Rapid Assessment of Avoidable Blindness (RAAB)

Image: Testing vision using Tumbling E, RAAAB7 Matebleland South Zimbabwe, 2019

 

What is RAAB?

The Rapid Assessment of avoidable blindness (RAAB) is a rapid survey methodology developed at ICEH, and used to complete over 300 surveys of visual impairment and blindness to date.

RAAB is rapid because it uses simplified examination techniques and, because it only includes examination of people 50+, requires a small sample size.

RAAB incorporates a standardised training programme supported by certified RAAB Trainers, mobile data entry with in-built logic, and automated analysis and report generation. RAAB data are collated on the RAAB repository.

 

This page provides an overview of the purpose of RAAB, the current RAAB7 development project, what RAAB is not, and RAAB trainers that you can contact for support. In addition:

 

 

 

What is RAAB for?

The main aims of RAAB are:

  • to estimate the prevalence and causes of avoidable blindness and visual impairment in people aged 50 and above
  • to assess cataract surgical coverage
  • to identify the main barriers to the uptake of cataract surgery
  • to measure outcome after cataract surgery.

Using sound epidemiological methods, these data are used to design and monitor eye care programmes in the surveyed area.

RAAB was originally designed for use at the district level, but is equally a valuable tool for reporting on national level estimates.

 

RAAB7: the next generation of RAAB

RAAB has been developed iteratively over the years. The 7th generation of RAAB – RAAB7 – is currently under development as a joint project between ICEH and Peek Vision. RAAB7 will fully digitise the RAAB workflow, delivered on the Peek Vision platform.  It will further enhance RAAB’s ability to support eye health planning and includes several new features that deliver higher integrity data and live tracking.

In addition, RAAB7 contains new modules developed to maximise the utility of RAAB in eye health planning. An optional disability module (using the Washington Group Short Set) has already been developed, and further new modules and inputs related to uncorrected refractive error, glaucoma and near vision are being explored.

RAAB7 is currently concluding testing and will be rolled out more widely soon.  For more information on early access to RAAB7, or to join a mailing list and receive RAAB7 updates, please contact Dr. Islay Mactaggart (islay.mactaggart@lshtm.ac.uk), who is leading this project at ICEH.

 

Image:  Explaining Vision Testing using Peek Acuity, RAAB7+DR in Occupied Palestinian Territories 2018

What RAAB is not

  • RAAB is not a case-finding exercise: it will not provide a list of names and addresses of all people who are blind due to (for example) cataract in an area.
  • RAAB is not a detailed vision survey: it provides a reasonably accurate estimate of the prevalence of blindness, and the proportion that is avoidable, in a geographic area. RAAB is not designed to give accurate estimates of the prevalence of specific causes of blindness and does not measure posterior segment disease in detail.
  • RAAB focuses on people aged 50 years and above and so it does not give an estimate of childhood blindness, which is better measured through other approaches such as the Key Informant Method.
  • RAAB6 does not provide data on human and financial resources, which are also imperative for eye health planning. However, a planning module and situational analysis support is being developed within the RAAB7 project.

Who should carry out a RAAB survey?

The entire process of carrying out a RAAB survey, from planning to the collection of field data, data analysis and report writing, can be conducted by local staff. 3-5 teams with transport can cover the usual required sample size in a minimum period of 5-6 weeks, including 1 week of training. The collection of data can be done by local ophthalmologists, or residents in ophthalmology, together with an assistant who does not need to be medically trained. The use of a local guide to introduce the survey team in the community is essential.

Want to carry out your own RAAB survey?

Good planning and organisation are vital for success. Although RAAB has the word “rapid” in its title it is neither easy nor straightforward to undertake. If the RAAB is not undertaken carefully and to a high quality then it will give biased results which will not help with planning or monitoring and will have wasted time and money. RAABs therefore need to be planned and undertaken carefully, and must be supported by a certified RAAB trainer. Further information on planning for a RAAB are available here. A full list of certified RAAB trainers by region is available at the bottom of this page. You must engaged with a certified RAAB trainer before undertaking a RAAB.

Diabetic retinopathy module in RAAB

It is well established that the prevalence of diabetes is rapidly increasing worldwide. However, there is little information on the prevalence of diabetic retinopathy (DR) in different parts of the world and particularly in low and middle income settings. The DR module for RAAB (RAAB+DR) was developed as a relatively rapid method for estimating the prevalence of diabetes and DR in the population aged >50 years in order to inform diabetic eye services.

RAAB+DR follows the standard RAAB methodology, with two additional components:

  1. i) Assessment of the diabetes status of survey participants
  2. ii) Assessment of DR among survey participants identified as having diabetes

In addition to RAAB outputs, RAAB+DR provides the following estimates for population aged 50 years and over:

  • The prevalence of diabetes
  • The prevalence of DR and sight threatening diabetic retinopathy
  • The proportion of people with known diabetes who have had a previous fundus examination
  • Indication of glycaemic control among people with diabetes

 Image: Random Blood Glucose (RBG) testing in RAAB DR in Nepal May 2019

What RAAB+DR is not

RAAB+DR only includes people aged >50 years and cannot estimate the prevalence of diabetes and DR in younger age groups. To keep the survey relatively rapid, RAAB+DR uses simplified examination procedures that can be conducted at the household, which has implications for the degree of clinical detail collected. Diabetes diagnosis is based on history of diabetes or elevated RBG rather than a fasting blood glucose or oral glucose tolerance test. This may slightly underestimate the prevalence of diabetes. DR assessment is by dilated examination by direct and indirect ophthalmoscope using a simplified grading system. RAAB+DR therefore does not provide comprehensive detail on the level of DR.

