The condition -- characterized by stinging, sensitivity to light, blurred vision and eye fatigue -- affects about 38 million Americans, and is currently treated with over-the-counter artificial tear drops such as GenTeal and Refresh. Prescription eye drops, such as Novartis' Xiidra, AbbVie Inc's Restasis and Sun Pharmaceutical's Cequa are also used to treat dry eye disease. Oyster Point said Tyrvaya, a twice daily nasal spray, was tested in a late-stage and two mid-stage trials covering over 1,000 patients with mild, moderate or severe symptoms of dry eye disease (DED).