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: CONCLUSION : Elevated IOP is a significant complication with the FA intravitreal implant but may be controlled with medication and surgery .
### Output Text:
CONCLUSION : Elevated IOP is a significant complication with the FA intravitreal implant but may be controlled with medication and surgery . 