Dysthyroid Optic Neuropathy

Abstract

Purpose: Dysthyroid optic neuropathy (DON) is a serious complication of Graves orbitopathy that can result in irreversible and profound visual loss. Controversy exists regarding the pathogenesis and management of the disease. The authors provide an overview of the current understanding of DON and present a therapeutic guideline.

Methods: A review of the literature.

Results: The mechanism of DON appears to be multifactorial: direct compression of the optic nerve by enlarged extraocular muscles, stretching of the optic nerve by proptosis, orbital pressure, vascular insufficiency, and inflammation. Some or all of these factors may be involved in an individual patient. There has only been one controlled trial comparing high-dose intravenous methylprednisolone to bony orbital decompression for DON. Both 2-wall and 3-wall decompression techniques successfully improve visual functions of patients with DON. There are few case reports/case series that suggest biologic agents may improve visual function in DON.

Conclusions: DON is a serious complication of Graves orbitopathy, the diagnosis and management of which is complex and requires a multidisciplinary approach. There is little evidence regarding the optimum management strategy. Based on the current literature, the first line of treatment is intravenous methylprednisolone, with the exact timing and indication of bony orbital decompression still to be determined. In addition, there may be a role for the use of biologic agents that will require a systematic program to determine efficacy.