Assertion: viagra's sildenafil | /r/HasSubevent | vision impairment
Facets:
value: in rare cases
type: TEMPORAL
Source sentences:
text: In July 2005, the FDA found that sildenafil could lead to vision impairment in rare cases, and a number of studies have linked sildenafil use with non-arteritic anterior ischemic optic neuropathy.
text: In July 2005, the FDA found that sildenafil could lead to vision impairment in rare cases, and a number of studies have linked sildenafil use with non-arteritic anterior ischemic optic neuropathy.