Intra-Operative Cap Repositioning in Small Incision Lenticule Extraction (SMILE) for Enhanced Visual Recovery

Three-Month Clinical Outcomes to Correct Myopia or Myopic Astigmatism Using a Femtosecond Laser for Lenticule Creation With Automated Centration and Cyclotorsion Compensation

PURPOSE

To individually evaluate the clinical outcomes for right and left eyes in the first 3 months after laser-assisted lenticule extraction for myopia and myopic astigmatism with the use of the new ATOS femtosecond laser system (Smart-Sight; SCHWIND eye-tech-solutions).

METHODS

A total of 331 eyes from 168 patients (166 right eyes and 165 left eyes) consecutively treated with SmartSight lenticule extraction were retrospective analyzed after a 3-month follow-up period. Patients' mean age was 26 ± 6 years (range: 18 to 47 years) and mean preoperative spherical equivalent (SEQ) was -5.07 ± 1.92 diopters [D] (range: -1.50 to -11.25 D) with a mean astigmatism of -1.04 ± 0.85 D (range: 0.00 to -4.00 D). At 3 months of follow-up, visual acuity, SEQ and cylinder, safety index, efficacy index, corneal higher order aberrations, and intraocular pressure (IOP) were analyzed. Furthermore, refractive and visual outcomes were also analyzed for the right and left eyes individually. All lenticule extraction treatments were performed with the SmartSight treatment method of the SCHWIND ATOS femtosecond laser.

RESULTS

At 3 months after surgery, mean SEQ was -0.12 ± 0.19 D and 98% of eyes were within ±0.50 D of the SEQ. All eyes were within ±1.00 D of the SEQ. Astigmatism of 0.50 D or less was achieved in 99% of eyes. The change in Snellen lines (difference between preoperative corrected distance visual acuity and postoperative uncorrected distance visual acuity) showed a gain of one or more lines in 13% and in 85% of the eyes the same was achieved. There was a loss of one or more lines at 3 months of follow-up in 1.6%. The safety index was 1.03 and efficacy index was 1.02. No significant difference between the right and left eyes was found.

CONCLUSIONS

The 3-month follow-up data show that SmartSight treatment for correction of myopia and myopic astigmatism with the SCHWIND ATOS is a safe, efficient, and accurate procedure. It provided excellent results in terms of visual recovery, predictability, and higher order aberrations. [J Refract Surg. 2024;40(1):e30-e41.].

First European results of a new refractive lenticular extraction procedure-SmartSight by SCHWIND eye-tech-solutions

BACKGROUND

To evaluate vision 3 months after SmartSight lenticule extraction treatments.

DESIGN

Case series.

METHODS

This case series of patients were treated at Specialty Eye Hospital Svjetlost in Zagreb, Croatia. Sixty eyes of 31 patients consecutively treated with SmartSight lenticule extraction were assessed. The mean age of the patients was 33 ± 6 years (range 23-45 years) at the time of treatment with a mean spherical equivalent refraction of -5.10 ± 1.35 D and mean astigmatism of 0.46 ± 0.36 D. Monocular corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA) were assessed pre- and post-operatively. Ocular and corneal wavefront aberrations have been postoperatively compared to the preoperative baseline values. Changes in ocular wavefront refraction, as well as changes in keratometric readings are reported.

RESULTS

At 3 months post-operatively, mean UDVA was 20/20 ± 2. Spherical equivalent showed a low myopic residual refraction of -0.37 ± 0.58 D with refractive astigmatism of 0.46 ± 0.26 D postoperatively. There was a slight improvement of 0.1 Snellen lines at 3-months follow-up. Compared to the preoperative status, ocular aberrations (at 6 mm diameter) did not change at 3 months follow-up; whereas corneal aberrations increased (+0.22 ± 0.21 µm for coma; +0.17 ± 0.19 µm for spherical aberration; and +0.32 ± 0.26 µm for HOA-RMS). The same correction was determined using changes in ocular wavefront refraction, as well as changes in keratometric readings.

CONCLUSION

Lenticule extraction after SmartSight is safe and efficacious in the first 3 months postoperatively. The post-operative outcomes indicate improvements in vision.

