Abstract:

Objective　To explore the differences in visual quality, dry eye parameters, and corneal biomechanics after femtosecond laser keratomileusis (FS-LASIK) and femtosecond laser small incision stroma lens extraction (SMILE). Methods　This study retrospectively selected 50 patients (100 eyes) with myopia and astigmatism who visited the Ophthalmology Refractive Center of the First Affiliated Hospital of Xi'an Medical University from January 2021 to January 2024. These patients were divided into a SMILE group and a FS-LASIK group, with 25 cases (50 eyes) in each group according to the surgical methods. In the SMILE group, there were 11 males and 14 females; the age ranged from 18 to 49 (26.84±7.57) years old; the preoperative spherical equivalent (SE) was (-5.42±1.51) D; the preoperative corneal resistance factor (CRF) was (9.56±1.67) mmHg (1 mmHg = 0.133 kPa); the preoperative corneal hysteresis (CH) was (9.61±1.42) mmHg. In the FS-LASIK group, there were 10 males and 15 females; the age ranged from 19 to 47 (26.56±7.68) years old; the preoperative SE was (-5.51±1.62) D; the preoperative CRF was (9.54±1.64) mmHg; the preoperative CH was (9.59±1.45) mmHg. The follow-up time points were 1 week, 1 month, 3 months, and 6 months after surgery. The visual quality (naked vision, SE, total high-order aberrations, and visual quality scale score), dry eye parameters [tear meniscus height and tear film break-up time (TBUT)], and corneal biomechanics [change in corneal resistance factor (ΔCRF) and change in corneal hysteresis (ΔCH)] were compared between the two groups at different time points. Statistical analysis was conducted using the χ² test, t test, and repeated measures analysis of variance. Results　①Repeated measures analysis of variance showed that the differences in time point effects of the comparison of naked eyesight, SE, and total high-order aberration between the two groups were statistically significant (F _{time point} =261.094, 221.946, and 35.371, all P<0.05); one week after surgery, the naked eye visual acuity (-0.01±0.03) and SE [(-0.24±0.29) D] in the FS-LASIK group were better than those in the SMILE group [0.03±0.01 and (-0.33±0.31) D] (both P<0.05). ②Repeated measures analysis of variance showed that the differences in time point effects of the comparison of the two groups of tear meniscus height and TBUT (F _{time point} = 27.699 and 5.251), between group effects (F _{between groups} = 21.767 and 9.314), and interaction effects (F _interaction = 3.832 and 3.651) were statistically significant (all P<0.05); the tear meniscus height [(0.27±0.04) mm and (0.28±0.03) mm] and TBUT [(12.81±3.51) s and (13.15±4.06) s] of the SMILE group were higher than those of the FS-LASIK group at 3 and 6 months after surgery [tear meniscus height: (0.23±0.05) mm and (0.24±0.03) mm, and TBUT: (10.95±3.69) s and (11.13±3.78) s], with statistically significant differences (all P<0.05). ③Repeated measures analysis of variance showed that ΔCH and ΔCRF of the two groups had an inter-group effect (F _{between groups} =92.007 and 37.760, both P<0.05); the ΔCH [(1.39±0.42), (1.25±0.38), (1.29±0.35), and (1.32±0.31) mmHg] and ΔCRF [(2.58±0.87), (2.37±0.91), (2.41±0.88), and (2.39±0.79) mmHg] in the SMILE group at 1 week, 1 month, 3 months, and 6 months after surgery were all smaller than those in the FS-LASIK group [ΔCH: (1.76±0.61), (1.73±0.58), (1.87±0.56), and (1.89±0.61) mmHg, ΔCRF: (2.94±0.89), (2.93±0.84), (3.01±0.95), and (2.98±0.81) mmHg] (all P<0.05). Conclusions　The visual quality recovery of SMILE and FS-LASIK is equivalent, and the dry eye parameters have different degrees of decline compared with preoperatively, which affect the corneal biomechanical stability; while the early visual quality recovery of SMILE is slower than that of FS-LASIK. However, 3 months and 6 months after SMILE, the dry eye parameters are better than FS-LASIK, and SMILE has a smaller effect on corneal biomechanics.

