This patient had familial amyloidosis. Amyloid stains with Congo red and shows distinctive yellow-green birefringence with polarized light. Most familial amyloidosis patients have a mutation of the gene that codes for transthyretin, and this patient’s condition was confirmed with genetic testing. Transthyretin is a protein in the serum and cerebrospinal fluid that transports retinol-binding protein to retinol and also transports the thyroid hormone thyroxine. The abnormal protein manifests as an amorphous material called amyloid, which can accumulate in the vitreous and elsewhere. Evidently, the retinal arteries exude amyloid, and intraretinal perivascular amyloid is sometimes seen. Though our patient was systematically asymptomatic, many patients develop systemic complications, most notably peripheral neuropathy, nephropathy, and cardiomyopathy. Systemic amyloid derives largely from the liver, and liver transplantation can prolong life in those with systemic involvement. However, further ocular involvement can occur on account of persistent retinal arterial exudation.
Our patient had bilateral vitrectomy, resulting in substantially improved subjective vision and a visual acuity of 20/20 OU.