State of science: Choroidal thickness and systemic health

The choroid is a highly vascular structure; therefore, a wide range of systemic conditions can affect it. Conversely, choroid health may also give us insight into systemic health. With the emergence of optical coherence tomography, there has been a surge in the research on choroidal thickness and factors affecting it. Studies regarding the effect of systemic health on the choroid have largely been in the form of cross-sectional, prospective, and case studies. We offer a summary of recent findings on the topic.