SMILE术中角膜帽下地塞米松平衡液冲洗与否的早期临床观察

目的观察飞秒激光小切口角膜基质透镜取出术(SMILE)中角膜帽下地塞米松平衡液冲洗与否对术后视觉质量及角膜组织结构形态的影响。方法选择拟进行双眼SMILE手术的24例(48眼)纳入研究,每例患者随机选取一眼透镜取出后,行地塞米松平衡液冲洗角膜帽下基质腔隙(实验组),对侧眼不冲洗(对照组)。分别于术后第1天、第7天及1个月对比观察两组的裸眼视力、屈光状态、角膜中央厚度(CCT)、眼压(NCT);同时利用共焦显微镜及前段光学相干断层扫描(OCT)检查对比观察两组角膜上皮细胞、神经纤维、基质细胞、内皮细胞形态结构。采用配对t检验比较两组的裸眼视力、屈光状态等各指标有无差异。结果术后第1天、第7天及1个月两组间裸眼视力比较:实验组为4.99±0.07、5.06±0.08、5.05±0.06;对照组为5.01±0.07、5.05±0.08、5.06±0.09;3个时间点两组间裸眼视力均无统计学差异(P均>0.05);术后第1天、第7天及1个月的屈光度(SE,D):实验组为0.03±0.49、0.1±0.37、0.02±0.4;对照组为0.09±0.54、0.19±0.48、0±0.52,3个时间点两组间SE比较均无统计学差异(P均>0.05)。共焦镜检查不同时间点比较:角膜上皮层细胞密度术前(4578.73±268.40,4539.57±329.25)个/mm^2,术后第1天(4565.21±247.31,4627.23±271.03)个/mm^2,术后第7天(4640.01±246.79,4517.71±281.43)个/mm^2];角膜内皮细胞密度术前(2541.50±259.59,2443.52±305.58)个/mm^2,术后第1天(2387.01±248.55,2495.27±238.52)个/mm^2,术后第7天(2484.49±223.71,2482.53±323.82)个/mm^2],术前术后两组间均无统计学差异(P>0.05);角膜上皮下神经纤维丛术前术后两组间比较无明显变化;切削界面高反光物两组间比较没有明显差异;角膜前基质细胞密度术前(789.51±67.17,802.03±67.94)个/mm^2,术后第1天(889.37±60.62,912.27±95.87)个/mm^2,术后第7天(796.67±75.03,818.39±59.65)个/mm^2]在术后第1天、第7天较术前均有增加,但两组之间没有统计学差异(P>0.05),术后1 d两组前基质细胞较术前增加,有统计学差异(P<0.05);角膜后基质细胞术后各时间点两组间比较无统计学差异(P>0.05)。角膜OCT在术后1 d、7 d两组在角膜帽下均未出现明显层间间隙和积液,两组间角膜中央厚度无统计学差异(P>0.05)。结论SMILE术中地塞米松平衡液角膜帽下冲洗对术后裸眼视力、屈光度及角膜组织结构形态无明显影响。

Early clinical observations of intraoperative corneal stromal pocket irrigation with dexamethasone in small incision lenticule extraction

Objective This study aimed to evaluate the postoperative vision recovery and corneal morphological changes after corneal stroma pocket irrigation with dexamethasone during Small Incision Lenticule Extraction(SMILE). Methods This was a prospective case-control study, which included 48 eyes from 24 patients who underwent SMILE. One eye from each case was randomly selected to have corneal pocket irrigation with dexamethasone(experimental group, EG), while the other eye did not undergo irrigation(control group, CG). The morphological changes of the cornea were observed using in vivo confocal microscopy and anterior segment optical coherence tomography(OCT), 1 day and 7 days after surgery. The uncorrected visual acuity(UCVA), spherical equivalent(SE), corneal center thickness(CCT), and non-contact tension(NCT)values between the groups were compared 1 day, 7 days, and 1 month after surgery. Results No significant differences were observed in the UCVA(EG: 4.99±0.07,5.06±0.08, 5.05±0.06; CG:5.01±0.07, 5.05±0.08, 5.06±0.09, P>0.05)and SE between the two groups(EG: 0.03±0.49, 0.1±0.37, 0.02±0.4; CG: 0.09±0.54, 0.19±0.48, 0±0.52)the same day as the procedure, and 1 day, 7 days, and 1 month after surgery, p>0.05. The two groups were compared at the same time, 1 day and 7 days before and after SMILE using confocal microscopy and anterior segment OCT. The cell shape, density, cell size and arrangement of the corneal epithelium［pre-operation(4 578.73±268.40, 4 539.57±329.25)cell/mm², post-1d(4 565.21±247.31, 4 627.23±271.03)cell/mm², post-7d(4 640.01±246.79, 4 517.71±281.43)cell/mm²］ and endothelium ［pre-(2541.50±259.59, 2 443.52±305.58)cell/mm², post-1d(2 387.01±248.55, 2 495.27±238.52)cell/mm², post-7d(2 484.49±223.71, 2 482.53±323.82)cell/mm²］ were not significantly different (P>0.05). There were no significant differences observed in the corneal sub-epithelial nerve fibers. The degree of active corneal stromal cells near the cutting interface was similar between the groups, without any significant differences. Regarding the density of the corneal superficial-stromal cells ［pre-(789.51±67.17, 802.03±6 794)cell/mm², post- 1d(889.37±60.62, 912.27±95.87)cell/mm², post-7d(96.67±75.03, 818.39±59.65)cell/mm² ］, both groups revealed no significant difference pre- or post-operation. However, a significant difference (P<0.05) was observed after SMILE in both groups between the day immediately before and after the procedure. Both groups revealed no significant differences regarding the density of the deep stromal cells. Comparisons of the preoperative and postoperative anterior segment OCT show no obvious inter-lamellar space and effusion in the corneal stromal pocket in the two groups. There was no significant difference in the CCT between the groups (P>0.05). Conclusion Irrigation with dexamethasone in the corneal stromal pocket during SMILE did not have a significant effect on postoperative UCVA, SE, and corneal morphological changes after surgery.