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: Although the intraocular pressure elevation caused by secondary acute angle - closure glaucoma decreased and ocular pain diminished , inexorable papilledema and exudative retinal detachment continued for 3 weeks .
### Output Text:
Although the intraocular pressure elevation caused by secondary acute angle - closure glaucoma decreased and ocular pain diminished , inexorable papilledema and exudative retinal detachment continued for 3 weeks . 