Red eyes after eyelash extensions may be caused by blepharitis, allergic conjunctivitis, blepharitis and so on. 1. Blepharitis: Blepharitis may be caused with Staphylococcus aureus infection, blepharosphenoid gland dysfunction, squamous lesions and so on. Patients will have eyelid margin congestion, eye itching, tingling, burning sensation in the eye, eyelash loss and other manifestations. If the eyes become red after eyelash extensions, it may be caused by blepharitis. 2. Allergic conjunctivitis: Allergic conjunctivitis is considered to be related to heredity and exposure to allergens. Patients will experience symptoms such as itchy eyes, redness of the white eyeballs, swelling of the eyelids, increased eye boogers, and fear of light. After eyelash extensions, if the eye is allergic to the glue, it is easy to induce allergic conjunctivitis, at this time, the patient may have the symptom of red eyes. 3. Blepharitis: Blepharitis is mainly caused by Staphylococcus aureus infection, and patients will have redness, swelling, pain and pustules at the root of the eyelashes. If the patient does not pay attention to eye hygiene after eyelash extensions, blepharitis is easily induced, which may cause the eyes to turn red. It is recommended that patients with red eyes after eyelash extensions seek medical attention, and the doctor will choose targeted measures to treat the cause of the condition.