Aniridic Fibrosis Syndrome

Excerpt

Aniridic fibrosis syndrome was first described by Tsai et al. in 2005. It is a rare complication of invasive intraocular surgery (especially cataract extraction with intraocular lens implantation) that may occur in patients with congenital aniridia. It is characterized by a progressive fibrotic membrane within the anterior chamber that occurs after ocular surgery. The membrane may grow over the ciliary body (leading to hypotony), disrupt the placement of intraocular lenses (IOLs), and contribute to retinal pathologies. Those who are affected typically have a history of multiple ocular surgeries to address sequela associated with the underlying congenital aniridia. At present, there are seventeen reported cases with ages ranging from eight months to 71 years.

Aniridic fibrosis syndrome occurs in the setting of congenital aniridia or the absence of the iris. Aniridia is an intricate congenital syndrome that can arise in an inherited or sporadic manner. The iris is responsible for regulating the amount of light that enters the posterior structures of the eye. In aniridia, the iris may be completely or partially absent and may be associated with other ocular manifestations, most commonly foveal hypoplasia and nystagmus. Other ocular manifestations may include glaucoma, cataract formation, keratopathy, and optic nerve coloboma with possible hypoplasia. These diseases may require surgical intervention and the insertion of implantable devices. Aniridia and its potential ocular comorbidities can result in poor visual acuity, typically 20/100 to 20/200, with foveal hypoplasia as the most significant limiting factor for these patient’s visual acuity. Aniridia is most commonly associated with various PAX6 gene mutations, and the specific mutation can have considerable effects on the observed phenotype and resultant pathologies. Some PAX6 mutations may also be part of various clinical syndromes (e.g., WAGR, or WAGRO syndromes), but other genetic mutations (e.g., FOXC1, PITX2, PITX3) and sporadic cases have been reported to cause aniridia.