Recent years, it is more and more recognized that dysbiosis of the microbiota in the skin, gut, and airways plays an important role in allergic diseases like atopic dermatitis, food allergies, and asthma. Ocular surface microbiome alterations were also reported to be closely associated with several ocular diseases. In this study, we identified the characteristics of ocular surface microbiome alterations in patients with allergic conjunctivitis.