Factors affecting long-term myopic regression after corneal refractive surgery for civilian pilots in southwest China.

BACKGROUND: The purpose of this study was to analyze myopic regression after corneal refractive surgery (CRS) in civilian pilots and to explore the factors that may cause long-term myopic regression. METHODS: We included civilian pilots who had undergone CRS to correct their myopia and who had at least 5 years of follow-up. We collected retrospective data and completed eye examinations and a questionnaire to assess their eye habits. RESULTS: A total of 236 eyes were evaluated in this study. 211 eyes had Intrastromal ablations (167 eyes had laser in situ keratomileusis, LASIK, 44 eyes had small incision lenticule extraction, SMILE) and 25 eyes had subepithelial ablations (15 eyes had laser epithelial keratomileusis, LASEK and 10 eyes had photorefractive keratectomy, PRK). The mean preoperative spherical equivalent (SE) was - 2.92 ± 1.11 D (range from - 1.00 to -5.00 D). A total of 56 eyes (23.6%) suffered from myopic regression after CRS. Comparisons of individual and eye characteristics between the regression and non-regression groups revealed statistically significant differences in age, cumulative flight time, postoperative SE (at 6 months and current), uncorrected visual acuity (UCVA), accommodative amplitude (AA), positive relative accommodation (PRA), postoperative period, types of CRS and eye habits. Generalized propensity score weighting (GPSW) was used to balance the distribution of covariates among different age levels, types of CRS, cumulative flying time, postoperative period and continuous near-work time. The results of GPS weighted logistic regression demonstrated that the associations between age and myopic regression, types of CRS and myopic regression, continuous near-work time and myopic regression were significant. Cumulative flying time and myopic regression, postoperative period and myopic regression were no significant. Specifically, the odds ratio (OR) for age was 1.151 (P = 0.022), and the OR for type of CRS was 2.769 (P < 0.001). The OR for continuous near-work time was 0.635 with a P value of 0.038. CONCLUSIONS: This is the first report to analyze myopic regression after CRS in civilian pilots. Our study found that for each year increase in age, the risk of civilian pilots experiencing myopic regression was increased. Intrastromal ablations had a lower risk of long-term myopia regression than subepithelial ablations. There is a higher risk of myopic progression with continuous near-work time > 45 min and poor accommodative function may be related factors in this specific population.

Comparative visual outcomes of the first versus second eye following small-incision lenticule extraction (SMILE).

BACKGROUND: This study aimed to compare the visual outcomes of the first operated eyes with those of the second operated eyes following small-incision lenticule extraction (SMILE). METHODS: A total of 202 patients (404 eyes) underwent SMILE using the tear film mark centration method for myopia and myopic astigmatism correction. Baseline characteristics, objective optical quality, decentered displacement, induced corneal aberrations, and modulation transfer function (MTF) values were assessed. Linear regression analyzed the relationship between decentration and visual quality parameters, including corneal aberrations and MTF values. RESULTS: No significant difference was observed in objective visual quality, efficacy, and safety indexes between the two groups (all P > 0.05). The average decentered displacement for the first and second surgical eyes was 0.278 ± 0.17 mm and 0.315 ± 0.15 mm, respectively (P = 0.002). The horizontal coma in the first surgical eyes were notably lower than in the second (P = 0.000). MTF values at spatial frequencies of 5, 10, 15, and 20 cycles/degree (c/d) were higher in the first surgical eyes compared to the second (all P < 0.05). Linear regression indicated that high-order aberrations (HOAs), root mean square (RMS) coma, spherical aberration, horizontal coma, vertical coma, and eccentric displacement were all linearly correlated. Furthermore, MTF values exhibited a linear relationship with eccentric displacement across these spatial frequencies. CONCLUSIONS: There was no discernible difference in visual acuity, efficacy, or safety between the two operated eyes. Nonetheless, the first operated eyes exhibited reduced decentered displacement and demonstrated superior outcomes in terms of horizontal coma and MTF values compared to the second operated eyes following SMILE. The variations in visual quality parameters were linearly correlated with decentered displacement.

Refraction and topographic risk factors for early myopic regression after small-incision lenticule extraction surgery.

