Outcomes of Re-treatment by LASIK After SMILE

Corneal Epithelial Remodeling Induced by Photorefractive Keratectomy Enhancement After Small-Incision Lenticule Extraction

Purpose

To assess changes in corneal epithelial thickness (ET) within 9-mm diameter cornea after photorefractive keratectomy (PRK) retreatment after small-incision lenticule extraction (SMILE).

Methods

A total of 28 eyes of 19 patients with mean spherical equivalent of -1.30 ± 0.60 D who underwent retreatment after SMILE were included in this retrospective study. ET mapped across a 9-mm diameter area was obtained using wide-field optical coherence tomography (OCT) before and at one, three, and six months after surgery. The ET changes were compared between the different time points and analyzed zones.

Results

Before enhancement, the ET were 63.64 ± 6.01 µm and 61.25 ± 4.32 µm in central and paracentral zones, respectively. The ET of central and paracentral zones significantly decreased at one month and subsequently increased until six months. Six months after surgery, significant epithelial thickening occurred in 2- to 9-mm diameter cornea (all P < 0.05), whereas no significant change was observed in central 2-mm diameter cornea (P = 0.460). There was no significant difference in the ET between the central and paracentral zones (P = 1.00). The degree of myopic correction significantly correlated with the average ET in the central (P = 0.046) and paracentral (P = 0.033) zones at six months after PRK enhancement. No significant correlation was detected between the average ET of all zones and the postoperative spherical equivalent at six months after surgery (all P > 0.05).

Conclusions

PRK enhancement did not alter the overall trend of corneal epithelial remodeling induced by SMILE. An asymmetric and flatter lenticule-like pattern of epithelial remodeling was observed six months after surgery, which did not affect the refractive outcomes.

Translational Relevance

An asymmetric and centrally flattened lenticule-like pattern of epithelial remodeling was observed after PRK enhancement. Surgeons should consider expanding the intended optical zones for enhancement surgery after SMILE.

Refractive Corneal Lenticule Extraction With the CLEAR Femtosecond Laser Application

PURPOSE

The aim of this study was to evaluate a new femtosecond laser application for refractive corneal lenticule extraction with suction control and computerized regulation of centration and alignment (Ziemer CLEAR).

METHODS

This was a retrospective, consecutive, noncomparative case series study. Patients undergoing CLEAR for spherical equivalent (SE) between -3 and -10 D, evaluating SE, defocus equivalent, refractive astigmatism, visual acuity, and centration at 10 months were evaluated in the study.

RESULTS

Fifty-three eyes of 42 patients (mean age 40.4 ± 8.6 years) were included, with preoperative SE -5.99 ± 1.49 D and mean corrected distance visual acuity (CDVA) of 0.05 ± 0.07 logMAR. With no suction losses, an intact lenticule was extracted in all eyes. In 6 eyes, peripheral adhesion was resolved by lenticulerrhexis, and in 1 eye, the incision was opened by a crescent blade. Moderate interface inflammation occurred in 3 eyes. At day 1, in the 42 eyes with uneventful surgery, the mean CDVA was 20/27, whereas in the 11 eyes with extra surgical manipulations, it was 20/36 ( P = 0.04). At 10 months, for the 53 eyes, the mean uncorrected distance visual acuity was 0.05 ± 0.09 logMAR; in 37 eyes (70%), it was 20/25 or better; and the mean CDVA was 0.04 ± 0.06 logMAR. Eight eyes (15%) lost 1 logMAR line. The mean SE was -0.13 ± 0.15 D. The mean defocus equivalent was 0.33 ± 0.32 D, with 46 eyes (87%) ≤0.50 D and 52 eyes (98%) ≤1 D. Refractive astigmatism was ≤0.50 D in 48 eyes (90%). The efficacy index was 1.00, and the safety index was 0.98. The mean decentration from the corneal vertex was 0.28 ± 0.07 mm.

CONCLUSIONS

The application yielded good predictability, efficacy, and safety. Slower visual recovery was observed after extra surgical manipulations.

Visual outcomes of early enhancement following small incision lenticule extraction versus laser in situ keratomileusis

Purpose

To compare visual outcomes of early enhancement following small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK).

