Laser-assisted In Situ Keratomileusis Treatment Research Articles

Femtosecond laser-assisted in situ keratomileusis with topography-guided or asphericity-adjusted derived data: a comparative contralateral eye study

BackgroundWavefront-optimized laser-assisted in situ keratomileusis (LASIK) ablation is the most commonly performed procedure in refractive surgery, but new technologies have become available. Our goal was to compare topography-guided (Contoura) and asphericity-guided (Custom-Q) customized ablation treatments for the correction of myopia with or without astigmatism.MethodsThis prospective, randomized, double-blind, contralateral eye study included 60 eyes of 30 patients with myopia or myopic astigmatism requiring femtosecond LASIK (FemtoLASIK) treatment. For each patient, one eye was randomized to undergo Contoura treatment, and the other underwent Custom-Q abaltion. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive spherical equivalent (MRSE), sphere (SPH), cylinder (CYL), 6.0-mm total corneal aberration root mean square (RMS), coma (COMA), trefoil (TREF), and spherical aberration (SA) were measured and analysed after a 1-year follow-up.ResultsThe UDVA was − 0.08 ± 0.06 logMAR in Contoura eyes and − 0.08 ± 0.05 logMAR in Custom-Q eyes (p = 0.309) after 12 months. Twenty-five eyes (83%) in the Contoura group and twenty-six eyes (87%) in the Custom-Q group had a UDVA of 20/16 at the end of 12 months, and 100% of eyes in both groups reached a UDVA of 20/25 or better. Ninety and 100% of eyes in the Contoura and Custom-Q groups, respectively, achieved a residual CYL ≤0.50 D (p = 0.237). No statistically significant difference was observed between the surgical techniques in the preoperative to 1-year postoperative changes for any of the parameters evaluated (MRSE, CYL, RMS, DEF, COMA, TREF, and SA).ConclusionsThe Contoura and Custom-Q techniques yielded excellent visual and refractive results, but the evidence did not reveal any clear differences between these two methods after 1 year of follow-up.Trial registrationReBEC - Registro Brasileiro de Ensaios Clínicos [Internet]: Rio de Janeiro (RJ): Instituto de Informação Científica e Tecnológica em Saúde (Brazil); 2010 -. Identifier RBR-8rs5kt Myopia and Astigmatism Topography-guided Refractive Surgery by Contoura Method Versus Customized by Asphericity in Contralateral Eyes: A prospective Double blind Randomized Study. Available from https://ensaiosclinicos.gov.br/rg/RBR-8rs5ktDate of registration: 02/03/2020 (dd/mm/yyyy).CAAE:96778718.9.0000.5192.Issuing authority: Plataforma Brasil.CEP:2.979.279.Issuing authority: HUOC.

Surgical versus optical treatment for anisometropia in adults: a randomized controlled trial

Background: We evaluated and compared outcomes of laser-assisted in situ keratomileusis (LASIK) versus optical spectacle correction for the treatment of anisometropia in adult patients.
 Methods: This prospective, randomized controlled clinical trial included 50 eyes of 50 patients. We randomly allocated participants to Group A (25 eyes with anisometropia assigned to LASIK treatment) and Group B (25 eyes with anisometropia assigned to optical spectacle correction). All patients underwent preoperative and postoperative visual acuity, subjective and cycloplegic refraction, fundus, slit-lamp, and corneal topography examinations.
 Results: In Group A, at 1-month postoperatively, there were statistically significant differences in uncorrected distance visual acuity, corrected distance visual acuity, refractive sphere, cylinder, and spherical equivalent (SE) as compared to baseline. At 3-months postoperatively in Group A, SE showed good stability within ± 0.50 diopter (D) in 22 eyes (88%) and within ± 0.75 D in 23 eyes (92%), while two eyes had an SE beyond 1.00 D emmetropia. Five eyes had amblyopia with minimal improvement in two eyes in Group A after LASIK, and no improvement in three eyes treated with spectacles in Group B. Two amblyopic eyes had developed ocular deviations by the end of the study that referred to the strabismus unit.
 Conclusions: Our outcomes revealed that LASIK was more effective and advantageous than spectacles in the treatment of different types of anisometropia in adults. However, future randomized trials should focus on optical versus surgical treatment of anisometropia and anisometropic amblyopia in both pediatric and adult patients, to verify these conclusions before generalizing this treatment modality.

