目的：应用广角扫频源光学相干断层扫描成像(swept-source optical coherence tomography, SS-OCT)的en face结构投射图研究玻璃体早期液化特征。方法：使用SS-OCT进行18 mm×18 mm 的容积（Cube）扫描，创建并分析健康未成年人（年龄5~18岁）70眼的系列玻璃体en face结构投射图。 结果：在未成年人中，视网膜前的玻璃体包含4种液化结构，分别为后皮质前玻璃体囊袋（posterior precortical vitreous pocket, PPVP）、视盘前Martegiani区（the area of Martegiani, AM）、血管前液化裂隙（prevascular vitreous fissures，PVF）和液化池（cistern）。所有研究眼均能检出PPVP、AM和PVF，其中22眼（31.4%）的PPVP和AM连通。41眼（58.6%）可检出液化池，且其年龄大于未检出液化池的个体（P =0.01），液化池的发生与年龄呈正相关（rs=0.315，P =0.008）。液化池的象限空间分布频率依次为颞上（90.2%）、鼻上（58.5%）、颞下（36.6%）、鼻下（24.4%），最常累及颞上象限（P＜0.001）。 结论：PPVP、AM和PVF是健康人群视网膜前玻璃体早期液化过程中均出现的特征。液化池的发生与年龄呈正相关，最常出现在颞上象限，可能是年龄相关性玻璃体液化变性的结果。
Objective: To investigate the early vitreous liquefaction characteristics using en face structural projection images obtained by wide-angle swept-source optical coherence tomography (SS-OCT). Methods: SS-OCT was employed to perform 18*18mm volumetric (Cube) scans. A series of en face structural projection images of the vitreous were created and analyzed for 70 eyes from healthy minors aged between 5 and 18 years. Results: In minors, four types of vitreous liquefaction structures were identified anterior to the retina: pre-posterior vitreous pocket (PPVP), the preoptic area of Martegiani (AM), pre-vascular liquefaction fissures (PVF), and cisterns. PPVP, AM, and PVF were detectable in all studied eyes, with PPVP and AM being interconnected in 22 eyes (31.4%). Cisterns were observed in 41 eyes (58.6%), and the mean age of individuals with cisterns was higher than those without (P =0.01). The occurrence of cisterns positively correlated with age (r=0.315; P=0.008). The frequency of cistern quadrant distribution was highest in the superotemporal quadrant (90.2%), followed by the superonasal quadrant (58.5%), inferotemporal quadrant (36.6%), and inferonasal quadrant (24.4%). The superotemporal quadrant was the most frequently affected (P <0.001). Conclusion: PPVP, AM, and PVF are features consistently observed in the early vitreous liquefaction process anterior to the retina in healthy individuals. The occurrence of cisterns positively correlates with age and is most common in the superotemporal quadrant, possibly representing the result of age-related vitreous liquefaction degeneration. These findings provide a theoretical foundation for studying the pathogenesis of vitreoretinal interface diseases.
巨噬细胞样细胞(macrophage-like cells, MLC)指起源、功能与巨噬细胞类似的免疫细胞，包括小胶质细胞、玻璃体细胞及巨噬细胞。将en face OCT显示层面设置在视网膜表明即可观测到视网膜表明的 MLC(epiretinal MLC, eMLC)，随后利用ImageJ软件即可对细胞进行提取和量化。研究表明，eMLC在炎症情况下均可出现细胞募集及活化现象，但在不同眼底病中各具特点。在糖尿病视网膜病变、视网膜静脉阻塞等视网膜缺血缺氧性疾病中，eMLC密度越高，黄斑水肿可能越严重。此外，eMLC密度更高的视网膜静脉阻塞患者抗VEGF疗效更差，视力预后不佳，提示基于en face OCT的eMLC不仅可用于评估视网膜炎情况，而且还能充当提示疾病疗效及预后的标志物。在葡萄膜炎等免疫炎症性疾病中，en face OCT亦可观测到eMLC密度、形态等改变。白塞病葡萄膜炎患者视网膜血管渗漏程度与eMLC密度相关性强，故eMLC密度可充当无创评估视网膜血管渗漏程度的新指标。然而，目前提取和量化eMLC的方法及标准不统一，降低了各研究间的可比性。因此，亟需制定统一的操作规范和评估标准。此外eMLC 所代表的具体细胞类型及功能仍需进一步探究。未来，研究者可以利用en face OCT对眼底炎症地进行无创评估。基于en face OCT的eMLC还能作为基础研究与临床研究之间的桥梁，为揭示疾病的致病机制提供重要参考。
Macrophage-like cells (MLC) refer to immune cells that originate from and function similarly to macrophages, including microglia, hyalocytes, and macrophages themselves. By setting the display level of en face OCT to the retinal surface, epiretinal MLC (eMLC) can be observed and subsequently extracted and quantified using ImageJ software. Studies indicate that eMLC can exhibit cell recruitment and activation in inflammatory conditions, each displaying distinct characteristics in different retinal diseases. In ischemic and hypoxic retinal conditions such as diabetic retinopathy and retinal vein occlusion, higher densities of eMLC are associated with more severe macularedema. Moreover, patients with retinal vein occlusion showing higher eMLC densities tend to have poorer responses to anti-VEGF treatments and worse visual prognoses, suggesting that eMLC identified via en face OCT can be used not only to assess retinal inflammation but also as biomarkers for disease efficacy and prognosis. In immune-inflammatory diseases like uveitis, changes in eMLC density and morphology can also be observed through en face OCT. Inpatients with Beh?et's disease, a strong correlation exists between the degree of retinal vascular leakage and eMLC density, making eMLC density a potential non-invasive marker for assessing retinal vascular leakage. However, the current methods and standards for extracting and quantifying eMLC are not unified, significantly reducing comparability between studies. Therefore, there is an urgent need to establish uniform operational protocols and assessment standards. Furthermore, the specific cell types and functions represented by eMLC observed via en face OCT require further investigation. In the future, en face OCT could be utilized for non-invasive assessment of retinal inflammation. eMLC based onen face OCT could also serve as a bridge between basic research and clinical studies, providing valuable insights into the pathogenic mechanisms of diseases.
