Department of Anatomy II, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany.
Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany.
Invest Ophthalmol Vis Sci. 2014 Jun 17;55(7):4541-51. doi: 10.1167/iovs.13-13765.
To analyze the peripheral fixation of the iris dilator muscle in normal eyes and in eyes with pigmentary glaucoma (PG).
Using 63 control eyes (age 18 months-99 years), the peripheral iris dilator was investigated by light microscopy, immunohistochemistry, and electron microscopy. Development was studied using 18 differently aged fetal eyes stained immunohistochemically against α-smooth muscle (SM) actin. The peripheral iris dilator muscle in PG was analyzed using semithin and ultrathin sections of six glutaraldehyde-fixed eyes from three donors aged 38, 62, and 74 years.
In normal eyes, the peripheral end of the iris dilator muscle is arranged in a sphincter-like manner. Arcade-shaped tendinous connections associated with myofibroblasts (iridial strands) anchor the iris dilator within the elastic-fibromuscular ciliary meshwork that also serves as fixation area for the elastic tendons of the inner ciliary muscle portions. The iridial strands are innervated and can adapt their length during accommodation. The PG eyes show incomplete circular bundles and iridial strands that are mainly anchored to the iris stroma and the flexible uveal parts of the trabecular meshwork.
The normal anchorage of the peripheral iris dilator and its presumably neuronally regulated length adaptation stabilize the peripheral iris during accommodation. Insufficient fixation in PG could promote posterior bowing of the iris with rubbing against the zonular fibers and pigment liberation from the iris pigmented epithelium.
分析正常眼和色素性青光眼（PG）眼中虹膜开大肌的周边固定情况。
使用 63 只对照眼（年龄 18 个月至 99 岁），通过光镜、免疫组织化学和电子显微镜研究周边虹膜开大肌。使用 18 只不同年龄的胎儿眼进行免疫组织化学染色，研究其发育情况，针对α-平滑肌（SM）肌动蛋白进行染色。使用来自 3 名年龄分别为 38、62 和 74 岁的供体的 6 只戊二醛固定眼的半薄和超薄切片分析 PG 中的周边虹膜开大肌。
在正常眼中，虹膜开大肌的周边末端呈括约肌样排列。与肌成纤维细胞（虹膜索）相关的弧形腱状连接将虹膜开大肌固定在弹性纤维-纤维肌肉睫状体网中，该网也是内环肌部分的弹性肌腱的固定区域。虹膜索被神经支配，并在调节时能够适应其长度。PG 眼中可见不完全的环形束和主要固定在虹膜基质和小梁网的弹性葡萄膜部分的虹膜索。
正常的周边虹膜开大肌的固定及其可能的神经调节长度适应性在调节时稳定周边虹膜。PG 中的固定不足可能会导致虹膜后凸，与悬韧带摩擦并使虹膜色素上皮中的色素释放。