A Literature Review of the Incidence, Management, and Prognosis of Corneal Epithelial-Related Complications After Laser-Assisted In Situ Keratomileusis (LASIK), Photorefractive Keratectomy (PRK), and Small Incision Lenticule Extraction (SMILE)

Our purpose is to provide a comprehensive investigation into the incidence, treatment modalities, and visual prognosis of epithelial-related complications in corneal refractive surgeries, including laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE). A systematic search of multiple databases was conducted by two independent examiners using various search terms related to epithelial-related complications and corneal refractive surgeries. A total of 91 research articles were included, encompassing a sample size of 66,751 eyes across the three types of surgeries. The average incidence of epithelial-related complications varied across the different types of corneal refractive surgeries. LASIK had an average incidence of 4.9% for epithelial defects, while PRK and SMILE had lower rates of 3.3% and 3.9%, respectively. Our findings indicate that SMILE has a lower incidence of epithelial defects compared to LASIK, potentially due to the less invasive nature of lenticule incision in SMILE. Visual prognosis after epithelial complications (EC) is generally favorable, with various supportive care and surgical interventions leading to significant improvements in postoperative visual acuity and full recovery. Understanding the incidence rates and management approaches for epithelial-related complications can guide clinicians in enhancing patient safety, refining surgical techniques, and optimizing postoperative outcomes in corneal refractive surgeries.

Comparing high and low energy outcomes on day one for SmartSight myopic-astigmatism treatments with the SCHWIND ATOS: a retrospective case series

BACKGROUND

Impact of low energy asymmetric spacings vs. high energy symmetric spacings on the immediate/early (postoperative day 1 (POD1)) outcomes of SmartSight lenticule extraction for myopic astigmatism with a new femtosecond laser system.

METHODS

The first 112 eyes of 56 patients consecutively treated using low energy asymmetric spacings (Group A; Study group) were compared at POD1 to the last 112 eyes of 56 patients consecutively treated using high energy symmetric spacings (Group S; Controls). Mean age of the patients was 28 ± 5 years with a mean spherical equivalent of -4.41 ± 1.76 diopters (D) and a mean magnitude of refractive astigmatism of 0.89 ± 0.82 D.

RESULTS

Laser Energy was -25 ± 1nJ lower for asymmetric treatments (p < .0001); Spot and Track distances were + 0.7 ± 0.1 µm larger and -0.8 ± 0.1 µm tighter for asymmetric treatments, respectively (p < .0001 for both). At POD1, astigmatism was -0.08 ± 0.02D lower for asymmetric treatments (p < .0003); uncorrected and corrected visual acuities (UDVA and CDVA, respectively) were -0.03 ± 0.01logMAR better for asymmetric treatments (p < .0007); differences between postop UDVA and preop CDVA along with change in CDVA were + 0.3 ± 0.1lines better for asymmetric treatments (p < .0003).

CONCLUSIONS

Lenticule extraction treatment using SmartSight is safe and efficacious already at POD1. Findings suggest that low energy asymmetric spacings may further improve the immediate and short-term outcomes of SmartSight lenticule extraction in the treatment of myopic astigmatism compared to conventional settings (high energy symmetric spacings).

Twelve-month outcomes of a new refractive lenticular extraction procedure

BACKGROUND

To evaluate the 12-month refractive and visual outcomes of Small Incision Guided Human-cornea Treatment (SmartSight®, SCHWIND eye-tech-solutions, Kleinostheim, Germany) in the treatment of myopia corrections with low to moderate astigmatism with the use of a new femtosecond laser system.

METHODS

221 eyes of 114 patients consecutively treated with SmartSight lenticule extraction were assessed. The mean age of the patients was 28±6 years at the time of treatment with a mean spherical equivalent refraction of -6.26±2.17D and mean astigmatism of 0.92±0.68D. Monocular corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA) were assessed pre- and post-operatively. Refractive changes have been determined in terms of changes in refraction, as well as changes in keratometric readings. The changes in central epithelial thickness have been determined.

RESULTS

At twelve months post-operatively, mean UDVA was 20/21±2. Spherical equivalent showed a residual refraction of +0.48±0.31D with refractive astigmatism of 0.13±0.18D postoperatively. There was a slight decrease of -0.1 Snellen lines at 12-months follow-up. The same correction was determined using changes in refraction, as well as changes in keratometric readings. The central epithelial thickness increased by +3±2µm. Spherical equivalent correction within ±0.50D was achieved in 199 eyes (90%), and cylindrical correction in 221 (100%). Preoperative corrected distance visual acuity (CDVA) was 20/20 or better in 213 eyes (96%), and postoperative uncorrected (UDVA) was 20/20 or better in 205 eyes (93%). No eye had lost two or more Snellen lines of CDVA.