Early changes in tear film protein profiles after femtosecond LASIK surgery

BackgroundFemtosecond laser-assisted in situ keratomileusis (LASIK) has proven to be an efficacious, predictable, and safe procedure for the correction of refractive errors. We examined the early tear protein changes of patients undergoing LASIK surgery in order to better understand the mechanisms and proteins related to laser corneal surgery and initial recovery.MethodsCorneal flaps were created with Ziemer FEMTO LDV Z6 I femtosecond laser and stroma was ablated using Wavelight EX500 excimer laser. Tear samples were collected preoperatively as well as 1.5 h and 1 month after LASIK treatment using glass microcapillary tubes. Relative quantification of tear proteins was performed with sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS).ResultsSWATH-MS revealed that 158 proteins had altered expression levels 1.5 h after the operation. Two-thirds of these proteins, mostly connected to migration and inflammation response, returned to preoperative levels within the first postoperative month. The other proteins, which did not return to baseline levels, included proteins connected to for example epithelial barrier function. We also identified several proteins, which correlated with surgical variables, such as the amount of correction, flap thickness and flap diameter.ConclusionsThe present study showed that an uneventful femtosecond LASIK refractive surgery induced a significant immune cell migration and inflammation-associated changes in tear proteomics profile quickly after the operation, but the expression of most proteins recovered almost completely to the preoperative levels within the first month. The individual proteins identified in our study are potential targets for the follow-up and modification of LASIK-induced biochemical processes.

Effects of flap diameter on dry eye parameters and corneal sensation after femtosecond laser-assisted LASIK.

PURPOSE:Although femtosecond laser-assisted LASIK (laser-assisted in situ keratomileusis). provides a controllable flap size than a mechanical microkeratome, patients still experience dry eye symptoms after LASIK. The purpose of this study is to investigate the effects of different flap sizes on postoperative dry eye syndrome and corneal sensitivity.PATIENTS AND METHODS:This is a retrospective comparative study. Fifty-seven consecutive patients (113 eyes) who underwent myopic femtosecond laser-assisted LASIK treatment were recruited. Basic Schirmer's test value, tear breakup time (TBUT), corneal fluorescein staining scores, conjunctival rose bengal staining scores, and corneal sensitivity were measured before surgery, at postoperative 1, 3, and 6 months follow-up.RESULTS:When the eyes were grouped by flap diameter sizes (8.7 mm as the cutoff value), there were no significant differences in terms of corneal sensitivity and all dry eye parameters investigated at any time points between the large or small flap diameter groups. However, when the eyes were grouped by the ratio of flap diameter/horizontal corneal white-to-white distance (0.756 as the cutoff value), the larger ratio group showed decreased basic Schirmer's test (7.52 ± 4.43 mm) than the smaller group (12.15 ± 8.14) at 3 months (P = 0.006). Moreover, the group that had larger flap/corneal diameter ratio showed shorter TBUT (4.20 ± 1.73 s) than the smaller group (5.67 ± 1.90 s) at 6 months postoperatively (P = 0.011).CONCLUSIONS:LASIK-related dry eye syndrome was associated with flap/corneal diameter ratio, and surgeons should keep this effect in mind when customizing the cornea flap sizes for dry eye patients during LASIK.

Risk Factors for Sporadic Diffuse Lamellar Keratitis After Microkeratome Laser-Assisted In Situ Keratomileusis: A Retrospective Large Database Analysis.

