To investigate the protective effect of a modified orbital decompression on postoperative eye position in thyroid-associated ophthalmopathy (TAO).

A cohort study was performed.One hundred and thirty-six eyes of 96 TAO patients who received orbital decompression in Henan Eye Hospital from July 2008 to July 2018 were enrolled.The patients were divided into two groups according to different operation methods.A depressed bone window was made in the region of orbital apex in the modified orbital decompression group with 100 eyes of 70 patients.A depressed bone window was made in the middle and anterior region of orbit in the traditional orbital decompression group with 36 eyes of 26 patients.The best corrected visual acuity, palpebral fissure, eyeball exophthalmos, strabismus, eyeball position、CT image and postoperative complications were compared.This study was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2020[07]), and written informed consent was obtained from each subject before surgery.

Strabismus was improved in 14 eyes of 10 patients, unchanged in 75 eyes of 52 patients and slightly aggravated in 11 eyes of 8 patients after operation in the modified orbital decompression group.In the traditional orbital decompression group, strabismus was slightly aggravated in 6 eyes of 4 patients, seriously aggravated in 30 eyes of 22 patients after surgery. In the modified orbital decompression group, the eyeball displacement was unchanged in 91 eyes of 64 patients, slightly aggravated in 9 eyes of 6 patients after surgery in the traditional orbital decompression group, the eyeball displacement was slightly aggravated in 15 eyes of 10 patients, seriously aggravated in 21 eyes of 16 patients after surgery.Significant differences were found in the number of eyes with different degree of strabismus and eyeball displacement between the two groups (Z=-9.634, -10.278, both at P<0.01). The postoperative eyeball exophthalmos values were (14.36±2.03)mm and (14.36±1.03)mm in the modified orbital decompression group and the traditional orbital decompression group, respectively, which were significantly lower than preoperative (20.47±1.92)mm and (20.28±2.03)mm (both atP<0.05). CT imaging showed that the bone window was clear in orbital apex and the compression of optic nerve was relieved postoperatively in the modified orbital decompression group, and the bone window was in anterior part of the orbit and the orbital apex was still crowded in the traditional orbital decompression group.No severe complication was seen during the fellow-up duration in the two groups.

Compared with traditional orbital decompression, the modified orbital decompression surgery can reduce the risks of strabismus and eyeball displacement, showing an obvious protective effect on eye position.

Thyroid-associated ophthalmopathy/surgery; Orbital decompression, modified/methods; Eyeball displacement/complication; Eye position