A man in his late teens with primary hyperoxaluria presented with floaters in both eyes. Dilated fundus examination demonstrated numerous yellow flecks in the retina and macular pigmentary clumping (Figure). The patient was diagnosed with crystalline retinopathy secondary to primary hyperoxaluria. His serum oxalate level was 0.37 mg/mL (to convert to micromoles per liter, multiply by 11.107). Primary hyperoxaluria is an autosomal recessive disorder characterized by high urinary oxalate excretion with progressive calcium oxalate urolithiasis and nephrocalcinosis. Approximately 30% of patients with type 1 disease, caused by a defect in alanine-glyoxylate aminotransferase, develop ophthalmic manifestations secondary to systemic deposition of oxalate crystals. Oxalate-induced crystalline retinopathy is characterized by numerous discrete yellow flecks scattered throughout all layers of the retina and retinal pigment epithelium. Similar crystalline flecks in the retina have been reported in acquired oxalosis associated with acute renal failure after methoxyflurane anesthesia.
Besirli CG. Retinal Flecks in Primary Hyperoxaluria. JAMA Ophthalmol. 2015;133(10):e151532. doi:10.1001/jamaophthalmol.2015.1532