Browsing by Author "Cook, Colin"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Retinopathy in diabetic patients evaluated at a primary care clinic in Cape Town
    (Health & Medical Publishing Group, 2007-10) Read, Olivia; Cook, Colin
    Diabetic retinopathy is the fifth leading cause of global blindness, affecting an estimated 1.8 billion people and responsible for 4.8% of blindness.1 In South Africa, it is the third leading cause of blindness after cataract and glaucoma, and is responsible for 5% of blindness (0.04% of the total population). Cataract and refractive error are prioritised for the first phase of Vision 2020 in South Africa, while strategies to deal with diabetic retinopathy are recommended as a priority for the second phase.2 These strategies will include provision of adequate screening and argon laser treatment. The prevalence of diabetes differs in different population groups in South Africa. Among black and coloured South Africans, diabetes has risen from 3% to 12% over the past 10 years. Overall, the prevalence is conservatively estimated to be 3 - 5% (30 000 - 50 000 per million population).2 The prevalence of retinopathy in people with diabetes is estimated to be 20% (6 000 - 10 000 per million population), and the prevalence of blindness among these is estimated to be 5% (300 - 500 blind per million population).2 The objective of this study was to evaluate the retinopathy status of patients with diabetes seen at a primary care clinic in Cape Town and to assess the adequacy of the current diabetic screening programmes.
  • Thumbnail Image
    Item
    Retinopathy of prematurity screening criteria and workload implications at Tygerberg Children’s Hospital, South Africa : a cross-sectional study
    (Health & Medical Publishing Group, 2016-05-12) Kift, Elsime Visser; Freeman, Nicola; Cook, Colin; Myer, Landon
    Background. Screening guidelines for retinopathy of prematurity (ROP) used in high-income countries are not appropriate for middle- income countries, and screening requirements may vary even between units within one city. Objective. To determine optimal ROP screening criteria, and its workload implications, for Tygerberg Children’s Hospital (TCH), Cape Town, South Africa. Methods. This cross-sectional study included premature infants screened for ROP at TCH from 1 January 2009 to 31 December 2014. Logistic regression analysis for prediction and classification was performed. Predictors were birth weight (BW) and gestational age (GA). Endpoints were clinically significant ROP (CSROP) and type 1 ROP (T1ROP). Results. Of 1 104 eligible infants, 33.4% had ROP (CSROP 9.1%, T1ROP 2.5%). All T1ROP infants received laser therapy. The number of screening examinations was inversely correlated with GA and BW. The number needed to screen to identify one infant requiring treatment was 41 (entailing 83 examinations, 4 screening hours, one technician and three doctors). Screening infants with a GA of ≤28 weeks or a BW of <1 000 g would have detected all infants with T1ROP but missed two outliers with CSROP. These outliers would only have been detected with a GA of ≤32 weeks or a BW <1 500 g. Conclusions. Detection of infants with T1ROP is resource intensive. Larger infants require screening to include a few outliers, but they require fewer examinations than smaller infants. Making local screening criteria narrower on the basis of a limited evidence base may be dangerous. Risk factors for CSROP in larger infants need to be researched.