Misdiagnosed Spontaneous Carotid Cavernous Sinus Fistula.

A 63-year-old female presented to the emergency department with worsening left-sided blurry vision and diplopia. She had previously seen several physicians and had been diagnosed with common ocular conditions - keratoconus and dry eye. However, despite treatment her symptoms were worsening. By the time her true underlying diagnosis was treated, she was left with permanent vision loss. This case report discusses the presentation, diagnosis, and treatment of her rare condition.