CONCLUSIONS

Myopic astigmatism correction with SmartSight provided good results for efficacy, safety, predictability, and visual outcomes at the twelve months of follow up. The central epithelial thickness barely increased by 3±2µm.

Epi-Bowman keratectomy versus alcohol-assisted photorefractive keratectomy: wound healing and complications

Purpose

In Epi-Bowman Keratectomy™ (EBK), a new dynamic multi-blade single-use device (Epi-Clear™, Orca Surgical, Israel) is utilized to remove the epithelium by sweeping movements across the corneal surface. Epithelial cells are discarded. Alcohol or other chemical agents are not utilized. We wanted to compare clinical results of Epi-Clear photorefractive kertectomy (PRK) to alcohol-assisted PRK.

Study design

Retrospective, comparative study.

Methods

Consecutive case series: Adult patients seeking laser vision correction of myopia or myopic astigmatism without ocular diseases or prior surgery were included. The Epi-Clear PRK group comprised 50 consecutive eyes of 27 patients and the PRK group 50 eyes of 25 patients.

Results

No intraoperative complications occurred. Epi-Clear PRK: At day 1, day 4, and 3 months, uncorrected distance visual acuity (UDVA) was 0.41/0.47/0.93 (decimal scale); epithelial defect diameter was 4.7/0.2/0 (mm); pain level was 3.8/0.3/0 (visual analogue scale, 0-10), respectively. At 3 months, efficacy index was 0.86 and spherical aberrations were unchanged. Three eyes (6%) showed (presumably sterile) infiltrates. PRK: At day 1, day 4, and 3 months, UDVA was 0.56/0.46/1.15; epithelial defect diameter was 6.3/0.2/0 (mm); pain level was 5.0/0.3/0, respectively. At 3 months, efficacy index was 1.1 and spherical aberrations were unchanged.

Conclusion

The new method of epithelial debridement with Epi-Clear before laser ablation seems to offer fast epithelial removal without nicking Bowman's layer (as observed with the laser microscope). However, we found significantly inferior results of Epi-Clear PRK compared to alcohol-assisted PRK. Furthermore, after Epi-Clear PRK corneal infiltrates as a new type of postoperative complication were observed.

Complications of small incision lenticule extraction

The procedure of small incision lenticule extraction (SMILE) was introduced in 2011, and since then there has been an increase in the number of cases undergoing this procedure worldwide. The surgery has a learning curve and may be associated with problems in the intraoperative and postoperative periods. The intraoperative problems during SMILE surgery include the loss of suction, the occurrence of altered or irregular opaque bubble layer and black spots, difficulty in lenticular dissection and extraction, cap perforation, incision-related problems, and decentered ablation. Most of the postoperative problems are similar as in other laser refractive procedures, but with decreased incidence. The identification of risk factors, clinical features, and management of complications of SMILE help to obtain optimum refractive outcomes.

Visual recovery after small incision lenticule extraction (SMILE) in relation to pre-operative spherical equivalent

PURPOSE

To assess visual recovery after small incision lenticule extraction (SMILE) in relation to pre-operative spherical equivalent.

METHODS

Two hundred fourteen eyes of 107 patients were enrolled. Following surgery, patients were examined pre-operatively, 1 day, 2 weeks, 1 month and 3 months later. High myopia was defined as pre-operative spherical equivalent ≤ - 5 D. A linear mixed-effects model was used.

RESULTS

Mean ± standard deviation pre-operative spherical equivalent was - 5.30 ± 1.36 D that reduced significantly to 0.04 ± 0.70 D (p < 0.001) at 1 month and - 0.02 ± 0.66 D (p < 0.001) at 3 months. Mean pre-operative LogMAR uncorrected distance visual acuity ± SD was 0.97 ± 0.09 that improved significantly to 0.04 ± 0.06 at 2 weeks (p < 0.001), 0.01 ± 0.04 at 1 month (p < 0.001) and 0.01 ± 0.04 at 3 months (p < 0.001). Eighty-eight eyes (41.2%) had uncorrected distance visual acuities of 0.0 at 1 day, 154 eyes (72.0%) at 2 weeks,194 eyes (90.7%) at 1 month and 199 eyes (93.0%) at 3 months. Significantly more eyes with low myopia (> - 5 D) achieved acuities of 0.0 at 1 day and 2 weeks (p = 0.041 and p < 0.001). Post-operative acuities were not associated with refractive targets, laser cut energy settings or other variables. Two hundred nine eyes (97.7%) were within ± 0.5 D of target and 213 eyes (99.5%) were within ± 1 D.