We sought to evaluate the topographic risk factors for early myopic regression after small-incision lenticule extraction (SMILE). A retrospective case‒control study was conducted, and individuals who underwent SMILE surgery were enrolled. Among them, 406 and 14 eyes were categorized into the nonregression and regression groups, respectively. The preoperative and postoperative parameters in the two groups were collected, including spherical refraction (SE), axial length (AXL) and topographic data. A generalized linear model was adopted to analyze the difference in each parameter between the two groups. After 6 months, UCVA decreased in the regression group, and SE increased in the regression group (both P < 0.05). The increase in the CCT at the thinnest point (P = 0.044), flat corneal curvature (P = 0.012) and TCRP (P = 0.001) were significantly greater in the regression group. Regarding the risk factors for myopic regression, preoperative SE, preoperative sphere power, preoperative AXL, preoperative flat corneal curvature, preoperative SA, early postoperative SE, early postoperative sphere power, early postoperative AXL and early postoperative CCT difference were significantly greater in the regression group (all P < 0.05). The SE, sphere power, AXL, preoperative flat corneal curvature, preoperative SA, and postoperative CCT difference correlate with early myopic regression after SMILE.

Femtosecond thin-flap laser assisted in situ keratomileusis for correction of post-penetrating keratoplasty ametropia: long-term outcome.

PURPOSE: To evaluate the long-term clinical outcomes of femtosecond thin-flap LASIK (femto-LASIK) for correction of refractive error after penetrating keratoplasty in keratoconus-affected eyes. SETTING: a private ophthalmology clinic. DESIGN: Prospective interventional case series. METHODS: This prospective interventional case series enrolled 22 eyes of 22 patients who underwent femto-LASIK for the management of post-penetrating keratoplasty ametropia. The refractive error, uncorrected (UDVA), and corrected (CDVA) distance visual acuities and vector analysis were reported in short-term and long-term period after surgery. RESULTS: The mean age was 32.7 ± 7.5 years (range, 23 to 47 years) at the surgery time. The average time between PK and femto-LASIK was 42.5 ± 31.7 months. The average follow-up duration after femto-LASIK was 81.2 ± 18.6 months. The mean preoperative UDVA significantly improved from 0.47 ± 0.15 logMAR to 0.35 ± 0.14 logMAR at 12 months (P = 0.048) and 0.4 ± 0.17 at final follow-up exam (P = 0.007). CDVA was 0.22 ± 0.1 at baseline which improved to 0.18 ± 0.15 and 0.15 ± 0.1 logMAR at 12 and 81 months, respectively. (Ps = 0.027, 0.014). The mean cylinder before surgery was - 5.04 ± 1.4D which significantly decreased to -1.5 ± 0.8 D at 12 months postoperatively. (P < 0.001). There was a significant increase in refractive astigmatism from 12 months to 81 months postoperatively (-3.1 ± 2.0, P = 0.002). At the final visit, the efficacy index was 0.83, and the safety index was 1.16. CONCLUSIONS: Despite the short-term outcome indicated that femo-LASIK was effective for correction of post-keratoplasty ametropia during short-term period, a notable regression in its effect was observed in the long-term follow-up. Therefore, the predictability of this technique might decrease in the long-term.

Changes in Corneal Epithelial Thickness in Different Areas After Femtosecond Laser-Assisted LASIK in Patients With High Astigmatism.

PURPOSE: To explore changes in corneal epithelial thickness (CET) after femtosecond laser-assisted laser in situ keratomileusis in patients with high astigmatism. METHODS: CET was measured at every intersection of the concentric circles and specific axes using AngioVue optical coherence tomography (Angio-OCT) preoperatively and 1 month postoperatively. The average thickness of corneal central, paracentral, and peripheral regions was the mean of the points within the central 2, 2 to 5, and 5 to 7 mm areas, respectively. Correlation analysis was performed to investigate the association between CET along different axes and other preoperative and postoperative parameters. RESULTS: Forty-two eyes of 28 patients were included. CET along the astigmatic (K1) and perpendicular (K2) axes in the central and paracentral areas increased (P < .001), whereas that along the K2 axis decreased in the peripheral area 1 month postoperatively (P = .001). The amount of CET change in the peripheral area between the K1 and K2 axes was significantly different (P < .001). In the central area, the change in CET along the K2 axis was positively correlated with ablation depth (r = 0.315, P = .042) and negatively with refractive power after surgery (r = -0.347, P = .024). In the peripheral area, the changes in CET along both K1 and K2 axes were negatively correlated with ablation depth (r = -0.431, P = .004; r = -0.387, P = .011, respectively). CONCLUSIONS: Epithelial modeling differed between the different astigmatism axes after refractive surgery. The compensatory response of the corneal epithelium is more pronounced along the steeper axis. [J Refract Surg. 2024;40(4):e239-e244.].

