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OPINION
Preventing diabetic
blindness: A priority for
South Africa
Karen Hofman is a medical graduate of the University of the Witwatersrand, Johannesburg, South Africa, and a paediatrician. She is Director of PRICELESS SA (Priority Cost Effective Lessons for Systems Strengthening), focused on ‘best buys’ in public health and based at the Medical Research Council/Wits Rural Public Health Unit (Agincourt) in the School of Public Health, Faculty of Health Sciences, University of the Witwatersrand. Colin Cook is a graduate of the University of Cape Town, South Africa, and Morris Mauberger Professor of Ophthalmology in the Department of Surgery, Faculty of Health Sciences, University of Cape Town and Groote Schuur Hospital, Cape Town. Dinky (Naomi) Levitt, also a UCT graduate, is Head of the Division of Diabetes and Endocrinology in the Department of Medicine at UCT and Groote Schuur Hospital and Director of the Chronic Diseases Initiative for Africa, Cape Town.
The prevalence of diabetes in South Africa is increasing rapidly, and diabetes is a significant cause of blindness. Diabetic complications can induce a cycle of poverty for affected families. Early detection of retinopathy and appropriate management can prevent blindness. Screening for retinopathy using a mobile retinal camera is highly cost-effective, with costs of screening and follow-up treatment being less than the expense of one year of a disability grant. Such a programme is a prime example of a ‘best buy’ that should be part of the national diabetes care package.
S Afr Med J 2014;104(10):661-662.
DOI:10.7196/SAMJ.8580
Around 300 million people worldwide are affected with diabetes, and this number is forecast to increase to over 550 million by the year 2030.1 Of those affected, 80% live in low- and middle-income countries (LMICs).1 In South Africa (SA), the prevalence of type 2 diabetes rose from 5.5% in adults in 2000 to 9.0% in 2009. Currently approximately 2 million South Africans live with type 2 diabetes, with a projected 115 000 new cases per year.1 It is of concern that about 55% of people with diabetes are likely to suffer from diabetic retinopathy.2 Diabetes is the third leading cause of blindness in SA, with retinopathy and cataracts2 accounting for 8 000 new cases of vision impairment every year. In a 2010 survey in Cape Town, diabetic retinopathy was responsible for 8% of blindness and 11% of severe visual impairment.3 In LMICs, including SA, diabetic blindness creates a poverty cycle that disables breadwinners and burdens caregivers. The fact that timely treatment of diabetic retinopathy can reduce the risk of visual impairment by 90%2 implies a need for screening and early detection. The Ophthalmology Society of South Africa has recommended a strategy for diabetic retinopathy screening using a validated grading system, an internet-based database and tracking system, and a patient-held ‘scorecard’.4
In 2007, a pilot study in Cape Town evaluated the impact of mobile fundus photography to screen for diabetic retinopathy.5 Following the screening, an ophthalmic specialist reviewed the photographs and if necessary referred the patient. This proved effective and allowed a single technician to screen about 10 000 patients annually, suggesting that scale-up is feasible.
Despite this, a systematic review revealed a lack of
information on the cost-effectiveness of using mobile fundus
cameras as a screening method.6
In response, PRICELESS-SA and collaborators measured the
prevalence of type 2 diabetes and its associated
complications in SA based on 2009 data.7
Using these estimates together with data from the pilot
project, modelling was performed on the cost and
consequences of using a mobile fundus camera in a primary
care setting.7 Screening via camera
alone cost an average of ZAR189 per person, including
follow-up operation procedures, ranging from a lower limit
of ZAR10 500 to an upper limit of ZAR23 327 per case of
blindness averted.