Methods

Retrospective analysis of eyes (patients operated in the setting of a tertiary eye care hospital between 2014 and 2020) requiring early enhancement (within one year of primary surgery) was conducted. Stability of refractive error, corneal tomography, and anterior segment Optical Coherence Tomography (AS-OCT) for epithelial thickness was performed. The correction post regression was done using photorefractive keratectomy and flap lift in eyes, wherein the primary procedure was SMILE and LASIK, respectively. Pre- and post enhancement corrected and uncorrected distance visual acuity (CDVA and UDVA), mean refractive spherical equivalent (MRSE), and cylinder were analyzed. IBM SPSS statistical software.

Results

In total, 6350 and 8176 eyes post SMILE and LASIK, respectively, were analyzed. Of these, 32 eyes of 26 patients (0.5%) post SMILE and 36 eyes of 32 patients (0.44%) post-LASIK required enhancement. Post enhancement (flap lift in LASIK, and PRK in SMILE group) UDVA was logMAR 0.02 ± 0.05 and 0.09 ± 0.16 (P = 0.009), respectively. There was no significant difference between the refractive sphere (P = 0.33) and MRSE (P = 0.09). In total, 62.5% of the eyes in the SMILE group and 80.5% in the LASIK group had a UDVA of 20/20 or better (P = 0.04).

Conclusion

PRK post SMILE demonstrated comparable results to flap lift post LASIK and is a safe and effective approach for early enhancement post SMILE.

[Enhancement Options after Lens and Corneal Refractive Surgery]

BACKGROUND

 Modern preoperative diagnostics as well as current surgical techniques allow cataract and refractive surgery to deliver precise refractive results.Occasionally, unsatisfactory refractive and visual results occur despite all the care taken. In these cases, subsequent improvement is required to achieve the best final visual outcome. This article shows the therapeutic options for the treatment of residual refractive errors after lens and corneal refractive surgery.

KEY MESSAGES

 The causes of postoperative refractive errors after refractive laser- or lens-based procedures are very diverse and require extensive workup of the cause as well as an individual solution to achieve the desired result. Before any further surgical intervention, specific complications of the primary procedure as well as concomitant ocular diseases must be excluded or treated. The appropriate enhancement after keratorefractive surgery depends primarily on the type of primary surgery, residual stromal thickness, possible complications from the initial surgery, and the patient's personal preference. For enhancements using surface treatments, such as PRK, the use of mitomycin C is recommended for prophylaxis of haze formation. After lens surgery, for low-grade postoperative refractive errors (spherical and astigmatic), keratorefractive enhancements provide the most accurate results. For higher refractive errors, lens-based procedures can be used, with add-on IOLs being safer and more precise compared with one IOL exchange. Low astigmatisms can be successfully treated with LRI or keratorefractive surgery, but higher astigmatisms should be corrected with an IOL exchange in the early postoperative period and with an add-on IOL in the later postoperative period. IOL explantations should be performed very cautiously, especially in cases of pronounced capsular fibrosis, previous posterior capsulotomy, and existing weakness of the zonular apparatus.

Enhancement-Optionen nach Linsen- und refraktiver Hornhautchirurgie

Gelegentlich kommt es trotz aller Sorgfalt und präziser Operationstechnik in der Katarakt- und Refraktivchirurgie zu unbefriedigenden refraktiven und visuellen Ergebnissen. In diesen Fällen ist eine nachträgliche Korrektur erforderlich, um das beste endgültige visuelle Ergebnis zu erzielen. Dieser Beitrag zeigt die Möglichkeiten zur Behandlung residualer Refraktionsfehler nach Linsen- und refraktiver Hornhautchirurgie auf.

Photorefractive Keratectomy Enhancement (PRK) After Small-Incision Lenticule Extraction (SMILE)

Purpose

To determine rates of enhancement and visual prognosis following photorefractive keratectomy (PRK) enhancement of small-incision lenticule extraction (SMILE).

Patients and Methods

This retrospective, single-site study reviewed all cases of primary SMILE at Hoopes Vision in Draper, Utah between March 14, 2017 and April 8, 2022 to identify any cases that required follow-up enhancement. Primary SMILE was performed using Visumax 500 kHz femtosecond laser (Carl Zeiss Meditec, Jena, Germany). All enhancements were performed with alcohol-assisted PRK, using a WaveLight EX500 excimer laser (Alcon Laboratories, Inc., Fort Worth, TX).