CONCLUSIONS

SMILE for low myopia had faster visual recovery in the early post-operative period with no significant differences between groups detected by 1 and 3 months.

Small incision lenticule extraction (SMILE) lenticule thickness readout compared to change in axial length measurements with the IOLMaster

PURPOSE

To compare theoretical values from the small incision lenticule extraction (SMILE) lenticule thickness readout with change in axial length measurements taken with the IOLMaster.

METHODS

We prospectively studied 214 eyes from 107 patients undergoing bilateral SMILE surgery for myopia or myopic astigmatism between December 2014 and May 2017 at an ophthalmological practice in Singapore. All eyes were examined pre-operatively and 1 and 3 months post-operatively with the IOLMaster following SMILE surgery. Achieved lenticule thickness was taken as the change in axial length after surgery. A linear mixed-effects model was used to examine changes in axial length, spherical equivalent and acuity over time. The relationships between change in axial length and theoretical lenticule thickness and spherical equivalent were examined with multiple linear regression analyses, and model prediction was assessed with adjusted R² statistics.

RESULTS

Mean (95% confidence interval [CI]) spherical equivalent pre-operatively was - 5.25 (95% CI - 5.38 to - 5.12) diopters (D), at 1 month was 0.04 (95% CI - 0.09 to 0.17) D (p < 0.001), and at 3 months was - 0.02 (95% CI - 0.15 to 0.11) D (p < 0.001). Mean (95% CI) pre-operative axial length was 27,726 (95% CI 25,595 to 25,857) μm. Post-operative axial length at 1 month was significantly shorter at 25,595 (95% CI 25,464 to 25,726) μm (p < 0.001) with no change thereafter (p = 0.647). Pre-operative mean ± standard deviation (SD) refractive target was 0.24 (± 0.3) D, and mean difference between target and post-operative spherical equivalent at 1 month was 0.20 D (95% CI 0.16 to 0.25 D, p < 0.001). Multiple regression analysis showed that change in axial length at 1 month was, on average, 5% lower than theoretical lenticule thickness, indicating an average difference of 5.4 μm (95% CI 5.2 to 5.6 μm). Preoperative spherical equivalent predicted negative association with change in axial length at 1 month (β = - 14.8, 95% CI - 18.2 to - 11.3, adjusted R² = 0.457, p < 0.001).

CONCLUSIONS

Calculated lenticule thickness values were less than expected, and post-operative refractive outcomes at 1 month showed a slight under-correction. Further research in this area is needed to validate these findings.

Small Incision Lenticule Extraction for Hyperopia: 3-Month Refractive and Visual Outcomes

PURPOSE

To evaluate visual and refractive outcomes of small incision lenticule extraction (SMILE) for hyperopia.

METHODS

This prospective study of vertex-centered hyperopic SMILE used the VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany). Inclusion criteria were maximum attempted hyperopic meridian of between +1.00 and +7.00 diopters (D) and corrected distance visual acuity (CDVA) of 20/40 or better. Lenticule parameters were 6.3- to 6.7-mm diameter, 2-mm transition zone, 30-µm minimum thickness, and 120-µm cap thickness. Standard outcomes analysis was performed for the 3-month data, including contrast sensitivity using the Functional Vision Analyzer.

RESULTS

For 93 eyes treated, 3-month data were available for 82 (88%). Attempted spherical equivalent refraction was +5.62 ± 1.20 D (range: +1.00 to +6.90 D) and cylinder was -0.91 ± 0.68 D (range: 0.00 to -3.50 D). For eyes targeted for emmetropia (n = 36), uncorrected distance visual acuity was 20/40 or better in 89%. Spherical equivalent refraction relative to target was -0.17 ± 0.85 D (range: -2.20 to +3.00 D), with 59% within ±0.50 D and 76% within ±1.00 D. There was one line loss of CDVA in 17% of eyes, and one eye lost three lines (1.2%) but recovered to one line lost at 9 months. There was no clinically significant change in contrast sensitivity.

