Objective To explore the ultrastructural alteration of extraocular muscle proprioceptor in congenital idiopathic nystagmus (CIN). Methods Case-control study. Ten extraocular muscle samples were collected from five CIN children who underwent nystagmus surgeries in Beijing Children''s Hospital from March 2015 to March 2016. Another ten extraocular muscle specimens were collected from five strabismus children in surgery at the same period as normal contrast. There were 3 male patients and 2 female patients of CIN with age of 61—147 months (median age: 91 months). The ultrastructure of extraocular muscle proprioceptors was compared between these two groups by transmission electron microscope. Results Twenty-three proprioceptors were found in extraocular muscle specimens of CIN children, whereas thirty-three proprioceptors were detected in strabismus children. The ultrastructure of extraocular muscle proprioceptor of CIN altered greatly comparing with that of the control. Fourteen extraocular muscle proprioceptors of CIN were discovered much smaller and vacuolated not only at inner capsules but also at the space between inner and outer capsules with lipofuscins and myeloid bodies in the intrafusal muscle fibers. Sensory nerve fibers degenerated greatly with a lot of lipofuscins and myeloid bodies in these sensory nerve fibers. Demyelination also appeared in some severe cases. Nine extraocular muscle proprioceptors of CIN showed significant dissolving degeneration of myofibrils and proliferation of collagen fibrils. The normal structures could not be distinguished in these proprioceptors. And these structural disorders also appeared in extrafusal muscle fibers and nerve endings. Conclusion The ultrastructure of extraocular muscle proprioceptor in CIN turned much smaller and had significantly structural disorder.%目的 研究先天性特发性眼球震颤(CIN)患儿眼外肌本体感受器的超微结构变化.方法 病例对照研究.收集2015年3月至2016年3月在首都医科大学附属北京儿童医院眼科就诊,因CIN行手术治疗的患儿5例手术中的眼外肌标本10例;同时收集同期因斜视在我科行手术治疗的患儿5例术中的眼外肌标本10例作为对照.5例CIN患儿中男性3例,女性2例;年龄61~147个月,中位数年龄91个月.应用透射电子显微镜观察CIN患儿眼外肌本体感受器较对照组可能出现的超微结构变化.结果 在10例CIN患儿眼外肌标本中共找到本体感受器23个,10例斜视患儿眼外肌标本中则找到33个.CIN患儿的14个本体感受器体积较对照组出现明显的缩小,内囊及内、外囊间隙出现空泡化,梭内肌纤维胞质内可见较多的脂褐素和髓样体.感觉神经纤维变性,可见大量髓样体和脂褐素,部分严重者还出现了有髓神经纤维脱髓鞘现象.9个本体感受器内肌原纤维出现大量变性溶解,感受器内部大量胶原纤维增生,无法辨认感受器内部的组织结构.同时,梭外肌纤维和神经末梢也出现结构紊乱.结论 CIN患儿眼外肌本体感受器超微结构出现明显的体积缩小和结构紊乱.
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