Using the White Disk Test to Predict Fusional Potential

Fusional potential in patients experiencing binocular torsional diplopia may be challenging for the clinician to assess, particularly when accompanied by vertical and horizontal diplopia.

To demonstrate a clinical test that may help predict if binocular fusion can be achieved once cyclotorsion is alleviated.

Video recording demonstrating how to perform the white disk test and retrospective chart review of patients tested with the white disk test.

Twelve patients with binocular torsional diplopia were included. All subjects had excyclotorsion, 11 (91.7%) had combined vertical and horizontal strabismus and 1 patient (8.3%) had vertical strabismus. Eleven patients (91.7%) were able to achieve single binocular vision with the white disk test and 1 patient (8.3%) demonstrated brittle fusion. The white disk test successfully predicted postoperative fusion in 10 of 11 patients (90.9%). Eight patients (66.7%) demonstrated improved stereopsis after surgery.

The white disk test was found to be very useful in predicting fusional potential in patients that experience binocular torsional diplopia.