Visual Quality Assessment After FS-LASIK Using Customized Aspheric Ablation Profile for Age-Related Accommodation Deficiency Compensation.

PURPOSE: To evaluate clinical outcomes and visual quality 12 months after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) performed with the Custom-Q algorithm for correction of myopia with or without astigmatism and compensate for age-related accommodation deficiency. METHODS: Patients who had Custom-Q FS-LASIK for myopia and myopic astigmatism with age-related accommodation deficiency were included in this retrospective study. Distance, intermediate, and near visual acuities, objective and subjective refractions, Q-factor, corneal higher order aberrations (HOAs), accommodation function, defocus curve, contrast sensitivity, and a subjective questionnaire assessing visual quality were evaluated 12 months postoperatively. RESULTS: Clinical data of 43 cases were analyzed. The mean age was 42.02 ± 1.85 years (range: 40 to 48 years). At the 12-month follow-up visit, there were 43 (100%), 42 (97%), and 33 (77%) patients who achieved a binocular uncorrected distance, intermediate, and near visual acuity, respectively, better than 20/20 separately. Defocus curves revealed better distance vision in the dominant eyes, and the nondominant eyes performed better at intermediate and near vergence (P < .001). The Q-value and corneal spherical aberration coefficient were more positive in the dominant eyes than those in the nondominant eyes (P < .001). The accommodative amplitude and relative accommodation improved binocularly (P < .001). The questionnaire demonstrated high patient satisfaction with near vision, and no one reported having severe visual disturbance. CONCLUSIONS: For myopic patients with age-related accommodation deficiency, the Custom-Q algorithm proved to be an effective way to achieve acceptable near vision without compromising distance vision. [J Refract Surg. 2024;40(4):e245-e252.].

The association of pre-photorefractive keratectomy Schirmer-1 test value with postoperative corneal epithelial thickness, ocular surface discomfort, and visual acuity.

PURPOSE: To investigate the association of pre-photorefractive keratectomy Schirmer-1 test value with post-photorefractive keratectomy central corneal epithelial thickness, ocular surface disease index score, and uncorrected distance visual acuity. METHODS: Patients were categorized according to preoperative Schirmer-1 value: the normal Schirmer Group (n=54; Schirmer-1 test value, >10 mm) and the low Schirmer Group (n=52; Schirmer-1 test value, between 6 and 10 mm). We analyzed ablation depth, visual acuity, result of Schirmer-1 test (with anesthesia), tear film break-up time, ocular surface disease index score, central corneal epithelial thickness, and spherical equivalent refraction. RESULTS: We found significant differences between the groups in Schirmer-1 test value, tear film break-up time, and ocular surface disease index score, both preoperatively and postoperatively (p<0.001). The preoperative central corneal epithelial thicknesses of the two groups were similar (p>0.05). After photorefractive keratectomy, the Schirmer-1 test value and spherical equivalent refraction decreased in both groups (p<0.05), and ocular surface disease index scores and central corneal epithelial thickness values increased in the low Schirmer Group (p<0.001) but not in the normal Schirmer Group (p>0.05). The postoperative central corneal epithelial thicknesses of the low Schirmer Group were significantly higher than those of the normal Schirmer Group (p<0.001). Postoperative uncorrected distance visual acuity did not differ significantly between the two groups (p>0.05). CONCLUSIONS: In patients with low Schirmer-1 test values before photorefractive keratectomy, the corneal epithelium thickened and ocular surface complaints increased during the postoperative period. However, changes in the corneal epithelium did not affect the postoperative uncorrected distance visual acuity. To reduce postoperative problems on the ocular surface in these patients, we recommend that dry eye be treated before photorefractive keratectomy.

Interface fluid syndrome caused by the corneal perforation injury after small incision lenticule extraction: a case report.

