Dry eye is the most common chronic inflammatory disease of the ocular surface,19 and the inflammatory response has been identified as the central basis of dry eye, irrespective of its underlying causes.37,38 In order to investigate the activation of the cGAS-STING pathway in dry eye, we extracted tear proteins from Schirmer strips of both dry eye patients and normal individuals (Supplementary Fig. 2a). Here, CGAS is linked to Keratoconjunctivitis sicca.