[Complications of femto-LASIK and features of cavitation injuries]. / Oslozhneniya femto-LAZIK i osobennosti kavitatsionnykh povrezhdenii.

Modern approach to refractive laser surgery features three main types of lamellar surgery. Two of them are types of open laser keratomileusis (LASIK and femtosecond laser-assisted LASIK), and the third - closed (SMILE). All of these techniques allow achieving good clinical outcomes but differ in possible complications. This article reviews the complications of femto-LASIK and specifically the post-operative cavitation injuries, describes the mechanism of their occurrence, variants of their course, and presents the prevention measures.

Toxicidad por marcador corneal en Femto-LASIK. Reporte de caso / Toxicity by corneal marker in Femto-LASIK. Case report

La violeta de genciana es un colorante orgánico sintético, descrito por primera vez por Charles Lauth en 1861. Tiene propiedades antibacterianas, antifúngicas, antihelmínticas, antitripanosómicas, antiantiogénicas y antitumorales. Tiene diversos mecanismos de acción, entre los que principalmente se encuentra bloquear la actividad de las nicotinamida adenina dinucleótido fosfato oxidasas, evitando la generación de radicales superoxidativos y la posterior inflamación. En los últimos años se ha utilizado en marcadores para procedimientos en diferentes especialidades médicas, incluidos los de oftalmología. La tinta de violeta de genciana se describe por el fabricante como no tóxica, sin embargo existe evidencia clínica y experimental que sugiere que puede ser tóxica para el endotelio corneal y puede llegar a generar queratitis lamelar difusa posterior a LASIK y Femto-LASIK. Se describe el caso de una paciente de 23 años de edad, que presentó diversas patologías en la córnea después del uso de marcador quirúrgico durante procedimiento refractivo Femto-LASIK.

Gentian violet is a synthetic and organic dye. First described by Charles Lauth in 1861. It has antibacterial, antifungal, anthelmintic, antitrypanosomal, antiangiogenic, and antitumoral properties. It has various mechanisms of action, among which is mainly blocking the activity of nicotinamide adenine dinucleotide phosphate oxidases, preventing the generation of superoxidative radicals and subsequent inflammation. In recent years, it has been used as markers for procedures in different medical specialties, including ophthalmology. Gentian violet ink is described by the manufacturer as non-toxic, however, there is clinical and experimental evidence suggesting that it may be toxic to the corneal endothelium and may cause diffuse lamellar keratitis after LASIK and Femto-LASIK. The case about a 23-year-old female patient who presented various pathologies in the cornea after the use of a surgical marker during the Femto-LASIK refractive procedure is described.

[Changes in accommodation in children with hyperopic anisometropia and unilateral amblyopia after laser refractive surgery and pleoptic treatment]. / Izmenenie akkomodatsii u detei s gipermetropicheskoi anizometropiei i odnostoronnei ambliopiei posle refraktsionno-lazernoi operatsii i pleopticheskogo lecheniya.

PURPOSE: This study comparatively analyzes the state of accommodation in children with hyperopic anisometropia and amblyopia after femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) combined with pleoptic treatment, and after conventional pleoptic treatment. MATERIAL AND METHODS: The first group consisted of 30 children with medium and high hyperopia, high and medium amblyopia, and anisometropia greater than 3.0 diopters, who underwent Femto-LASIK in the amblyopic eye. The second group consisted of 28 children with similar local status, who were prescribed traditional correction and received conservative treatment. The follow-up period was 1.5 years. RESULTS: After 1.5 years, higher visual acuity (p<0.05) was achieved in the first group. A significant increase in the coefficient of accommodative response (CAR) was observed in the operated amblyopic eyes in group 1 - by 0.1±0.02 c.u. compared to the control group (p<0.05). In both groups there was an upwards trend for the coefficient of microfluctuations (CMF) in the amblyopic eye, but in the first group CMF increased more significantly (p<0.05). The objective accommodative response (OAR) and positive relative accommodation (PRA) of the amblyopic eye showed a double increase - by 1.0±0.23 and 0.9±0.38 diopters, respectively, at the end of treatment in the first group. The increase in similar indicators in the second group was insignificant (p<0.05). In children of the first group the difference in ciliary muscle thickness (CMT) of the amblyopic eye with disabled and enabled accommodation increased by 0.04±0.01 mm (p<0.05) in the anterior part of the ciliary muscle at the levels of CMTmax and CMT1. CONCLUSION: The data obtained in this study indicate the strong effect of refractive laser surgery in combination with pleoptic treatment on improving the visual acuity and the state of accommodation of the amblyopic and paired dominant eyes in children with hyperopic anisometropia, in contrast to conventional methods of treatment.

