Iris Ectropion Syndrome

Excerpt

Iris ectropion syndrome (ectropion iridis or ectropion uveae) is characterized by ectropion or the presence of the pigmented epithelium of the iris on the anterior surface of the iris. Iris ectropion syndrome can be congenital or acquired. Congenital ectropion uveae (CEU, or primary iris pigment epithelial hyperplasia) was first reported by Colsman in 1869. However, he was actually describing iris flocculi. Iris flocculi are congenital smooth cyst-like benign structures arising from the pigmented epithelium at the pupillary margin.

Boleslaw Wicherkiewicz, a Polish ophthalmologist in 1891 and Spiro in 1896, are credited with reporting iris ectropion syndrome. Congenital iris ectropion is usually unilateral and nonprogressive, though bilateral cases have been reported. Progressive open-angle glaucoma may be associated in some cases due to the dysgenesis of the angle of the anterior chamber.

The posterior pigment epithelium of the iris is found on the anterior stroma at birth. The iris surface is glassy smooth and devoid of crypts. The pupil is usually round and reactive. Other features are anterior insertion of the root of the iris and trabecular dysgenesis. The sphincter muscle of the iris and the stroma are not affected. Developmental glaucoma is a frequent association. Mild to moderate ptosis with good levator function may be seen. Neurofibromatosis, Prader-Willi syndrome, facial hemihypertrophy, prominent corneal nerves, asthma, dental problems (late-onset), and Rieger anomaly may be associated with congenital iris ectropion.

Acquired iris ectropion can occur in many conditions and is more common than congenital ectropion uveae. Fibrovascular membrane formation on the anterior surface of the iris causes tractional forces pulling the posterior pigment epithelium of the iris to the anterior surface. This is associated with neovascularization of the iris. This membrane can form due to proliferative diabetic retinopathy, venous occlusions, and ischemic, inflammatory, and neoplastic etiologies. Unlike congenital ectropion uveae, acquired ectropion is progressive unless the underlying causes are treated.