Flash Focus: Vision Training In Minutes A Day Codes -

Daily training bonuses:
Collect the indicated number of stamps by completing the daily recommended training activities to unlock the corresponding bonus.

"C" Count: 7 stamps. 
Basketball: 4 stamps. 
Circle Spot: 5 stamps. 
Custom Training mode: 1 stamp. 
Eye Knowledge mode: 14 stamps. 
Fast Match: 9 stamps. 
Football: 10 stamps. 
Letter Count: 3 stamps. 
Number Tap: 11 stamps. 
Record Challenge mode: 13 stamps. 
Soccer: 8 stamps. 
Stamp Design No. 5: 12 stamps. 
Stamp Design No. 6: 15 stamps. 
Stamp Design No. 7: 23 stamps 
Table Tennis: 2 stamps. 
Volleyball: 6 stamps. 

Hard versions:
Earn the highest rank for an activity to unlock hard mode for that specific activity. Note: Core activities require an "Advanced" rank of 80%. Sports activities require a "Pro" rank of 90%. Alternately, the hard versions will eventually become unlocked after you keep getting stamps after reaching a total of fifteen.