The aperture rule trainer tests and trains the positive and negative vergence. 

Not only the fusional vergence is tested and trained, but also the speed of the fusional vergence reaction. With this device you can easily create up to 30 pdpt b.o. and 9 pdpt b.i. without using prisms! Card set for training is included (item 80297 - manufacturer no. BC1050CBBK). The device is portable and light weight, and can be rented to your clients. A tranaglyph goggle is not necessary. With the two included blinds you can test and train divergence and convergence.