1974
Bilateral visual field constriction was observed in 59 % of patients currently taking VGB , 43 % of patients who previously took VGB , and 24 % of patients with no 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