Diagnosis and Treatment of Thelazia callipaeda Infection: A Case Report

This study reports a 50-year-old male case of Thelazia callipaeda infection without a history of pet contact. The patient exhibited chronic ocular surface inflammation after exposure to wild insects and was misdiagnosed multiple times with bacterial conjunctivitis before definitive diagnosis by an ophthalmic specialist. This report emphasizes the core steps of the T. callipaeda extraction procedure. These steps include preoperative preparation, topical ocular anesthesia using 0.4% oxybuprocaine hydrochloride eye drops, sufficient exposure of the surgical field with an eyelid speculum, precise clamping and complete removal of nematodes under ophthalmic visualization, and immediate postoperative management. The entire procedure was recorded in a supplementary operative video. Additionally, the procedure can be conducted under conventional outpatient clinic conditions, making it suitable for primary medical institutions. Postoperatively, the patient received anti-infective therapy with 0.5% levofloxacin eye drops, administered four times daily, and ocular surface moisturization with 0.1% sodium hyaluronate eye drops, administered four times daily, for 1 week, with standard follow-up at 1, 3, and 6 months postoperatively. The clinical manifestations, including conjunctival hyperemia and foreign body sensation, were completely alleviated without recurrence, and ocular surface function returned to normal. Etiological confirmation was verified through morphological observation, characterized by serrated cuticular striations, a hexagonal buccal capsule, and a gravid female reproductive system, and recombinase polymerase amplification-CRISPR-Cas12a molecular detection targeting the 18S ribosomal ribonucleic acid gene. Critical procedural precautions to prevent nematode fragmentation and residual inflammation are also underscored. This case enriches the clinical reports of T. callipaeda. infection without a pet contact history and offers a practical diagnosis and treatment protocol for ophthalmologists.