BACKGROUND: To report a case of interface fluid syndrome (IFS) following traumatic corneal perforation repair after small incision lenticule extraction (SMILE). CASE PRESENTATION: A 23-year-old woman, with a past history of SMILE, was struck in the left eye with a barbecue prod and subsequently underwent corneal perforation repair at local hospital. Primary wound repaired with a single 10 - 0 nylon suture at the area of leakage. After the surgery, her best corrected visual acuity (BCVA) was 20/30. Four days later, she presented at our hospital with blurred vision, and interface fluid syndrome (IFS) was diagnosed. Intraoperative optical coherence tomography (iOCT) was used to guide the resuturing of the corneal perforation in the left eye, followed by anterior chamber gas injection. At the first postoperative month, the BCVA was 20/25. The corneal cap adhered closely to the stroma, the surface became smooth. CONCLUSIONS: This case illustrates that any corneal perforation following lamellar surgery, including SMILE, may lead to IFS. It is crucial to consider the depth of corneal perforation, and intraoperative optical coherence tomography (iOCT) plays a unique role in the repair procedure.

Biochemical component analysis of human myopic corneal stroma using the Raman spectrum.

PURPOSE: This study aimed to measure the Raman spectrum of the human corneal stroma lens obtained from small incision lenticule extraction surgery (SMILE) in Asian myopic eyes using a confocal Raman micro-spectrometer built in the laboratory. METHODS: Forty-three myopic patients who underwent SMILE with equivalent diopters between - 4.00 and - 6.00 D were selected, and the right eye data were collected. Corneal stroma lenses were obtained during surgery, and the Raman spectra were measured after air drying. The complete Raman spectrum of human myopic corneal stroma lens tissue was obtained within the range of 700-4000 cm-1. RESULTS: Thirteen characteristic peaks were found, with the stronger peaks appearing at 937 cm-1, corresponding to proline, valine, and the protein skeleton of the human myopic corneal stroma lens; 1243 cm-1, corresponding to collagen protein; 1448 cm-1, corresponding to the collagen protein and phospholipids; and 2940 cm-1, corresponding to the amino acid and lipids, which was the strongest Raman peak. CONCLUSION: These results demonstrated that Raman spectroscopy has much potential as a fast, cost-effective, and reliable diagnostic tool in the diagnosis and treatment of eye diseases, including myopia, keratoconus, and corneal infection.

Suboptimal visual outcome after femto-LASIK ablation in a high myopic patient.

A 28-year-old nurse had an aberration-free femto-laser in situ keratomileusis (LASIK) performed for her myopia of -6.25 -0.50 × 096 and -6.75 -0.50 × 175 in the right and left eye, respectively. Corrected distance visual acuity (CDVA) preoperatively was 20/16. Preoperatively, there were no abnormalities on Scheimpflug imaging, and a pachymetry of 585 µm was measured in both eyes. Flap thickness was 115 µm. The patient was quite nervous during the surgery. Since the surgery, her uncorrected distance visual acuity (UDVA) and CDVA are suboptimal at 20/30 and 20/20 in the right eye, and 20/20 and 20/16 in the left eye. 3 months postoperatively, there is a stable manifest refraction of +0.25 -1.25 × 030 and +0.25 -0.00 × 0. The keratometric astigmatism in the Scheimpflug imaging is 1.2 diopter (D) × 114 and 0.4 D × 78 in the right and left eyes, respectively (FIgures 1 and 2). Thinnest pachymetry is 505 µm and 464 µm in the right and left eye, respectively. Her wavefront analysis shows refraction in a 6 mm zone of -0.99 -1.22 × 32 and -0.91 -0.36 × 136. The cycloplegic refraction is 1.25 -1.00 × 023 and +1.00 -0.25 × 006 (Figures 3 and 4). What is the cause of the suboptimal visual outcome in this case? What would be your treatment strategy to improve visual outcome?

Fourier analysis of corneal irregular astigmatism after small-incision lenticule extraction and transepithelial photorefractive keratectomy: A comparative study.

