Prevalence, Causes and Socio-Economic Determinants of Vision Loss in Cape Town, South Africa

PURPOSE: To estimate the prevalence and causes of blindness and visual impairment in Cape Town, South Africa and to explore socio-economic and demographic predictors of vision loss in this setting. METHODS: A cross sectional population-based survey was conducted in Cape Town. Eighty-two clusters were selected using probability proportionate to size sampling. Within each cluster 35 or 40 people aged 50 years and above were selected using compact segment sampling. Visual acuity of participants was assessed and eyes with a visual acuity less than 6/18 were examined by an ophthalmologist to determine the cause of vision loss. Demographic data (age, gender and education) were collected and a socio-economic status (SES) index was created using principal components analysis. RESULTS: Out of 3100 eligible people, 2750 (89%) were examined. The sample prevalence of bilateral blindness (presenting visual acuity <3/60) was 1.4% (95% CI 0.9-1.8). Posterior segment diseases accounted for 65% of blindness and cataract was responsible for 27%. The prevalence of vision loss was highest among people over 80 years (odds ratio (OR) 6.9 95% CI 4.6-10.6), those in the poorest SES group (OR 3.9 95% CI 2.2-6.7) and people with no formal education (OR 5.4 95% CI 1.7-16.6). Cataract surgical coverage was 68% in the poorest SES tertile (68%) compared to 93% in the medium and 100% in the highest tertile. CONCLUSIONS: The prevalence of blindness among people ≥50 years in Cape Town was lower than expected and the contribution of posterior segment diseases higher than previously reported in South Africa and Sub Saharan Africa. There were clear socio-economic disparities in prevalence of vision loss and cataract surgical coverage in this setting which need to be addressed in blindness prevention programs

Estimated prevalence of blindness (VA<3/60), severe visual impairment (VA<6/60–3/60) and visual impairment (VA<6/80–6/60) in Cape Town by person and eyes with available correction.

<p>CI, Confidence Interval; VA, Visual Acuity;</p><p>NB: data for persons refers to VA in the better eye.</p

Visual acuity outcome after cataract surgery (eyes) with available correction.

a<p>WHO classification of visual outcome after cataract surgery. Good: VA>6/18; borderline: VA 6/18–6/60; poor: VA<6/60.</p

Age and gender distribution of the survey sample and census population.

<p>Age and gender distribution of the survey sample and census population.</p

The relationship between demographic and socio-economic characteristics and vision loss (bilateral VA<6/18 with available correction).

<p>VA, Visual Acuity.</p>a<p>Odds ratios from multivariate logistic regression analysis including all listed variables.</p>b<p>Socio-economic status.</p

Cataract surgical coverage^* by persons and eyes.

<p>VA, Visual Acuity.</p><p>*Cataract surgical coverage is the proportion of persons (or eyes) with ‘operable’ cataract who have received cataract surgery.</p

Principal cause of bilateral blindness (VA<3/60), bilateral severe visual impairment (VA<6/60–3/60) and bilateral visual impairment (VA<6/80–6/60) among persons with available correction.

<p>VA, Visual Acuity.</p>a<p>Avoidable causes: Cataract (including un-operated cataract and postoperative complications), refractive error, trachoma, and other causes of corneal scars.</p

Relational hubs for collaborative landscape stewardship

Landscape stewardship is considered an important place-based approach to addressing sustainability challenges. Working at landscape-level requires collaboration between diverse landscape stakeholders. In this study, we partnered with local stewardship practitioners across six cases in South Africa to investigate how they facilitate collaboration towards social-ecological sustainability outcomes. We found that practitioners facilitate collaboration among stakeholders by operating as relational hubs in the landscape. Through these hubs, they build new inter-personal relationships among stakeholders, creating social networks which enable stewardship practice. The hubs deepen human-nature relationships by creating enabling conditions for stewards to put stewardship ethics into action. Drawing on insights from these cases, we call for a relational approach to landscape stewardship which focuses on human-to-human and human-to-nature relationships. Moreover, we argue that landscape stewardship initiatives need to re-focus stewardship on stewards, recognizing them as key agents of change in addressing the conflict between agriculture and conservation inherent in many landscapes

Transforming knowledge systems for life on Earth : Visions of future systems and how to get there

Formalised knowledge systems, including universities and research institutes, are important for contemporary societies. They are, however, also arguably failing humanity when their impact is measured against the level of progress being made in stimulating the societal changes needed to address challenges like climate change. In this research we used a novel futures-oriented and participatory approach that asked what future envisioned knowledge systems might need to look like and how we might get there. Findings suggest that envisioned future systems will need to be much more collaborative, open, diverse, egalitarian, and able to work with values and systemic issues. They will also need to go beyond producing knowledge about our world to generating wisdom about how to act within it. To get to envisioned systems we will need to rapidly scale methodological innovations, connect innovators, and creatively accelerate learning about working with intractable challenges. We will also need to create new funding schemes, a global knowledge commons, and challenge deeply held assumptions. To genuinely be a creative force in supporting longevity of human and non-human life on our planet, the shift in knowledge systems will probably need to be at the scale of the enlightenment and speed of the scientific and technological revolution accompanying the second World War. This will require bold and strategic action from governments, scientists, civic society and sustained transformational intent.Peer reviewe