If a patient sleeps and feels swollen in one eye, there are usually the following diseases: First, the most common is an infectious factor. When the eye is infected with bacteria, viruses or fungi and other pathogenic microorganisms such as mycoplasma and chlamydia in the bulbar conjunctiva while sleeping, the clinical signs and symptoms of swelling in one eye will occur due to inflammatory infection. Second, in hypertension, retinal lesions of the fundus can occur, which can also lead to swelling of one eye, but usually with varying degrees of fundus congestion. Thirdly, when the intracranial pressure is increased, the brain cells in the brain will have different degrees of edema, so there will be different degrees of puffiness in one eye after sleeping.