To determine the factors associated with sporadic diffuse lamellar keratitis (DLK) after microkeratome laser-assisted in situ keratomileusis (LASIK). This large database retrospective study included consecutive cases of LASIK performed between 2007 and 2016 at Care-Vision Laser Centers, Tel-Aviv, Israel. Patients were divided into 2 groups according to whether or not they subsequently developed DLK. A total of 24,026 eyes of 12,013 patients with a mean age of 32.9 ± 10.3 years were included. Post-LASIK DLK developed in 464 eyes (1.9%), and the annual rate decreased from 7.1% (2007) to 1.7% (2016) (P < 0.001). The DLK group had a higher proportion of males (58.5% vs. 52.1%, P = 0.006), greater preoperative central corneal thickness (549.5 ± 32.6 vs. 545.3 ± 30.5 μm, P = 0.005), and a lower proportion of high astigmatism (>3 D) (0.4% vs. 1.6%, P = 0.05). The DLK group had a higher proportion of previous LASIK treatment (2.8% vs. 1.3%, P = 0.006), Moria M2 (rather than the SBK) microkeratome (71.1% vs. 34.0%, P < 0.001), smaller suction ring number (P < 0.001), greater stop size (P < 0.001), and greater flap thickness (119.2 ± 50.4 vs. 110.8 ± 22.2, P = 0.007). In multivariable analysis, a smaller suction ring number [odds ratio (OR) 0.89, P = 0.04], Moria M2 microkeratome (OR 5.26, P < 0.001), larger optical zone (OR = 2.04, P = 0.01), and higher spherical equivalent (OR = 1.08, P = 0.02) were associated with DLK. In the modern LASIK era, the incidence of DLK continues to decrease. Higher preoperative ametropia, smaller suction ring number, an older type of microkeratome, and larger optical zones are associated with higher DLK rates after LASIK.

The ablation depth effect on dry eye after LASIK treatment for myopia

Purpose The aim was to investigate the effect of ablation depth on the incidence and severity of the dry eye after laser-assisted in-situ keratomileusis (LASIK) treatment of myopia. Patients and methods This was a prospective, noncomparative, interventional case series study that included myopic patients who underwent LASIK treatment for myopia ranging from −1.75 to −12.00 D. All patients had a comprehensive preoperative ophthalmologic evaluation. Tear breakup time (TBUT) and Schirmer 1 tests were undertaken for all patients preoperatively and at 1, 3, and 6 months postoperatively. The main outcome measures included the incidence and severity of the dry eye and their correlation with ablation depth at 1, 3, and 6 months postoperatively. Results 104 eyes of 53 myopic patients (14 males and 39 females) with a mean age of 27.4±6.06 years (range: 21–45 years). At the baseline, the mean spherical equivalent was −6.38±2.82 D (range: −1.5 to −12 D), mean TBUT was 12.93±1.60 s (range: 10–17 s), and the mean Schirmer 1 score was 17.9±62.52 mm (range: 14–30 mm). Mean post-LASIK TBUT was 7.58±4.32, 10.22±5.38, and 12.07±4.02 s at 1, 3, and 6 months, respectively (P Conclusions There was moderate to strong negative correlation between ablation depth and the degree of post myopic LASIK dryness assessed objectively by TBUT and Schirmer 1 tests.

Corneal clarity measurements in patients with myopia undergoing laser assisted in situ keratomileusis and laser assisted sub‐epithelial keratectomy

PurposeTo compare the preoperative and postoperative corneal densitometry of patients undergoing Laser Assisted in Situ Keratomileusis (LASIK) and Laser Assisted Sub‐epithelial Keratectomy (LASAK) and to determine how result differed between the 2 types of surgery.MethodsA retrospective and comparative study was performed at Manchester Royal Eye Hospital,UK. Preoperative and postoperative corneal densitometry data were collected from the Oculus Pentacam. The data were taken at 3 corneal depths (anterior,centre and posterior) and at 3 corneal annulus ring diameter (0‐2 mm, 2‐6 mm and 6‐10 mm). Postoperative data were collected at the time 6 weeks, 3 and 6 months post treatment.Quality of vision pre and post‐surgery was determined by BCVA.ResultsData of 60 eyes from 16 LASIK and 14 LASEK patients were collected with a mean age of 37.06 ± 10.0 and 37.7 ± 6.6 respectively. There was statistically significant increase of corneal densitometry in all concentric zones in all corneal layers after 6 weeks in the LASIK treatment group (p &lt; 0.05). There was a statistically significant increase in densitometry after LASEK but only in the central and posterior layers at all concentric zones (p &lt; 0.05). Pre and Postoperative BCVA did not significantly differ after LASIK but found statistically difference at 6 weeks and 3 months in post LASEK (p &lt; 0.05).BCVA post treatment was significantly different between groups at 6 weeks (p &lt; 0.0001) and 3 months (p = 0.001).ConclusionsCorneal wound healing plays an important role in determining corneal transparency and may be responsible for an increase in corneal haze following refractive surgery.This response differs based on the type of procedure used shown by the increased haze in the anterior layer of the LASIK group which corresponds to the region where the flap was cut which will lead to increased would healing and inflammation.

