Dacryocystitis is an infection of the tear sac, located at the inner corner of the eye. It occurs when the tear duct becomes blocked, leading to the accumulation of tears and bacteria. Symptoms often include redness, swelling, and pain near the inner eye, along with discharge that may be yellow or green. Treatment typically involves antibiotics to address the infection, and in some cases, surgery may be necessary to clear the blockage. If left untreated, dacryocystitis can lead to more serious complications, making early diagnosis and management important for eye health.