Results

Four hundred and five eyes underwent primary SMILE, of which 15 later underwent PRK enhancement (enhancement rate of 3.7%). No significant difference in pre-SMILE data was identified between the enhancement and non-enhancement groups. The average age of those who underwent PRK enhancement was 33.8±6.3 years old and ranged from 25 to 45. Following primary SMILE, 13 eyes (87%) had an uncorrected distance visual acuity (UDVA) of 20/40 or better, and none had a UDVA of 20/20 or better. After one year of post-enhancement follow-up, all eyes had a UDVA of 20/40 or better, and 13 eyes (87%) had a UDVA of 20/20 or better (Figure 1). All were within one diopter of target spherical equivalent (SEQ), 13 (87%) were within 0.50 D, and 10 (67%) were within 0.25 D. Of those with 12-month follow-up data, none had UDVA worse than corrected distance visual acuity (CDVA), and none had lost lines of CDVA. Efficacy and safety indices were 1.03 and 0.99, respectively.

Conclusion

Following SMILE, ophthalmologists may anticipate an enhancement rate of one to seven percent. In these cases, PRK is a safe and effective procedure for enhancement of SMILE.

Femtosecond LASIK Retreatments After Primary Myopic Photorefractive Keratectomy (Femtosecond LASIK Retreatments of PRK)

PURPOSE

The purpose of the study was to evaluate the results and complications of laser-assisted in situ keratomileusis (LASIK) using a femtosecond laser as a retreatment modality of myopia and myopic astigmatism after previous myopic photorefractive keratectomy (PRK).

METHODS

In this retrospective, consecutive, noncomparative case series study, 69 eyes of 41 patients receiving femtosecond LASIK after previous myopic PRK were evaluated. The mean age was 43.0 ± 8.9 years. The preoperative mean SE was -1.82 ± 1.01 diopter (D), range -0.62 to -6.25. The mean central epithelial thickness was 65 ± 5 μm. A flap was created using a low-energy femtosecond laser (Ziemer LDV Z8), with a programmed thickness calculated by adding 40 μm to the epithelial thickness. Refractive ablation was performed using a Technolas Teneo 317 laser (Bausch and Lomb).

RESULTS

Twelve months after LASIK, the mean SE was -0.03 ± 0.17 D, with all eyes ≤0.50 D of SE. The mean DE was 0.30 ± 0.25, with 62 eyes (89.9%) ≤0.50 D and all eyes ≤1 D. The mean corrected distance visual acuity (CDVA) was 0.04 ± 0.10 logMAR; no eye lost more than 1 line of CDVA. The mean uncorrected distance visual acuity was 0.07 ± 0.13 logMAR, being 20/25 or better in all eyes. The safety index (postoperative CDVA/preoperative CDVA) was 1.05. The efficacy index (postoperative uncorrected distance visual acuity/preoperative CDVA) was 0.98. No significant complications occurred.

CONCLUSIONS

Myopic retreatments by femtosecond LASIK after primary PRK yielded excellent refractive results without relevant complications. The flap thickness must be tailored to the epithelial thickening after PRK.

SmartSurfACE transepithelial photorefractive keratectomy with mitomycin C enhancement after small incision lenticule extraction

Background

To evaluate predictability, stability, efficacy, and safety of transepithelial photorefractive keratectomy (TPRK) using smart pulse technology (SPT) (SmartSurface procedure) of Schwind Amaris with mitomycin C for correction of post small incision lenticule extraction (SMILE) myopic residual refractive errors.

Method

This study is a prospective, non-comparative case series conducted at a private eye centre in Ismailia, Egypt, on eyes with post-SMILE myopic residual refractive errors because of undercorrection or suction loss (suction loss occurred after the posterior lenticular cut and the creation of side-cuts; redocking was attempted, and the treatment was completed in the same session with the same parameters) with myopia or myopic astigmatism. The patients were followed up post-SMILE for six months before the SmartSurface procedure, and then they were followed up for one year after that. TPRK were performed using Amaris excimer laser at 500 kHz. The main outcomes included refractive predictability, stability, efficacy, safety and any reported complications.

