Foggy eyes can be caused by conjunctivitis, glaucoma, cataract and other diseases. 1. Conjunctivitis: Conjunctivitis may be caused by infection, allergy, physical and chemical stimulation, and spread of neighboring organs. Patients will have symptoms such as conjunctival congestion, increased conjunctival secretion, blurred vision, and so on, which manifests itself as foggy eyes that are hard to see clearly. 2. Glaucoma: Glaucoma may be caused by factors such as elevated intraocular pressure, excessive close eye use and eye trauma. Patients will have blurred vision, headache, eye swelling and other symptoms, which can be manifested as foggy eyes. 3. Cataract: Cataract may be caused by aging, heredity, local nutritional disorders, immune abnormalities, poisoning, radiation and other factors. Patients will appear cloudy vision, blurred, always feel foggy in front of the eyes, and accompanied by vision loss, refractive changes and other symptoms. There are many reasons that cause patients to have foggy eyes to see clearly, need to go to the regular hospital to find out the cause of the disease.