FREE GROUND SHIPPING on all US web orders over $99! (excluding AK and HI)

215-884-8105 Toll-Free 1-800-659-2250 Fax 215-884-0418

Magnetic VF Prism (3 BI, 12 BO)

Product Number: 11207

Purchase the Magnetic Vergence Facility Prism here.  This special 3 BI, 12 BO prism is used in tests for binocular vision disorders.  Does not include magnetic stick!  To purchase with magnetic stick, search for “11208.” Note: Custom diopter combinations are available.  Call 215-884-8105 ext. 103.


Vergence Facility testing has been shown to be one of the most important methods of detecting patients with binocular vision disorders and symptoms. Diagnosis of non-strabismus binocular vision abnormalities can be improved through the use of vergence facility testing at near. The test is performed at 40 cm as the patient views a vertical 20/30 target or similar.

The procedure requires less than 2 minutes of chair time, inexpensive equipment and minimal patient cooperation. Vergence facility has a sensitivity of 0.80 (correctly identifying binocular vision problems) and a specificity of 0.65 (correctly identifying normal binocular vision) and therefore maybe used as screening a test for binocular vision problems. Vergence facility testing is easy to learn and can be administered by a technician.