Abstract
Purpose: :
To evaluate the surgical results of vertical strabismus in patients with dysthyroid ophthalmopathy.
Methods: :
Sixty–six patients with thyroid–associated ophthalmopathy (TAO) were examined at Shiga University of Medical Science Hospital from April 1994 to March 2005. Of them, 44 had ocular motility disturbance due to TAO. We performed strabismus surgery on seven patients with vertical strabismus and binocular diplopia in primary gaze despite steroid therapy. The vertical strabismus ranged from 10 to 23 degrees preoperatively; four patients had strabismus greater than 15 degrees. Vertical muscle recession of 4 mm or less was performed in six patients to avoid eyelid retraction due to strabismus surgery. In the other patient who had hypotropia of 22 degrees, 6–mm recession of the inferior rectus (IR) muscle and separation of the Lockwood ligament from the IR were performed to prevent eyelid retraction.
Results: :
Fused binocular vision in primary gaze was achieved postoperatively in the three patients with vertical strabismus of less than 15 degrees preoperatively. Residual vertical strabismus of 9 to 12 degrees remained postoperatively in the three patients with strabismus exceeding 15 degrees preoperatively who underwent vertical muscle recession of 4 mm or less. The patient who had 22 degrees of hypotropia preoperatively and underwent 6–mm recession of the IR with Lockwood ligament separation also regained fused binocular vision without remarkable eyelid retraction. The corrections of the ocular position in each patient ranged from 1.8 to 3.3 degrees per 1–mm recession.
Conclusions: :
: Recession of 4 mm or less is effective with less than 15 degrees of strabismus. For patients with TAO who have large vertical strabismus exceeding 15 degrees, vertical muscle recession exceeding 4 mm is necessary. With larger vertical muscle recession, Lockwood ligament separation from the IR muscle may be useful to reduce the degree of eyelid retraction.
Keywords: strabismus: treatment • eye movements • orbit