Waking up in the morning with swollen eyes can be caused by drinking too much water, nephrotic syndrome, heart failure or mosquito bites. If you drink too much water before going to bed and keep your head in a lower position while sleeping at night, it leads to a decrease in the flow of blood to the heart, which leads to swollen eyes. Patients with renal diseases such as nephrotic syndrome, because of renal dysfunction and fluid retention in the body, patients may have eyelid edema, which may also be accompanied by lower limb edema. Heart failure and other diseases, because of heart dysfunction, resulting in blood reflux obstacles, so that the water in the blood leakage, may lead to patients with eyelid swelling. Swelling of the eyelids can also be caused by mosquito bites while resting at night. Patients with significant eyelid swelling are advised to seek medical attention to evaluate their condition and to follow their doctor’s instructions.