Iris cyst

Iris cysts are hollow cavities in the eye filled with secretion. They come in various sizes, numbers, shapes, pigments and can be free-floating, attached to the pupillary margin or within the posterior chamber. Most frequently iris cysts don’t cause any issues, but they can cause problems like: “fly biting” behavior, corneal endothelial pigment, lens capsular pigmentation, altered iris movement, decreased aqueous outflow with subsequent glaucoma or block the vision when grown to big. They can be acquired or innate. Possible causes are inflammation, drug-induced, uveitis, a trauma, tumor-induced, parasitic or implantation. Most frequently iris cysts are benign and need no treatment. Sometimes iris cysts are causing problems and need to be deflated. Iris cysts can be treated with trans corneal diode laser treatment, fine-needle aspiration or surgical excision. For the treatment of iris cysts is a conservative approach favored. Iris cysts are hollow cavities in the eye filled with secretion. They come in various sizes, numbers, shapes, pigments and can be free-floating, attached to the pupillary margin or within the posterior chamber. Most frequently iris cysts don’t cause any issues, but they can cause problems like: “fly biting” behavior, corneal endothelial pigment, lens capsular pigmentation, altered iris movement, decreased aqueous outflow with subsequent glaucoma or block the vision when grown to big. They can be acquired or innate. Possible causes are inflammation, drug-induced, uveitis, a trauma, tumor-induced, parasitic or implantation. Most frequently iris cysts are benign and need no treatment. Sometimes iris cysts are causing problems and need to be deflated. Iris cysts can be treated with trans corneal diode laser treatment, fine-needle aspiration or surgical excision. For the treatment of iris cysts is a conservative approach favored. Mackenzie diagnosed the first iris cyst in 1830, which was a posttraumatic iris cyst in the anterior chamber. Because of the wide variety of iris cysts, a categorization was needed. This categorization was proposed by Shields in 1981 and was based on 2 main groups: primary and secondary cyst. Primary cysts origin is neuroepithelial, and rarely causes any issue. Primary cysts can be subcategorized based on their location in the eye. However, secondary cysts can cause problems like decreased vision, secondary glaucoma, uveitis or corneal edema and origin from implantation, metastasis, miotics or parasites. Secondary cysts are further categorized based on their origin. The iris is a thin circular structure in the eye which consists of two layers, on top is the stroma and underneath the pigmented epithelial cells. It separates the eye in the anterior and posterior chamber, is responsible for the eye’s color, and its function is to regulate the size of the pupil. By controlling the size of the pupil it regulates the amount of light reaching the retina. Depending on the amount of light, the iris opens with high intensity light and closes with low intensity light. The iris is able to control the size of the pupil due to radial and circular muscles which attach to the stroma. The circular muscle, sphincter muscle, contracts in a circular motion, making the pupil smaller, but by contracting the radial muscles, dilator muscles, the pupil enlarges. The classification of primary cysts is according to the categorization of Shields. 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 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.