Human Ocular Dirofilariasis in Hong Kong

Purpose. Human dirofilariasis is a helminthic infestation caused by filarial nematodes of the genus Dirofilaria. We report two cases of subconjunctival dirofilariasis in adult Chinese patients. Case Reports. Case 1: A 57-year-old woman presented to us with 1-day history of left eye redness and migratory foreign body sensation. Physical examination showed a temporal subconjunctival motile mass in her left eye. Immediate surgical exploration showed a live nonpigmented roundworm measuring 120 mm in length with morphology compatible with Dirofilaria. It was later identified to be Dirofilaria repens by sequence analysis. Case 2: A 69-year-old woman presented with left eye redness and foreign body sensation for 2 weeks. She was treated elsewhere initially with topical antibiotics without any improvement. On slitlamp examination, a mobile subconjunctival mass was noted. Immediate surgical removal was performed under local anesthesia, revealing a live 50-mm-long worm. It was identified as Dirofilaria hongkongensis. Both patients had normal systemic workup results and remained symptom-free after surgical removal of the nematode. Clinical findings, diagnosis, pathogenesis, and management are discussed. Conclusions. Ophthalmic dirofilariasis is a rare condition. Clinicians should be aware of this disease entity so that prompt diagnosis and treatment could be offered to the patients.