应用超声生物显微镜探讨原发性闭角型青光眼的发病机制

目的探讨原发性闭角型青光眼的发病机制,研究睫状体改变在青光眼发病中的作用。方法应用超声生物显微镜（ｕｌｔｒａｓｏｕｎｄｂｉｏｍｉｃｒｏｓｃｏｐｙ,ＵＢＭ）结合Ａ超检测９９只原发性闭角型青光眼及５８只正常眼的活体眼前节结构,并对两组测量参数进行对比研究。其中急性闭角型青光眼（急闭）５０只眼,慢性闭角型青光眼（慢闭）４９只眼。结果原发性闭角型青光眼与正常眼相比,角膜小、前房浅、眼轴短、晶体厚、相对晶体位置偏前、睫状突肿胀、睫状体前置,以上差异均有显著性（Ｐ＜００５）。急闭与慢闭相比,前者前房更浅,相对晶体位置更偏前,差异有显著性（Ｐ＜００１）。急闭与正常眼相比,前者的睫状体与晶体距离较短,差异有显著性（Ｐ＜００５）;而慢闭与正常眼相比,前者的睫状体与晶体距离亦较短,但差异无显著性（Ｐ＞００５）。结论原发性闭角型青光眼的发病与其自身的解剖特点有关。其中晶体位置前移导致的瞳孔阻滞及继发的房角变窄是闭角型青光眼发病的共同机制;而睫状突肿胀、睫状体位置的改变及与年龄相关的晶体厚度增大是导致晶体位置前移的可能原发因素。对于急闭而言,瞳孔阻滞是其发病的更重要因素。

Studies of mechanism of primary angle closure glaucoma using ultrasound biomicroscope

OBJECTIVE: To investigate the mechanism of primary angle closure glaucoma (PACG) especially the role of the changes of ciliary body using ultrasound biomicroscope (UBM) combined with general A scan. METHOD: 99 eyes with PACG, including 50 eyes with acute and 49 eyes with chronic PACG, were evaluated and 58 normal eyes were in the control group. RESULTS: Compared with the normal eyes the PACG eyes had their anatomic features. They had a smaller corneal diameter, shorter axial length, shallower anterior chamber, thicker lens, more relative anterior location of lens, swelling of ciliary process and anterior rotation of ciliary body. All these differences were significant statistically (P < 0.05). Compared with the chronic PACG eyes the acute PACG eyes had a shallower anterior chamber and a more anteriorly situated lens position. The differences were significant statistically (P < 0.01). Compared with the normal eyes the acute PACG eyes had a shorter ciliary body - lens distance and the difference was significant (P < 0.05); the chronic PACG eyes also had a shorter ciliary body-lens distance, but the difference was not significant (P > 0.05). CONCLUSIONS: The PACG eyes have their anatomic features. Among these factors the pupillary block caused by the anterior displacement of lens and the narrow angle induced consequently are the common mechanism. The swelling ciliary process, the positional changes of the ciliary body and age-related thicker lens are possibly the initial causes causing the forward movement of lens, and the pupillary block plays a more important role in the pathogenesis of acute PACG.