Results

This study included 68 eyes of 40 patients out of 1920 total eyes (3.5%) with post-SMILE technique myopic residual refractive errors. The average duration between the SMILE surgery and TPRK was 6.7 ± 0.4 months (range 6 to 8 months). The mean refractive spherical equivalent (SE) was within ± 0.50 D of plano correction in 100% of the eyes at 12 months post-TPRK. Astigmatism of < 0.50 D was achieved in 100% of the eyes. The mean of the residual SE error showed statistically significant improvement from preoperative − 1.42 ± 0.52 D to 0.23 ± 0.10 D (P < 0.0001). Uncorrected distance visual acuity (UDVA) (measured by Snellen's chart and averaged in logMAR units) was improved significantly to 0.1 ± 0.07 (P < 0.0001). UDVA was 0.2 logMAR or better in 100% of the eyes, 0.1 logMAR or better in 91.2% of the eyes, and 0.0 logMAR in 20.6% of the eyes. Corrected distance visual acuity (CDVA) remained unchanged in 79.4% of eyes. 14.7% of eyes gained one line of CDVA (Snellen). 5.9% of eyes gained two lines of CDVA (Snellen).

Conclusion

Transepithelial photorefractive keratectomy using smart pulse technology with mitomycin C enhancement after SMILE is a safe, predictable, stable, and effective technique.

Research Progress on Morphological Changes and Surgery-related Parameters of Corneal Cap in Small Incision Lenticule Extraction

Small incision lenticule extraction (SMILE) is an "all-in-one" surgical method for refractive correction. An advantage of the SMILE over traditional surgery is that it depends on the corneal cap's design. This review discusses the morphological evaluation of the corneal cap, selection of the corneal cap with different thickness and diameters, influence of the corneal cap design on retreatment, and management of corneal cap-related complications. The following points should be recognized to define the correct morphology and design of the operation-related parameters of the corneal cap during SMILE: (1) the thickness and diameter of the corneal cap are predictable and influence postoperative visual quality, (2) the change in anterior surface curvature of the corneal cap should be considered in the design of nomogram value, (3) for patients with moderate myopic correction, early visual quality is better with a 6.9-mm than with a 7.5-mm diameter corneal cap, (4) there is no significant difference in visual quality or biomechanics among corneal caps with different thickness; (5) primary corneal cap thickness plays an important role in the SMILE retreatment, (6) a 7.78-mm diameter corneal cap has a greater risk of suction loss than a 7.60-mm diameter corneal cap, (6) if suction loss occurs when lenticular scanning exceeds 10%, then SMILE can be continued by changing corneal cap thickness, (7) preventive collagen cross-linking with SMILE caps are 90-120 μm thick and 7-7.8 mm in diameter, and (8) properly treating SMILE-related complications ensures better postoperative results. The data presented herein shall deepen the understanding of the importance of the corneal cap during SMILE and provide diversified analysis for personalized operational design of corneal cap parameters.

[Regression and ablation profiles in corneal refractive surgery]

Regression after corneal refractive surgery is a complex phenomenon which seems inevitable. The choice of surgical technique has very little influence on regression for low myopia or myopic astigmatism. However, LASIK and SMILE are the two techniques of choice in the correction of high myopia. LASIK is also better for the correction of hyperopia, hyperopic astigmatism and mixed astigmatism. Intraoperatively, the choice of a wide optical zone and adherence to a thick residual stromal bed provide stability. Regression may also be reduced by modulating anti-inflammatory therapy, treating dry eye, and using mitomycin C in PKR. In all cases, obtaining keratometry during patient follow-up helps to identify the cause of the regression. The objective of this review is to synthesize recent data from the literature on regression in refractive surgery as a function of the ablation profiles used.

Short-Term Impact of FS-LASIK and SMILE on Dry Eye Metrics and Corneal Nerve Morphology

PURPOSE

To analyze the short-term (up to 1 month) clinical outcomes in patients undergoing corneal laser refractive surgery and the impact on dry eye disease (DED) metrics and corneal nerves using in vivo confocal microscopy (IVCM).

