白内障超声乳化术中前房深浅对角膜曲率的影响

The impact of anterior chamber depth during the phacoemulsification on post-operative corneal curvature

目的观察白内障超声乳化术中改变前房压力、形成不同深度的前房,对术后角膜曲率变化的影响。方法36例(40只眼)白内障患者,采用上方3mm巩膜隧道切口行超声乳化术,扩大至5.5mm后植入PMMA硬性人工晶状体。然后根据后继处理方式的不同将上述患者随机分为A、B两组。A组19例(20只眼),用虹膜恢复器轻压切口下唇,待房水放出、前房变浅后,再将切口上唇由角膜向巩膜方向按摩,其余处理为:将结膜瓣复位,球下注射庆大霉素、地塞米松,术毕;B组17例(20只眼),使前房维持在正常或略深的状态下,一边注水的同时一边抽出注吸头,其余处理同A组。结果术后1周A组有13只眼(65%)视力≥0.5,而B组仅有6只眼(30%)视力≥0.5,提示A组患者视力恢复好于B组(P<0.05,χ2检验)。同时,90°轴向角膜曲率改变程度,两组间亦有显著性差异(P<0.05,配对t检验),其中A组与术前比较无显著性差异(P>0.05),B组显示角膜曲率半径明显增加(P<0.05)。180°轴向角膜曲率两组间比较、两组分别与术前比较差异均无显著性(P>0.05)。术后1月,90°、180°轴向角膜曲率组间比较、两组分别与术前比较差异均无显著性(P>0.05)。此时,A组有14只眼(70%)视力好于0.5,高于B组的11只眼(55%)。结论手术结束前减少灌注使前房变浅、降低眼压并整复切口,有助于使切口两唇恢复到原始位置,由自然生成的房水将前房恢复,从而减少手术引起角膜曲率改变,减少手术后散光,可使手术眼视力获得较快恢复。

Objective To observe the impact of modulating anterior chamber depth during the cataract phacoemusification extraction surgery on post-surgical changes in corneal curvature. Methods The nucleus of cataract was removed from 40 eyes of 36 patients through a 3mm superior sclera tunnel incisions with the method of phacoemusification, followed by the implantation of a PMMA introcular lens through the incision that was enlarged. Then, all the patients were randomly divided into two groups. In group A （ containing 19 patients with 20 eyes operated）, the lower lip of the incision was gently pressed with a iris spade to let aqueous humor out so that a flat anterior chamber was formed. Then the incision was restored by massaging on it from corneal side to sclera side. Finally, bulbar conjunctiva was recovered, Dexamethasone and Gentamycin were injected into sub bulbar conjunctiva. In group B （containing 17 patients with 20 eyes operated）, the anterior chamber was maintained when the I/A tip was withdrawn at the injecting phase, then the bulbar conjunctiva was recovered and the remaining maneuvers were the same as that in group A. Results One week after the surgery, 13 eyes （65%） in group A gained UCVA .≥20/40, comparing only 6 eyes （30%） in group B for such vision（ P 〈0.05, X^2 test）. A significant change in vertical curvature was found in group B after the surgery （ P 〈 0.05）, while this change in group A was not significant, resulting in a significant post-surgery difference in this curvature between the two groups （ P 〈 0.05）. However, there was no significant change in horizontal curvature after the surgery, neither the significant difference between the groups. The vertical curvature change in group B appeared to be temporary and was totally recovered one month after the surgery. At this time, 14 eyes （70%）in group A showed UCVA≥20/20, which was higher than that in group B （11 eyes, 55% ）. Conclusions Allowing the anterior chamber to be flattened and restoring the incision before the ending of the surgery could help both lips of the incision move to the original location. This manipulation decreased the postoperative corneal astigmatism and resulted in quicker recovery of visual acuity.