Topical interferon in recurrent inflammatory macular edema following a cat bite

Treating chronic macular edema (CME) post endophthalmitis is a challenge. Use of steroids may reactivate the infection and repeated intravitreal therapy with anti-vascular growth factor inhibitors (Anti-VEGF) puts the patient again at the risk of exacerbation of inflammation or endophthalmitis. We describe a case of CME post traumatic endophthalmitis successfully treated with topical interferon therapy.

A 34-year-old Asian Indian lady with a history of cat bite to her right eye and treated elsewhere as traumatic endophthalmitis with recurrent macular edema, presented to us 1 year after the injury. She had received anti-VEGF injection for same. Her medical history was non-contributory except for close contact with her cat. Therapeutic trials with oral doxycycline followed by oral albendazole with steroids, as well as repeated anti-VEGF therapy failed to prevent recurrence of CME. Patient's steroid responsiveness and reluctance for injections, made us to opt for a novel topical Interferon therapy. Macular edema resolved in 2 months. Interruption of interferon therapy due to COVID-lock down resulted in recurrence of the CME, which again responded well to interferon monotherapy.

Topical interferon may have a role in the treatment of inflammatory macular edema and can serve as a, safer, economical and non-invasive treatment option compared to intravitreal steroids and anti-VEGFs.