METHODS

The unaided distance visual acuity, corrected distance visual acuity, and spherical equivalent refraction (SEQ) were determined in 16 and 13 patients undergoing FS-LASIK and SMILE, respectively. DED metrics assessed were Ocular Surface Disease Index, Dry Eye Questionnaire 5-items (DEQ-5), tear film osmolarity, tear meniscus height, noninvasive keratograph breakup time (NIKBUT), ocular staining, and meibomian gland atrophy. An automated analysis of corneal nerve fiber density, corneal nerve branch density, corneal nerve fiber length (CNFL), and corneal nerve fiber fractal dimension were obtained from the IVCM scans using ACCMetrics software (University of Manchester).

RESULTS

Both surgical techniques provided good refractive and visual outcomes. DED symptoms were found to be higher after FS-LASIK compared with SMILE (P < 0.05). A decrease in tear meniscus height (∼31%) and NIKBUT (∼40%) was reported after FS-LASIK (P = 0.005 and P = 0.001, respectively) but not after SMILE. Both procedures affected corneal nerve fiber density, corneal nerve branch density, CNFL, and corneal nerve fiber fractal dimension, but the impact was significantly greater with FS-LASIK (P = 0.001). Only CNFL correlated with the reported symptoms (DEQ-5) after FS-LASIK (r = -0.545, P = 0.029).

CONCLUSIONS

FS-LASIK and SMILE provided good refractive and visual outcomes. There was an increased impact on DED symptoms after FS-LASIK compared with SMILE, although there were no significant differences between the procedures for most of the other ocular surface metrics assessed. The IVCM findings showed that SMILE had less impact on corneal nerves compared with FS-LASIK.

Advances in refractive corneal lenticule extraction

Refractive errors are the leading cause of reversible visual impairment worldwide. In addition to the desired spectacle independence, refractive procedures can improve quality of life, working ability, and daily working performance. Refractive corneal lenticule extraction (RCLE) is a relatively new technique, dependent only on a femtosecond laser (FS). This leads to potential benefits over laser-assisted in situ keratomileusis (LASIK) including a quicker recovery of dry eye disease, a larger functional optical zone, and no flap-related complications. SMILE, available with the VisuMax FS (Carl Zeiss Meditec AG, Jena, Germany), is the most established RCLE application, offering visual and refractive outcomes comparable to LASIK. SmartSight (SCHWIND eye-tech-solutions GmbH, Kleinostheim, Germany) and CLEAR (Ziemer Ophthalmic Systems AG, Port, Switzerland) are two new RCLE applications that received Conformité Européenne (CE) approval in 2020. In this article, we review refractive and visual outcomes, advantages, and disadvantages of RCLE and also report on the latest advances in RCLE systems.

Small Incision Lenticule Extraction (SMILE): Myths and Realities

The emergence of SMILE in the last decade has provided an alternative to LASIK for patients considering cornea laser refractive surgery. SMILE offers a novel approach using the femtosecond laser to create an intrastromal lenticule that can be removed through a small three to four millimeter incision.The purpose of this study is to review the recent literature on popular SMILE claims - reduced iatrogenic dry eye, better recovery of corneal sensation, and a biomechanically stronger cornea - summarize the published outcomes, and determine which claims are myths versus realities.SMILE is still in its infancy as a refractive technique in the US after recent USFDA approval for its treatment of myopia astigmatism in October 2018. Future randomized controlled studies are needed to compare its outcomes to LASIK, which has well-documented good visual outcomes, rapid postoperative recovery, and good safety profile.

Decade - long journey with small incision lenticule extraction: The learnings

Over the past decade, small incision lenticule extraction (SMILE) has revolutionized the field of keratorefractive surgery. With the promise of superior corneal biomechanics and reduced postoperative dry eye, SMILE afforded a distinct advantage over flap-based procedures. Our evolving understanding of the surgical technique and management of its unique complications has further enhanced the outcomes. This review will highlight specific pearls on various preoperative and intraoperative principles allowing optimization of outcomes with SMILE.

