Two patients were diagnosed as having unilateral iris pigment epithelial (IPE) cysts that were documented to enlarge and induce angle closure. Transpupillary IPE cystotomies were performed using the Nd:YAG laser as a prophylactic measure to prevent angle-closure glaucoma. Anterior chamber anatomy and cyst dimensions were assessed before, during, and after long-term follow-up using slit-lamp biomicroscopy, gonioscopy, and 20- or 35-MHz high-frequency ultrasound imaging. Cystotomy resulted in immediate, visible deflation of both IPE cysts with subsequent resolution of angle closure. The cyst contents appeared clear and no secondary inflammation or glaucoma occurred. No evidence of cyst recurrence has been noted during 3 and 8 years of follow-up, respectively. Transpupillary Nd:YAG laser cystotomy offered a minimally invasive and effective treatment for angle closure induced by progressive IPE cysts.
Transpupillary Nd:YAG Laser Cystotomy for Iris Pigment Epithelial Cysts with Secondary Progressive Angle Closure
From The New York Eye Cancer Center (PK, KJC, NG, PTF); New York University School of Medicine (PK, NG, PTF); and The New York Eye and Ear Infirmary (PK, NG, PTF), New York, New York.
Supported by The Eye Cancer Foundation, Inc. ( http:eyecancerfoundation.net), New York, New York. The sponsors had no role in the manuscript.
Dr. Kathil received an ophthalmic oncology fellowship from the International Council of Ophthalmology. The remaining authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Paul T. Finger, MD, The New York Eye Cancer Center, 115 East 61st Street, Suite 5B, New York, NY 10065. E-mail: firstname.lastname@example.org; web site: http://paultfingermd.com
Received: December 23, 2010
Accepted: February 23, 2011
Posted Online: March 24, 2011
Iris pigment epithelial (IPE) cysts are typically benign and asymptomatic. They are thought to arise from the faulty apposition of layers of iris epithelium (representing the inner and outer layer of the optic cup) during intrauterine development. They are lined by a monolayer of IPE cells with mostly clear fluid in the lumen. The exact composition of the fluid content of cysts is unknown.1 Progressive growth may occur in some cases, leading to secondary angle closure, glaucoma, corneal decompensation, inflammation, and obstruction of the visual axis.2–4
Reported treatments include serial observation, aspiration with cryotherapy, argon laser photocoagulation, and surgical resection.4 We report the use of transpupillary Nd:YAG laser cystotomy in the management of two primary IPE cysts with secondary appositional angle closure.
Design and Methods
This study was conducted in accordance with the Declaration of Helsinki and Institutional Review Board and Ethics Committee approvals were obtained. Two patients were noted to have unilateral IPE cysts that were documented to enlarge and induce angle closure. The patients gave their informed consent prior to inclusion in the study. Transpupillary IPE cystotomies were performed using Nd:YAG laser. Patients were observed for cyst recurrence and procedural complications, including comparative examination with high-frequency (20 or 35 MHz) ultrasound biomicroscopy (UBM).
A 79-year-old woman was referred for evaluation of an iris mass in her right eye. Her ocular history was significant for phacoemulsification and intraocular lens implantation. According to patient history, cataract surgery performed more than 6 years before our evaluation and by another surgeon was uneventful. There was a subsequent Nd:YAG laser capsulotomy. Her best-corrected visual acuity was 20/25. Slit-lamp biomicroscopy of the right eye revealed prolapse of IPE in the inferotemporal quadrant of the pupil with forward displacement of iris stroma. It was classified as a primary cyst of the IPE, involving the peripheral, mid-zonal, and central iris.4 Intraocular pressure was 10 mm Hg. Gonioscopy revealed focal angle narrowing in the inferotemporal quadrant. Dilated examination revealed a larger area of IPE prolapse and normal fundus (Fig. 1). UBM revealed a large IPE cyst extending beyond the pupillary margin and focal narrowing of the angle. The cyst had hyperechoic walls and an echolucent interior suggestive of fluid. The cyst’s initial maximum dimensions were 6.2 × 3.9 mm base and 1.5-mm thickness (Fig. 1). Adjacent ciliary body and the rest of the anterior segment were within normal limits. Observation as treatment was advised.
Figure 1. Case 1. Slit-Lamp Photography of Iris Pigment Epithelial Cyst Shows (A) Extension of the Cyst Beyond the Pupillary Border (arrow) and (B) a Deflated Cyst with Minimal Extension Beyond the Dilated Pupillary Border After Laser Cystotomy. The Image was Magnified to Demonstrate the Site of Cystotomy (arrow). (C) High-Frequency (35-MHz) Ultrasound in Longitudinal Section Before Laser Treatment Demonstrates the Large Cyst with Relative Appositional Angle Closure (arrow). (D) Markedly Reduced Intra-Luminal Diameter of the Cyst with Resolution of Angle Closure (arrow) After Laser Treatment.
