目的探讨显微小梁切除术后视力减退的原因。方法对术后眼压正常的221只眼的视力、视野、眼压、屈光间质及眼底进行了长达2～5年的随访研究。结果在显微小梁切除术后眼压正常的221只眼中，68只眼视力发生了减退。结论视力减退与术后白内障形成或加重、术后慢性隐蔽性葡萄膜炎、视乳头血管灌注不良、屈光状态改变、黄斑囊样水肿以及眼压降得不够充分有关。 Objective To investigate the causes of visual impairment after trabeculectomy. Methods The visual acuity, visual field, intraocular pressure, refractive mesenchyme and fundus of 221 eyes with normal intraocular pressure were studied for up to 2 to 5 years. Results Of the 221 eyes with normal IOP after trabeculectomy, 68 eyes had a decrease in vision. Conclusions The relationship between visual acuity and postoperative cataract formation or exacerbation, postoperative chronic subtle uveitis, poor perfusion of optic canal, changes of refractive status, cystoid macular edema and inadequate intraocular pressure.