SMILE – Small Incision Lenticule Extraction

Die SMILE (small incision lenticule extraction) zählt zu den Verfahren der refraktiven Lentikel-Extraktion und hat sich im letzten Jahrzehnt zu einem etablierten Bestandteil des modernen refraktivchirurgischen Spektrums entwickelt. Dieser Beitrag gibt einen Überblick über Patientenselektion, Operationsmethode, mögliche Komplikationen und klinische Ergebnisse dieser Methode.

[SMILE - Small Incision Lenticule Extraction]

Refractive lenticule extraction is a corneal surgical technique that uses a femtosecond laser exclusively to create an intrastromal refractive lenticule for the correction of myopia and myopic astigmatism. In small incision lenticule extraction (SMILE) the generated refractive lenticule is subsequently extracted through a small incision. The reported efficacy, predictability and safety of the flap-less SMILE procedure is similar to those of femtosecond laser in situ keratomileusis (LASIK). Advantages of SMILE over LASIK include less iatrogenic dry eye, fewer induced higher-order aberrations, and potentially less biomechanical weakening of the cornea. However, there is a steeper surgeon learning curve for SMILE as the procedure is technically more challenging than LASIK. Furthermore, the current SMILE laser platform cannot use cyclotorsion control or eye-tracking technology and retreatment options are more complex compared to LASIK. This review looks at patient selection, surgical method, possible complications, retreatment options, and postoperative outcome of the SMILE technique.

Refractive surgery beyond 2020

Refractive surgery refers to any procedure that corrects or minimizes refractive errors. Today, refractive surgery has evolved beyond the traditional laser refractive surgery, embodied by the popular laser in situ keratomileusis or 'LASIK'. New keratorefractive techniques such as small incision lenticule extraction (SMILE) avoids corneal flap creation and uses a single laser device, while advances in surface ablation techniques have seen a resurgence in its popularity. Presbyopic treatment options have also expanded to include new ablation profiles, intracorneal implants, and phakic intraocular implants. With the improved safety and efficacy of refractive lens exchange, a wider variety of intraocular lens implants with advanced optics provide more options for refractive correction in carefully selected patients. In this review, we also discuss possible developments in refractive surgery beyond 2020, such as preoperative evaluation of refractive patients using machine learning and artificial intelligence, potential use of stromal lenticules harvested from SMILE for presbyopic treatments, and various advances in intraocular lens implants that may provide a closer to 'physiological correction' of refractive errors.

TransPRK treatment for residual refractive error and induced aberrations in eye undergone SMILE treatment

In this case report, we propose to correct refractive errors after SMILE a refractive lenticule surgery technique with transepithelial Photorefractive keratectomy (TransPRK).The advantage of this technique is that the measured aberrations with topography o the Cornea are also treated on the Surface of the Cornea.

Enhancement Options After Myopic Small-Incision Lenticule Extraction (SMILE): A Review

PURPOSE

To provide an overview of the currently available retreatment methods after myopic small-incision lenticule extraction (SMILE).

DESIGN

Systematic literature review.

METHODS

The PubMed library was searched for articles containing the terms "small-incision lenticule extraction" and "enhancement" or "retreatment". The last search was performed on May 1, 2019.

RESULTS

In contrast to laser in-situ keratomileusis (LASIK), which can be retreated by a flap relift, repeat SMILE retreatment is currently not approved and only seldomly performed. As substitutes, surface ablation, cap-to-flap conversion using the CIRCLE program in the VisuMax platform, and thin-flap LASIK have been recently established. While all options offer safety and efficacy comparable to LASIK retreatments, each has its patient-specific advantages and disadvantages. While surface ablation preserves the flap-free approach of the primary procedure, the aspect of pain and a slow visual recovery might render it less attractive as compared with CIRCLE and thin-flap LASIK which offer quick recovery, however at the price of flap creation. Besides, each retreatment method generates specific tissue responses and has a different impact on corneal biomechanics, which is strongly dependent on the previous SMILE parameters, especially the cap thickness.

CONCLUSIONS

Refractive enhancement after SMILE is currently mostly performed by surface ablation, CIRCLE cap-to-flap conversion or thin-flap LASIK, which all offer safety and efficacy comparable to LASIK retreatments. In this review, a detailed overview over each method, its technical aspects, and specific advantages and disadvantages is given.

