The iris is a unique structure, with exquisite variations in colour and form. Pathological changes, specifically including iris cysts and tumours are relatively uncommon, difficult to diagnose, and yet potentially blinding or life-threatening. Based on a comprehensive literature review, with highly illustrated key case examples, this report aims to guide the clinician in filtering the differential diagnoses of iris cysts and tumours. Evaluation is in the context of key diagnostic clinical tools and management considerations. Diagnostic imaging techniques include serial anterior segment photography, ultrasound, anterior segment optical coherence tomography, and iris fluorescein angiography, however, the roles of computerised topography and magnetic resonance imaging are also considered in this review. Management includes categorisation in terms of solid iris tumours (melanocytic vs. non-melanocytic), or iris cysts (primary vs. secondary) that may be usefully differentiated by clinical assessment, avoiding more invasive interventions. Cystic lesions are generally benign, although implantation cysts in particular cause significant complications and surgical challenges. Most solid tumours are melanocytic and also typically benign. However, in larger lesions, rapid growth, symptoms and complications more likely indicate malignancy, requiring further investigation.

An iris cyst is a nonkeratinized squamous epithelial-lined space involving a layer of iris. The presentation of iris cyst can be variable-innocuous or presenting with secondary complications. The identification of whether the cyst is primary or secondary is important. The prognosis of primary iris cysts is good, as the majority does not require treatment and that of secondary iris cysts is much more capricious depending on their presentation. Their optimal management often poses a challenge for ophthalmologists. Here, we will present two cases of iris cysts with diverse presentation along with a review of the literature of this rare clinical entity.