To compare changes in the spherical component, regular astigmatism, and irregular astigmatism of the anterior surface of the cornea after small-incision lenticule extraction (SMILE) and transepithelial photorefractive keratectomy (TransPRK). Fifty-six patients underwent SMILE in 56 eyes, and 68 patients underwet TransPRK in 68 eyes. The right eye was chosen to enter the group. Six months after the procedure, Scheimpflug images were acquired, and Fourier analysis of the anterior surface of patients' corneas was performed using the Pentacam built-in software. Fourier parameters encompass various measurements such as the steepest radius of the curvature and average eccentricity of the spherical components (SphRmin and SphEcc), maximum decentration (MaxDec), central and peripheral regular astigmatism (regular astigmatism at the center [AstC] and regular astigmatism at the periphery [AstP]), and irregularity (Irr). At 6 months postoperatively, SphEcc decreased significantly (P < .001), MaxDec increased significantly (P < .001), and Irr increased insignificantly (P = .254) in the SMILE group. SphEcc decreased significantly (P < .001) and MaxDec and Irr increased significantly (P < .001) in the TransPRK group. TransPRK caused greater changes in SphEcc, MaxDec, and Irr on the anterior corneal surface than SMILE (P < .05). The amount of MaxDec-induced changes in SMILE and TransPRK was significantly correlated with the amount of higher-order aberrations and spherical aberration changes (P < .05). SMILE and TransPRK increase overall irregular astigmatism on the anterior surface of the cornea, more so with TransPRK, where changes in decentration are associated with with increased higher-order aberrations.

308 nm excimer laser and tacrolimus ointment in the treatment of facial vitiligo: a systematic review and meta-analysis.

This study aimed to investigate the effects and safety of 308 nm excimer laser (308 nm EL) and tacrolimus ointment (TO) in the treatment of facial vitiligo (FV). We searched Cochrane Library, PUBMED, EMBASE, CNKI, and WANGFANG from inception to June 1, 2023. Outcomes included overall response rate (ORR), total adverse reaction rate (TARR), recurrence rate at 3-month (RR-3) and recurrence rate at 6-month (RR-6). The outcome data were presented as odds ratios (OR) with 95% confidence intervals (CI). The risk of bias was assessed by Cochrane risk-of-bias tool and data analysis was performed by RevMan 5.4 software. This study included a total of 19 trials involving 2085 patients. When comparing 308 nm EL monotherapy with 308 nm EL plus TO, significant differences in the ORR (OR = 4.29, 95% CI [2.97, 6.19], I2 = 0%, P < 0.001), RR-3 (OR = 0.18, 95% CI [0.05, 0.69], I2 = 0%, P = 0.01), and RR-6 (OR = 0.38, 95% CI [0.14, 1.03], I2 = 39%, P = 0.06) were found between the two managements. When comparing TO monotherapy with TO plus 308 nm EL, its results showed significant differences in the ORR (OR = 4.21, 95% CI [2.90, 6.11], I2 = 0%, P < 0.001), TARR (OR = 0.42, 95% CI [0.22, 0.81], I2 = 4%, P = 0.009), and RR-3 (OR = 0.32, 95% CI [0.01, 8.03], P = 0.49) between the two modalities. The results of this study suggest that the combination of 308 nm EL and TO is more effective than either treatment alone for the treatment of FV.

Photorefractive Keratectomy in Student Naval Aviators: Outcomes of the U.S. Navy Accessioning Study.

PURPOSE: To present the outcomes of the U.S. Navy photorefractive keratectomy (PRK) accessioning study conducted between 2000 and 2005 that helped lead to the acceptance of laser vision correction within the U.S. aviation industry. METHODS: In this prospective masked study, a total of 301 students who had PRK and underwent naval flight training were compared to 4,368 untreated peers. Three training pipelines were compared: propeller/jet transport, jet fighters, and helicopters. The evaluated metrics were flight and academic performance (assessed for the primary and advanced stage of the training as normalized Navy Standard Score [NSS]), as well as the student attrition rate from training. RESULTS: The attrition rate was lower in the PRK group compared to controls (15.9% vs 23.2%; P = .004). In the primary stage of training, students who had PRK outperformed controls in flight training performance in the propeller/jet transport pipeline (average NSS after PRK: 52.4 ± 7.5 vs controls: 50.7 ± 6.4, P = .02), but the flight performance in the jet fighter and helicopter pipelines was comparable between the two groups. Academic performance in the primary stage of training was approximately 7% to 13% higher in students who had PRK for all training pipelines. During the advanced training stage, there was no difference in the flight performance between the groups in any of the presented pipelines. Academic performance was significantly better for students who had PRK in the helicopter pipeline (51.2 ± 11.0 vs 46.7 ± 11.7 P < .001) but comparable between the two groups in the remaining pipelines. CONCLUSIONS: Refractive surgery did not have adverse effects on flight performance metrics. Pilots who had PRK had comparable or better outcomes than their untreated peers. [J Refract Surg. 2024:40(3):e173-e181.].

