23702
Recent studies , however , suggest that most Graves ' patients have mild or no GO at presentation , while moderate - to - severe GO is rare , and sight - threatening GO ( mostly due to dysthyroid optic neuropathy ) is exceptional in non - tertiary referral centers .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None