[Stage-related therapy of congenital aniridia]

Abstract

Background: The main reasons for the markedly reduced visual acuity in pediatric patients with congenital aniridia are foveal dysplasia and optic nerve hypoplasia. During the lifetime a lack of depth of focus and increased sensitivity to glare due to a partly or completely lacking iris may be accompanied by further complications such as cataracts, various types of glaucoma and corneal opacity.

Therapy: In principal, microsurgical intervention should be as minimally invasive as possible to avoid excessive intraocular fibrosis. It is not advisable to use any type of esthetic iris substitute in phakic eyes. Cataract surgery should be performed via small incisions with a foldable intraocular lens (IOL) but not by using a 10 mm diameter polymethyl methacrylate (PMMA) anirida IOL. The conservative therapy of the often progressive limbal stem cell deficiency of the cornea includes artificial tears containing unpreserved hyaluronic acid, gels, autologous serum and amniotic membrane transplantation. Limbal transplantation of various kinds with and without penetrating keratoplasty and the Boston keratoprothesis type I should be considered only in cases of significant reduction of visual acuity and/or recurrent epithelial defects. Glaucoma surgery should be performed primarily as trabeculotomy. Drainage devices (e.g. Ahmed valve) are suggested as a second line approach. The risk of scarring of the filtering bleb in trabeculectomy with mitomycin C is very high in childhood and adolescence.

Conclusions: The stage-related therapy of congenital aniridia should always be based on a global view of the potentially increasing severity of cataract, glaucoma and corneal limbal stem cell deficiency during the lifetime. Each microsurgical intervention should be performed by the appropriate specialist and should be kept as minimally invasive as possible.