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.