Opthea Limited, a clinical stage biopharmaceutical company, engages in the development and commercialization of therapies primarily for eye disease in Australia.

The company's development activities are based on the intellectual property portfolio covering Vascular Endothelial Growth Factors (VEGF) VEGF-C, VEGF-D, and VEGF Receptor-3 for the treatment of diseases associated with blood and lymphatic vessel growth, as well as vascular leakage.

Its lead product candidate is Sozinibercept (OPT 302), a soluble form of vascular endothelial growth factor receptor-3 "VEGFR-3", currently under Phase 3 clinical development as a novel therapy for wet age-related macular degeneration and diabetic macular edema.

The company was formerly known as Circadian Technologies Limited and changed its name to Opthea Limited in December 2015.

Opthea Limited was incorporated in 1984 and is based in South Yarra, Australia.