Comparison of Iris-Claw Phakic Lens Implant versus Corneal Laser Techniques in High Myopia: A Five-Year Follow-Up Study.

Background. This study aimed to compare the efficacy and safety of Femto-LASIK, PRK, and Artiflex/Artisan phakic lens implantation in the surgical correction of myopia at different moments of postoperative follow-up; to propose a linear predictive model of visual acuity without correction at five years of refractive procedures; and to evaluate its validity. Methods. A retrospective observational analysis was performed. Patients were clinically reviewed after three months, one year, two years, and five years. Univariate and bivariate analyses and a multivariate linear regression model were performed. Results. Six hundred seventy-nine eyes were analyzed: 18.9% Artiflex, 2.8% Artisan, 42.3% Femto-LASIK, and 36.1% PRK. There were significant differences in effectiveness and safety after five years when comparing Artiflex/Artisan versus PRK and Femto-LASIK (p < 0.01). The linear regression model explained 30.32% of the patients' visual acuity variability after five years. Conclusions. PRK surgery, Femto-Lasik, and Artiflex/Artisan type phakic lens implantation are effective, safe, and predictable techniques with stable refractive results. Phakic lenses magnify myopic patients who improve their UCVA and BCVA. Concerning phakic lens implantation, corneal endothelial cells remain stable. The predictive model calculated that surgery with a phakic lens increased the UCVA result at five years, and surgery with PRK slightly decreased the long-term results.

Femto-LASIK after Deep Anterior Lamellar Keratoplasty to Correct Residual Astigmatism: A Long-Term Case Series Study.

Purpose: To evaluate the long-term outcomes of femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) to correct residual astigmatism after deep anterior lamellar keratoplasty (DALK). Methods: This retrospective case series study included 10 eyes that underwent Femto-LASIK after a DALK. The refractive error, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, thinnest corneal thickness (TCT), and central corneal thickness (CCT) were registered. The postoperative follow-up ranged between 36 and 60 months. Results: All surgeries were uneventful, with no intra- or postoperative complications. The mean UDVA (Snellen scale) rose from 0.13 ± 0.05 to 0.47 ± 0.15 six months after Femto-LASIK (p < 0.001). All cases experienced a significant improvement in UDVA. None of the eyes lost lines of CDVA, and seven eyes (70%) improved the CDVA compared to preoperative values. The refractive cylinder changed from a preoperative value of −3.88 ± 1.00 D to −0.93 ± 0.39 six months after Femto-LASIK (p < 0.0001). In eight eyes (80%), the UDVA and refractive outcomes remained stable at postoperative follow-up visits. In contrast, one eye experienced a refractive regression over the follow-up. TCT and CCT were stable at the different postoperative follow-up visits. Conclusions: Our findings suggest that Femto-LASIK might safely and effectively corrects residual astigmatism after DALK. Despite these encouraging results, further long-term studies, including a larger number of cases, are required to confirm the safety of the procedure. The refractive stability in eyes with prior RK might be lower than for other DALK indications.

Changes of Subjective Symptoms and Tear Film Biomarkers following Femto-LASIK.

Femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) represents a common treatment modality in refractive surgery and shows excellent results in terms of safety, efficacy, predictability, and long-term stability. However, patients may be affected by dry eye symptoms. The aim of this study was to identify a potential association between subjective dry eye symptoms, objective dry eye markers, and possible changes in the tear film, which could be a target for future therapy development. Therefore, clinical (dry eye) examinations (OSDI, Schirmer test, lissamine green and fluorescein staining, BUT, visual acuity) were carried out before LASIK as well as 5 and 90 days post-OP. The dry eye marker MMP-9, cytokines (IL-1ß, IL-8), and pain markers (NGF, CGRP) were quantified in tear samples with immunoassays. In addition, correlation analyses were performed. Clinical examinations revealed an upregulated OSDI score 5 days post-OP and an increased lissamine green staining score 90 days post-OP. Downregulated CGRP levels were noted 5 days post-OP, while other protein markers were not significantly altered after Femto-LASIK. Hence, Femto-LASIK surgery induced subjective symptoms like that of dry eye which could objectively rather be classified as Femto-LASIK-related discomfort. In the future, this could possibly be better detected and treated using pain markers such as CGRP.

Femto-LASIK outcomes obtained by a fellowship trainee during a refractive surgery training program.

PURPOSE: To report, for the first time, the clinical outcomes and patient satisfaction of laser refractive surgery performed by a trainee during a corneal and refractive surgery fellowship program in Latin America. METHODS: This prospective and interventionist study reviewed the clinical charts of the first 100 consecutive refractive surgery cases performed by a single Cornea Fellowship trainee between March 2018 and June 2018 in the Blindness Prevention Association of Mexico (Asociación para Evitar la Ceguera en Mexico). Femtosecond LASIK was performed in all eyes. Visual and refractive outcomes were evaluated during the first year of follow-up. Patient satisfaction was measured using 5 author-created questions 6 months after surgery. RESULTS: Data of 100 eyes of 50 consecutive patients were evaluated. One year after the surgery, mean uncorrected distance visual acuity (UDVA) was 0.01 logMAR. Spherical equivalent error passed from -3.91 ± 2.28 D preoperatively to -0.22 ± 0.28 D. No eyes lost lines in corrected distance visual acuity (CDVA). Manifest refraction maintained stable during the first year after surgery. The five author-created questions revealed a high level of confidence and patient satisfaction. CONCLUSIONS: Femto-LASIK performed by a corneal and refractive surgery fellowship trainee showed good refractive and visual outcomes, as well as high patient satisfaction and confidence in a refractive surgery centre in Latin America.

Matched comparison of corneal higher order aberrations induced by SMILE to femtosecond assisted LASIK and to PRK in correcting moderate and high myopia: 3.00mm vs. 6.00mm.

BACKGROUND: The refractive surgeries induce corneal higher order aberrations (C-HOAs). In this study, change of C-HOAs after small-incision lenticule extraction (SMILE) compared to femtosecond assisted laser in situ keratomileusis (femto-LASIK), and to photorefractive keratectomy with mitomycin-C (PRK) under photopic and mesopic conditions. METHODS: In this prospective study, age, gender, and apical corneal thickness (ACT) matched cases with moderate myopia [spherical equivalent (SE) 3.00 to 6.00D) to high myopia (SE > 6.00D)] were enrolled. In addition to visual acuity and refraction, total C-HOA, coma, spherical aberration (SA), and trefoil in the 3- and 6-mm zones were measured before and 3 and 6 months after surgery. RESULTS: Overall, 372 moderate myopia cases (124 eyes of 124 individuals in each surgical group) and 171 high myopia cases (57 eyes of 57 individuals in each surgical group) were enrolled. At baseline, the differences in age, gender, ACT, uncorrected and corrected visual acuity, and SE were not statistically significant between subgroups of surgical methods within each myopia group (all P > 0.05). At 12 months, in the moderate myopia group, there was less increase in 6-mm zone total C-HOA, coma, and SA with SMILE compared to the other groups (all P < 0.05). In the high myopia group, there was greater increase in photopic total C-HOA and trefoil and less increase in mesopic SA with SMILE (all P < 0.05). CONCLUSIONS: In correction of moderate myopia, SMILE has better results in mesopic condition. In high myopia correction, femto-LASIK and PRK have better results in photopic and SMILE in mesopic condition.