When should RAAB+DR be conducted?

Including the DR component in RAAB adds significantly to the time, resources, cost and complexity of the survey and should only be undertaken if a)the prevalence of diabetes is expected to be high (e.g. >15% among people aged 50+ years), b)there are sufficient resources, experienced DR graders and time c)diabetic and DR services are available and accessible and d) the information will be used for planning DR services. If these are not available, a standard RAAB should be undertaken.

RAAB6 software package

The RAAB6 software package is for the entry and analysis of data from rapid assessment of avoidable blindness surveys (RAABs). The package contains software (Windows only), supporting documentation and training materials.

RAAB is coordinated by the International Centre for Eye Health and RAAB stakeholders are involved in RAABs updates and evolution. RAAB6 is currently available to download here.

 

Certified RAAB trainers

Africa

EMRO

Europe

South Asia

Latin America and Caribbean

Western Pacific

 

How to become a certified ICEH RAAB trainer:

This is a two stage process involving firstly attending a RAAB Training of Trainers (ToT), which is a week to 10 days long intensive training on the methodology and techniques for training up a team to conduct a RAAB.

Secondly, within one year of the first stage training, to conduct a RAAB training under supervision of a senior certified RAAB trainer. This training must be judged by the certified trainer to reach the required standard.

A trainee must successfully complete both parts of the training to become certified.

ICEH intends to convene a new RAAB ToT in 2020, once the RAAB7 platform is fully launched. Please contact Islay Mactaggart or Ian McCormick at ICEH if interested in more details.

 

Acknowledgements

We would to thank the organisations which have generously supported the development of RAAB:

 

Publications

  • Rapid Assessment of Avoidable Blindness: looking back, looking forward. Mactaggart, I., Limburg, H., Bastawrous, A., Burton, M.J. and Kuper, H., 2019. British Journal of Ophthalmology, 103(11), pp.1549-1552. Access
  • Rapid assessment of avoidable blindness for health service planning.Mactaggart, Islay, Sarah Wallace, Jacqueline Ramke, Matthew Burton, Andrew Bastawrous, Hans Limburg, Muhammad Babar Qureshi, Allen Foster, and Hannah Kuper. Bulletin of the World Health Organization 96, no. 10 (2018): 726. Access
  • Measuring the impact of cataract services in the community. Polack S, Kuper H. Comm Eye Health 2014; 85(27): 15. Access
  • Rapid assessment of avoidable blindness and diabetic retinopathy in Taif, Saudi Arabia. Al Ghamdi AH, Rabiu M, Hajar S, Yorston D, Kuper H, Polack S. Br J Ophthalmol. 2012 Sep;96(9):1168-72. Abstract
  • A rapid assessment of avoidable blindness in Southern Zambia. Lindfield R, Griffiths U, Bozzani F, Mumba M, Munsanje J. PLoS One. 2012;7(6):e38483. Access
  • The Nakuru posterior segment eye disease study : Methods and prevalence of blindness and visual impairment in Nakuru, Kenya. Mathenge W, Bastawrous A, Foster A, Kuper H. Ophthalmology. 2012 Oct;119(10):2033-9. Abstract
  • Rapid assessment of avoidable blindness and diabetic retinopathy in Chiapas, Mexico. Polack S, Yorston D, López-Ramos A, Lepe-Orta S, Baia RM, Alves L, Grau-Alvidrez C, Gomez-Bastar P, Kuper H. Ophthalmology. 2012 May;119(5):1033-40. Epub 2012 Feb 18. Abstract
  • Results of a rapid assessment of avoidable blindness (RAAB) in Eritrea. Müller A, Zerom M, Limburg H, Ghebrat Y, Meresie G, Fessahazion K, Beyene K, Mathenge W, Mebrahtu G. Ophthalmic Epidemiol. 2011 Jun;18(3):103-8. Abstract
  • Findings from a rapid assessment of avoidable blindness (RAAB) in Southern Malawi. Kalua K, Lindfield R, Mtupanyama M, Mtumodzi D, Msiska V. PLoS One. 2011 Apr 25;6(4):e19226. Access
  • Rapid assessment of avoidable blindness in the Occupied Palestinian Territories. Chiang F, Kuper H, Lindfield R, Keenan T, Seyam N, Magauran D, Khalilia N, Batta H, Abdeen Z, Sargent N. PLoS One. 2010 Jul 29;5(7):e11854. Access
  • Rapid assessment of avoidable blindness in India. Neena J, Rachel J, Praveen V, Murthy GV; Rapid assessment of avoidable blindness India study group. PLoS ONE 2008 Aug 6;3(8):e2867. Access
  • Rapid assessment of avoidable blindness in Kunming, China. Wu M, Yip JLY, Kuper H. Ophthalmology 2008 Jun;115(6):969-74. Abstract
  • Rapid assessment of avoidable blindness in Negros Island and Antique district, Philippines. Eusebio C, Kuper H, Polack SR, Enconada J, Tongson N, Dionio D, DumDum A, Limburg H, Foster A. Br J Ophthalmol 2007 Dec;91(12):1588-92. Access

 

Find out more

Contact us for more information on our research.

Contact us for details about ICEH certification for RAAB trainers.

For details of RAABs already carried out, please visit the RAAB repository

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