Қабықшадағы ісіктер: түрлері, диагностикасы және емдеуі

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 too big. 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. 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. 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.

Ultrasound B scan (USB) uses wavelengths of 10 20 MHz to form an image of the eye. USB can be used to identify the extension of the iris cyst in either the anterior or posterior chamber. It can also be used to identify midzonal cysts behind the iris and to determine whether there is ciliary body involvement. The preferred method to determine ciliary body involvement, however, is not USB but ultrasound biomicroscopy.

Fine needle aspiration (FNA) is, as discussed earlier, also a diagnosis method but can also be used as a treatment. With FNA a very fine needle is inserted in the eye in the cyst. The purpose of the needle is to penetrate the membrane of the cyst, so that the cyst will deflate. This method has proven to be successful but there is a possibility that the cyst will not disappear fully but only shrink. If the cyst has shrunk enough that it is not causing any pain or trouble anymore, then a second treatment might not be necessary. But if the cyst is still causing an issue after the treatment, the treatment must be repeated, or another method has to be used.

Antimitotic agents are used mainly when a cyst is resistant to all other treatments apart from surgery, since surgery is the last resort. Antimitotic agents are injected into the cyst and left inside for 5 minutes; after 5 minutes the agents are rinsed out. Antimitotic agents have the side effect of creating a small inflammation which can easily be treated with topical steroids. Antimitotic agents stop the mitose of the cells of the cyst by interfering with a particular phase of the cell cycle, which stops the cyst from growing and will eventually kill the cells and thus the cyst. Unreliable source: date=December 2018

Surgery is considered to be the last resort because surgery has the highest chance at complications. The surgical approach depends on where the cyst is located, how big the cyst is and the number of cysts.

There are many options when treating an iris cyst. Mentioned above are the most used treatments but in the past there have been other methods but they haven't been successful enough to be still used today. A clinician has to consider a lot of things when choosing a treatment. The golden rule when treating iris cysts however is to choose the least invasive method. That means that cysts which are not causing any problems will not be treated but observed. The least invasive treatment is laser therapy and is, therefore, also the preferred method to treat an iris cyst. Depending on the kind of cyst, the clinician will choose either antimitotic agents or AS OCT, if laser has failed or if laser is not possible. It is unlike that FNA will be used due to its low potential for removing the cyst. Surgery is the most invasive method and the one with the highest chance of complications. That is why surgery is the last resort.