Treatment of moderate-to-high hyperopia with the WaveLight Allegretto 400 and EX500 excimer laser systems.

PurposeTo evaluate the efficacy of treating patients with +3.00 diopters (D) to +6.00 D of hyperopia via laser-assisted in situ keratomileusis (LASIK) with the WaveLight Allegretto 400 and EX500 excimer laser systems.SettingPrivate clinical ophthalmology practice.Patients and methodsThis was a retrospective study of patients undergoing LASIK treatments of +3.00 to +6.00 D on two different WaveLight laser systems: 163 eyes on the 400 (Hertz) Hz system and 54 eyes on the 500 Hz system. The duration of follow-up was 6 months postoperation. Data were evaluated for uncorrected distance visual acuity, corrected distance visual acuity (CDVA), spherical equivalents (SEQs), and changes in these parameters (eg, loss of vision, regression over time).ResultsTreatment with both lasers was safe and effective, with loss of one line of CDVA in four of 162 eyes using the 400 Hz laser system, and none of the 54 eyes with the 500 Hz laser system. Overall, regression ≥0.75 D from goal at 6 months was observed in 11.7% (19/163) of eyes in the 400 Hz laser group and 9.26% (5/54) of eyes in the 500 Hz laser group (regression ≥0.50 D =77.9% [127/163] and 77.8% [42/54], respectively). The mean SEQ regressions for all eyes with moderate hyperopia were 0.10 and 0.18 D for those with high hyperopia.ConclusionsBoth the 400 and 500 Hz excimer laser systems were safe and effective for the LASIK treatment of moderate-to-high hyperopia. The overall rate of regression was low and the amount of regression was relatively small with both systems.

Retreatment of residual error after femtosecond laser-assisted in-situ keratomileusis in correcting high hyperopia

Purpose The aim of the present study was to evaluate the results of femtosecond laser-assisted in-situ keratomileusis (LASIK) in correcting high hyperopia. Patients and methods The study was carried out at El-Gowhara Eye Center, Ismailia, Egypt. A prospective case series study was carried out. Hyperopic eyes with a spherical equivalent (SE) greater than or equal to +3.00 D were corrected by LASIK. The flaps were created with the VisuMax femtosecond laser. The refractive ablations were performed with the 500-kHz Amaris excimer laser. Full cycloplegic refraction was the target refraction. Patients were divided into two groups. Group A included patients with residual refractive errors less than or equal to +0.50 D of the target refractions and had no further LASIK retreatment, and group B included patients with residual refractive errors greater than +0.50 D of the target refractions along with retreatment 1 month after the primary LASIK. The refractive predictability and stability of the treated and retreated eyes were followed-up for 6 months after LASIK. Results Sixty-four patients (115 eyes) received primary hyperopic femtosecond LASIK. The mean±SD age of all patients was 40.30±13.4 years with a range of 21–64 years. The preoperative mean±SD cycloplegic SE refraction was +4.29±1.5 D with a range from +3.00 to +9.00 D. One month after the primary LASIK treatment, 79.1% (91 eyes) of the treated patients had a mean cycloplegic SE refraction of +0.36±0.13 D (group A). After 6 months of follow-up, 62.6% of eyes (n=72) had an uncorrected distance visual acuity of 0.3±0.21 log MAR. Four (3.5%) eyes lost one line of corrected distance visual acuity (CDVA) (Snellen). Five (4.3%) eyes lost two lines of CDVA (Snellen). Seven (6.1%) eyes gained one line of CDVA (Snellen). Twenty-one (18.3%) eyes gained two lines of CDVA (Snellen). The mean±SD cycloplegic SE refraction was +0.41±0.32 D. In group B (20.9%) (24 eyes), patients had a mean±SD cycloplegic SE refraction of +2.41±0.96 D at the first month after primary LASIK. These patients required a second-stage LASIK retreatment by lifting the original flap. After 6 months of follow-up, 83.3% of eyes (n=20) had an uncorrected distance visual acuity of 0.6±0.13 log MAR. Seven (29.2%) eyes gained one line of CDVA (Snellen). Two (8.3%) eyes lost one line of CDVA, and two (8.3%) eyes lost two lines of CDVA (Snellen). The mean±SD cycloplegic SE refraction was +0.25±0.21 D. No epithelial ingrowth was recorded in both groups. Conclusion Femtosecond LASIK for the correction of high hyperopia is predictable and safe; 79.1% of the patients underwent correction during the primary treatments, and 20.9% were totally corrected after retreatments. No cases of epithelial ingrowth were recorded over the 6-month follow-up period.

