Retreatment of residual refractive errors with flap lift laser in situ keratomileusis

Laser-Assisted In Situ Keratomileusis (LASIK) Enhancement for Residual Refractive Error after Primary LASIK

Background: To evaluate the safety, efficacy, and predictability of laser-assisted in situ keratomileusis (LASIK) enhancement after primary LASIK and compare to Food and Drug Administration (FDA) criteria. Methods: Patients who underwent LASIK enhancement after primary LASIK between 2002 and 2019 were compared to those who underwent LASIK without retreatment. Patient demographics, preoperative characteristics, visual outcomes, and postoperative complications were compared between groups. Epithelial ingrowth (EI) development was stratified based on duration between primary and secondary procedures. Results: We compared 901 eyes with LASIK enhancement to 1127 eyes without retreatment. Age, sex, surgical eye, sphere, cylinder, and spherical equivalent (SE) were significantly different between groups (p < 0.05). At 12 months post-enhancement, 86% of the eyes had an uncorrected distance visual acuity of 20/20 or better and 93% of eyes were within ±0.50 D of the target. Development of EI (6.1%) demonstrated an odds ratio of 16.3 in the long-term compared to the short-term (95% CI: 5.9 to 45.18; p < 0.0001). Conclusions: Older age at primary LASIK, female sex, right eye, and larger sphere, cylinder and SE were risk factors for enhancement. Risk of EI significantly increased when duration between primary and enhancement procedures exceeded five years. LASIK enhancements produce favorable outcomes and meet FDA benchmarks for safety, efficacy, and predictability.

Femtosecond-Assisted Laser in situ Keratomileusis with de novo Flap Creation Following Previous Microkeratome Laser in situ Keratomileusis

Purpose

To report the outcomes of laser in situ keratomileusis (LASIK) in patients with previous microkeratome LASIK using a femtosecond laser platform to create a de novo flap.

Methods

The charts of 17 patients that underwent femtosecond-assisted LASIK with de novo flap creation for consecutive refractive error following previous microkeratome LASIK were retrospectively reviewed at a single private practice institution. The baseline characteristics, intraoperative findings and postoperative outcomes were analyzed.

Results

All 17 eyes underwent femtosecond-assisted LASIK with de novo flap creation without significant intraoperative or postoperative complications. Uncorrected visual acuity improved postoperatively (p<0.0001) and remained stable at 6 months follow-up. None of the subjects lost any lines of best spectacle corrected visual acuity or developed epithelial ingrowth during the postoperative period.

Conclusion

The femtosecond laser technique described in this report can provide a safe and effective method to deliver LASIK following previous microkeratome LASIK. Future investigations are required to further validate the findings in this study.

Risk Factors for Dry Eye After Refractive Surgery

PURPOSE

To determine the factors associated with clinically significant dry eye after keratorefractive surgery.

METHODS

This is a large database retrospective study that included consecutive cases of myopic laser in situ keratomileusis (LASIK) or photorefractive keratectomy performed between 2008 and 2016 at Care-Vision Laser Center, Israel. Patients were divided into 2 groups according to whether they developed clinically significant dry eye.

RESULTS

A total of 25,317 right eyes of 25,317 patients, with a mean age of 27.0 ± 8.3 years, were included. Postoperative dry eye developed in 1518 eyes (6.0%). The dry eye group was older (29.2 ± 9.0 vs. 27.6 ± 8.3 yrs, P < 0.001) and had a higher proportion of women (48.5% vs. 44.8%, P = 0.005), lower preoperative spherical equivalent (3.7 ± 2.0 vs. 4.0 ± 2.3D, P < 0.001), lower preoperative best-corrected visual acuity (0.019 ± 0.057 vs. 0.016 ± 0.064 Logarithm of the Minimum Angle of Resolution (LogMAR), P = 0.04), and lower proportion of preoperative soft contact lens wearers (40.6% vs. 45.5%, P < 0.001). In the postoperative dry eye group, a high proportion underwent LASIK (52.4% vs. 38.7%, P < 0.001) and were treated with a 7.0-mm (as opposed to 6.0 mm) optic zone (18.9% vs. 16.3%, P < 0.001). In multivariable analysis, older age [odds ratio (OR) 1.013, P < 0.001], female gender (OR 0.87, P = 0.009), lower preoperative refractive error (OR 1.05, P < 0.001), and LASIK (OR 0.67, P < 0.001) were associated with postoperative dry eye.

CONCLUSIONS

Patients who are of older age, are of female gender, and have a lower preoperative refractive error and those undergoing LASIK are more likely to develop dry eye disease after keratorefractive surgery.

