Abstract
M.Phil. (Optometry)
Despite many years of research, diabetic retinopathy (DR), and diabetic macular
edema (DME) remain difficult to diagnose, prevent, and treat. The complicated nature of
the disease, the limited information on DR and DME and the increasing prevalence of
diabetes mellitus (DM) in South Africa, provided motivation for this study. To the best of
my knowledge, this is the first study in our country to identify demographic, medical and
visual aspects ofDR and DME collectively. A further incentive was the availability in
optometry of recently developed computer software based upon multivariate statistics,
which provided a unique opportunity to analyze, for example, tri-variate contrast
sensitivity acuities using stereo-pair scatter plots. All refractive status measurements were
also analyzed and compared with the same method. Together, the results from this study
provide a broader clinical and research perceptive on DR and DME.
In this cross-sectional study, 202 diabetic patients at the Helen Joseph Hospital in
Johannesburg were recruited. Demographic variables included age, gender, race, age of
diagnosis, duration of DM, and social habits. Medical variables included systemic
conditions present, blood pressures, body mass index (BMI), lipid profiles, glycerated
haemoglobin (HbAlc), and other available biochemical data (for example cholesterol, urea
and creatinine levels). Visual variables included, distance, pinhole and near visual
acuities, contrast sensitivity acuities, refractive status measured with autorefraction,
colour vision, Amsler grid, intraocular pressures (lOP), and fundus photography.
Administration of the Impact of Visuallmpainnent (IVI) questionnaire provided new
information concerning the restrictions in daily living participation caused by DR or
DME. The predominant characteristics of the study population consisted of Type 1DM
among female Coloured subjects. Approximately 66% of all subjects had also been
diagnosed with hypertension. The mean age ofthe subjects was 52 (± 14) years, age of
diagnosis 41 (± 13) years, and duration ofDM 10.8 (± 9.7) years. Mean blood pressures
(136/81 ± 20.5/11 mmHg) and glycated haemoglobin (HbAlc, 9.9 ± 3.4%) values were
slightly higher than the recommended control levels (BP= 120/80 mmHg and HbAlc = 6
to 7%).