Hyperreflective foci (HRF) were defined as well-circumscribed and scattered dots with hyperreflective signals in optical coherence tomography (OCT). HRF can be seen in the vitreous cavity as well as the retinal and choroidal layers. Different OCT examination equipment and modes have differences in HRF detection results, and HRF counting methods gradually develop from manual counting to semi-automatic counting and automatic counting. HRF may be lens fragments, inflammatory cells, migrating photoreceptor complexes, exuded proteins or lipids, activated microglia, degenerated photoreceptor cells, migrating retinal pigment epithelial cells, and degraded lipofuscin deposits. The number and distribution of HRF are associated with the progression and the prognosis of a variety of ocular diseases, such as diabetic retinopathy, age-related macular degeneration, central serous chorioretinopathy, retinal dystrophy, etc. HRF are clinically important in guiding the personalized treatment of patients.