Corneal Surface Ablation Laser Refractive Surgery for the Correction of Myopia: A Network Meta-analysis

PURPOSE

To systematically compare the efficacy, predictability, safety, postoperative haze, pain scores, and epithelial healing time of four corneal surface ablation procedures.

METHODS

PubMed, Embase, Cochrane Library, and the U.S. trial registry were searched up to June 2018. Randomized controlled trials were selected. Efficacy (uncorrected distance visual acuity of 20/20 or better), predictability (refractive spherical equivalent within ±0.50 diopters [D] of the target), and safety (loss of two or more lines of spectacle corrected distance visual acuity) were set as primary outcome measures. Haze, pain scores, and epithelial healing time were set as secondary outcome measures.

RESULTS

Eighteen studies involving 1,423 eyes were included. According to the Grading of Recommendations Assessment, Development, and Evaluation, the quality of outcomes were moderate to high (70.6%). There were no differences in efficacy, predictability, safety, haze, day 1 pain, and epithelial healing time between treatments. Epithelial laser in situ keratomileusis (epi-LASIK) had statistically significantly higher pain scores on day 3 compared to photorefractive keratectomy (PRK) (weighted mean differences [WMD] = 2.2, 95% credible intervals [CrI] = 0.19 to 4.01) and transepithelial PRK (T-PRK) (WMD = 2.7, 95% CrI = 0.51 to 4.84). The surface under the cumulative ranking curve ranking results (best to worst) showed laser epithelial keratomileusis (LASEK) ranked highest for efficacy, predictability, safety, and day 1 pain scores. Epi-LASIK ranked best for grade 1 haze scores. T-PRK ranked best for haze of 0.5 or higher, haze scores day 3 pain scores, and epithelial healing time.

CONCLUSIONS

Surface laser refractive surgeries are comparable in terms of efficacy, predictability, safety, and postoperative haze except for day 3 pain scores, with epi-LASIK being more painful compared to PRK and T-PRK. [J Refract Surg. 2018;34(11):726-735.].

Risk Factors for Epithelial Ingrowth Following Microkeratome-Assisted LASIK

PURPOSE

To analyze the incidence and risk factors associated with epithelial ingrowth following uncomplicated microkeratome-assisted LASIK.

METHODS

All patients who underwent microkeratome-assisted LASIK between January 2006 and December 2014 in a single surgical center were reviewed. Epithelial ingrowth cases were identified and associated factors were assessed.

RESULTS

Overall, 149 (0.49%) of 30,574 cases developed epithelial ingrowth. The epithelial ingrowth group was older compared to controls (35.3 ± 12.3 vs 31.7 ± 10.3 years, P = .001) and had a higher percentage of moderate to high hyperopia (13.7% vs 5.3%, P < .001), early postoperative flap slippage requiring flap repositioning (9.4% versus 2.8%, P < .001), or flap lifting for enhancement (48.6% vs 4.3%, P < .001), were treated with a smaller optic zone (6 mm) (37.7% vs 15.2%, P < .001), with a Moria M2 microkeratome (Moria SA, Antony, France) (70.1% vs 55.5%, P = .02), by low volume surgeons (n < 1,000) (5.8% vs 1.3%, P < .001), in a lower operating room temperature (22.3 ± 1.8 vs 22.8 ± 1.6, P = .005), and with a greater maximum ablation depth (67.3 ± 29.7 vs 57.3 ± 30.3, P < .001). There was a high incidence of epithelial ingrowth in the enhancement group compared to primary LASIK (4.8% vs 0.2%, P < .001). The time between treatments (primary and enhanced LASIK) was significantly greater in the epithelial ingrowth group (mean: 1,110 ± 870 vs 626 ± 662 days, P < .001). There was a significant rise in epithelial ingrowth rates as time between primary and enhancement LASIK increased, peaking at 4 to 5 years (P < .001). In multivariate analysis, flap lifting for enhancement (odds ratio [OR] = 19.5, P < .001), 6-mm optic zone (OR = 2.2, P < .001), moderate to severe hyperopia (OR = 2.4, P = .005), greater ablation depth (OR = 1.005, P < .001), and low volume surgeon (OR = 3.9, P = .01) were associated with epithelial ingrowth (total R² = 15.4).

CONCLUSIONS

The potential risk factors described above may forewarn surgeons as to which individuals merit closer observation for this complication. [J Refract Surg. 2018;34(2):100-105.].

