At month 36 , the difference between FAc 0.2 g/day and sham control in the percentage of patients who gained 15 letters or more was significantly greater in chronic DME patients ( FAc 0.2 g/day , 34.0 % vs. sham , 13.4 % ; P < 0.001 ) , compared with patients with nonchronic DME ( FAc 0.2 g/day , 22.3 % vs. sham , 27.8 % ; P = 0.275 ) .