A modified 3D stereophotogrammetry-based distraction test for assessing lower eyelid tension

AIM: To investigate the reliability of a modified threedimensional distraction test(3D-DT) and three-dimensional pinch test(3D-PT) for assessing lower eyelid tension(LET).METHODS: A cross-sectional study was conducted among 97 volunteer s including 97 eyelids with no history of trauma, tumor, or reconstructive surgeries. Six three-dimensional photographs were acquired for each par ticipant, including two photographs obtained in a neutral position(NP), two using a modified 3D-DT with a 15.9-grammes stainless steel eyelid hook performed, and two using 3D-PT.RESULTS: The mean absolute differences between NP, 3D-DT, and 3D-PT measurements varied between 0.07 and 7.42, 0.10 and 13.10, and 0.07 and 15.97, respectively;technical error of measurement varied between 0.05 and 7.81, 0.09 and 10.19, and 0.07 and 12.47, respectively;and relative error measurements varied between 0.10% and 11.50%, 0.16% and 30.51%, and 0.11% and 38.75%, respectively. For intra-rater reliability, the intraclass correlation coefficients(ICCs) were more than 0.80 in seven out of eight measurements obtained in the NP and 3D-DT, whereas those obtained in the 3D-PT were as low as less than 0.30 by rater 1;the ICCs of all the measurements obtained in all the positions(NP, 3D-DT, and 3D-PT) were more than 0.80 by rater 2. For inter-rater reliability six out of eight NP and 3D-DT measurements had an ICC greater than 0.80, whereas those of 3D-PT measurements were less than 0.30. For intra-method reliability, the ICCs of all the NP measurements were more than 0.87, whereas those of the six 3D-DT measurements and four 3D-PT measurements were more than 0.80.CONCLUSION: Our study results prove that the modified 3D-DT, which involves the use of an eyelid hook, can be a highly reliable method for evaluating LET. Furthermore, this novel and simple method may be utilized as the basis for further investigation and routine pre-and postoperative clinical evaluation.

Segmental Kinematic Coupling of the Human Spinal Column during Locomotion

As one of the most important daily motor activities, human locomotion has been investigated intensively in recent decades. The locomotor functions and mechanics of human lower limbs have become relatively well understood. However, so far our understanding of the motions and functional contributions of the human spine during locomotion is still very poor and simultaneous in-vivo limb and spinal column motion data are scarce. The objective of this study is to investigate the delicate in-vivo kinematic coupling between different functional regions of the human spinal column during locomotion as a stepping stone to explore the locomotor function of the human spine complex. A novel infrared reflective marker cluster system was constrncted using stereophotogrammetry techniques to record the 3D in-vivo geometric shape of the spinal column and the segmental position and orientation of each functional spinal region simultaneously. Gait measurements of normal walking were conducted. The preliminary results show that the spinal column shape changes periodically in the frontal plane during locomotion. The segmental motions of different spinal functional regions appear to be strongly coupled, indicating some synergistic strategy may be employed by the human spinal column to facilitate locomotion. In contrast to traditional medical imaging-based methods, the proposed technique can be used to investigate the dynamic characteristics of the spinal column, hence providing more insight into the functional biomechanics of the human spine.

The occlusal plane in the facial context:inter-operator repeatability of a new three-dimensional method

The repeatability of a non-invasive digital protocol proposed to evaluate the three-dimensional（3D） position of the occlusal plane in the face is assessed.Dental virtual models and soft tissue facial morphology of 20 adult subjects were digitally integrated using a 3D stereophotogrammetric imaging system.The digital 3D coordinates of facial and dental landmarks were obtained by two different operators.Camper＇s（facial） and occlusal（dental） planes were individuated,and their 3D relationships were measured.The repeatability of the protocol was investigated and showed no significant differences in repeated digitizations.The angle between occlusal and Camper＇s planes was smaller than 26 in the frontal and horizontal projections.In the sagittal projection,the angle was observed to be,on average,4.9 6.The determined occlusal plane pitch,roll and yaw values show good agreement with previously published data obtained by different protocols.The current non-invasive method was repeatable,without inter-operator differences and can facilitate assessment of healthy subjects.

3D Surface Digitization in Scientific Research and Product Development

This comprehensive review participates in the use of three different non-invasive surface scanning techniques directed in scientific research of medical, anthropology, archaeology forensic science, and product designing. 3D surface examining tools speak to a promising technique to provide reproducible data such as map the facial soft or hard tissues of a subject document skeletal remains, and trauma, generating 3D imitations of the components for documented and illustrative purposes while simultaneously holding exactness and unwavering quality. Three-dimensional imaging is rapidly turning into a vital tool for reconstruction and examination in scientific research. The final 3D mesh can be 3D printed or the digital version can be shared online with scientific researchers. This review manuscript highlights several studies utilizing non-invasive scanning techniques, depicts the pro and cons of the 3D scanning techniques, and different features of the scanners irrespective of the cost which would be helpful for future research work. A resourceful review was conducted using 7 databases;PubMed, CENTRAL, Science Direct, Scopus, Google Scholar, Research Gate, and IEEE Xplore from 2002 to 2020. Search terms were;“3D Laser scanning”, “Photogrammetry”, “Skeleton preservation”, “Documentation”, “Surface Scanning”, etc. Papers with quality work and related to the field of forensic science, anthropometry, 3D facial scanning, and product development were selected. From all the studies, 71 studies met the eligibility criteria, and other articles were excluded which were non-relevant, had duplicate records, and did not meet search criteria. This review provides in-depth understanding and discussions into methods, restrictions, and inferences from respective research publications.