Epithelial ingrowth following laser in situ keratomileusis (LASIK): prevalence, risk factors, management and visual outcomes

The number of laser in situ keratomileusis (LASIK) procedures is continuing to rise. Since its first application for correcting simple refractive errors over 25 years ago, the role of LASIK has extended to treat other conditions, including postkeratoplasty astigmatism/ametropia, postcataract surgery refractive error and presbyopia, among others. The long-term effectiveness, predictability and safety have been well established by many large studies. However, due to the creation of a potential interface between the flap and the underlying stroma, interface complications such as infectious keratitis, diffuse lamellar keratitis and epithelial ingrowth may occur. Post-LASIK epithelial ingrowth (PLEI) is an uncommon complication that usually arises during the early postoperative period. The reported incidence of PLEI ranged from 0%–3.9% in primary treatment to 10%–20% in retreatment cases. It can cause a wide spectrum of clinical presentations, ranging from asymptomatic interface changes to severe visual impairment and flap melt requiring keratoplasty. PLEI can usually be treated with mechanical debridement of the affected interface; however, additional interventions, such as alcohol, mitomycin C, fibrin glue, ocular hydrogel sealant, neodymium:yttriumaluminum garnet laser and amniotic membrane graft, may be required for recurrent or refractory cases. The aims of this review are to determine the prevalence and risk factors of PLEI; to describe its pathogenesis and clinical features and to summarise the therapeutic armamentarium and the visual outcome of PLEI.

Flap lift and photorefractive keratectomy enhancements after primary laser in situ keratomileusis using a wavefront-guided ablation profile: Refractive and visual outcomes

PURPOSE

To analyze results of wavefront-guided laser vision correction retreatments performed either by lifting the original flap or by surface ablation over the flap.

SETTING

Optical Express, Glasgow, United Kingdom.

DESIGN

Retrospective case series.

METHODS

This retrospective study included patients grouped according to whether they had flap lift enhancement or photorefractive keratectomy (PRK) performed over the LASIK flap. All retreatment procedures were performed with the Visx Star S4 IR excimer laser with wavefront-guided ablation profile derived from the iDesign aberrometer. Visual acuities, refractive outcomes, vector analysis of refractive cylinder and complications were analyzed in this study. The results of the last available clinical visit are presented.

RESULTS

This retrospective study included 290 eyes of 202 patients divided into 2 groups: 119 eyes that had flap lift enhancement (Group A), and 171 eyes in which photorefractive keratectomy (PRK) was performed over the LASIK flap (Group B). The mean follow-up was 4.0 ± 1.9 months in Group A and 4.2 ± 1.6 in Group B. The mean postoperative manifest spherical equivalent was -0.01 ± 0.35 D and +0.06 ± 0.39 D in Groups A and B, respectively. The percentage of eyes with postenhancement UDVA 20/20 or better was 87.4% in Group A and 79.5 % in Group B (P = .09). In Group A, 22 eyes (18.5%) developed epithelial ingrowth, of which surgical intervention was required in 2 eyes (1.7%). Grade 1 or less haze was noted in 9 (5.3%) eyes in Group B, and resolved in all cases within the first 6 postoperative months.

CONCLUSION

Both retreatment techniques were considered to be effective, predictable, and safe.

FINANCIAL DISCLOSURE

Steven C Schallhorn MD is a consultant to Abbott Medical Optics and Zeiss, and Global Medical Director for Optical Express. None of the other authors have a financial or proprietary interest in the products and materials presented in this paper.

Safety and efficacy of VisuMax® circle patterns for flap creation and enhancement following small incision lenticule extraction

Background

The purpose of this case series is to evaluate the safety and efficacy of VisuMax® Circle patterns in eyes that have undergone small incision lenticule extraction, thus creating a flap to perform an enhancement procedure or residual lenticule extraction.

Methods

This prospective, single center, case study series evaluated the use of a VisuMax® Circle pattern to create a corneal flap following small incision lenticule extraction. Patients were treated and followed at TRSC International LASIK Center (Bangkok, Thailand) for 3 months to assess the efficacy and safety of the procedure. Efficacy was determined by the surgeon’s ability to lift the created corneal flap.

Results

The study enrolled 28 eyes. Twenty-seven underwent the VisuMax® Circle pattern procedure for refractive enhancement, and one for residual lenticule extraction. In 100 % of cases (28 eyes) the lifting of the flap was possible, as planned. In all cases of refractive enhancement (27 eyes) by laser in situ keratomileusis (LASIK), the exposure of the stromal bed was sufficient for the necessary excimer laser ablation. No eyes lost two or more Snellen lines of corrected distance visual acuity (CDVA) and no procedure or flap-related complications or serious adverse events occurred.

Conclusions

This initial case series demonstrates that VisuMax® Circle pattern is efficacious and a suitable method to create a corneal flap for enhancement, following small incision lenticule extraction.

