Analysis of the Relationship Between the Morphological Characteristics of the Maxillomandibular Region in a 3D Representation and the Refractive Status of the Eye After the Completion of Growth and Development
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 120
- 试验地点
- 1
- 主要终点
- Axial length (AL)
研究概览
简要总结
The goal of this observational study is to learn more about the relationship between the size and shape of the eye and the shape of the face in healthy young adults. In particular, the study focuses on whether specific eye measurements are linked to certain facial characteristics after growth and development have been completed.
The main question it aims to answer is:
Does the size and internal structure of the eye relate to the three-dimensional shape of the face in young adults aged 21 to 25, and are these relationships different in people who are nearsighted (myopic), farsighted (hyperopic), or have normal vision (emmetropic)?
Refractive errors such as nearsightedness and farsightedness are very common and are largely influenced by the length of the eye (axial length) and other internal eye measurements. During childhood and adolescence, it develops at the same time as the eye socket (orbit) and the bones of the face. However, most previous studies have examined either the eye or the bony orbit separately. Very few have combined detailed eye measurements with modern three-dimensional (3D) facial measurements in the same individuals.
This study will include 120 healthy young adults between 21 and 25 years of age, after facial growth is complete. Participants will be divided into three groups based on their refractive status: myopic (nearsighted), emmetropic (normal vision), and hyperopic (farsighted), with similar numbers of men and women in each group.
All participants will undergo a standard ophthalmologic examination. This will include measurement of visual acuity, refraction (to determine glasses prescription), and detailed eye biometry using a non-contact optical device (IOLMaster 700). The measurements will include axial length (eye length), corneal curvature, anterior chamber depth, lens thickness, and corneal diameter (white-to-white). These are routine, non-invasive measurements commonly used in clinical eye care.
In addition, participants will undergo non-invasive 3D facial imaging. A short video of the face will be recorded while a camera moves around the participant. Using photogrammetry software, this video will be converted into a precise 3D model of the face. From this model, specific facial landmarks will be identified, and distances and proportions of different facial regions (upper, middle, and lower thirds of the face; cheek width; jaw width; chin projection) will be measured. This method does not involve radiation and does not cause discomfort.
The researchers will then analyze whether there are statistical relationships between eye measurements and facial dimensions. They will also compare the three refractive groups to determine whether certain facial patterns are more common in myopic, emmetropic, or hyperopic individuals.
Participation is voluntary. All participants will sign informed consent before enrollment. The study has been approved by relevant ethics committees and will be conducted according to international ethical standards. All data will be anonymized and stored securely. No additional risks are expected beyond those associated with a routine eye examination.
The results of this study may improve understanding of how eye growth and facial development are related. In the long term, this could contribute to better knowledge of the anatomical background of refractive errors and support future interdisciplinary research in ophthalmology, orthodontics, and craniofacial medicine.
详细描述
This study is designed as a cross-sectional observational investigation aiming to evaluate the relationship between ophthalmologic biometric parameters and three-dimensional craniofacial morphometric characteristics in healthy young adults aged 21 to 25 years, after completion of growth and development. A total of 120 participants are planned to be included. Participants will be divided into three groups according to refractive status: myopes, emmetropes, and hyperopes, with approximately equal numbers in each group and balanced representation by sex. To minimize the influence of population-related morphological variability, only individuals of the same ethnic background will be included.
Eligible participants will be healthy young adults with best-corrected visual acuity of at least 1.0 and normal findings of the anterior and posterior ocular segments. Refractive status will be determined using objective autorefractometry and confirmed by subjective refraction according to standard clinical guidelines. Individuals with a history of ocular or facial surgery, craniofacial anomalies, active or previous orthodontic therapy affecting maxillomandibular relationships, strabismus, amblyopia, ocular or facial trauma, or systemic diseases that may influence facial morphology or ocular biometric parameters will be excluded. To reduce the potential influence of general body proportions on morphometric measurements, only participants with a body mass index between 18.5 and 24.9 kg/m² will be included. All ophthalmologic examinations will be performed in the same healthcare institution according to a standardized protocol. All facial recordings and landmark identification procedures will be conducted by the same investigator to reduce inter-examiner variability and enhance reproducibility.