Relevance to policy
Advocacy for preventive screening of diabetic retinopathy intersects early stages in the development of SA’s National Health Insurance (NHI). As the NHI will not cover diagnostic procedures outside its approved guidelines and protocols, it is essential that screening for diabetic retinopathy be considered for scale-up nationally and therefore for inclusion in these guidelines. At present, screening for retinopathy at primary care level is almost non-existent, despite current guidelines recommending annual screening.6 , 8 In addition, ophthalmic referral and treatment in the form of laser therapy and operations are reserved for the tertiary care sector.9
Difficulty of access to screening and treatment of
diabetic blindness is exacerbated by the 55% of diabetic
patients who remain undiagnosed. The government provides
support through monthly disability grants for the blind,
totalling ZAR12 120 per year per blind person.10
In comparison, the cost-effectiveness study showed that the
ZAR10 500 per blindness case averted is less than the
expense of one year of a disability grant. Prevention of
blindness would also extend the number of working years for
every diabetic patient. The use of mobile fundus cameras has
huge savings potential compared with the current situation
of diabetes treatment and disability coverage.
International comparisons
Canadian researchers found fundus cameras to be cost-effective compared with their alternative specialist-based programme. Camera screening saved 67 sight-years at US$3 900 per sight-year, while the alternative programme saved only 56 sight-years at US$9 800 per sight-year.11 Although the SA pilot project was performed in an urban setting, similar projects in rural communities in Australia12 and France13 proved to be effective. US researchers14 have also built a prototype mobile fundus camera that will cut costs significantly and potentially make screening for diabetic blindness even more cost-effective. Smart-phone technology that might allow screening for diabetic retinopathy using mobile phones is now being tested elsewhere in Africa.15
International examples show that camera screening for diabetic vision impairment is successful at a national scale. Such systematic screening has been established in Iceland for over 30 years. In 1980, 2.4% of Iceland’s population was legally blind, but by 2005 the prevalence had dropped to 0.5%.16 Similarly, Israel’s prevalence of preventable blindness dropped by half from 33.8/100 000 in 1999 to 16.6/100 000 in 2008.17 These declines can be attributed to the availability of treatment and preventive measures and illustrate the importance of implementing treatment guidelines for diabetic vision impairment.
In sub-Saharan Africa, countries have utilised other
alternatives by task-shifting cataract operations from
ophthalmologists to non-physician cataract surgeons (NPCSs).
NPCSs in Kenya, Tanzania and Ethiopia, for example, performed
over 77 000 operations in 2000 - 2004.18 Results showed no
difference between specialised ophthalmologists and NPCSs in
respect of the quality of surgeries conducted.19
Although the use of NPCSs is not widely accepted, they
represent a cost-effective alternative solution. Laser
treatment for diabetic retinopathy by appropriately trained
doctors at secondary level and district hospitals would be a
feasible solution to deal with diabetic retinopathy-related
blindness in SA.
‘Best buys’ for policy makers
Under the current economic circumstances, every ZAR must work
more effectively, efficiently and equitably. In order for the
SA government to discern a ‘best buy’ among cost-effective
options, it needs access to valid, reliable and comparable
information on costs and consequences of policy alternatives.
International examples do provide useful information, but this
must be complemented by local context-specific evidence.
Prevention interventions offer particularly good value, as
they produce the largest gain.
Conclusion
The use of mobile fundus cameras to screen for diabetic vision impairment is a paradigm of an innovative approach to achieve economies of scale to reduce preventable blindness effectively on a national level. The use of mobile fundus cameras would interface well with the screening strategy recommended by the Ophthalmology Society of South Africa. One of the challenges for the evolving NHI is how value for money and affordability can be balanced across competing priorities. This approach is one example of a ‘best buy’ that could potentially be incorporated in a diabetes care package.
