Changes in Field of Binocular Single Vision and Ocular Deviation Angle After Balanced Orbital Decompression in Thyroid Eye Disease.

PURPOSE: To evaluate influential factors for changes in the binocular single vision (BSV) and ocular deviation angle in the medial direction after bilateral balanced orbital decompression in thyroid eye disease.

METHODS

This retrospective study included 41 patients. The areas of BSV and the angles of medial ocular deviation on the Hess chart were measured. The percentages of pre- and postoperative areas against the normal area (%BSV) and the change in BSV after surgery were calculated. Postoperative change in the angle was calculated by subtraction of the preoperative angle from the postoperative one. Influential factors for the change in BSV and that in the medial deviation angle were evaluated via multivariate linear regression analysis.

RESULTS

The maximum cross-sectional area of the medial rectus muscle, preoperative %BSV, and preoperative medial ocular deviation angle were significant factors of change in BSV (adjusted r2 = 0.449, p < 0.001), although age, history of anti-inflammatory treatment, volume of removed orbital fat, findings on CT images, maximum cross-sectional areas of the other rectus muscles, and presence or absence of a periosteal flap did not affect change in BSV (p > 0.050). On the contrary, all variables did not influence postoperative changes in the medial ocular deviation angle (p > 0.050).

CONCLUSIONS

In balanced orbital decompression, the maximum cross-sectional area of medial rectus muscle, preoperative field of BSV, and medial ocular deviation were significant influential factors for postoperative changes in field of BSV.