Patients with clear vision in one eye and blurred vision in the other eye may be caused by monocular cataract, myopia, keratitis and other reasons. 1. Cataract: Due to age, heredity, local nutritional disorders, trauma, poisoning, radiation and other reasons, the patient’s crystalline protein degeneration, resulting in the formation of cataract, resulting in blurred vision in the patient’s diseased eye, while the vision of the other eye is normal. 2. Myopia: myopia is a very common eye disease, if the patient has long-term monocular vision, the affected eye myopia, when seeing distant objects, one eye can appear clear and one eye blurred phenomenon. 3. Keratitis: Keratitis is caused by infectious and non-infectious causes, resulting in corneal epithelial cells occurring point-like or flaky detachment, causing corneal edema in patients. After corneal edema, patients may experience blurred vision and loss of vision, which usually occurs unilaterally. It is recommended that patients with blurred vision in one eye should seek prompt medical attention to evaluate their condition and follow the doctor’s instructions for treatment.