恒定性和间歇性外斜视黄斑区视网膜血流密度及厚度特征

目的：应用光学相干断层扫描血管成像（OCTA）分析恒定性外斜视（XT）和间歇性外斜视（IXT）黄斑区视网膜血流密度及厚度特征。方法：病例对照研究。收集2020年9月至2021年9月在温州医科大学附属眼视光医院杭州院区就诊的患者72例（144眼），其中XT25例（50眼）作为XT组、IXT22例（44眼）作为IXT组，正常对照组25例（50眼）。通过OCTA测量黄斑区3mm×3mm范围视网膜浅层毛细血管丛（SCP）和深层毛细血管丛（DCP）血流密度、中心凹无血管区面积、内外层视网膜厚度。各参数组内（研究眼和对侧眼）比较采用配对t检验，组间比较采用广义线性模型方差分析，并采用Pearson 相关分析研究密度和厚度各参数之间以及与斜视度之间的相关性。结果：XT组研究眼总SCP和旁中心凹上方区域SCP血流密度均低于对侧眼（t=-2.10，P=0.047；t=-2.28，P=0.032），旁中心凹上方和下方区域DCP血流密度均低于对侧眼（t=-2.26，P=0.033；t=-2.43，P=0.023）；IXT组两眼间差异均无统计学意义。3组间总体比较发现研究眼总SCP和旁中心凹上方区域SCP血流密度，以及总DCP和除鼻侧外的其他旁中心凹区域DCP血流密度差异均有统计学意义（均P<0.05）。两两比较发现XT组研究眼总SCP和旁中心凹上方区域SCP血流密度，以及总DCP和除鼻侧外的其他旁中心凹区域DCP 血流密度均低于正常对照组（均P<0.05）；IXT组研究眼总DCP和旁中心凹上下方区域DCP血流密度均低于正常对照组（均P<0.05）；XT组中研究眼旁中心凹颞侧内层视网膜厚度低于对侧眼（t=-2.84，P=0.009）。Pearson相关性分析提示内层黄斑中心凹视网膜厚度与远、近斜视度均呈负相关（r=-0.36，P=0.012；r=-0.37，P=0.010）。结论：利用OCTA发现XT患者主斜眼与对侧眼相比有更低的黄斑区视网膜血流密度和更薄的旁中心凹颞侧区域内层视网膜厚度。IXT患者较正常对照者有更低的黄斑区DCP血流密度。

Clinical Characteristics of Macular Perfusion Density and Retinal Thickness in Constant and Intermittent Exotropia

Objective: To measure the macular microvasculature and thickness parameters using optical coherence tomography angiography (OCTA) in constant exotropia (XT) and intermittent exotropia (IXT). Methods: In this case-control study, a total of 72 participants (exotropia 44 eyes) who were treated at Eye Hospital, Wenzhou Medical University from September 2020 to September 2021 were recruited, including 25 XT patients (50 eyes), 22 IXT patients (44 eyes)and 25 controls (50 eyes). OCTA examination was performed to evaluate the macular perfusion density of the superficial capillary plexus (SCP), deep capillary plexus (DCP), foveal avascular zone(FAZ) area, inner and outer retinal thickness in XT and IXT patients and age-matched controls. Data in the macular microvasculature and thickness parameters were compared by paired t-test between the two eyes. The analysis of variance of generalized linear model was used for the comparison between groups. Pearson correlation analysis was used for the correlation of the macular microvasculature with thickness parameters. Results: Compared with contralateral eyes, the study eyes in XT group showed significant decrease in the macular perfusion density of SCP in the whole (t=-2.10, P=0.047) and parafoveal superior regions (t=-2.28, P=0.032), and DCP in parafoveal superior and inferior region (t=-2.26, P=0.033; t=-2.43, P=0.023). There was no statistically significant difference between the two eyes in IXT group. Comparison between three groups, the study eyes showed significant difference in macular perfusion density of SCP in the whole and parafoveal superior regions as well as DCP in the whole and parafoveal superior, inferior, temporal regions (all P<0.05). The study eyes in XT group showed lower perfusion density of SCP in the whole and parafoveal superior regions as well as DCP in the whole and parafoveal superior, inferior, temporal regions than the control group (all P<0.05). In IXT group, the study eyes showed significant decrease of DCP perfusion density in the whole and parafoveal superior and inferior regions than that of the control group (all P<0.05). In XT group, the temporal region of inner retinal thickness in the study eyes showed significant thinner than in the contralateral eyes (t=-2.84, P=0.009). Inner retinal thickness in the fovea was negatively correlated with the angle of exodeviation at distance (r=-0.36, P=0.012) and at near (r=-0.37, P=0.010). Conclusions: In XT patients, OCTA revealed lower macular perfusion density and thinner inner retinal thickness in the temporal region. In IXT group, the study eyes showed significant decrease of DCP perfusion density than that of the control group.