[Postoperative change of the Bielschowsky head tilt test in patients with unilateral congenital superior oblique palsy].

OBJECTIVE

To investigate the postoperative changes of the head tilt test in patients with unilateral congenial superior oblique palsy.

METHODS

Thirty-eight cases with congenital unilateral superior oblique palsy underwent the ipsilateral inferior oblique or/and contralateral inferior rectus weakening procedure. Bielschowsky head tilt test was evaluated quantitatively before and after the operation by the prism cover test while the patient fixated at 33 cm and 6 m on the small light target. A positive Bielschowsky head tilt test was defined as one in which the vertical deviation when the head tilt to the side of the paresis was at least 5.0(Delta) greater than that on tilt to the uninvolved side.

RESULTS

Before the operation, the hyperdeviation of the involved eye was 3.0(Delta) - 25.0(Delta) (average 11.0(Delta)) in primary position. The deviation on tilt to the side of the paresis was 23.0(Delta) (15.0(Delta) - 40.0(Delta)) and the deviation on tilt to the uninvolved side was 2.5(Delta) (0.0(Delta) - 10.0(Delta)). A positive Bielschowsky tilt test was found in all cases preoperatively. After the operation, the hyperdeviation of the involved eye was 0.0(Delta) - 5.0(Delta) (average 2.0(Delta)) in primary position. The result of Bielschowsky tilt test was still positive in 34 cases and negative in only 4 cases.

CONCLUSION

In most cases with unilateral superior oblique paresis, the results of Bielschowsky tilt test do not change to negative postoperatively. The significance of using this test for evaluating surgical results remains to be determined.