VOLUME 7 NUMBER 3 • SEPTEMBER 2010
119
SA JOURNAL OF DIABETES & VASCULAR DISEASE
Hands On
USE OF THE RETINAL CAMERA IN
DIABETES EYE CARE IN SOUTH AFRICA
T
his article outlines the rationale for a screening programme for diabetic retinopathy. This
includes an understanding of the pathogenesis of the disease and the need for early inter-
vention to prevent blindness. It explains the requirements for such a screening programme
to function properly, including the need to train staff, use the correct equipment and have an ap-
propriate follow-up and referral protocol and quality control. The main purpose of the article is to
advocate for a pilot project so that the resources are in place when a comprehensive programme is
instituted. Such a programme will require the commitment of the medical profession, government
and civil society in order to function properly.
S Afr J Diabetes Vasc Dis 2010;
7
: 119–121
Grant Ladner
Moorfields Eye Hospital, London, UK
Tel: +44 (0)20 725 33411
e-mail:
with and without clinically significant macular oede-
ma.
5
Clinically significant macular oedema and pro-
liferative diabetic retinopathy can result in significant
and profound visual loss, respectively.
Retinal disease in diabetes is multi-factorial and
poorly understood. There are multiple mechanisms,
including the release of vascular endothelial growth
factors (VEGFs), abnormal platelet function, increased
blood viscosity, and dysfunction of pericytes in the
small blood vessel walls. These factors result in the
leakage of retinal vessels, infarcts, the formation of
abnormal new vessels and fibrovascular membranes.
The formation of new vessels signals the presence of
proliferative retinopathy.
The treatment of diabetic retinopathy has been
assessed in various trials. The Diabetic Retinopathy
study found that the use of pan-retinal photocoagula-
tion significantly decreased the progression to loss of
vision in those with proliferative retinopathy including
high-risk characteristics (HRC).
6-10
The ETDRS found that early treatment of proliferative
retinopathy prevented the progression to HRCs, and
that 50% of patients with severe non-proliferative dia-
betic retinopathy progressed to proliferative retinopa-
thy within one year. However the recommendations of
this study were to await the onset of HRC before start-
ing treatment.
11
There is now a trend to treat those with
diabetic retinopathy at a less advanced stage, particu-
larly in our setting in South Africa, as there is often
poor disease education and difficulty with follow up.
The incidence of type 2 diabetes is increasing world-
wide.¹ The most significant increase will be in the
developing world.
2
One study found the incidence
of the metabolic syndrome in Mexico to be 40 and
60% in men and women, respectively.
3
The metabolic
syndrome predisposes people to diabetes. Diabetes is
one of the most common causes of irreversible blind-
ness in the elderly and the leading cause of visual im-
pairment in those in the adult working age group in
England and Wales.
4
The magnitude of the disease and the efficacy
of early treatment warrant the implementation of a
screening programme. Such a programme would
require the combined efforts and co-ordination of
medical practitioners, government and civil society.
A useful tool in such a screening programme, which
would identify those needing referral, diagnosis and
management, is the non-mydriatic retinal camera.
The pathogenesis, pathology and
treatment of diabetic retinopathy
The purpose of retinal photography is to screen those
with diabetic retinopathy who need referral for pos-
sible treatment. The Early Treatment of Diabetic Retin-
opathy study (ETDRS) provides the guidelines for when
to treat retinal damage caused by diabetes. This study
classified patients into the following groups: no retin-
opathy, non-proliferative diabetic retinopathy and pro-
liferative retinopathy.
5
Maculopathy is classified into two groups: patients
