Bony Orbital Decompression in Patients with High Myopia and Pseudoexophthalmos

High myopic eyes grow in length (> 0.35 mm/dpt) more than in height and width leading to a disturbing unilateral exophthalmos in patients with anisomyopia and - more rarely - a bilateral exophthalmos in high myopia affecting both eyes. Secondary consequences are sicca symptoms and painful eye mobility due to a large bulbus in a too small bony orbit. The aim of the work was to evaluate the effectiveness of bony orbital compression in cases of high myopia.

Four patients underwent bony orbital decompression between the years 2012 and 2019. Two of the patients received lateral and two of them balanced (medial endonasal endoscopic and lateral) decompression. The decompression effect, complications and the influence of decompression on eye position and motility were evaluated.

Significant decompression effect was achieved in all patients. As a result, symmetry was restored in all unilaterally affected patients. No complications occurred. The lateral decompression had a positive effect on the preexisting convergent strabismus (reduction of the "eso" position, neutral to the vertical deviation). The carefully dosed medial decompression did not lead to any change of the horizontal position in one patient and in the other exotropic patient it resulted in a 10 pdpt of "exo" reduction without developing an "eso" position.

The bony orbital decompression provides a sufficient decompression effect in the four patients to reduce the myopic pseudoexophthalmos. The alignment anomalies associated with a high myopia ("heavy eye") was favourably influenced by the lateral decompression.