Iris cyst
They come in various sizes, numbers, shapes, pigments and can be free-floating, attached to the pupillary margin or within the posterior chamber.
[1] 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.
Possible causes are inflammation, drug-induced, uveitis, a trauma, tumor-induced, parasitic or implantation.
Iris cysts can be treated with trans corneal diode laser treatment, fine-needle aspiration or surgical excision.
This categorization was proposed by Shields in 1981 and was based on 2 main groups: primary and secondary cyst.
[2] 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.
By controlling the size of the pupil it regulates the amount of light reaching the retina.
[3] The iris is able to control the size of the pupil due to radial and circular muscles which attach to the stroma.
Primary cysts are rarely causing any problems, fluid-filled and have smooth surfaces.
Acquired secondary cysts, on the other hand, require very rarely treatment and often occur at a later age.
Secondary cysts may obstruct the eye's vision, cause intraocular pressure or iris displacement.
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.
[2] Primary cysts come in various sizes and number but are usually fluid-filled, with regular borders and a smooth surface.
Secondary cysts usually have a rough surface, irregular borders, solitary and unilateral.
The preferred method to determine ciliary body involvement, however, is not USB but ultrasound biomicroscopy.
[9][2] Fine-needle aspiration, FNA, is only used if every other method has failed to establish what kind of cyst it is and if it is presumably a solid tumor.
The preferred treatment option is observation, since most iris cysts do not hurt or cause any pressure.
A common side effect of this method is an inflammation in the anterior chamber, but this can easily be treated with topical steroids (cream or gel with anti-inflammatory properties).
Antimitotic agents have the side effect of creating a small inflammation which can easily be treated with topical steroids.
Despite not having the highest success rate it is nowadays the most preferred treatment against iris cyst because it is the least invasive method since the eye doesn't need to be punctured or cut.
The least invasive treatment is laser therapy and is, therefore, also the preferred method to treat an iris cyst.
