Corneal biomechanical change assessment using biomechanical waveform analyzer parameters: Contralateral comparison of eyes having femtosecond lenticule extraction and small-incision lenticule extraction for moderate to high myopia
Abstract:We report the first paired-eye study to directly compare Ocular Response Analyzer (ORA) derived corneal waveform parameters after the two all-femtosecond laser refractive techniques, ReLEx FLEX (FLEX) and ReLEx SMILE (SMILE). A total of 34 patients, treated with FLEX in one eye, and SMILE in the other for moderate to high myopia, were examined before and 6 months after surgery. Overall, the 37 corneal waveform parameters from the ORA were not able to detect any major differences in corneal biomechanical proper… Show more
“…Four studies included FLEX as a comparison treatment [45, 46, 48, 49]. In those four studies, the flap thickness was between 100 to 120 μ m with 7.5 to 7.9 mm in diameter and the diameter of lenticule was between 6 to 6.5 mm.…”
Section: Resultsmentioning
confidence: 99%
“…In the subgroup analysis which included only the RCT studies of Vetergaard et al and Kamiya et al, the difference of Hedges’ g was − 0.04 (95% CI, − 0.54 to 0.47; p = 0.882; I 2 = 55%). In 2019, Vestergaard et al used the data from the same cohort to obtain the new parameters of ORA [46]. No differences between SMILE and FLEX were found in the majority of 37 outcomes except that w11 slightly favoured FLEX.Fig.…”
Background
The aim of this study was to compare the postoperative corneal biomechanical properties between small incision lenticule extraction (SMILE) and other corneal refractive surgeries.
Methods
A systematic review and meta-analysis were conducted. Articles from January 2005, to April 2019, were identified searching PubMed, EMBASE, Web of Science, and International Clinical Trials Registry Platform. Studies that compared SMILE with other corneal refractive surgeries on adult myopia patients and evaluated corneal biomechanics were included. Multiple effect sizes in each study were combined. Random-effects model was conducted in the meta-analysis.
Results
Twenty-two studies were included: 5 randomized controlled trials (RCTs), 9 prospective and 6 retrospective cohort studies, and 2 cross-sectional studies. Using the combined effect of corneal hysteresis (CH) and corneal resistance factor (CRF), which were obtained from ocular response analyzer (ORA), the pooled Hedges’ g of SMILE versus femtosecond laser-assisted in situ keratomileusis (FS-LASIK) was 0.41 (95% CI, 0.00 to 0.81;
p
= 0.049; I
2
= 78%), versus LASIK was 1.31 (95% CI, 0.54 to 2.08;
p
< 0.001; I
2
= 77%), versus femtosecond lenticule extraction (FLEX) was − 0.01 (95% CI, − 0.31 to 0.30;
p
= 0.972; I
2
= 20%), and versus the group of photorefractive keratectomy (PRK) and laser-assisted sub-epithelial keratectomy (LASEK) was − 0.26 (95% CI, − 0.67 to 0.16;
p
= 0.230; I
2
= 54%). The summary score of Corvis ST (CST) after SMILE was comparable to FS-LASIK/LASIK with the pooled Hedges’ g = − 0.05 (95% CI, − 0.24 to 0.14;
p
= 0.612, I
2
= 55%).
Conclusions
In terms of preserving corneal biomechanical strength after surgeries, SMILE was superior to either FS-LASIK or LASIK, while comparable to FLEX or PRK/LASEK group based on the results from ORA. More studies are needed to apply CST on evaluating corneal biomechanics after refractive surgeries.
Electronic supplementary material
The online version of this article (10.1186/s12886-019-1165-3) contains supplementary material, which is available to authorized users.
“…Four studies included FLEX as a comparison treatment [45, 46, 48, 49]. In those four studies, the flap thickness was between 100 to 120 μ m with 7.5 to 7.9 mm in diameter and the diameter of lenticule was between 6 to 6.5 mm.…”
Section: Resultsmentioning
confidence: 99%
“…In the subgroup analysis which included only the RCT studies of Vetergaard et al and Kamiya et al, the difference of Hedges’ g was − 0.04 (95% CI, − 0.54 to 0.47; p = 0.882; I 2 = 55%). In 2019, Vestergaard et al used the data from the same cohort to obtain the new parameters of ORA [46]. No differences between SMILE and FLEX were found in the majority of 37 outcomes except that w11 slightly favoured FLEX.Fig.…”
Background
The aim of this study was to compare the postoperative corneal biomechanical properties between small incision lenticule extraction (SMILE) and other corneal refractive surgeries.
Methods
A systematic review and meta-analysis were conducted. Articles from January 2005, to April 2019, were identified searching PubMed, EMBASE, Web of Science, and International Clinical Trials Registry Platform. Studies that compared SMILE with other corneal refractive surgeries on adult myopia patients and evaluated corneal biomechanics were included. Multiple effect sizes in each study were combined. Random-effects model was conducted in the meta-analysis.
Results
Twenty-two studies were included: 5 randomized controlled trials (RCTs), 9 prospective and 6 retrospective cohort studies, and 2 cross-sectional studies. Using the combined effect of corneal hysteresis (CH) and corneal resistance factor (CRF), which were obtained from ocular response analyzer (ORA), the pooled Hedges’ g of SMILE versus femtosecond laser-assisted in situ keratomileusis (FS-LASIK) was 0.41 (95% CI, 0.00 to 0.81;
p
= 0.049; I
2
= 78%), versus LASIK was 1.31 (95% CI, 0.54 to 2.08;
p
< 0.001; I
2
= 77%), versus femtosecond lenticule extraction (FLEX) was − 0.01 (95% CI, − 0.31 to 0.30;
p
= 0.972; I
2
= 20%), and versus the group of photorefractive keratectomy (PRK) and laser-assisted sub-epithelial keratectomy (LASEK) was − 0.26 (95% CI, − 0.67 to 0.16;
p
= 0.230; I
2
= 54%). The summary score of Corvis ST (CST) after SMILE was comparable to FS-LASIK/LASIK with the pooled Hedges’ g = − 0.05 (95% CI, − 0.24 to 0.14;
p
= 0.612, I
2
= 55%).
Conclusions
In terms of preserving corneal biomechanical strength after surgeries, SMILE was superior to either FS-LASIK or LASIK, while comparable to FLEX or PRK/LASEK group based on the results from ORA. More studies are needed to apply CST on evaluating corneal biomechanics after refractive surgeries.
Electronic supplementary material
The online version of this article (10.1186/s12886-019-1165-3) contains supplementary material, which is available to authorized users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
