1975
Assessment of retinal function revealed abnormal responses in 48 % of current VGB users and 22 % of prior VGB users , but in none of the patients without previous exposure to VGB .
 Chemical: VGB; Chemical: VGB; Chemical: VGB
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: VGB; Chemical: VGB; Chemical: VGB