Femtosecond-LASIK outcomes using the VisuMax®-MEL® 80 platform for hyperopia and hyperopic astigmatism refractive surgery.

The present study evaluated the efficacy, the safety and the predictability of the Femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) procedure for hyperopia and hyperopic astigmatism. We retrospectively analyzed the postoperative 12-month evolution of 593 eyes with hyperopia and hyperopic astigmatism that underwent Femto-LASIK treatment. The procedure was predictable and effective. No eye lost 2 lines of corrected distance visual acuity (CDVA), demonstrating a safety profile of the procedure. Nine percent of the eyes gained at least one line of CDVA. The accuracy of the spherical equivalent after 12 months was 74% within ±1.0 diopter (D) of emmetropia. The refractive outcomes were stable during the follow-up period. There were no significant complications during the procedure. Femto-LASIK using the VisuMax®-MEL® 80 platform was demonstrated to be a suitable option to correct selected cases of hyperopia and hyperopic astigmatism. A longer follow-up period is required to better assess the refractive results and to detect any further regression.

Topography-Guided Femto-LASIK in Virgin Eyes: Treating Manifest versus Measured Astigmatism.

PURPOSE: To assess the stability, safety, predictability, and efficacy of topography-guided myopic Femto-LASIK with two different treatment protocols. SETTING: Ebsar Eye center, Benha, Qalyopia, Egypt. DESIGN: Single-center, retrospective, COHORT control study. METHODS: A total of 330 eyes enrolled in the study in group A and 322 eyes enrolled in group B underwent uncomplicated primary bilateral topography-guided Femto-LASIK. Group A was treated with the subjective clinical refraction; however, group B was treated with the modified refraction according to ALCON protocol. RESULTS: The mean preoperative refractive spherical equivalent (MRSE) was -4.85±1.90D and -5.0±1.93D in group A and B, respectively (P = 0.86), and a cylinder of -0.95±0.80 D and -0.92±0.81D, respectively. At the 12 months' postoperatively, the residual manifest SE within ± 0.5D was achieved by 82.86% of eyes in group A compared to 83.93% in group B. Of eyes, 92.06% had ≤0.5 astigmatism dioptre, while 100% of eyes had ≤1.0 astigmatism dioptre in group A (315 eyes); however, 91.80% of eyes had ≤0.5 astigmatism dioptre, while 100% of eyes had ≤1.0 astigmatism dioptre in group B. CONCLUSION: Topographic modification of the magnitude and axis of astigmatism treated using ALCON protocol when different from the clinical refraction may offer good refractive outcomes when we apply the Alcon precalculation considerations.

Long Term Follow-Up Safety and Effectiveness of Myopia Refractive Surgery.

(1) Background: Refractive surgery is an increasingly popular procedure for decreasing spectacle or contact lens dependency. The two most common surgical techniques to correct myopia are photorefractive keratectomy (PRK) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK). This study demonstrates the long-term effectiveness, safety, and predictability of both techniques for the refractive surgery of myopia. (2) Methods: A retrospective non-randomized study was performed. We followed 509 PRK eyes and 310 FS-LASIK surgeries for ten years. Patients were followed-up after 3 months and after 1, 2, 5, and 10 years, gathering data on their uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA). The safety index of both procedures was defined as the quotient between the postoperative BCVA and the preoperative BCVA. We defined a procedure as safe if this quotient was equal to or greater than 1. The effectiveness index was calculated as the quotient between postoperative UCVA divided by the preoperative BCVA. (3) Results: The safety index was higher than 1 (1.09) and an effectiveness index of 0.82 after ten years of surgery in both groups was found. (4) Conclusion: These data demonstrated excellent safety and effectiveness indices for both techniques, although FS-LASIK is a technique with better safety and effectiveness indices than PRK.

Comparison of visual outcomes after femtosecond laser-assisted LASIK versus flap-off epipolis LASIK for myopia.

