Patients with blurred vision like a layer of fog, may be related to visual fatigue, may also be dry eye, cataract and other causes. 1. Visual fatigue: If patients use their eyes excessively for a long period of time, visual fatigue is easily induced, and patients may have blurred vision, like a layer of fog in front of their eyes, which may be accompanied by dry eyes, pain and other uncomfortable symptoms. 2. Dry eye: dry eye patients because of the lack of tears in the eyes, the eye surface dry, concerned about dry eyes, foreign body sensation and other discomforts, because of the tear film stability decline, the patient may also appear blurred vision and other discomforts. 3. Cataract: cataract patients because of the decline in transparency of the lens, resulting in blurred vision, like a layer of fog in front of the eyes, may also be accompanied by glare, visual field defects and other symptoms. It is recommended that patients with blurred vision consult a doctor to evaluate their condition and follow the doctor’s instructions for treatment.