目的：空泡蝶鞍（Empty sella，ES）的概念在1951年由Busch首次ᨀ出，其在尸体解剖时发现尸体鞍膈不完全缺失，垂体萎缩、蝶鞍空虚，蝶鞍内充满蛛网膜下腔的脑脊液，故命名空泡蝶鞍[1]。脑脊液充满垂体窝导致蝶鞍扩大，从而产生的一组临床症候群被称为空泡蝶鞍综合征（Empty sella symptom，ESS），其分为原发性空蝶鞍综合征（Primary empty sella syndrome，PESS）和继发性空蝶鞍综合征（Secondary empty sella syndrome，SESS）。原发性空泡蝶鞍综合征的病因不明确，有多种学说，如先天性鞍膈缺损、免疫反应、多胎妊娠、垂体卒中、脑脊液压力长期作用等[2]。继发性空泡蝶鞍综合征多由垂体手术或放疗导致[3]。空泡蝶鞍综合征的临床表现包括头痛，视功能损害如视力减退、视野缺损、视乳头水肿及视神经萎缩，脑脊液漏，垂体内分泌功能异常，肥胖，高血压等[4]。空泡蝶鞍的诊断主要依靠磁共振成像（Magnetic resonance imaging，MRI）。曾有文章指出，SESS患者再次手术过程中，往往能观察到视神经形成疝突入鞍区，和视交叉受到瘢痕组织牵拉[5]。这可能是SESS患者视觉功能损害的原因之一。本研究的目的是：1. 观察原发性和继发性空泡蝶鞍相关的视功能损害；2. 探究ES视交叉下陷程度与视功能损害的相关性；3. 进一步探讨空泡蝶鞍导致视功能损害的发病机制。方法：研究时间为2017年1月至2019年6月。北京协和医院住院患者中ESS患者28人，其中无视功能损害的空泡蝶鞍对照组24人，存在视功能损害的病例组4人，病例组中PESS患者2人，SESS患者2人。病例组中每位患者均进行了眼科相关检查，包括视力、视野、眼压，并进行了影像学检查即垂体增强MRI。ESS诊断依靠垂体增强MRI检查，包括冠状位T1增强相、矢状位T1增强相、冠状位T2相。MRI诊断标准：1. 鞍内部分或全部被脑脊液充满；2. 垂体腺的高度＜2mm；3. 垂体柄有或无受压位移；4. 排除垂体腺萎缩或正在发育的垂体。排除标准：1. SESS经≥2次鞍区手术治疗；2. 存在其他内分泌疾病或其他垂体窝肿瘤；3. 存在其他影响视功能的疾病，如白内障、青光眼、视网膜病变；4. 屈光不正大于±3D。结果：所有患者中，男：女=9：19，平均年龄57.0±19.8。视功能损害的ESS患者中，有鞍区手术或放疗史的患者，即SESS患者占50%，PESS占50%。ES对照组中，SESS占37.5%，PESS占62.5%。OR=1.67。P＞0.05。存在视功能损害的患者的MRI中可观察到视交叉下陷。结论：ESS患者是否存在视功能损害与鞍区手术或放疗史无明显关联，可能与视交叉下陷有关。可能视交叉下陷越多，患者视功能损害越严重，包括视力下降、眼压增高、视野受损。

Object: The term “empty sella (ES)” was first proposed by Busch in 1951 at autopsy studies to refer to the finding the defects of the diaphragm sellae, flattening of the pituitary gland, and the empty sella was full of cerebrospinal fluid (CSF)~[1]. Empty sella syndrome is an anatomical and clinical entity composed of intrasellar reposition of the CSF and compression of the pituitary tissue. Two types of empty sella should be distinguished. Primary empty sella (PES) is unrelated to any known previous pathogenesis. There has been several hypotheses of the pathogenesis of PES, such as congenital deficiency of diaphragmatic sellae, immunoreaction, multiple pregnancies, pituitary apoplexy, long-term effects of cerebrospinal fluid (CSF)~[2]. SESS is usually due to surgery or radiotherapy~[3]. Clinical manifestations of ESS mainly include headache, visual impairment (hypopsia, visual field defects, papilloedema and optic atrophy), CSF leak and endocrine function disturbances, obesity and hypertension~[4]. The empty sella is mainly diagnosed by magnetic resonance imaging (MRI).It was reported that second surgical exploration of SESS usually confirmed downward herniation of the optic nerves and chiasm into an enlarged sella due to traction by tethering scar tissue~[5].That might be one of the pathogeneses of SESS visual function impairment. The object of our study is:1. Observation of PESS and SESS visual function impairment; 2. Study the relevance of ES optic chiasma downward herniation and visual function impairment; 3. Study the pathogenesis of the ES visual function impairment.Methods: During the past 6 months，we recruited 28 ESS patients in Peking Union Medical College Hospital. The control group had 24 ES patients without visual impairment, and the case group had 4 ES patients with visual impairment (2 PESS and 2 SESS). Diagnosis was made by MRI (including sagittal and coronal weighted T1 enhanced images and coronal T2 images). Diagnostic criteria: 1. empty sella is defined as partial or total when less or more than 50% of the sella is filled with CSF respectively; 2. the gland thickness being < 2 mm; 3.pituitary stalk was or not compressed or displaced; 4. excluding pituitary atrophy or developing pituitary gland. Exclusion criteria: 1. SESS patients that went through 2 or more than 2 sella turcica surgeries; 2. patients had other severe endocrine diseases; 3. other ophthalmic comorbidity that might affect vision function, such as cataracts, glaucoma, and retinopathy; 4. refractive error ≥±3.Results: Among all 28 patients, male/female = 9/19, and the mean age is 57.0±19.8. Among ESS patients with visual impairment, SESS (with history of sella turcica surgery) accounts for 50%, and PESS also accounts for 50%. In the ES control group, SESS accounts for 37.5%, and PESS accounts for 62.5%. OR=1.67. P＞.05. But chiasma downward herniation could be observed among patients with visual function impairment on their MRI images.Conclusion: There might be no significant correlation between history of sella turcica surgery or radiotherapy and visual function impairment among ES patients, but the impairment might has correlation with chiasma downward herniation. And visual impairment might depend on the severity of chiasma herniation.