The Changes in Optic Nerve after Orbital Decompression Surgery for Thyroid Eye Disease and Case Reports of Ischemic Optic Neuropathy

Abstract

Purpose. To demonstrate the changes in the retinal nerve fiber layer (RNFL) after orbital decompression for thyroid eye disease (TED). Methods. We retrospectively enrolled 52 surgical TED patients, 30 nonsurgical TED patients, and 30 control subjects. Five surgical TED eyes with disc edema were excluded. The surgical TED patients were classified into the “dysthyroid optic neuropathy (DON)” group (16 eyes) and the “non-DON” group (83 eyes). Optical coherence tomography (OCT) and visual field (VF) examinations were performed preoperatively and 6 months later. The control subjects and nonsurgical TED patients received two OCT examinations at 6-month intervals. The postoperative changes in the RNFL thickness were compared between groups. Three cases with severe postoperative vision loss were presented additionally. Results. The changes in the RNFL thickness of the controls ( 0.5 ± 3.4 μ m ) and the nonsurgical TED patients ( 0.3 ± 2.8 μ m ) were significantly smaller than the surgical TED patients ( P < 0.001 ). The DON group ( − 9.2 ± 9.2 μ m ) had greater RNFL thickness reduction than the non-DON group ( − 3.9 ± 5.4 μ m ) ( P = 0.002 ). Bone removal decompression was associated with decreased RNFL in the non-DON ( P = 0.025 ; β = − 2.49 ) and DON ( P = 0.042 ; β = − 9.43 ) groups. Three cases who were hard to operate due to extensive fibrosis experienced severe vision loss postoperatively due to anterior ischemic optic neuropathy, posterior ischemic optic neuropathy, and posterior ciliary artery occlusion, respectively. Conclusions. TED patients experienced subclinical optic nerve injury and significant RNFL loss after the orbital decompression surgery. Aggressive manipulation during decompression surgery may lead to dreadful vision loss. Tailored surgical plans and delicate manipulation are warranted.

Preliminary Diffusion‐Tensor Imaging Evidence for Trans‐Synaptic Axonal Degeneration in Dysthyroid Optic Neuropathy Due to Thyroid‐Associated Ophthalmopathy

“…Optical coherence tomography (OCT) has been used to detect damage to the anterior visual pathway (retrograde TSD), 15 and RNFL changes have been reported in DON. 16,17 Diffusion-tensor imaging (DTI) has been widely applied in studying various visual pathway-related disorders owing to its advantage of non-invasively and accurately detecting the microstructural integrity of the neural pathways associated with vision. [18][19][20][21] In recent years, the combination of DTI and OCT has been employed to investigate bidirectional TSD in the human visual system.…”

Assessment of retinal and choroidal vessel density and nerve fibre layer thickness changes after orbitotomy in patients with severe non-active thyroid orbitopathy: a prospective study

“…After decompression surgery in the Non-DON group, RNFL thickness in all quadrants (except in the temporal quadrant) decreased signi cantly. [13] Our study showed decreasing peripapillary, and inferior hemi eld RNFL thickness, and increasing cup/disc horizontal ratio following decompression surgery, but disc area and cup/disc area didn't show any change.…”

“…Some of these types of surgeries are performed for cosmetic reasons. To date, few studies investigated the thickness of RNFL which showed a decrease following decompression surgery, [11][12][13] while studies focusing on postoperative changes of the vascular density of the retinal layer are lacking. All of these studies were conducted on those patients with TED associated with ischemia of optic nerve.…”

The Changes in Ocular Biomechanical Response Parameters and Intraocular Pressure After Surgical Treatment for Thyroid Eye Disease

“…Dysthyroid optic neuropathy was diagnosed if the patient suffered from decreased visual acuity (logarithm of the minimal angle of resolution > 0.2) and had the following signs: relative afferent pupillary defect, and/or impaired color vision, and/or visual field defect, and/or reduced amplitude and prolonged latency of visual evoked potentials test, and apical crowding on orbital imaging using computerized tomography. 4 , 22 …”

“… 2 , 3 These changes can result in vision-threatening complications such as dysthyroid optic neuropathy and exposure keratopathy. 2 , 4 , 5 Orbital decompression surgery is a well-established procedure to correct disfiguring proptosis and related complications. 6 Various types of non-surgical treatment modalities and lid surgeries, 2 , 7 such as anterior blepharotomy, 3 , 7 could be performed to correct upper eyelid retraction.…”