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2. Bertram MY, Jaswal AV, Van Wyk VP, Levitt NS, Hofman KJ. The non-fatal disease burden caused by type 2 diabetes in South Africa, 2009. Glob Health Action 2013;6:12944. [http://dx.doi.org/10.3402/gha.v6i0.19244]
3. Cockburn N, Steven D, Lecuona K, et al. Prevalence, causes and socio-economic determinants of vision loss in Cape Town, South Africa. PloS One 2012;7(2):e30718. [http://dx.doi.org/10.1371/journal.pone.0030718]
4. Cook S. Diabetic retinopathy – the Ophthalmology Society of Southern Africa screening programme. S Afr Med J 2013;103(7):449-451. [http://dx.doi.org/10.7196/samj.7136]
5. Mash B, Powell D, Du Plessis F, Van Vuuren U, Michalowska M, Levitt N. Screening for diabetic retinopathy in primary care with a mobile fundal camera – evaluation of a South African pilot project. S Afr Med J 2007;97(12):1284-1288.
6. Jones S, Edwards RT. Diabetic retinopathy screening: A systematic review of the economic evidence. Diabet Med 2010;27(3):249-256. [http://dx.doi.org/10.1111/j.1464-5491.2009.02870.x]
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8. Guideline Committee. 2012 SEMDSA guideline for the management of type 2 diabetes mellitus. Journal of Endocrinology, Metabolism and Diabetes of South Africa 2012;17(1):S1-94.
9. Department of Health, Republic of South Africa. Strategic Plan for the Prevention and Control of Non-Communicable Diseases 2013-7: 57. Pretoria, 2013. http://www.hsrc.ac.za/.../NCDs%20STRAT%20PLAN%20%20CONTENT% (accessed 15 August 2014).
10. Department of Social Development. Disability Grant. http://www.dsd.gov.za/index.php?option=com_content&task=view&id=112 (accessed 15 August 2014).
11. Maberley D, Walker H, Koushik A, Cruess A. Screening for diabetic retinopathy in James Bay, Ontario: A cost-effectiveness analysis. CMAJ 2003;168(2):160-164.
12. Spurling GKP, Askew DA, Hayman NE, Hansar N, Cooney AM, Jackson CL. Retinal photography for diabetic retinopathy screening in Indigenous primary health care: The Inala experience. Aust N Z J Public Health 2010;34(S1):S30-S33. [http://dx.doi.org/10.1111/j.1753-6405.2010.00549.x]
13. Beynat J, Charles A, Astruc K, et al. Screening for diabetic retinopathy in a rural French population with a mobile non-mydriatic camera. Diabetes Metab 2009;35(1):49-56. [http://dx.doi.org/10.1016/j.diabet.2008.07.002]
14. Tran K, Mendel TA, Holbrook KL, Yates PA. Construction of an inexpensive, hand-held fundus camera through modification of a consumer ‘point-and-shoot’ camera. Invest Ophthalmol Vis Sci 2012;53(12):7600-7607. [http://dx.doi.org/10.1167/iovs.12-10449]
15. Peek Vision. Eye care: Everywhere. http://www.peekvision.org (accessed 25 August 2014).
16. Zoega GM, Gunnarsdóttir Þ, Björnsdóttir S, Hreiðarsson ÁB, Viggósson G, Stefánsson E. Screening compliance and visual outcome in diabetes. Acta Ophthalmol Scand 2005;83(6):687-690. [http://dx.doi.org/10.1111/j.1600-0420.2005.00541.x]
17. Skaat A, Chetrit A, Belkin M, Kinori M, Kalter-Leibovici O. Time trends in the incidence and causes of blindness in Israel. Am J Ophthalmol 2012;153(2):214.e1-221.e1. [http://dx.doi.org/10.1016/j.ajo.2011.08.035]
18. Courtright P, Ndegwa L, Msosi J, Banzi J. Use of our existing eye care human resources : assessment of the productivity of cataract surgeons trained in eastern Africa. Arch Ophthalmol 2007;125(5):684-687. [http://dx.doi.org/10.1001/archopht.125.5.684]
19. Yorston D, Foster A. Audit of extracapsular cataract extraction and posterior chamber lens implantation as a routine treatment for age related cataract in east Africa. Br J Ophthalmol 1999;83(8):897-901. [http://dx.doi.org/10.1136/bjo.83.8.897]
Accepted
26 June 2014.
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