Burden of Disease Study. Lancet Glob Health. 2021 Feb;9(2):e130-e143. doi: 10.1016/S2214-109X(20)30425-3. Epub 2020 Dec 1.

Reference Type: RESULT

PMID: 33275950 (View on PubMed)

Burton MJ, Ramke J, Marques AP, Bourne RRA, Congdon N, Jones I, Ah Tong BAM, Arunga S, Bachani D, Bascaran C, Bastawrous A, Blanchet K, Braithwaite T, Buchan JC, Cairns J, Cama A, Chagunda M, Chuluunkhuu C, Cooper A, Crofts-Lawrence J, Dean WH, Denniston AK, Ehrlich JR, Emerson PM, Evans JR, Frick KD, Friedman DS, Furtado JM, Gichangi MM, Gichuhi S, Gilbert SS, Gurung R, Habtamu E, Holland P, Jonas JB, Keane PA, Keay L, Khanna RC, Khaw PT, Kuper H, Kyari F, Lansingh VC, Mactaggart I, Mafwiri MM, Mathenge W, McCormick I, Morjaria P, Mowatt L, Muirhead D, Murthy GVS, Mwangi N, Patel DB, Peto T, Qureshi BM, Salomao SR, Sarah V, Shilio BR, Solomon AW, Swenor BK, Taylor HR, Wang N, Webson A, West SK, Wong TY, Wormald R, Yasmin S, Yusufu M, Silva JC, Resnikoff S, Ravilla T, Gilbert CE, Foster A, Faal HB. The Lancet Global Health Commission on Global Eye Health: vision beyond 2020. Lancet Glob Health. 2021 Apr;9(4):e489-e551. doi: 10.1016/S2214-109X(20)30488-5. Epub 2021 Feb 16. No abstract available.

Reference Type: RESULT

PMID: 33607016 (View on PubMed)

Dandona L, Dandona R. What is the global burden of visual impairment? BMC Med. 2006 Mar 16;4:6. doi: 10.1186/1741-7015-4-6.

Reference Type: RESULT

PMID: 16539747 (View on PubMed)

Glewwe P, West KL, Lee J. The Impact of Providing Vision Screening and Free Eyeglasses on Academic Outcomes: Evidence from a Randomized Trial in Title I Elementary Schools in Florida. J Policy Anal Manage. 2018;37(2):265-300. doi: 10.1002/pam.22043.

Reference Type: RESULT

PMID: 29693366 (View on PubMed)

Keil S, Fielder A, Sargent J. Management of children and young people with vision impairment: diagnosis, developmental challenges and outcomes. Arch Dis Child. 2017 Jun;102(6):566-571. doi: 10.1136/archdischild-2016-311775. Epub 2016 Nov 16.

Reference Type: RESULT

PMID: 27852581 (View on PubMed)

Ma X, Zhou Z, Yi H, Pang X, Shi Y, Chen Q, Meltzer ME, le Cessie S, He M, Rozelle S, Liu Y, Congdon N. Effect of providing free glasses on children's educational outcomes in China: cluster randomized controlled trial. BMJ. 2014 Sep 23;349:g5740. doi: 10.1136/bmj.g5740.

Reference Type: RESULT

PMID: 25249453 (View on PubMed)

Naidoo KS, Raghunandan A, Mashige KP, Govender P, Holden BA, Pokharel GP, Ellwein LB. Refractive error and visual impairment in African children in South Africa. Invest Ophthalmol Vis Sci. 2003 Sep;44(9):3764-70. doi: 10.1167/iovs.03-0283.

Reference Type: RESULT

PMID: 12939289 (View on PubMed)

Ma Y, Congdon N, Shi Y, Hogg R, Medina A, Boswell M, Rozelle S, Iyer M. Effect of a Local Vision Care Center on Eyeglasses Use and School Performance in Rural China: A Cluster Randomized Clinical Trial. JAMA Ophthalmol. 2018 Jul 1;136(7):731-737. doi: 10.1001/jamaophthalmol.2018.1329.

Reference Type: RESULT

PMID: 29801081 (View on PubMed)

Wang X, Yi H, Lu L, Zhang L, Ma X, Jin L, Zhang H, Naidoo KS, Minto H, Zou H, Rozelle S, Congdon N. Population Prevalence of Need for Spectacles and Spectacle Ownership Among Urban Migrant Children in Eastern China. JAMA Ophthalmol. 2015 Dec;133(12):1399-406. doi: 10.1001/jamaophthalmol.2015.3513.

Reference Type: RESULT

PMID: 26426113 (View on PubMed)

Williams WR, Latif AH, Hannington L, Watkins DR. Hyperopia and educational attainment in a primary school cohort. Arch Dis Child. 2005 Feb;90(2):150-3. doi: 10.1136/adc.2003.046755.

Reference Type: RESULT

PMID: 15665167 (View on PubMed)

Other Identifiers

Glewwe Transfer

Identifier Type: -

Identifier Source: org_study_id