Reversal of dysthyroid optic neuropathy following orbital fat decompression

Abstract

Aims: To document the successful treatment of five patients with dysthyroid optic neuropathy by orbital fat decompression instead of orbital bone decompression after failed medical therapy.

Methods: Eight orbits of five patients with dysthyroid optic neuropathy were selected for orbital fat decompression as an alternative to bone removal decompression. Treatment with systemic corticosteroids and/or orbital radiotherapy was either unsuccessful or contraindicated in each case. All patients satisfied clinical indications for orbital bone decompression to reverse the optic neuropathy. High resolution computerised tomographic (CT) scans were performed in all cases and in each case showed signs of enlargement of the orbital fat compartment. As an alternative to bone decompression, orbital fat decompression was performed on all eight orbits.

Results: Orbital fat decompression was performed on five patients (eight orbits) with optic neuropathy. Optic neuropathy was reversed in all cases. There were no cases of postoperative diplopia, enophthalmos, globe ptosis, or anaesthesia. All patients were followed for a minimum of 1 year.

Conclusions: In a subset of patients with an enlarged orbital fat compartment and in whom extraocular muscle enlargement is not the solitary cause of optic neuropathy, fat decompression is a surgical alternative to bony decompression.

Figure 1

Preoperative CT scan of patient 1. Axial mid-orbit (A) and coronal apical section (B). Note apical enlargement of the medial recti more significant on the left.

Figure 2

(A) Axial CT scan of patient 2 before radiotherapy. Note enlarged medial recti worse left than right. (B) Axial CT scan of patient 2, after completion of radiotherapy. Note reduction in size of medial recti, absence of apical crowding of the optic nerve, and straightening of the optic nerve shadows.

Figure 3

Preoperative axial (A) and coronal (B) CT scan of patient 3. Note bilateral enlargement of medial, inferior, and superior recti.

Figure 4

Preoperative axial (A) and coronal (B) CT scan of patient 5. Note bilateral enlargement of all rectus muscles with straightening of the optic nerve shadow and crowding of the orbital apices bilaterally.