3D AESTHETIC ANALYSIS OF ORBIT AND PERIORBITAL REGION

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Background and Aim. Evaluation of preoperative and postoperative conditions is essential in lower lid blepharoplasty and midface lift. The laxity of the lower lid and insufficient malar bone prominence accompanied by excessive eye prominence known as a «negative vector» are the common condition which can lead to unsatisfactory aesthetic result and various ophthalmological complications. At the current moment the pre- and post-operative evaluation is based on two-dimensional photography and physical examination. Material and Methods. We developed the 3D evaluation methodology for the midface region based on photogrammetric study and computed tomography. The photogrammetry scanning is performed on a patient in upright position. On CT images the skeletal tissue of face, eye globes and soft tissue complex are segmented and calculation of 3D models of these structures in performed. Then the acquired 3D model is aligned to soft tissue model from CT data by defining points and regions. Results and Discussion. The relative position of the eye globe to orbit and orbital rim is assessed by the mass center of these anatomical structures. To correlate the traditional ophthalmometry the eye prominence is measured from bicanthal frontal plane. The skin surface geometry is analyzed by curvature analysis allowing contrasting relief features as a nasojugal groove, nasolabial fold and tearing trough. To evaluate its ptosis degree the position of the nasojugal groove is measured relatively to the arcus marginalis. Soft tissue thickness analysis is performed to access the midface soft tissue distribution. Conclusions. The described analysis method is able to provide substantial data for clinical evaluation of periorbital region.