Dysthyroid Optic Neuropathy

Excerpt

Dysthyroid optic neuropathy (DON) represents the most dreaded manifestation of Thyroid Eye Disease (TED), one of the most common autoimmune diseases of the orbit. DON, previously termed as the crowded orbital apex syndrome, is characterized by thyroid-related impairment of optic nerve function that may lead to a profound loss of vision. The European Group on Grave’s Orbitopathy (EUGOGO) classifies the severity of TED as mild, moderate-severe, or sight-threatening. Sight threatening TED, characterized by DON and/or keratopathy, warrants the need for urgent intervention.

DON is a multifactorial entity, the diagnosis of which is extremely challenging, owing to its early subclinical stage, presence of confounding factors, and alternative causes of sight loss in TED. A thorough evaluation of DON and subsequent timely management is crucial to avoid permanent blindness in TED.