Purpose To investigate ultrasound biomicroscopy (UBM) characteristics of patients with ocular toxocariasis (OT) and to explore the role of UBM in the diagnosis and differential diagnosis of OT.

Design Cross-sectional study.

Methods 78 eyes of 77 patients clinically consistent with OT and confirmed by serum and/or intraocular antibodies in a single tertiary centre (Fudan University Eye and ENT Hospital, Shanghai) between July 2009 and July 2016 were included in the study. UBM was performed, and the outcomes were analysed.

Results Mean age of the patients included was 12.8±10.3 years. Positive UBM findings were observed in 72 of 78 eyes (92.3%). The primary imaging feature was peripheral granulomas (66 eyes; 84.6%), of which 78.5% were adjacent to the nasal or temporal side of horizontal meridian and 79.7% located on the surface of the ciliary body, presenting as olivary foci on radical section and botuliform foci on coronal section. Moreover, 12 of the peripherally involved eyes were accompanied with posterior pole granulomas, which could be termed ‘combined type’. Other UBM findings included vitreous strands (53 eyes; 67.9%), peripheral tractional retinal detachment (41 eyes; 52.6%) and tractional cyclodialysis (32 eyes; 41.0%).

Conclusions The utilisation of UBM verifies the existence of the combined subtype (with both peripheral and posterior pole granulomas) and improves the detection rate of peripheral granulomas, which is of great importance to the diagnosis and differential diagnosis of OT.