Secondary Logo

Share this article on:

The Value of Clinical Case Reports in Evidence-Based Practice

Twa, Michael D.

doi: 10.1097/OPX.0000000000001052

Editor-in-Chief, Optometry and Vision Science

Optometry and Vision Science has been publishing clinical case reports for decades. Past cases have often focused on rare and unique conditions, new clinical interpretations of diagnostic findings, and treatments of exotic diseases. Going forward, the journal will place less emphasis on reporting the unusual and more on clinical relevance.

Although there is some value in spotlighting atypical cases, it can be done in a way that brings value to the community of readers, practitioners, and society members. One way to achieve this is to link case reports to larger, more fundamental clinical questions. As an illustration, consider the impact that optical coherence tomography has had on the detection and management of diabetic macular edema.1 Clinical practice is evolving because of the ability to better detect subtle signs of disease. Although the details provided in these images are fascinating (even dramatic), case reports that focus on the findings alone are not a publication priority. Larger questions addressing how to use this additional insight to improve patient outcomes would have greater value. It will be years before results from longitudinal studies can definitively address questions regarding how clinicians should use these new diagnostic insights, e.g. when to treat, how to treat, whom to treat, the visual prognosis associated with various presentations, etc. Nevertheless, clinical case reports can help identify gaps in the available evidence and even help prioritize the research agenda by raising important questions for consideration and discussion. A thoughtful clinical question, well illustrated by a case presentation, can help provide direction and important clinical context for future research.

Case reports also offer opportunities to illustrate the application of evidence-based recommendations to the care of individual patients. Evidence-based clinical practice necessarily evolves as new evidence accumulates and as our understanding and ability to apply new knowledge improves. As an example, the 2014 guidelines for adult hypertension management increased the systolic pressure limit to 150 mmHg in adults over 60 years of age.2 Case reports explicitly linking the care of individual patients to evidence-based recommendations have educational value and can effectively illustrate how research and practice interconnect. Evidence-based case reports will be a top priority for the journal, and these can take many forms:

Diagnostic case reports—These reports evaluate diagnostic test performance, e.g. validity (can we trust it?) and reliability (do we get the same result every time?). Comparisons of both the new test and the gold standard are most informative. Clinical cases illustrating failures of diagnostic test performance may be of interest, but should also address underlying reasons for test failures or give useful insights on the underlying anatomy, physiology, or related patient factors that influence diagnostic test outcomes.

Therapeutic case reports—Therapeutic case reports describe the efficacy or clinical course of drug treatments, surgical procedures, alternative methods of service delivery, or other interventions. Although case reports offer less influential evidence when compared to randomized clinical trials, it is useful to know how the results from such trials translate to clinical practice. Bias in the form of subject selection, exclusion, retention, and study design can affect how study results translate to routine patient care. Case reports can help spotlight these limitations and help raise awareness of them. Subjects enrolled in clinical trials differ from clinical populations in important ways.3 Moreover, a patient’s ability or willingness to accept and adhere to recommended practices even when based upon well-established evidence presents additional challenges. Case reports can help illustrate the practical challenges that patients and providers face when attempting to bridge this gap between study recommendations and clinical practice.

Prognostic case reports—Although a longitudinal cohort study design is the best way to understand factors that influence prognosis, case reports could offer informative insights on factors that influence the course of a patient’s disease. The preferred study design to establish evidence for disease prognosis is longitudinal cohort study. Because patients selected for case reports cannot substitute for a randomized sample or give unbiased insights, clinical practice has a distinct advantage when it comes to long-term follow-up. It is not unusual for practitioners to follow individuals or families for decades and that can provide powerful insights. Here again, the value of an individual prognostic case report is not to establish causation but to offer mechanistic reasoning and illustrative clinical context.

Global health case reports—As a journal that reaches a worldwide audience, Optometry and Vision Science is aware that the range and scope of clinical optometric practice around the world can differ widely by region, training, resources, etc. Moreover, there is value in discussing how clinical vision care provided to individuals is influenced by social, economic, political, and environmental context. The journal BMJ Case Reports has led with a similar initiative on the practice of general medicine.4 Optometry and Vision Science is interested in publishing quality, informative global health case reports. There are numerous opportunities for global health case reports related to vision, including telemedicine, humanitarian services, remote and low-resource environments, global trends, and innovations.

Regardless of the specific topic, priority will be given to cases that demonstrate

  • Critical thinking
  • Clinical decision making
  • Mechanistic reasoning
  • Links to basic sciences, e.g. pathophysiology, anatomy, and physiology, etc.
  • Applications of evidence-based practice principles to individuals

Authors should also consult the CARE guidelines on best practices for preparing case reports ( These guidelines and others are available through the equator network (

Back to Top | Article Outline

Clinical Care Timeline Figures

One of the recommendations of the CARE guidelines is for authors to include a timeline figure that provides, in graphical format, a summary of the patient’s care: visits, diagnostic procedures, test results, interventions, clinical outcomes, etc. This infographic is an efficient and helpful way of summarizing and communicating what transpired during the case and when important events occurred. This is helpful, much like a table summarizing the most important data analysis can be better conveyed in tabular form than attempting to describe the rows and columns of numbers. Similarly, timeline figures can provide iconic graphical elements that simplify grasping the patterns and events related to the clinical scenario. An example of such a figure is provided above, but of course this figure will have greater relevance and utility in the context of a specific case (Fig. 1).



Good case reports should tell a compelling story. They should encourage critical thinking and challenge conventional thought. Optometry and Vision Science is looking forward to improving the value of case reports published in the journal to help accomplish these objectives.

Michael D. Twa


Optometry and Vision Science

Back to Top | Article Outline


1. Cunha-Vaz J, Santos T, Ribeiro L, et al. OCT-leakage: a new method to identify and locate abnormal fluid accumulation in diabetic retinal edema. Invest Ophthalmol Vis Sci 2016;57:6776–83.
2. James PA, Oparil S, Carter BL, et al. 2014 evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA 2014;311:507–20.
3. United States Food and Drug Administration (USFDA). Clinical Research Versus Medical Treatment. Available at:; last updated: October 26, 2016. Accessed January 9, 2017.
4. BMJ Case Reports: Instructions for Authors. British Medical Journal (BMJ). Available at: Accessed January 9, 2017.
© 2017 American Academy of Optometry