One side of the cat’s eye is swollen and cannot be opened. It may be caused by inflammation, nasal congestion, injury, etc. First, check the condition of the cat’s eye and use a cotton swab for simple treatment. If it is inflamed, you can use Fengge eye drops and give it every day. If the cat is infected with nasal congestion, the cat should be sent to the pet hospital for examination and treatment. During this period, pay attention to the hygiene and cleanliness of the cat's living environment, which will facilitate the cat's physical recovery.