Comprehensive Assessment of Posterior Corneal Asphericity Change Calculated by Tangential Radius of Curvature After FS-LASIK and SMILE.

PURPOSE: To evaluate changes in posterior corneal asphericity (ΔQ) using the tangential radius of curvature after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) procedures. METHODS: One hundred twenty right eyes of myopic patients who underwent either FS-LASIK or SMILE procedures were analyzed using Sirius 3D corneal topography for assessment. The tangential radius was employed to calculate both preoperative and postoperative posterior corneal Q-values across each semimeridian. After both surgical interventions, the ΔQ value variations across the 360° semimeridional regions of the posterior corneal surface were compared. RESULTS: A marked postoperative increase in the posterior corneal Q-value was documented. No significant differences were noted between the postoperative Q-values or ΔQ-values of the two surgical approaches. Among patients with moderate myopia, postoperative Q-value exhibited considerably lower increases and ΔQ-value significantly smaller than their counterparts with high myopia. Moreover, the fluctuation in ΔQ across semimeridional regions was less evident in patients with moderate myopia than in those with high myopia. Notably, the degree of ΔQ fluctuation across semimeridional regions was similar between both surgical categories. These data offer insights into variations in the posterior corneal surface after refractive surgeries depending on the degree of myopia, illuminating their clinical relevance. CONCLUSIONS: Both FS-LASIK and SMILE introduce notable changes to posterior corneal asphericity among patients with different myopia intensities. Furthermore, the influence on the asphericity across the entire posterior surface is similarly distributed between FS-LASIK and SMILE techniques. [J Refract Surg. 2024;40(3):e133-e141.].

[Peripheral sterile corneal infiltrates after small incision lenticule extraction].

A 31-year-old female patient with refractive error in both eyes underwent small incision lenticule extraction. On the 4th day after surgery, arc-shaped peripheral corneal infiltrates appeared in the right eye. Tobramycin and dexamethasone eye drops, 0.3% gatifloxacin eye drops, and a corneal bandage lens were applied to the eye. After bacterial infection was ruled out, dexamethasone sodium phosphate was injected subconjunctivally near the corneal lesion. The symptoms improved and the corneal lesion subsided afterwards.

Clinical outcomes of SMILE and WFG-LASIK used to treat myopia and astigmatism: A systematic review and meta-analysis.

PURPOSE: To evaluate the safety, efficacy and postoperative visual quality of small incision lenticule extraction (SMILE) and Wavefront-Guided Laser in situ keratomileusis (WFG-LASIK) and to analyze their efficacy in correcting astigmatism. METHODS: A systematic literature search was performed using Cochrane Collaboration methodology. Databases searched included PubMed, Embase, the Cochrane Library and Web of Science. RevMan software version 5.3.0 was used for meta-analysis. RESULTS: A total of 976 eyes were included in 8 studies, of which 539 eyes underwent SMILE and 437 eyes underwent WFG-LASIK. There were no statistically significant differences in the proportion of eyes achieving uncorrected distance visual acuity of 20/20 or better (P=0.18), the proportion of eyes within±0.50 diopter of target refraction postoperatively (P=0.10), or the postoperative magnitude of cylinder (P=0.10). Regarding the Alpins vector analysis of astigmatism, there was no statistically significant difference in the surgical magnitude of error (P=0.09) between the two groups. WFG-LASIK has a lower surgical angle of error (P= 0.002) and higher surgical correction index of cylinder (P=0.03) than SMILE. In terms of aberrations, higher order aberrations (P=0.46), spherical aberrations (P=0.22) and trefoil (P=0.56) were not statistically different, while WFG-LASIK induced less coma than SMILE surgery (P=0.02). CONCLUSION: Both SMILE and WFG-LASIK are safe and effective ways to correct myopia and astigmatism. Compared with SMILE, WFG-LASIK has a lower surgical angle of error, higher surgical correction index of cylinder and induces less coma.

Impact of removing soft contact lenses 1 day versus 1 month before surgery on the outcomes of microkeratome laser in situ keratomileusis.