CONCLUSIONS

Refractive and visual outcomes 3 months after SMILE for hyperopia were promising, given the high degree of hyperopia corrected and relatively reduced CDVA in this population. Undercorrection of more than 1.00 D in 5 eyes might be partly explained by latent hyperopia in these young patients. [J Refract Surg. 2019;35(1):24-30.].

Effect of the Learning Curve on Visual and Refractive Outcomes of Small-Incision Lenticule Extraction

PURPOSE

To investigate the effect of the learning curve for small-incision lenticule extraction during the first 2 years of experience.

METHODS

Small-incision lenticule extraction was performed using the 500-kHz VisuMax femtosecond laser (Carl Zeiss Meditec) by the same surgeon. The initial 100 patients since the surgeon started operating independently were considered as group 1; the recent 100 patients were considered as group 2. The same laser settings and technique were used. The visual and refractive outcomes were compared between groups at postoperative 1 week and 6 months. Vector analysis was performed for eyes with astigmatic correction.

RESULTS

Two hundred right eyes of 200 patients were included. Age, preoperative corrected visual acuity, manifest refraction, and central corneal thickness were similar between groups (P ≤ 0.154). Postoperatively, the efficacy index at 1 week was better in group 2 (group 1: 0.85 ± 0.16 vs. group 2: 0.91 ± 0.10, P = 0.019) but was similar between groups at 6 months (group 1: 0.91 ± 0.14 vs. group 2: 0.94 ± 0.08, P = 0.181). The safety index was higher in group 2 at 1 week (group 1: 0.93 ± 0.10 vs. group 2: 0.95 ± 0.08, P = 0.045) and 6 months postoperatively (group 1: 0.97 ± 0.07 vs. group 2: 0.99 ± 0.03, P = 0.011). Vector analysis showed that postoperative residual astigmatism and misalignment of astigmatic correction were lower in group 2 than in group 1 (P ≤ 0.039) at 1 week and 6 months. The duration of docking and that of lenticule extraction was shorter in group 2 (P ≤ 0.034).

CONCLUSIONS

Our study showed that faster visual recovery, better safety profile, and more accurate astigmatic correction could be attained with increasing surgical experience.

OCT layered tomography of the cornea provides new insights on remodeling after photorefractive keratectomy

OCT (optical coherence tomography) of corneal layers was generated to analyze the remodeling of the epithelium and stroma after photorefractive keratectomy (PRK). Myopic PRK was performed in 15 patients. One eye underwent manual scraping of epithelium while the other was treated with Epi clear. Epi clear allowed a gentler removal of the epithelium compared to manual scraping. Scheimpflug (Pentacam, OCULUS Optikgerate Gmbh, Wetzlar, Germany) and OCT (RTVue, Optovue Inc., Fremont, California, USA) scans of the cornea were performed before and after PRK (3 months). The OCT scanner and Pentacam acquired 8 and 25 radial 2-D scans of the cornea, respectively. The results showed similar topographic changes on the anterior corneal surface between Scheimpflug and OCT imaging. The curvature of the underlying anterior surface of the stroma after PRK was similar to the anterior corneal surface (air-epithelium interface), when measured with OCT. Aberrometric changes were mostly similar between Scheimpflug and OCT. However, Scheimpflug imaging reported greater changes in spherical aberration and corneal higher order aberrations than OCT after PRK. This is the first study to quantify the curvatures of the stromal layers with OCT after PRK. New insights were gained, which could be useful for refinement of surgical ablation algorithms, refractive procedures and detection of ectasia.

Interface healing and its correlation with visual recovery and quality of vision following small incision lenticule extraction

Purpose:

To study the time course of interface healing and its correlation with visual acuity, modulation transfer function (MTF), and aberrations after myopic small-incision lenticule extraction (SMILE) correction.

Methods:

Seventy-eight eyes of 78 patients (1 eye per patient) with a mean age of 25.7 years and mean spherical equivalent (SE) of −3.74D, undergoing bilateral SMILE procedure, were included in this study. On postoperative day 1, 2 weeks, and 3 months, dilated retroillumination photographs were taken and morphology of corneal interface was graded by comparing them with 5 standard templates representing 5 grades of interface roughness (IRG): IRG – 0 (clear), IRG – 1 (mild), IRG – 2 (moderate), IRG – 3 (severe), and IRG – 4 (severe IRG with Bowman's folds in visual axis). Pearson's correlations were computed to study correlation associations, and Wilcoxon signed-rank test was used for intragroup comparison of means. P ≤ 0.05 was considered statistically significant.