All procedures in the study are non-invasive. Ophthalmologic data will be collected using standard clinical methods, including measurement of best-corrected visual acuity, objective autorefractometry, and keratometry. Detailed ocular biometric parameters will be obtained using optical biometry with the IOLMaster 700 (Carl Zeiss Meditec AG, Jena, Germany). The recorded biometric variables will include axial length, corneal curvature radii, anterior chamber depth, lens thickness, horizontal corneal diameter (white-to-white), and calculated intraocular lens power. All measurements will be performed according to a standardized protocol within the same institution.
Three-dimensional facial morphology will be assessed using standardized video-based 3D imaging. A mobile device will be used to record a video sequence while the camera is moved continuously around the participant in a circular trajectory exceeding 180 degrees, enabling reconstruction of a three-dimensional facial surface model using digital photogrammetry without exposure to ionizing radiation. During recording, participants will be positioned in natural head position, with their gaze directed straight ahead and a neutral facial expression. Lighting conditions and camera distance will be standardized to ensure measurement reproducibility. The recorded video sequences will be processed to generate 3D facial models, which will then be calibrated and standardized prior to analysis. Further processing and morphometric analysis will be conducted using MeshLab software (Visual Computing Lab, ISTI-CNR, Italy).
On each 3D model, standardized anthropometric landmarks will be identified according to established guidelines used in orthodontic and craniofacial analysis. These landmarks will include trichion, glabella, nasion, subnasale, labrale superius, stomion, labrale inferius, supramentale, pogonion, menton, gnathion, right and left zygion, right and left gonion, and right and left tragion. Based on these landmarks, linear distances describing vertical, sagittal, transverse, and depth-related facial proportions will be calculated. Vertical measurements will include the upper, middle, and lower facial thirds (Tr-G, G-Sn, Sn-Gn), total facial height (N-Gn), and subdivisions of the lower facial third (Sn-Sto and Sto-Me). Lip dimensions will be assessed using Ls-Sto and Sto-Li distances. Sagittal proportions will be evaluated by measuring chin and labiomentale projection (Sm-Pg) and lower facial projection (Sn-Pg). Transverse dimensions will include bizygomatic width (ZyR-ZyL) and bigonial width (GoR-GoL). Lateral depth measurements will be determined by distances between tragion and subnasale (TrR-Sn, TrL-Sn) and between tragion and gnathion (TrR-Gn, TrL-Gn). All linear measurements will be calculated automatically within the 3D modeling environment to reduce measurement error associated with two-dimensional techniques.
研究设计
- 研究类型
- Observational
- 观察模型
- Other
- 时间视角
- Cross Sectional
入排标准
- 年龄范围
- 21 Years 至 25 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy young adults aged 21 to 25 years.
- •Same ethnic background (to reduce population-related morphological variability).
- •Best-corrected visual acuity ≥ 1.
- •Normal findings of the anterior and posterior ocular segments.
- •Refractive status determined by objective autorefractometry and confirmed by subjective refraction.
- •Body mass index (BMI) between 18.5 and 24.9 kg/m².
- •Willingness to participate and provision of written informed consent.
排除标准
- •Previous ocular surgery.
- •Previous facial surgery.
- •Craniofacial anomalies.
- •Active or previous orthodontic therapy that may affect maxillomandibular relationships.
- •Strabismus.
- •Ocular trauma.
- •Facial trauma.
- •Systemic diseases that may affect facial morphology or ocular biometric parameters.
研究组 & 干预措施
Healthy young adults stratified by refractive status
Healthy young adults aged 21 to 25 years, of the same ethnic background, with normal ocular health and best-corrected visual acuity ≥ 1.0, stratified into myopic, emmetropic, and hyperopic groups, and with body mass index between 18.5 and 24.9 kg/m².
干预措施: No intervention; Observational study (Other)
结局指标
主要结局
Axial length (AL)
时间窗: Assessed once during the ophthalmologic examination.
Axial length is the distance from the anterior corneal surface to the retinal pigment epithelium along the optical axis of the eye. It represents the anatomical length of the eyeball and is a principal determinant of refractive status, with increased axial length typically associated with myopia.
次要结局
未报告次要终点
研究者
Maja Malenica Ravlić
MD
University of Zagreb