What are the main causes, clinical features, etiology, and complications of infections of the lacrimal system?

Canaliculitis is an inflammation of the canaliculi and is one of the main causes of chronic unilateral conjunctivitis.
Dacryocystitis is an inflammation of the lacrimal sac and the nasolacrimal duct, which can be acute or chronic.
The etiology of dacryocystitis can be bacterial, fungal, or viral.
Complications of dacryocystitis can include pericystic abscess and external lacrimal fistula.