Surface Ablation Versus CIRCLE for Myopic Enhancement After SMILE: A Matched Comparative Study

PURPOSE

To compare the outcomes of enhancement after small incision lenticule extraction (SMILE) using surface ablation versus the VisuMax CIRCLE option (Carl Zeiss Meditec AG, Jena, Germany), which converts the SMILE cap into a femtosecond laser-assisted laser in situ keratomileusis flap.

METHODS

The databases of the SMILE Eyes centers in Munich, Marburg, and Cologne, Germany, and Linz, Austria, were screened for eyes that had undergone enhancement using surface ablation with mitomycin C or CIRCLE. Eyes from both enhancement methods suitable for a retrospective matched analysis were identified based on pre-SMILE and pre-enhancement mean refractive spherical equivalent (MRSE), astigmatism, age, and corrected and uncorrected distance visual acuity (CDVA/UDVA). Refractive and functional outcomes were compared after a follow-up of 3 months.

RESULTS

After the application of the matching criteria on 2,803 SMILE procedures, 24 eyes (12 in each group) with a follow-up of 3 months or longer were available for analysis. Enhancement was performed after a mean 9.7 ± 7.2 (surface ablation) and 11.0 ± 4.4 (CIRCLE) months for a residual MRSE of -0.91 ± 0.55 (surface ablation) and -0.90 ± 0.61 (CIRCLE) diopters. At 3 months, residual MRSE showed comparable accuracy with -0.07 ± 0.19 (surface ablation) and 0.04 ± 0.22 (CIRCLE) diopters (P = .18). UDVA improvement was similar to a final value of 0.02 ± 0.10 (surface ablation) versus 0.03 ± 0.07 (CIRCLE) logMAR (P = .78). Only one eye in the surface ablation group and no eye in the CIRCLE group lost one line of CDVA. At 3 months, the safety (surface ablation: 1.00, CIRCLE: 1.06; P = .36) and efficacy (surface ablation: 0.95, CIRCLE: 1.03; P = .36) indices were equivalent. In terms of speed of visual recovery, at week 1 UDVA and CDVA were significantly better after CIRCLE than surface ablation (P = .008 and .002, respectively).

CONCLUSIONS

In this first study directly comparing surface ablation versus CIRCLE enhancement after SMILE, both methods yielded comparable results at 3 months. However, CIRCLE re-treated eyes showed a markedly increased speed of recovery concerning UDVA and CDVA compared to surface ablation. [J Refract Surg. 2019;35(5):294-300.].

Inferior pseudo-hinge fulcrum technique and intraoperative complications of laser in situ keratomileusis retreatment after small-incision lenticule extraction

PURPOSE

To describe the evolution of a flap-lift technique for laser in situ keratomileusis (LASIK) retreatment after small-incision lenticule extraction (SMILE) and report the incidence of complications.

SETTING

London Vision Clinic, London, United Kingdom.

DESIGN

Retrospective case series.

METHODS

All retreatments between September 2013 and January 2017 were included. A bimanual inferior pseudo-hinge fulcrum flap-lift technique was developed to minimize the chance of tearing or entering the small incision. A flap lifter and a McPherson forceps were inserted into the inferior one third of the flap, slightly angled up to avoid perforating the small-incision lenticule extraction interface. One instrument provided countertraction, and the second separated the interface superiorly, keeping the tip away from the incision. One instrument was held against the hinge for the second instrument to separate the inferior one third. The incidence of intraoperative complications was analyzed.

RESULTS

The study evaluated 162 retreatments (4.12%) for 3933 small-incision lenticule extraction treatments (1-year maturity). The retreatment was LASIK (n = 135), side-cut only (n = 1), cap-to-flap procedure (CIRCLE) (n = 3), or photorefractive keratectomy (n = 23). Two eyes (1.4%) had a tear to the small incision. The small-incision lenticule extraction interface was accessed in 8 eyes (5.8%), 1 (0.7%) centrally, and the interface was lifted in 1 eye (0.7%). There were no complications in the last 84 consecutive procedures (60%) using the finalized technique.

CONCLUSION

The bimanual inferior pseudo-hinge fulcrum decreased the risk for accessing the small-incision lenticule extraction interface or tearing the small incision.