When case report became case series: 45 cases of late traumatic flap complications after laser-assisted in situ keratomileusis and review of Chinese literature

ObjectiveTo report 45 cases of late traumatic flap complications after laser-assisted in situ keratomileusis (LASIK) and discuss the continually increasing number of cases in China.MethodsA multicentre retrospective survey of eye...

Case Report: The correction of a high magnitude of astigmatism with laser-assisted in situ keratomileusis

Background Laser-assisted in situ keratomileusis (LASIK) has undergone several evolutions since it was first approved by the U.S. Food and Drug Administration. Currently, excimer lasers are approved by the U.S. Food and Drug Administration to treat refractive errors with a standard ablation profile, a wavefront-optimized ablation profile, or a wavefront-guided ablation profile. Wavefront-optimized ablation profiles provide a simple method to precompensate for the expected fourth-order spherical aberration and higher-order astigmatism in the average eye. Case report We report a case of a 39-year-old white man, with a high magnitude of mixed astigmatism in the right and left eyes, who was seeking refractive surgical options because he was unable to tolerate contact lenses. The patient underwent bilateral wavefront-optimized LASIK to correct his high degree of astigmatism. Wavefront-guided ablation, as in this patient, can not always be performed because the parameters are not within the allowable treatment profile. Four months after the primary LASIK treatment, the patient underwent a bilateral wavefront-optimized LASIK enhancement for residual astigmatism. Conclusion This case focuses on the utilization of a wavefront-optimized LASIK treatment profile to eliminate a high magnitude of astigmatic refractive error without inducing higher-order aberrations. Wavefront-guided treatments are not required in most cases but should be considered if the magnitude of preoperative root-mean-square higher-order aberrations is greater than 0.35 μm. Wavefront-optimized aspheric corneal ablations attempt to avoid reducing the prolate eccentricity of the average cornea, and optimized treatments have shown improved visual outcomes compared with conventional LASIK treatments. A thorough knowledge of refractive surgery is important for any treating eye care practitioner to provide patients with the full range of options to correct all types of refractive errors.

Efficacy and Safety of Short-Duration Topical Treatment with Azithromycin Oil-Based Eyedrops in an Experimental Model of Corneal Refractive Surgery

To assess the tolerance and side effects of azithromycin eyedrops at the ocular surface after corneal refractive surgery in an experimental animal model. The effect of azithromycin eyedrops was evaluated in hen corneas that underwent laser-assisted in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) surgery in 1 eye, using the fellow eye (not manipulated) as a control. Animals were treated bid 3 days prior to surgery and 3 days after surgery with T1225 1.5% azithromycin eyedrops or saline eyedrops (balanced salt solution), or were left untreated as a control. Clinical course and cell biology (apoptosis, proliferation, and differentiation) measurements were assessed. Infections were present in the following proportions of corneas operated on by LASIK: 0% treated with azithromycin, 60% treated with BSS, and 30% untreated. No corneal abscess or keratitis were present in any PRK or unmanipulated corneas. Conjunctival edema and redness were less prevalent in LASIK-operated eyes treated with azithromycin than in BSS-treated or untreated eyes and were not observed in any PRK or unmanipulated corneas. In PRK-operated eyes treated with azithromycin, a decrease was observed in the apoptosis and an increase in the stromal proliferation. There were no differences in these parameters for LASIK and unmanipulated eyes. Topical administration of T1225 oil-based azithromycin eyedrops was well tolerated in both unmanipulated hen corneas and those treated with corneal refractive surgery (PRK and LASIK). T1225 demonstrated a potent antibiotic effect after LASIK treatment.