BACKGROUND: This study clinically evaluated the visual outcomes after refractive surgery for myopia using femtosecond laser-assisted in situ keratomileusis (femto-LASIK) and flap-off epipolis LASIK (epi-LASIK). METHODS: In this retrospective case series study, 40 eyes of 27 patients were divided into two groups depending on the technique used for refractive surgery. Femto-LASIK and flap-off epi-LASIK flaps were created using femtosecond laser and Epi-K™ epikeratome, respectively. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity, manifest refraction, corneal asphericity, and corneal higher-order aberrations (HOAs) were assessed pre- and postoperatively. RESULTS: The improvement in logarithm of the minimum angle of resolution (logMAR) UDVA after refractive surgery was statistically significant for both groups (P < 0.001 for all groups); it was significant better in UDVA in femto-LASIK than flap-off epi-LASIK, 0.03 ± 0.06 logMAR (femto-LASIK) and 0.54 ± 0.31 logMAR (flap-off epi-LASIK), at 1 day postoperatively; 0.02 ± 0.05 logMAR (femto-LASIK) and 0.14 ± 0.13 logMAR (flap-off epi-LASIK), at 1 week postoperatively (P < 0.001 and P = 0.019). With regard to the corneal HOAs, the increment in spherical aberration (Z4,0) was greater in flap-off epi-LASIK than femto-LASIK: 0.626 ± 0.232 µm and 0.479 ± 0.139 µm in the front cornea; 0.556 ± 0.227 µm and 0.430 ± 0.137 µm in the total cornea (P = 0.016 and P = 0.017). However, the back corneal HOA changes did not have a significant effect on the total corneal HOA changes. CONCLUSION: Femto-LASIK yielded better early visual outcomes than did flap-off epi-LASIK, but there was no significant difference between the outcomes of the two procedures, 1 week postoperatively.

Higher Order Aberrations (HOA) Changes after Femto-LASIK in Topography and Wavefrontguided Treatments.

BACKGROUND: Publications have focused on comparing the effect of various methods of refractive surgery or ablation profiles on higher order aberrations (HOA), yet the effect of WG compared to TG ablation in femtosecond laser-assisted in-situ keratomileusis femto-LASIK on HOAs has not been studied adequately. MATERIALS AND METHODS: We reviewed the changes of HOAs before and after femto-LASIK for simple myopia or compound myopic astigmatism after topography-guided (TG) and wavefront-guided (WG) ablation profiles. In this retrospective study, 42 eyes underwent TG and 31 WG femto-LASIK. RESULTS: The total HOAs increased from 0.41±0.16 µm pre-operatively to 0.66±0.30 µm post-operatively in the TG group and from 0.42±0.13 µm pre-operatively to 0.59±0.27 µm post-operatively in the WG group without statistically significant difference between the two groups. However, the postoperative change of secondary astigmatism showed a statistically significant difference between the two groups [0.20 (0.0-0.53) vs. 0.0 (0.0-0.20) for TG and WG groups, respectively; p=0.009]. CONCLUSIONS: The total HOAs increased compared to pre-operative data, in both the TG and WG ablation profile groups. The extent of increase of secondary astigmatism was significantly lower in the WG group, which might favour the postoperative quality of vision.

Comparison of visual quality after Femto-LASIK and TransPRK in patients with low and moderate myopia.

