'Pneumofornix' (air under the eyelid): A normal finding

Normal pockets of air under the eyelids have not been previously described in the literature. To assess the incidence and patterns of normal air bubbles in the region of the eyelid, computed tomography (CT) scans of 126 normal orbits and 36 orbits of patients with thyroid orbitopathy were assessed. Twenty-eight (22%) of the normal orbits and 14 (39%) of the thyroid orbits had a well-defined medial or lateral air bubble (or both) on axial views (.1 > P > .05). Oval central or paracentral air bubbles in sections through the superior or inferior fornix were seen in 19 (15%) of the normal orbits and 10 (28%) of the thyroid orbits (.1 > P > .05). It is important to be aware of the incidence and patterns of these normal air bubbles to ensure their accurate differentiation from pathologic air bubbles.