Femtosecond laser cataract surgery

Femtosecond laser (FSL) cataract surgery is in its infancy but is rapidly gaining popularity due to the improved consistency and predictability for corneal incisions and anterior capsulorhexis. It enables subsequently less phacoemulsification energy and time to be employed, which has gains in terms of reduced corneal oedema. In addition, the FSL allows better circularity of the anterior capsulotomy, capsule overlap, intraocular lens (IOL) placement and centration of the IOL. These advantages have resulted in improved visual and refractive outcomes in the short term. Complication rates are low which reduce with surgeon experience. This review article focuses on the Alcon LenSx system.

3-Year follow-up after Lasik: assessing the risk factors for retreatment

The purpose of this study was to evaluate the correlation of important risk factors for LASIK retreatment and the retreatment rate. A retrospective cohort study was conducted. Records of patients who underwent LASIK between January 2011 and January 2012 at the Zambrano-Hellion Medical Center, Tec de Monterrey (México), and posteriorly underwent LASIK retreatment were identified and risk factors to receive retreatment were assessed using relative risk. Main outcomes were retreatment rate, risk factors for retreatment, and uncorrected distance visual acuity (UDVA). 482 eyes from 241 patients were available for a 36-month follow-up analysis. 68.5 % had primary myopic LASIK; 37 % were ≤ 2 diopters (D), 52 % were > 2 and < 6 D, and 11 % were ≥ 6 D of myopia. 31.5 % of the eyes had hyperopic LASIK. Retreatment was performed in 6.85 % eyes. Myopia > 6 D (RR 4.13), hyperopic refraction (RR 3.18), and age > 40 (RR 3.07) were the most important risk factors for retreatment (P = 0.004, P = 0.007, P = 0.006, respectively). UDVA was ≥ 20/40 in 92.1 % and ≥ 20/20 in 81.6 % of the retreated eyes and 82 % of the eyes within ± 0.50 D of target refraction. Increasing degrees of myopia, followed by hyperopic refraction, and age were the most important associated factors to retreatment. LASIK retreatment was safe and effective.

Management of residual refractive error after laser in situ keratomileusis and photorefractive keratectomy

PURPOSE OF REVIEW

To review the various steps and methods in managing residual refractive error after laser in situ keratomileusis and photorefractive keratectomy (PRK).

RECENT FINDINGS

Past studies have shown the efficacy and safety of flap relifts over recuts and for surface ablation over the flap. Other previous and also more recent studies show the use of a femtosecond laser for side cuts only. Recently, the creation of a femtosecond mini flap has been described. New studies also demonstrate the use of collagen cross-linking in postrefractive surgery ectasia.

SUMMARY

Residual refractive error is a known complication after both laser in situ keratomileusis and PRK. A systematic approach should be taken to manage this complication starting with a thorough evaluation to determine if an enhancement is indicated and if so, which method will be the safest and most efficacious for the patient.

Laser in situ keratomileusis in 2012: a review

Laser in situ keratomileusis (LASIK) is a safe and effective treatment for refractive error. A combination of technological advances and increasing surgeon experience has served to further refine refractive outcomes and reduce complication rates. In this article, we review LASIK as it stands in late 2012: the procedure, indications, technology, complications and refractive outcomes.

Femtosecond laser-assisted enhancements after laser in situ keratomileusis

We describe a technique of femtosecond laser-assisted enhancement after primary LASIK with a mechanical microkeratome-created flap. The vertical side-cut incision by the femtosecond laser creates a wound configuration that decreases mechanical trauma to the epithelium and prevents epithelial cell migration. These factors may decrease the risk for post-LASIK enhancement epithelial ingrowth.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

Femtosecond LASIK retreatment using side cutting only

PURPOSE

To present visual and refractive outcomes in 11 eyes that underwent femtosecond LASIK and subsequent retreatment with flap lifting using only side cutting.

METHODS

Seven patients (11 eyes) with a mean age of 30.55±5.42 years (range: 24 to 39 years) underwent retreatment 18.18±5.41 months (range: 12 to 26 months) after primary LASIK treatment with side cutting only using a femtosecond laser for the correction of residual refractive error.

RESULTS

Mean follow-up after retreatment was 7.72±1.48 months (range: 6 to 10 months). No intra- or postoperative complications were found after LASIK retreatment. Uncorrected distance visual acuity (UDVA) improved in all patients. Mean UDVA improved from 0.54±0.12 (decimal scale) (range: 0.4 to 0.7) preoperatively to 0.99±0.03 (range: 0.9 to 1.0) after retreatment. No patient lost lines of corrected distance visual acuity.

CONCLUSIONS

Retreatment using a femtosecond laser to create only a side cut is an effective modality to treat residual refractive errors in postoperative LASIK patients.