Treatment of congenital anophthalmos with self-inflating polymer expanders: a new method

Abstract

Congenital anophthalmos is a rare malformation in which the optic vesicle fails to develop. This leads to a small bony orbit, a constricted mucosal socket, short eyelids, reduced palpebral fissure and malar hypoplasia. The treatment includes both aesthetic and functional aspects. Therefore, a two-step procedure is described using a new self-inflating hydrogel expander. A lens-shaped expander with a diameter of 8 mm expands the lids and the mucosal socket to allow insertion of an eye prosthesis. As a second step, orbital expansion is performed with a spherical device. The expanders absorb lacrimal fluid from the mucosal socket or tissue fluid and start swelling when implanted in the orbital tissue. The insertion of an expander into the orbit as well as into the conjunctival pocket including its fixation by a single suture took only a few minutes and was an easy procedure. The expansion of the small conjunctival sockets was successfully completed in all cases within a period of 2-4 weeks. The weight (= volume in ml) of devices increased from 0.15-1.5 g (lens-shaped expander; weight in grams = volume in ml) respectively, 0.3-3.5 g (spherical device). The expanders inserted in orbital tissue increased from 0.4-4.4 g. This is equivalent to a 10 to 11 fold increase in their water-free volumes. Orbital expansion with spherical devices in combination with the inserted eye prosthesis enlarges the lid and palpebral fissures also. In contrast to conventional silicon balloon expanders, the procedure using self-inflating hydrogel expanders is simple and highly efficient.