The near point rule is the point closest to the bridge of the nose where convergence and binocular single vision can no longer be maintained as an object approaches.
 
The Near Point Accommodation Rule is engraved with Centimeters, Inches, Diopter Scales and Duane Age (the mean of the near point of accommodation at different ages according to Duane Age) with sliding cardholder.
 
Includes 4 cards.