Pearl Cyst of the Iris

By Paul T. Finger, MD


Slit-lamp photography shows the white pearl-cyst within the temporal iris stroma. In this case, a history of tumor growth and a mild iritis were noted.
Slit-lamp photography shows the white pearl-cyst within the temporal iris stroma. In this case, a history of tumor growth and a mild iritis were noted.

A rare complication of cataract surgery, the “pearl-cyst” may grow from on and within the iris. The tumors are thought to be caused by displaced conjunctival or epidermal epithelium. Rupture of these mucous-containing cysts (within the eye) can cause severe glaucoma.


Most patients present due to ocular inflammation. They may notice the white tumor growing

High frequency ultrasound demonstrates three layers (a mantle, mucus content, and cholesterol crystals at the center).

on the iris.


The diagnosis of “Pearl Cyst” should be considered when a patient who has had intraocular surgery (cataract, corneal transplant, or filtering for glaucoma) presents with a slowly

enlarging white iris stromal tumor. High-frequency ultrasound imaging will show three layers: an outer mantle, a low reflective mucus

layer and a central, high-reflective cholesterol crystal core.


When “Pearl-cyst” of the iris is suspected, complete surgical excision is warranted. Though difficult, the surgeon should try to remove the cyst intact. Should the cyst rupture during removal, the surgeon should be ready to aspirate or removal the cyst contents. The mucoid contents have been reported to cause secondary glaucoma. If the outer epithelial layer, the mantle, is left behind one runs the risk of cyst recurrence.

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Iris Cysts

By Paul T. Finger, MD


Cysts can form in different parts of the iris and ciliary body. Most remain undetected, unless they push on the iris or get relatively large. The most common is the neuro-epithelial iris cyst, which is typically located beneath the iris root. Cysts can also be located in the ciliary body, the iris stroma, and be formed by splitting (schisis) of the iris pigment epithelium). These cysts can push the iris forward, appear as a mass or tumor and may cause angle closure glaucoma.


Almost all iris cysts are located behind the iris and cause no symptoms. They are found by the eye care specialist during ophthalmic examination. Iris stromal cysts can become visible on the surface of the iris. Most commonly, the eye doctor sees a bulge in the iris stroma and considers that a tumor may be pushing it forward. At that point, the doctor may send the patient for an ocular tumor evaluation (to look behind the iris with ultrasound or OCT imaging).


Most iris cysts can be diagnosed by clinical examination with high-frequency ultrasonography.

Large cysts can be seen by routine slit-lamp examination.

High frequency ultrasonography reveals internal echolucency consistent with the diagnosis of iris stromal cyst.
This iris stromal cyst extends from the iris stroma onto the corneal endothelium.









Though cysts are benign, periodic observation is necessary due to the rare instances of secondary angle closure glaucoma (only seen with giant cysts, multifocal cysts and iris schisis cysts). 

Slit-lamp photograph of an Iris Pigment Epithelial Cyst. Note its smooth, rounded surface.
High-frequency ultra-sonography of a neuro-epithelial iris cyst. Note anterior displacement of the iris with focal angle closure.









High-frequency ultrasonography (aka UBM) has revolutionized our ability to image and thus “see” tissues behind the iris. It has allowed for evaluation of tumor thickness, depth of penetration, and invasion of adjacent tissues. Ultrasounds ability to determine if a tumor is solid or cystic has been particularly helpful.


  • Most iris cysts do not require treatment.
  • Treatment is performed for the rare instances of secondary glaucoma or when the visual axis (pupil) becomes blocked. Laser has been used to deflate iris pigment epithelial cysts with minimal side effects.
  • The natural history of iris cysts has not been determined. In my experience, some get smaller, some get larger and most stay the same. Until eye care specialists understand which cysts will grow, periodic observation is warranted.


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