The origin of primary cysts is neuroepithelial. Primary cysts are rarely causing any problems, fluid-filled and have smooth surfaces. They are subcategorized according to their location in the eye. Pupillary cysts, also central cysts, are located from the pupillary margin to the iris root, midzonal cysts are located from the iris root to the ciliary body, and peripheral cysts are located at the iridociliary sulcus. Free-floating cysts can occur in the anterior and vitreous chamber and are usually dislodged epithelium cysts. Cysts of the iris stroma are anteriorly located and as they develop, they usually cause deformation of the iris and need treatment. Especially the congenital secondary cysts require often treatment. They are usually unilateral and solitary. Acquired secondary cysts, on the other hand, require very rarely treatment and often occur at a later age. Secondary cyst Secondary cysts are usually unilateral and solitary and have a smooth surface. Secondary cysts may obstruct the eye's vision, cause intraocular pressure or iris displacement. The categorization of secondary cysts is categorized according Shields categorization. Secondary cysts are classified into 6 subcategories. - Implantation cysts are the most common secondary cysts. They can originate from a surgical trauma or a penetrating wound. An invasion of conjunctival or corneal epithelial cells creates the cyst. - Drug-induced cysts are related with the use of miotics or latanoprost but can get smaller after stopping inducing the drug. - Uveitic cysts can arise when the eye is or has been inflamed. - Tumor-induced secondary cysts are caused by a tumor. - The rarest iris cyst is the parasitic cyst, which can develop with the presence of a parasite. - At last secondary cysts can be caused by a systematic disorder like: diabetes mellitus, Menkes syndrome or malignancies. Diagnosis Iris cyst must be differentiated from other kinds of possible “bodies” in the eye. After the body has been established as an iris cyst, it must be categorized as primary or secondary. It is necessary to differentiate secondary cysts even further. Clinical examination can achieve this differentiation with the use of multimodal imaging techniques like UBM, ultrasound B-scan (USB), anterior segment optical coherence tomography (as-OCT) and magnetic resonance imaging. Clinical presentation Primary cysts come in various sizes and number but are usually fluid-filled, with regular borders and a smooth surface. The iris could be slightly displaced anteriorly because of a primary cyst, but normally no problems occur with primary