Advances in multimodal imaging for diagnosis of pigmented ocular fundus lesions

Pigmented ocular fundus lesions can range from benign to malignant. While observation is reasonable for asymptomatic benign lesions, early recognition of tumours that are vision or life threatening is critical for long-term prognosis. With recent advances and increased accessibility of multimodal imaging, it is important that providers understand how to best use these tools to detect tumours that require early referral to subspecialty centres. This review aims to provide an overview of pigmented ocular fundus lesions and their defining characteristics using multimodal imaging. We cover the spectrum of pigmented ocular fundus lesions, including freckle and focal aggregates of normal or near-normal uveal melanocytes, retinal pigment epithelium (RPE) hyperplasia, congenital hypertrophy of the RPE, RPE hamartoma associated with familial adenomatous polyposis, congenital simple hamartoma of the RPE, combined hamartoma of the retina and RPE (congenital hypertrophy of the RPE), choroidal nevus, melanocytosis, melanocytoma, melanoma, adenoma, and RPE adenocarcinoma. We describe key diagnostic features using multimodal imaging modalities of ultra-widefield fundus photography, fundus autofluorescence, optical coherence tomography (OCT), enhanced-depth imaging OCT, ultrasonography, fluorescein angiography, indocyanine green angiography, and OCT angiography (OCTA), with particular attention to diagnostic features that could be missed on fundus examination alone. Finally, we review what is on the horizon, including applications of artificial intelligence. Through skilled application of current and emerging imaging technologies, earlier detection of sight- and life-threatening melanocytic ocular fundus tumours can lead to improved patient prognosis.