Key words:

Femtosecond laser keratomileusis, Femtosecond laser small incision stroma lens extraction, Visual quality, Dry eye parameters,  , Corneal biomechanics

摘要：

目的　探讨飞秒激光制瓣的准分子激光原位角膜磨镶术（FS-LASIK）、飞秒激光小切口角膜基质透镜取出术（SMILE）术后视觉质量、干眼参数及角膜生物力学的差异。方法　本研究回顾性选取2021年1月至2024年1月就诊于西安医学院第一附属医院眼科屈光中心的近视散光患者50例（100只眼），根据手术方式分为SMILE组、FS-LASIK组各25例（50只眼）。SMILE组男11例，女14例；年龄18~49（26.84±7.57）岁；术前等效球镜屈光度（SE）为（-5.42±1.51）D；术前角膜阻力因子（corneal resistance factor，CRF）为（9.56±1.67）mmHg（1 mmHg=0.133 kPa）；术前角膜滞后值（corneal hysteresis，CH）为（9.61±1.42）mmHg。FS-LASIK组男10例，女15例；年龄19~47（26.56±7.68）岁；术前SE为（-5.51±1.62）D；术前CRF为（9.54±1.64）mmHg；术前CH为（9.59±1.45）mmHg。随访时间为术后1周、1个月、3个月、6个月，比较两组不同时间点的视觉质量（裸眼视力、SE、总高阶像差、视觉质量量表评分）、干眼参数［泪河高度、泪膜破裂时间（TBUT）］、角膜生物力学［角膜阻力因子变化量（ΔCRF）、角膜滞后值变化量（ΔCH）］。采用χ²检验、t检验、重复测量方差分析进行统计学分析。结果　①重复测量方差分析显示，两组裸眼视力、SE、总高阶像差比较的时点效应差异均有统计学意义（F_时点=261.094、221.946、35.371，均P<0.05）；FS-LASIK组术后1周的裸眼视力（-0.01±0.03）、SE［（-0.24±0.29）D］优于SMILE组［0.03±0.01、（-0.33±0.31）D］（均P<0.05）。②重复测量方差分析显示，两组泪河高度、TBUT比较的时点效应（F_时点=27.699、5.251）、组间效应（F_组间=21.767、9.314）、交互效应（F_交互=3.832、3.651）差异均有统计学意义（均P<0.05）；SMILE组术后3个月、6个月的泪河高度［（0.27±0.04）mm、（0.28±0.03）mm］、TBUT［（12.81±3.51）s、（13.15±4.06）s］高于FS-LASIK组［泪河高度：（0.23±0.05）mm、（0.24±0.03）mm，TBUT：（10.95±3.69）s、（11.13±3.78）s］，差异均有统计学意义（均P<0.05）。③重复测量方差分析显示，两组ΔCH、ΔCRF比较的组间效应差异均有统计学意义（F_组间=92.007、37.760，均P<0.05）；SMILE组术后1周、1个月、3个月、6个月的ΔCH［（1.39±0.42）、（1.25±0.38）、（1.29±0.35）、（1.32±0.31）mmHg］、ΔCRF［（2.58±0.87）、（2.37±0.91）、（2.41±0.88）、（2.39±0.79）mmHg］均小于FS-LASIK组［ΔCH：（1.76±0.61）、（1.73±0.58）、（1.87±0.56）、（1.89±0.61）mmHg，ΔCRF：（2.94±0.89）、（2.93±0.84）、（3.01±0.95）、（2.98±0.81）mmHg］（均P<0.05）。结论　SMILE与FS-LASIK术后视觉质量恢复相当、干眼参数较术前有不同程度下降、影响角膜生物力学稳定性；SMILE术后早期视觉质量恢复比FS-LASIK慢，但SMILE术后3个月、6个月干眼参数优于FS-LASIK，SMILE对角膜生物力学的影响更小。

关键词:

飞秒激光制瓣的准分子激光原位角膜磨镶术, 飞秒激光小切口角膜基质透镜取出术, 视觉质量, 干眼参数, 角膜生物力学