Ophthalmic Epidemiology 2: Application to Eye Disease
Using epidemiology to improve public health eye care
Learn to critically analyse the different features of the main epidemiological study designs and how they are used to address different research questions in eye health.
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Materials from the course are published under a Creative Commons license (CC BY-NC-SA-4.0) which permits non-commercial re-use without asking for permission. We encourage you to download, adapt and share these Open Educational Resources (OER) for teaching and learning.
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Week 1. Cross sectional studies in cataract blindness
Week 2. Case-control studies in AMD
Week 3. Cohort studies in diabetic retinopath
Week 4. Randomised control trials in glaucom
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Week 1 Cross sectional studies in cataract blindness
Estimating the burden of cataract blindness
Examine how the cross-sectional study design is used in eye care using the example of cataract blindness. Identify the main features of population-based studies and RAAB surveys and critique the strengths and weaknesses of both
Welcome to the course and session 1
Dr Daksha Patel, lead educator, introduces the course and the topics explored in week 1
Video & teaching slides: The epidemiology of cataract
In this session, we introduce the epidemiology of cataract and also explore the strengths and weaknesses of population based surveys and rapid assessment methodologies used in eye health.
Video & teaching slides: Cross-sectional study for cataract
In this step we start by re-examining the main features of the cross-sectional study and introduce the Rapid Assessment of Avoidable Blindness methodology as an alternative to a population-based survey.
Article: RAAB methodology: An overview
In this article we introduce the practicalities of carrying out a RAAB survey in order to find the prevalence and causes of blindness in a local setting.
Article: Ethics, training and logistics in population based surveys
In this step we examine how quality was managed in the Nigeria national blindness and visual impairment survey.
Video & teaching slides: Strengths & weaknesses of rapid assessment
Rapid assessment methods are used in many areas of health to address the need of programme planners and decision makers to generate baseline data and evaluate interventions in situations where large population-based surveys are not possible.
Video & teaching slides: Confounding factors and outcomes in cross-sectional studies
In this video we discuss how to recognise when a variable may be a confounder and what can happen when confounding is present.
Article: Critique a RAAB survey
In this step we ask you to read and critically review a peer-reviewed research paper on this study which was published in PLoS ONE in 2008.
Week 2 : Case-control studies in AMD
In this week we look in detail at the epidemiology of age-related macular degeneration (AMD) and explore the use of case control studies in eye care through AMD.
Article: Welcome to session 2
Video & teaching slides: The epidemiology of AMD
In this video, lecturer Jennifer Evans looks closely at the case definition, classification and magnitude of AMD and at how research is building understanding about the risk factors. She also summarises the treatments currently in place for the condition.
Video & teaching slides: Selection and sources of cases and controls
In all case-control studies, as in all epidemiological studies, we must begin with a clearly defined question or hypothesis. We also need to establish a clear case definition at the very outset of the study.
Video & teaching slides: Recall and observer bias
In this week we look at what researchers can do to ensure that the impact of bias is minimised
Video & teaching slides: Calculating the association between disease and exposure
In this week reflect on the difference between the concepts of “probability” and “odds.” and think about the reasons why we wouldn’t use a case-control study to obtain information on incidence.
Article: Nested case-control studies
In this step we ask you to read a short introduction to the strengths and weaknesses of nested case-control studies and two summaries of eye disease studies which used this methodology. At the end of each summary, we ask you to reflect on some key questions about the study.
Article: Critique a case-control study
In this step we ask to read the following summary of a case-control study that aimed to assess the risk of age-related macular degeneration (AMD) associated with statin use. As you read, critically appraise the study’s methodology and findings.
Week 3. Cohort studies in diabetic retinopathy
Article: Welcome to session 3
Video & teaching slides: The challenge of diabetic retinopathy
Currently about 347 million people are affected by diabetes., Professor Murthy shares his insight on ophthalmic complications of diabetes include diabetic retinopathy (DR).
Video & teaching slides: Identifying the population in a DR cohort study
In this video we look at why, In a cohort study, it is essential to select study participants who are representative of the population from which they are drawn, apart from their exposure status.
Video & teaching slides: Error in cohort studies
In this video we look at the major challenge for all cohort studies – the feasibility of long-term follow-up in terms of cost and resources.
Video & teaching slides: Calculating the association between exposure and outcome
In this video we look at relative risk – the simple ratio which compares the occurrence of the outcome in the exposed group to the occurrence in the unexposed group.
Article: Guidelines for diabetic retinopathy screening
In this step we ask you to read and critically assess a brief extract from the ICO guidelines for diabetic eye care..
Article: Critique a cohort study
In this step we ask you to read and critically assess cohort study from the United Kingdom that aimed to calculate the optimum screening intervals for diabetic retinopathy.
Week 4. Randomised control trials in glaucoma
Article: Welcome to session 4
Video & teaching slides: Epidemiology of the glaucomas
In this video, Dr Winifred Nolan, consultant ophthalmologist at Moorfields Eye Hospital, presents a brief overview of the epidemiology of glaucomas.
Video & teaching slides: Main features of RCTs
In this video, we look at the definition, key elements and main design types of the randomised control trial (RCT).
Video & teaching slides: Key design elements in RCTs
In this video we look at the main advantages and disadvantages of RCT and the common methods of randomisation.
Article : Evidence based practice: Cochrane reviews
In this activity we introduce the essentials of evidence-based medicine through the work of the International Cochrane Collaboration.
Article : Challenges in glaucoma management
In this article we are asking you to think about the challenges you face in your setting with glaucoma patients.
Article : The KIM methodology
In this article we look at the Innovative approach: Childhood blindness and the key informant method (KIM)
Article : Qualitative research
In this article we consider how – in the context of glaucoma – the qualitative study design can be used to better understand patient health seeking behaviour?
Video & teaching slides: Conclusion
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