Ataka Shinsuke, Kohno Takeya, Kurita Kaori, Wada Sonomi, Takahashi Yasuhiro, Shiraki Kunihiko
Department of Ophthalmology, Osaka Ekisaikai Hospital, 2-1-10 Honden, Nishi-ku, Osaka 550-0022, Japan.
Graefes Arch Clin Exp Ophthalmol. 2004 Mar;242(3):245-9. doi: 10.1007/s00417-003-0814-6. Epub 2003 Nov 26.
A 'double-ring' sign may be seen during continuous curvilinear anterior capsulorhexis in cataract surgery. This sign has been attributed to partial splitting of the anterior lens capsule at the continuous curvilinear anterior capsulorhexis edge. Because horizontal intracapsular splits away from the capsule edge have also been reported, a double-ring sign has been hypothesized to be a precursor to true exfoliation. We report new histopathological findings for both anterior capsule and lens epithelium changes, the latter being similar to those of true exfoliation.
Three anterior capsules from two patients with a double-ring sign during capsulorhexis were examined via light and transmission electron microscopy.
Light microscopy revealed step formations in the capsule edges and surface-parallel intracapsular splits in the anterior capsules. Transmission electron microscopy revealed stratified, banded structures consisting of alternating electron-dense and -lucent granular belts (300-400 nm) at the central area of the anterior capsule, as well as vacuole-like spaces and expansion of intercellular spaces in the lens epithelium.
The thickened, stratified structure of the anterior capsule suggests abnormal lens epithelium in patients with a double-ring sign. The horizontal splits in the anterior capsule, with concomitant epithelial changes, i.e., the vacuole-like spaces and widened intercellular spaces, support the relation between a double-ring sign and true exfoliation.
在白内障手术连续环形撕囊过程中可能会出现“双环”征。该征象被认为是由于连续环形撕囊边缘处晶状体前囊膜部分裂开所致。由于也有报道称在远离囊膜边缘处出现水平性囊内裂开，因此有人推测双环征是真正剥脱的先兆。我们报告了前囊膜和晶状体上皮细胞变化的新组织病理学发现，后者与真正剥脱的变化相似。
对两名在撕囊过程中出现双环征患者的三个前囊膜进行了光学显微镜和透射电子显微镜检查。
光学显微镜显示囊膜边缘有阶梯状形成，前囊膜内有与表面平行的囊内裂开。透射电子显微镜显示在前囊膜中央区域有分层的带状结构，由交替的电子致密和电子透亮颗粒带（300 - 400纳米）组成，以及晶状体上皮细胞内有空泡样间隙和细胞间隙增宽。
前囊膜增厚、分层的结构提示双环征患者晶状体上皮细胞异常。前囊膜的水平裂开以及伴随的上皮细胞变化，即空泡样间隙和细胞间隙增宽，支持了双环征与真正剥脱之间的关系。
