Effect of Rim-Off Deep Lateral Orbital Decompression on Interpalpebral Fissure Shape.

PURPOSE: The purpose of this study is to compare the palpebral fissure shape after rim-off deep lateral decompression with and without restoration of the lateral orbital rim.

METHODS: Retrospective cross-sectional quantitative analysis of the palpebral fissure images of 17 patients (25 eyes) who underwent rim-off deep lateral orbital decompression without repositioning of the rim (G1) and of 20 patients (34 eyes) operated with rim restoration. Quantification of palpebral fissure images included MRD1 and MRD2, two lateral mid-pupil lid margin (MPD) distances, the width of the palpebral fissure, and the height and shape of the lateral canthus.

RESULTS: Proptosis reduction did not differ significantly between G1 and G2. In both groups, decompression reduced the mean values of the MRD1 and MRD2, the lateral height of the upper eyelid, and the height and angle of the lateral canthus. The palpebral fissure width and lateral height of the lateral lower eyelid were not affected. There was no significant difference between the mean changes of G1 and G2. Multivariate analysis showed that the lateral canthus decrease was correlated with changes in MRD1 and MRD2.

CONCLUSIONS: Small changes in palpebral fissure shape after deep lateral decompression are not dependent on the presence or absence of the lateral rim.