Tuisku Ilpo S, Konttinen Yrjö T, Konttinen Liisa M, Tervo Timo M
Helsinki University Eye Hospital, Helsinki, Finland.
Exp Eye Res. 2008 Jun;86(6):879-85. doi: 10.1016/j.exer.2008.03.002. Epub 2008 Mar 12.
The aim of the study was to assess subjective symptoms and objective clinical signs of dry eye in relation to corneal nerve morphology and sensitivity in primary Sjögren's syndrome. Twenty eyes of 20 primary Sjögren's syndrome patients and ten eyes of 10 healthy age- and sex-matched controls were included in the study. Ocular surface disease index (OSDI) questionnaire and visual analog scales were used to assess subjective symptoms. The mechanical sensitivity of the central cornea was measured using a modified Belmonte non-contact esthesiometer followed by an analysis of corneal nerve morphology using scanning slit confocal microscopy (ConfoScan 3). OSDI symptom scores were high in primary Sjögren's syndrome patients, compared with controls. Accordingly, the mean corneal detection threshold was low in patients implicating corneal mechanical hypersensitivity (54.5+/-40.1ml/min vs. 85.0+/-24.6ml/min, P=0.036). However, nerve densities were similar, and no correlation was present between corneal sensitivity and nerve density. In contrast, alterations in nerve morphology were found; stromal nerves appeared thicker, and nerve growth cone-like structures were seen in 20% of patients, often associated with dendritic antigen-presenting cells. Sjögren's syndrome patients presented with corneal mechanical hypersensitivity, although corneal nerve density did not differ from controls. However, alterations in corneal nerve morphology (nerve sprouting and thickened stromal nerves) and an increased amount of antigen-presenting cells, implicating the role of inflammation, were observed. These observations offer an explanation for the corneal mechanical hypersensitivity, or even hyperalgesia often observed in these patients. We hypothesize that patients with primary Sjögren's syndrome dry eye suffer from neuropathic corneal mechanical hypersensitivity induced by ocular surface inflammation.
本研究旨在评估原发性干燥综合征中干眼的主观症状和客观临床体征与角膜神经形态及敏感性之间的关系。本研究纳入了20例原发性干燥综合征患者的20只眼以及10例年龄和性别匹配的健康对照者的10只眼。采用眼表疾病指数（OSDI）问卷和视觉模拟量表评估主观症状。使用改良的贝尔蒙特非接触式感觉计测量中央角膜的机械敏感性，随后使用扫描裂隙共聚焦显微镜（ConfoScan 3）分析角膜神经形态。与对照组相比，原发性干燥综合征患者的OSDI症状评分较高。相应地，患者的平均角膜检测阈值较低，提示角膜机械性超敏反应（54.5±40.1ml/min对85.0±24.6ml/min，P=0.036）。然而，神经密度相似，角膜敏感性与神经密度之间无相关性。相反，发现了神经形态的改变；基质神经看起来更粗，20%的患者可见神经生长锥样结构，且常与树突状抗原呈递细胞相关。干燥综合征患者存在角膜机械性超敏反应，尽管角膜神经密度与对照组无差异。然而，观察到角膜神经形态的改变（神经发芽和基质神经增粗）以及抗原呈递细胞数量增加，提示炎症起了作用。这些观察结果为这些患者中经常观察到的角膜机械性超敏反应甚至痛觉过敏提供了解释。我们推测原发性干燥综合征干眼患者患有由眼表炎症引起的神经性角膜机械性超敏反应。
