White letters on a black background can be easier to see for the eyes.  

Includes:
Full size  professionally printed 11x23 inch black and white eye chart poster (black background, white letters), printed on a $14,000 professional color printer on premium poster vinyl. 

Matching mini eye chart in black and white (business card size)
 
Includes instructions.
 
TWO WEEKS SHIPPING TIME (this may be faster once the initial run is received) This is at the most. 
 
Returns permitted within seven days of unused items in original packaging, buyer pays return shipping.

Free shipping within the US.