Abstract：
BACKGROUND: To compare and contrast morpho-volumetric features between Down syndrome (DS) cornea and non-DS keratoconic cornea by three-dimensional (3D) modelling.
METHODS: Forty-three subjects (43 eyes) with DS and 99 patients matching their age and sex (99 eyes) with keratoconus (KC) were included in this single-center cross-sectional study. Main outcome measures were high-order aberrations (HOA), central corneal thickness (CCT), spherical equivalent refraction, and morpho-volumetric parameters established using a 3D corneal model, such as deviation of anterior and posterior corneal apices (Dapexant/Dapexpost) and minimum thickness points (Dmctant/Dmctpost) from corneal vertex, areas of the anterior and posterior surfaces (Aant/Apost), sagittal area passing through the anterior and posterior corneal apices (Aapexant/Aapexpost) and minimum thickness point (Amctpost) and corneal volume of the complete cornea (Vtotal).
RESULTS: Age, gender, spherical equivalent refraction, CCT and Vtotal were similar between the net on-DS KC and DS groups (P > 0.05), while non-DS KC group had higher HOA than the DS group (P < 0.05). Dapexant, Aant, Apost and Aapexant showed higher values in the DS group than in the non-DS KC group, whereas Dapexpost showed a reduction in the DS group when compared with the non-DS KC group (P < 0.05).
CONCLUSIONS: This study demonstrated that anterior and posterior corneal apex dynamics were specifically different in DS subjects, as the anterior apex tends to displace more prominently when compared to that from the non-DS KC group, while the posterior apex appears to be more stable than that in non-DS KC, which also support the theory that DS patients suffer from a specific keratopathy, distinctively different to KC but strongly related to it, and probably showing a diversity of corneal phenotypes in all cases of DS.
METHODS: Forty-three subjects (43 eyes) with DS and 99 patients matching their age and sex (99 eyes) with keratoconus (KC) were included in this single-center cross-sectional study. Main outcome measures were high-order aberrations (HOA), central corneal thickness (CCT), spherical equivalent refraction, and morpho-volumetric parameters established using a 3D corneal model, such as deviation of anterior and posterior corneal apices (Dapexant/Dapexpost) and minimum thickness points (Dmctant/Dmctpost) from corneal vertex, areas of the anterior and posterior surfaces (Aant/Apost), sagittal area passing through the anterior and posterior corneal apices (Aapexant/Aapexpost) and minimum thickness point (Amctpost) and corneal volume of the complete cornea (Vtotal).
RESULTS: Age, gender, spherical equivalent refraction, CCT and Vtotal were similar between the net on-DS KC and DS groups (P > 0.05), while non-DS KC group had higher HOA than the DS group (P < 0.05). Dapexant, Aant, Apost and Aapexant showed higher values in the DS group than in the non-DS KC group, whereas Dapexpost showed a reduction in the DS group when compared with the non-DS KC group (P < 0.05).
CONCLUSIONS: This study demonstrated that anterior and posterior corneal apex dynamics were specifically different in DS subjects, as the anterior apex tends to displace more prominently when compared to that from the non-DS KC group, while the posterior apex appears to be more stable than that in non-DS KC, which also support the theory that DS patients suffer from a specific keratopathy, distinctively different to KC but strongly related to it, and probably showing a diversity of corneal phenotypes in all cases of DS.
摘要：
背景：通过三维（3D）建模，比较和对比唐氏综合征（DS）角膜和非DS角膜的形态体积特征。
方法：这项单中心横断面研究包括43例DS患者（43只眼）和99例年龄和性别相匹配的患者（99只眼）与圆锥角膜（KC）相匹配。主要结局指标是高阶畸变(HOA)，中央角膜厚度(CCT),球面等效折射，和使用3D角膜模型建立的形态体积参数，如角膜前顶点和后顶点（Dapexant/Dapexpost）和最小厚度点（Dmctant/Dmctpost）与角膜顶点的偏差，前表面和后表面区域（Aant/Apost），通过前角膜尖和后角膜尖（Aapexant/Aapexpost）和最小厚度点（Amctpost）的矢状区域以及完整角膜的角膜体积（Vtotal）。
结果：年龄，性别,球面等效折射，净DSKC和DS组之间的CCT和Vtotal相似（P>0.05），非DSKC组的HOA高于DS组（P<0.05）。Dapexant,Aant,Apost和Aapexant在DS组显示出比非DSKC组更高的值，与非DSKC组相比，DS组Dapexpost降低（P<0.05）。
结论：这项研究表明，在DS受试者中，前、后角膜顶点动力学是特别不同的，由于与非DSKC组相比，前尖倾向于更明显地移位，虽然后顶点似乎比非DSKC更稳定，这也支持DS患者患有特定角膜病变的理论，与KC截然不同，但与KC密切相关，并且可能在所有DS病例中显示出角膜表型的多样性。
方法：这项单中心横断面研究包括43例DS患者（43只眼）和99例年龄和性别相匹配的患者（99只眼）与圆锥角膜（KC）相匹配。主要结局指标是高阶畸变(HOA)，中央角膜厚度(CCT),球面等效折射，和使用3D角膜模型建立的形态体积参数，如角膜前顶点和后顶点（Dapexant/Dapexpost）和最小厚度点（Dmctant/Dmctpost）与角膜顶点的偏差，前表面和后表面区域（Aant/Apost），通过前角膜尖和后角膜尖（Aapexant/Aapexpost）和最小厚度点（Amctpost）的矢状区域以及完整角膜的角膜体积（Vtotal）。
结果：年龄，性别,球面等效折射，净DSKC和DS组之间的CCT和Vtotal相似（P>0.05），非DSKC组的HOA高于DS组（P<0.05）。Dapexant,Aant,Apost和Aapexant在DS组显示出比非DSKC组更高的值，与非DSKC组相比，DS组Dapexpost降低（P<0.05）。
结论：这项研究表明，在DS受试者中，前、后角膜顶点动力学是特别不同的，由于与非DSKC组相比，前尖倾向于更明显地移位，虽然后顶点似乎比非DSKC更稳定，这也支持DS患者患有特定角膜病变的理论，与KC截然不同，但与KC密切相关，并且可能在所有DS病例中显示出角膜表型的多样性。
