目的：比较白内障术前应用不同浓度聚维酮碘(PI)在结膜囊作用不同时间，观察PI的消毒效果，以及对结膜囊菌群、眼表的影响，筛选PI的最佳浓度和作用时间。

方法：本研究为前瞻性研究，选择2015-06/2017-06于我院行白内障手术患者270例270眼，根据用药浓度(5、1、0.5g/L)随机分为三组，每组90眼。根据不同作用时间(30s，1、2min)进一步随机分配各个亚组，每亚组各30眼。患者按分组情况进行术前PI结膜囊冲洗，并于冲洗前后进行结膜囊细菌样本采集，比较PI冲洗前后结膜囊细菌菌群变化和细菌培养阳性情况。同时比较术前3d与术后1、3d，1wk，1、3mo的泪膜破裂时间(BUT)、角膜荧光素染色(CFS)变化，观察PI冲洗结膜囊对眼表的影响。

结果：(1)结膜囊菌群变化：PI冲洗前结膜囊细菌培养共12种，其中革兰氏阳性菌9种，革兰氏阴性菌3种； PI冲洗后结膜囊细菌培养共4种，其中革兰氏阳性菌2种，革兰氏阴性菌2种。(2)结膜囊细菌培养阳性情况的比较：PI冲洗前结膜囊细菌培养阳性15眼，冲洗后细菌培养阳性5眼，PI冲洗前后细菌培养阳性眼数减少(P<0.05)。(3)安全性：所有患者术后末次随访，术眼均未发生眼内炎，除0.5g/L、30s组及5g/L、2min组外的所有组别，BUT均在术后3mo恢复术前水平。0.5g/L、30s组BUT术后1mo就恢复到术前水平，5g/L、2min组BUT至术后3mo仍未恢复至术前； 所有组别CFS均在术后1mo恢复至术前水平。

结论：0.5g/L PI结膜囊冲洗30s能有效减少结膜囊细菌，较其他作用时间和浓度组对眼表的损伤更小，用于白内障术前结膜囊消毒是安全有效的。

METHODS: From June 2015 to June 2017 cataract surgery was performed in 270 cases 270 eyes. According to the concentration(0.5%, 0.1%, 0.05%)of the PI the patients were randomly divided into three groups(A, B, C,). Group A was randomly divided into three subgroups(A1, A2, A3)respectively according to different irrigation time: 30s, 1min and 2min. group B and group C were divided to subgroups similar to group A. In all groups, the conjunctiva was flush irrigate with 3ML of PI of the respective concentration. Conjunctival specimens were obtained before PI irrigation and after PI irrigation. The change of conjunctival sac bacterial flora and bacterial culture positive rate were studied. Tear break up time(BUT), cornea fluorescein staining(CFS)were evaluated 3d preoperative and 1d, 3d, 1wk, 1mo, 3mo postoperative.

RESULTS:(1)The change of conjunctival sac bacterial flora. A total of 12 species of conjunctival sac bacteria were cultured before PI irrigation including 9 Gram positive bacteria and 3 Gram negative bacteria. A total of 4 species of conjunctival sac bacteria were cultured after PI irrigation including 2 Gram positive bacteria and 2 Gram negative bacteria.(2)Comparison of the positive rate of bacterial culture in conjunctival sac. Positive conjunctival sac culture for 15 eyes before PI irrigation, 5 eyes show positive after washing, the amount of positive bacteria culture was lower(P<0.05).(3)No endophthalmitis was found in all patients at the last follow-up. The BUT in all groups except the groups of 0.5g/L, 30s and 5g/L, 2min were restored to preoperative level at 3mo after surgery, The BUT in group 0.5g/L, 30s was restored to preoperative level 1mo after surgery, while the BUT in groups 5g/L, 2min, was still not restored to preoperative level 3mo after surgery. The CFS in all groups recovered to preoperative level at 1mo after surgery.

CONCLUSION: 0.5g/L PI with 30s irrigation time may effectively reduce the conjunctival sac bacteria. Compared with other groups, its damage to the eye surface is smaller. It is safe and effective in preparation for cataract surgery.