Results:

At 3 months, 90.70% eyes were Grade 0 while 9.30% eyes still had Grade 2 interface granularity. Mean IRG significantly improved from 2.47 ± 0.57 at day 1 to 0.62 ± 0.53 at 3 months (P = 0.00). At day 1, pre-SE showed a significant positive correlation with IRG; however, mean postoperative corrected distant visual acuity (CDVA, in decimal), corneal Strehl ratio (SR), and MTF showed weak but significant negative correlation with IRG (r² = 0.28 for SE, −0.052 for CDVA, −0.017 for SR, and −0.39 for MTF, respectively, P < 0.05 for all correlations). At 2 weeks and 3 months, corneal MTF continued to show a significant negative correlation, whereas other parameters did not show any correlation with IRG.

Conclusion:

Visual quality and corneal MTF may be significantly affected by the IRG in the immediate postoperative period after SMILE and may take 3 months or more for complete recovery.

Effect of Cap-Lenticule Diameter Difference on the Visual Outcome and Higher-Order Aberrations in SMILE: 0.4 mm versus 1.0 mm

Purpose

To evaluate the effect of cap-lenticule diameter difference (CLDD) on the visual outcome and higher-order aberrations (HOAs) of small-incision lenticule extraction (SMILE).

Methods

A total of 132 patients who had bilateral SMILE for myopia or myopic astigmatism were included. The CLDD was 0.4 mm in 54 patients (group 1) and 1.0 mm in 78 patients (group 2). The refractive parameters, uncorrected (UDVA) and corrected distance visual acuity (CDVA), and HOAs were determined preoperatively and during six months follow-up.

Results

Group 1 had better CDVA (in logMAR) compared to group 2 at day 1 (−0.07 ± 0.07 versus 0.04 ± 0.07, resp.; p < 0.001) and week 1 (−0.07 ± 0.07 versus –0.04 ± 0.07, resp.; p = 0.001). The visual acuity improved more in group 1 than in group 2. The UDVA (in logMAR) was 0.07 ± 0.07 and 0.29 ± 0.09 at day 1 (p < 0.001) and −0.08 ± 0.07 and −0.06 ± 0.06 at six months (p = 0.038) in group 1 and group 2, respectively. Group 1 was associated with significantly less induction of HOAs (0.24 ± 0.08 μm and 0.32 ± 0.26 μm, resp.; p = 0.002).

Conclusions

In SMILE, 0.4 mm CLDD is associated with better visual outcome and less induction of HOAs than 1.0 mm. Narrow CLDD should be considered in SMILE to increase the visual acuity particularly in the early postoperative period.

Cap Lenticular Adhesion During Small Incision Lenticular Extraction Surgery: Causative Factors and Outcomes

PURPOSE

To study the factors causing cap lenticular adhesion (CLA), a rare complication of small incision lenticule extraction (SMILE) surgery, and its effect on surgical outcomes.

DESIGN

A prospective, observational, cross-sectional study involving 550 eyes of 285 subjects.

METHODS

SMILE was performed using the VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) with a minimum of 3 months follow-up. Preoperative visual quality assessment, measurement of corneal biomechanics, and Bowman membrane imaging were performed. Based on the mean refractive spherical equivalent (MRSE), subjects were classified into mild, moderate, and high myopes. Causes of CLA and postoperative outcomes were evaluated.

RESULTS

CLA was seen in 1.8% of patients, in whom the median preoperative MRSE was -1.5 (-2.75 to -1.38), deformation amplitude was 1.13 (1.10 to 1.21), and lenticular thickness was 46.2 (39.9 to 54.31). They had microdistortions in the Bowman layer and poor quality of vision. A median Strehl ratio of 0.08 (0.07 to 0.11) and modulation transfer function of 9.88 (8.98 to 13.34) were noted on the first day after surgery, which gradually improved to 0.17 (0.15 to 0.18) and 33.90 (27.27 to 38.94), respectively. On observing the surgical videos, a distinct shining reflection, "the shimmer sign," was seen around the dissector in patients with CLA when the posterior plane was dissected before the anterior.

CONCLUSIONS

Cap lenticular adhesion was associated with a low preoperative MRSE and thin lenticules. The shimmer sign serves as an indicator for identification of the correct plane of dissection.