Comparison of 2-wall versus 3-wall orbital decompression against dysthyroid optic neuropathy in visual function: A retrospective study in a Chinese population.

ABSTRACT: To compare visual function of 2-wall (medial and lateral) versus 3-wall (medial, lateral, and inferior) orbital decompression in patients with dysthyroid optic neuropathy (DON).A total of 52 eyes of 37 patients underwent orbital decompression for DON between 2013 and 2019 were retrospectively reviewed. Two- or 3-wall decompression was performed in 31 eyes of 23 patients and 21 eyes of 14 patients, respectively. We examined best-corrected visual acuity (BCVA), visual field mean deviation (MD) and pattern standard deviation (PSD), pattern-reversed visual evoked potential (PVEP) for P100 latency and amplitude at 60 and 15 arcmin stimulation checkerboard size, as well as proptosis using Hertel exophthalmometry.Whether 2-wall or 3-wall decompression, all parameters of visual function were improved after surgery (all P < .05). The improvement in BCVA, MD, and PSD was not statistically significant between groups (all P > .05). Proptosis reduction was higher after 3-wall decompression (P = .011). Mean increase in P100 amplitude after 3-wall decompression was statistically higher than that of after 2-wall decompression at 60 and 15 arcmin (P = .045 and .020, respectively), while the mean decrease in P100 latency was similar between the groups (P = .821 and .655, respectively). Six patients (66.67%) had persistent postoperative diplopia and 1 patient (20%) had new-onset diplopia in 3-wall decompression group, which were higher than in 2-wall decompression group (46.15% persistent postoperative diplopia and no new-onset diplopia).Both 2-wall and 3-wall decompression can effectively improve visual function of patients with DON. Three-wall decompression provides better improvement in P100 amplitude and proptosis, however new-onset diplopia is more common with this surgical technique.