Cobalt-chromium toxic retinopathy case study

To report the clinical case of a 65-year-old male who developed retinal dysfunction following cobalt-chromium toxicity. A review of the clinical, haematological, radiological and electrophysiological investigations into a single patient was performed in order to form a case report. A 65-year-old male presented to his ophthalmologist with a 1-year history of worsening vision on the background of a multisystem illness including motor axonopathy, pericardiomyopathy and bulbar palsy. His medical history included hypertension, hypercholesterolaemia and a metallic hip prosthesis. Ocular examination revealed significantly reduced visual acuity bilaterally along with very poor colour vision. Cornea, fundi and optic discs all appeared normal. Bilateral moderate nuclear sclerosis was noted. Basic investigations including mitochondrial studies, auto-immune screen and MRI of brain were unremarkable. Further investigations showed significantly elevated plasma cobalt and chromium levels. Electrophysiological studies revealed an abnormality in all phases of the ERG including a negative b-waveform, suggestive of inner retinal pathology. Following subsequent revision of the hip, cobalt and chromium levels decreased and the patient's vision improved. Further electrophysiological testing indicates a persistent ERG abnormality despite a significant improvement in both the patient's visual acuity and colour vision. These results suggest that cobalt-chromium toxicity can cause inner retinal dysfunction.