In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: PURPOSE : Glucocorticoid administration can lead to the development of ocular hypertension and corticosteroid glaucoma in a subset of the population through a decrease in the aqueous humor outflow facility .
### Output Text:
PURPOSE : Glucocorticoid administration can lead to the development of ocular hypertension and corticosteroid glaucoma in a subset of the population through a decrease in the aqueous humor outflow facility . 