Three months later, a progressive increase in the size of the cyst was documented by UBM and digital slit-lamp photography. Gonioscopy revealed appositional angle closure for 180°. Considering rapid progression and risk of angle-closure glaucoma, the patient was offered Nd:YAG laser cystotomy.
After dilation, an Abraham iridotomy YAG laser lens (Ocular Instruments, Inc., Bellevue, WA) was used to magnify the iris cyst. With the energy level set at 2.4 mJ in single pulse mode, the first shot perforated the cyst, resulting in immediate and visible deflation. Subsequent resolution of anterior chamber angle closure was documented (Fig. 1). The cyst contents were clear and no secondary inflammation or rise in intraocular pressure occurred. There has been no cyst recurrence or change in visual acuity during 3 years of follow-up.
A 65-year-old man was referred for the evaluation of an iris tumor in his left eye. There was no history of trauma, inflammation, or intraocular surgery. His best-corrected visual acuity was 20/20. Slit-lamp biomicroscopy of the left eye revealed protrusion of IPE into the inferotemporal pupillary quadrant (Fig. 2). It was classified as a primary cyst of the IPE involving the peripheral, mid-zonal, and central iris.4 Intraocular pressure was 20 mm Hg. Gonioscopy showed angle closure in three involved quadrants. UBM revealed a large IPE cyst involving 270° of iridociliary sulcus that measured 1.1 mm in thickness (Fig. 2). Observation as treatment was advised.
Figure 2. Case 2. Slit-Lamp Photography of Iris Pigment Epithelial Cyst Before (A) and After (B) Laser Cystotomy. Regressed Cyst was Seen only After Pupillary Dilation. High-Frequency Ultrasound in Longitudinal Section (C) Before (at 20 MHz) and (D) After (at 35 MHz) Laser Treatment. Arrow Denotes Regression of Cyst.
One year later, follow-up examination revealed enlargement of the IPE cyst. Although gonioscopy revealed progression, UBM documented the IPE cyst involving almost 360° of iridociliary sulcus. Intraocular pressure was 18 mm Hg. Nd:YAG laser cystotomy was performed using 1.3-mJ laser energy (2 shots in single pulse mode), which decompressed the cyst and relieved the angle closure as documented by UBM (Fig. 2). The cyst contents appeared clear and no secondary inflammation or rise in IOP occurred. With 8 years of follow-up, there has been no evidence of recurrence or change in visual acuity.
Nd:YAG laser cystotomy was effective in the prophylactic treatment of two large IPE cysts with secondary angle closure. This relatively noninvasive treatment can diminish the risk of acute glaucoma with secondary corneal decompensation and inflammation. It resolved cyst-related obstruction of the visual axis.
Cystic lesions occurring within the anterior segment may be classified as primary or secondary. Primary cysts are of neuroepithelial origin, whereas secondary cysts may result from implantation of conjunctival or corneal epithelial cells after penetrating or surgical trauma, inflammation, parasites, or chronic miotic use. Primary cysts are further divided into pigment epithelial and stromal types. Pigment epithelial cysts can be classified anatomically into central (pupillary), mid-zonal (retroiridic), peripheral (iridociliary), and dislodged types (free floating in aqueous/vitreous or fixed).4,5 Secondary cysts are more likely to give rise to complications due to their propensity to grow or contain inflammatory material.2–4
Observation as treatment can be employed for nonprogressive cysts. When necessary, reported interventions include aspiration, cryotherapy, argon laser photocoagulation, and surgical resection.4 Disadvantages include recurrence of cyst and those related to intraocular surgery (inflammation, hemorrhage, infection, secondary glaucoma, and cataract). Large surgical iridectomies are associated with symptomatic glare.
The Nd:YAG laser has been used for treatment of primary IPE cyst causing obstruction of visual axis and secondary cyst.6,7 It was used for iridocystotomy in patients with bilateral acute angle-closure glaucoma without visible cysts and relief of pain with argon laser photocoagulation.8,9 However, we could find no reported use of transpupillary Nd:YAG laser cystotomy for management of primary IPE cysts with angle closure (searching the words “YAG,” “cyst,” “iris,” “pigment,” and “epithelium” on PubMed.gov).
Although most IPE cysts can be managed by serial observation, our cases suggest that transpupillary Nd:YAG laser cystotomy offers a minimally invasive and effective treatment for angle closure induced by progressive IPE cysts.
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- Xiao Y, Wang Y, Niu G, Li K. Transpupillary argon laser photoco-agulation and Nd:YAG laser cystotomy for peripheral iris pigment epithelium cyst. Am J Ophthalmol. 2006;142:691–693. doi:10.1016/j.ajo.2006.04.050 [CrossRef]