PRIMARY CYSTS OF THE IRIS PIGMENT-EPITHELIUM - CLINICAL-FEATURES AND NATURAL COURSE IN 234 PATIENTS

Objective: To describe the clinical characteristics, natural course, a nd complications of a large group of patients with primary iris pigmen t epithelium (IPE) cysts. Design: Observational case series. Participa nts: Two hundred thirty-four patients with primary IPE cysts participa ted. Results: Primary IPE cysts were classified as central in 6 patien ts (3%), midzonal in 50 patients (21%), peripheral in 170 patients (73 %), and dislodged in 8 patients (3%). Central (pupillary) IPE cysts we re found only in males, peripheral IPE cysts were found most often in females (69%), and no gender predilection was detected for midzonal an d dislodged IPE cysts. Central and peripheral IPE cysts occurred in yo ung patients (mean age, 20 and 33 years, respectively), whereas midzon al and dislodged IPE cysts were seen in slightly older patients (mean age, 52 and 45 years, respectively). Central IPE cysts were visible wh en the pupil was not dilated and appeared most often as a round or col lapsed brown lesion arising from the pupillary margin, most commonly s uperonasally, Midzonal IPE cysts were brown and fusiform, best visuali zed after pupillary dilation. Peripheral IPE cysts produced a characte ristic bulging in the iris stroma near the iris root, but they were di rectly visible in only 78% of cases. After wide dilation and patient a nd slit-lamp positioning, they appeared as a round clear lesion behind the iris, most often in the inferotemporal quadrant. Finally, dislodg ed IPE cysts appeared as a brown oval lesion, free floating in the ant erior chamber (12%) or in the vitreous (12%), or fixed in the anterior chamber angle (75%). One hundred twenty-four patients (53%) were foll owed for a mean of 35 months (range, 3 months-19 years). In these pati ents, complications associated with IPE cysts included lens subluxatio n in one case (1%), iritis in one case (1%), focal cataract in two cas es (2%), glaucoma in two cases (2%), and corneal touch in five cases ( 4%), Conclusion: Primary IPE cysts have characteristic clinical featur es that serve to differentiate them from intraocular malignancies. Mos t cysts have a benign clinical course, and treatment is rarely necessa ry.