Digital Evaluation of Orbital Cyst Associated with Microphthalmos: Characteristics and Their Relationship with Orbital Volume

PurposeTo study the characteristics of orbital cyst associated with microphthalmos in a group of Chinese patients, and to analyze the relationship between orbital cyst and orbital volume.DesignCross-sectional comparative study.Participants120 patients who were diagnosed as unilateral clinical blind microphthalmos, in which 20 patients had orbital cyst in the affected eye.MethodParticipants had computed tomography (CT) scan. CT images were analyzed with a computer-aided software.Main Outcome MeasuresVolume and position of orbital cyst, microphthalmic to contralateral ratio (MCR) of orbital volume, height and depth and orbital rim displacement.Results38.1% of the cysts located anterior to or at the equator of the globe, 75% of which located infratemporally and all of which were outside the muscle cone. Most (84.6%) of the posterior cysts were inside the muscle cone. The anterior cysts were larger than the posterior cysts (p = 0.005). MCR of orbital volume (pConclusionsMicrophthalmic eyes with large cyst-plus-globe volume showed better similarity with the contralateral eyes, comparing with microphthalmic eyes without orbital cyst or with small cyst-plus-globe volume. It suggested that the existence of orbital cysts (especially large cysts) in microphthalmic eyes might play a positive role in the orbital development.