A patient complained of pain and discharge in medial canthal region. Slit-lamp examination showed swelling of the lower canaliculus and yellowish discharge on lacrimal sac compression. Syringing was patent. Gram staining of the discharge showed the following picture. 
 

a. What does the picture show?

Answer
Gram-positive bacteria which are fungus-like. The bacteria have filamentous branches. 
 

b. What is the diagnosis?

Answer
Actinomycosis. It is the most common cause of canaliculitis
and the most common species involved is Actinomyces israelii.
The discharge may contain the characteristic "sulphur" granules.