PURPOSE: To compare the visual quality after surgery of femtosecond-assisted laser in situ keratomileusis (Femto-LASIK) and transepithelial photorefractive keratectomy (TransPRK) in low and moderate myopia patients. METHODS: A prospective controlled study was performed on 114 eyes of 62 patients with low to moderate myopia, including 64 eyes of 36 cases in Femto-LASIK group and 50 eyes of 26 cases in TransPRK group. The uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), residual spherical equivalent (SE), wavefront aberration and contrast sensitivity were examined and analyses preoperatively, 1 month and 3 months postoperatively. RESULTS: The UCVA over 0.8 was 100% in two groups at 1 month and 3 months postoperatively. Femto-LASIK group (96.49%) had a higher percentage than TransPRK group (67.39%) of UCVA over 1.0 at 1 month postoperatively (p < 0.001), but it was similar in two groups (97.78%, 90.48%) at 3 months postoperatively (p = 0.15). Femto-LASIK group (77.19%, 86.67%) had a higher percentage than TransPRK group (30.43%, 52.38%) of UCVA over 1.2 at 1 month and 3 months postoperatively (p < 0.001, p = 0.001). The SE of Femto-LASIK group was 0.07 ± 0.21 D, 0.02 ± 0.23 D at 1 month and 3 months postoperatively, and of TransPRK group was 0.11 ± 0.31 D, 0.14 ± 0.38 D; two groups had no significant differences (p = 0.57, p = 0.08). The safety index was 2.0 in Femto-LASIK group and 1.6 in TransPRK, while the efficacy index was 1.67 and 0.4, respectively. The vertical coma, spherical and higher-order aberrations of Femto-LASIK group were 0.37 ± 0.54 µm, 0.31 ± 0.27 µm, 0.89 ± 0.49 µm at 1 month postoperatively, and of TransPRK group were 0.12 ± 0.38 µm, 0.14 ± 0.28 µm, 0.71 ± 0.26 µm. There was significant difference between two groups at 1 months postoperatively (p < 0.001, p = 0.001, p = 0.006), but no significant difference at 3 months (p > 0.05). The contrast sensitivity without glare in 18 c/d spatial frequencies of Femto-LASIK group was 1.08 ± 0.26 at 1 month postoperatively, and that in TransPRK group was 0.99 ± 0.22. There was significant difference between two groups (p = 0.02). The contrast sensitivity with glare in 12 c/d and 18 c/d spatial frequencies at 1 month postoperatively had significant differences between Femto-LASIK and TransPRK groups (1.52 ± 0.17, 1.10 ± 0.23 vs 1.38 ± 0.39, 1.00 ± 0.27, p = 0.02, p = 0.03). While there were no significant differences at 3 months postoperatively (p > 0.05). CONCLUSION: Femto-LASIK had a higher increase in whole eye higher-order aberrations and contrast sensitivity than TransPRK at 1 month postoperatively, but they were similar at 3 months postoperatively in low and moderate myopia patients.

Quality of life after refractive surgery: ReLEx SMILE vs Femto-LASIK.

PURPOSE: The safety and effectiveness of complex myopic astigmatism correction using ReLEx SMILE or Femto-LASIK techniques have been well established. The purpose of the current study is to compare quality of life (QoL) outcomes following ReLEx SMILE or Femto-LASIK procedures in parallel with functional vision and anatomic outcomes of treated eyes. PATIENTS AND METHODS: This prospective, consecutive series included 118 patients, 18-43 years of age, out of which 56 underwent ReLEx SMILE and 62 underwent Femto-LASIK surgery for correction of myopic astigmatism. All patients underwent standard comprehensive ophthalmic examinations, and additionally, completed The Quality of Life Impact of Refractive Correction Questionnaire to determine the impact the vision-correction treatment had on their QoL. RESULTS: In both treatment groups, the postoperative refractive outcomes were comparable, with visual acuity improvements for both groups noted the day following surgery. After laser correction of complex myopic astigmatism using Femto-LASIK and ReLEx SMILE methods, the overall QoL indicators are statistically significant (P<0.01) exceeding preoperative values 1 month after the operation and reaching the maximum values by the end of the observation period (P<0.0001). CONCLUSION: The results of the study suggest that patients require some time to adapt to their new visual function and its impact on their daily living, delaying detectable improvements in QoL. Moreover, these results may suggest a higher satisfaction trend and long-term QoL in patients undergoing ReLEx SMILE in comparison to Femto-LASIK. Long-term results from the study demonstrated high patient satisfaction with both methods.

Femtosecond laser-assisted LASIK versus PRK for high myopia: comparison of 18-month visual acuity and quality.

