The prism flipper is composed of a pair of 3 △ Bi (base in) prisms and a pair of 12 △ Bo (base out) prisms installed on the flip racket. Under the condition that the adjustment stimulus of both eyes remains unchanged, two pairs of prisms with different values make the trainer's collection needs constantly switch, and promote the conversion of fusion image collection and adjustment collection while improving the collection flexibility.

Method: 

① The subject's far ametropia is corrected completely.

② Place a 3 △ Bi (base in) prism in front of the subject and ask him to look at a single row of 0.6 visual targets nearly 40cm.

③ Switch the 12 △ Bo (base out) prism, instruct the measured eyes to look at the 40 cm single row 0.6 visual target, try to melt the image and start timing. After the fusion of the visual target, switch to the 3 △ Bi (base in) prism again until the fusion of the two eyes. This process is a switching cycle, and the collective flexibility of the normal two eyes is 15C/min.

Indications: Convergence facility delay,Low function of fusional convergence