PURPOSE: To compare 18-month outcomes between femtosecond laser-assisted LASIK (femto-LASIK) and photorefractive keratectomy with mitomycin-C (PRK-MMC) for myopia of more than 7.0 D in terms of visual acuity and quality. METHODS: In this comparative nonrandomized clinical trial, 60 eyes from 30 patients (30 eyes in each group) were enrolled. The two procedures were compared in terms of 18-month changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, ocular and corneal higher order aberrations (HOAs), and contrast sensitivity (CS). RESULTS: Mean myopia was -8.65 ± 1.51 and -8.04 ± 1.70 D (P = 0.149) and mean ablation depth was 109.37 ± 9.07 and 105.09 ± 12.59 µm (P = 0.138), in the femto-LASIK and PRK-MMC groups, respectively. Baseline parameters were not significantly different between the two groups (all P > 0.05). At 18 months postoperatively, 75 % in the femto-LASIK, versus 57.1 % in the PRK-MMC group, had 20/20 UDVA (P = 0.017). CDVA remained similarly unchanged in both groups (P = 0.616). No case had residual refractive error more than 1.0 D in the femto-LASIK group, while 33.5 % in the other group had more than 1.0 D residual error (P = 0.390). Changes in corneal HOA were not significantly different between the two groups (P = 0.260). Cases in the femto-LASIK group showed more increase in ocular HOA (P = 0.032) and coma (P = 0.083, power = 72 %). CS remained similarly unchanged in all spatial frequencies in both groups (all P > 0.05). CONCLUSION: Although femto-LASIK induces more HOA compared to PRK-MMC, considering outcomes in terms of 20/20 UDVA, residual refractive error, and CS stability, femto-LASIK provides more favorable results than PRK-MMC in high myopia.

Femtosecond laser-assisted in situ keratomileusis multifocal ablation profile using a mini-monovision approach for presbyopic patients with hyperopia.

PURPOSE: To report the visual outcomes of the femtosecond laser-assisted multifocal aspheric corneal ablation profile using a mini-monovision approach and to evaluate if corneal multifocality was effective, and to report the relative benefits of this approach. PATIENTS AND METHODS: Bilateral femtosecond laser-assisted in situ keratomileusis using a multifocal aspheric corneal ablation profile was performed on 19 hyperopic patients (38 eyes). They were divided into two groups based on eye dominance: dominant eye (DE) group targeting emmetropia and the nondominant eye (NDE) group targeting -0.5 D slight myopia. The uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), and retreatment rates were reported from baseline to 6 months. RESULTS: The UNVA, UIVA, and UDVA improved significantly in both groups (Kruskal-Wallis test, DE and NDE: P<0.00001, P<0.000005, and P=0.00001, respectively). Corrected distance visual acuity (CDVA) baseline was better in both groups in comparison to UDVA at 6 months (Wilcoxon test, DE: P<0.001, 95% confidence interval (CI) of the median 0.0-0.0 LogMAR and 0.1000-0.1218 LogMAR and NDE: P=0.010, 95% CI of the median 0.0-0.0 LogMAR and 0.00-0.10 LogMAR). There was a significant loss of lines between CDVA baseline and UDVA at 6 months in both groups (DE group: 68% of eyes lost one line or more; NDE group: 58% of eyes lost one line or more). The corrected near visual acuity baseline compared to UNVA at 6 months was not statistically important (Wilcoxon test, DE: P=0.8125, 95% CI of the median 0.0-0.0 LogMAR and 0.0-0.0 LogMAR and NDE: P=0.82, 95% CI of the median 0.0-0.0 LogMAR and 0.0-0.0 LogMAR). The comparison among the UDVA, UIVA, and UNVA between the two groups at baseline and during all follow-ups was not statistically important. Two cases from the DE group were retreated (6%). CONCLUSION: Use of this multifocal aspheric corneal ablation profile in patients with hyperopic presbyopia significantly improved UDVA, UIVA, and UNVA. This improvement was due to created multifocality of the cornea. The mini-monovision seems not to affect UDVA, UIVA, and UNVA between the two groups. The retreatment rates at the 6-month evaluation were significantly less in our study when compared with other studies. This method seems to improve UDVA, UIVA, and UNVA but could result in a significant statistical difference between CDVA baseline and UDVA at 6 months that leads to loss of lines in distance vision. Despite promising results, this is a preliminary evaluation of this new profile, and a larger number of eyes are needed to verify visual outcomes, retreatment rates, and safety.