PURPOSE: To compare the outcomes, safety, efficacy, and predictability of microkeratome laser in situ keratomileusis (LASIK) 24 h and one month or more after removing soft contact lenses. SETTING: ULTRALASIK Eye Center, Dubai, United Arab Emirates. METHODS: The patients were divided based on the time of discontinuation of the soft contact lenses before LASIK (Group 1 at 24 h and Group 2 at one month or longer), and the two groups were well matched. Schirmer's testing, tear break-up time, corrected distance visual acuity, uncorrected distance visual acuity, manifest refraction spherical equivalent, and infection rate were evaluated preoperatively and at one week, one month, and six months after treatment. RESULTS: Group 1 (G1) comprised 1025 eyes, and group 2 (G2) had 1052 eyes. The groups were comparable preoperatively. The overall-mentioned outcomes were comparable between groups with uncorrected distance visual acuity of - 0.084 ± 0.12 logMAR in G1 and - 0.078 ± 0.17 logMAR in the G2 at 6 months (P = 0.322). Tear break-up time as well as Schirmer's testing results was also comparable with no evidence of increased risk of dry eyes or non-inflammatory complications in any of the groups on follow-up visits at 1 week (P = 0.421), 1 month (P = 0.101), and 6 months (P = 0.399) postoperatively. Finally, no infectious complications were recorded in either of the groups. CONCLUSION: With the absence of corneal warpage, no statistical or clinical difference in microkeratome LASIK outcomes and safety was spotted between the groups despite the difference in SCL discontinuation time before the procedure.

Refractive outcomes of small lenticule extraction (SMILE) Pro® with a 2 MHz femtosecond laser.

PURPOSE: To evaluate the initial visual outcomes of Small Incision Lenticule Extraction (SMILE) Pro® using a 2 MHz femtosecond laser (VisuMax 800, Carl Zeiss Meditec) and to assess the efficacy, safety, predictability, accuracy, and complication rate. METHODS: This retrospective analysis included eyes which underwent the SMILE Pro® procedure using VisuMax 800 femtosecond laser to correct myopia. All surgeries were performed by one surgeon (DB). Follow-up was conducted 3 months postoperatively to evaluate visual outcomes after neuroadaptation, corrected visual acuity (CDVA) and intra- and postoperative complications. RESULTS: One hundred and fifty-two eyes of 82 patients (mean age 31 ± 6 years) results at 3 months are presented. The mean spherical equivalent (SE) was - 4.44 ± 1.86 D preoperatively while -0.24 ± 0.32 D postoperatively. 99% of eyes achieved SE within ± 1.0 D of attempted correction and 91% were within ± 0.5 D. Efficacy index was 0.93 while the safety index was 1. No complications occurred intra- or postoperatively. No eyes lost more than 1 line of their preoperative CDVA. All highly myopic eyes (- 6.25 to - 10.00 D; n = 18) achieved 20/20 at 3 months postoperatively and were within 0.5 D from the attempted SE and no eyes lost more than 1 line of CDVA. CONCLUSION: The SMILE Pro® is a safe, efficient, and predictable procedure for the treatment of myopia and myopic astigmatism, with comparable results of conventional SMILE surgery. High myopic eyes achieve better results than low and moderate myopia. No complications were recorded in our patients.

Prevention and Treatment of Persistent Epithelial Defects After Common Refractive Surgery Procedures.

PURPOSE: To discuss the prevention and treatment of persistent epithelial defects after the most common refractive surgeries-photorefractive keratectomy, laser in situ keratomileusis, or small incision lenticule extraction. METHODS: PubMed was used to search the medical literature. RESULTS: Persistent epithelial defects are infrequent after photorefractive keratectomy, laser in situ keratomileusis, or small incision lenticule extraction. In the authors' opinion, any persistent epithelial defect present at 1 week or beyond after surgery should be treated aggressively with a properly fit bandage contact lens, lubrication with non-preserved artificial tears, and treatment of any eyelid abnormalities, including nocturnal lagophthalmos. Consideration should be given for presumptive treatment for herpes simplex virus or varicella zoster virus infection. If the persistent epithelial defect does not close within 2 weeks, then other measures should be considered, such as autologous serum drops, topical losartan, amniotic membranes, and topical human recombinant nerve growth factor to limit corneal scarring fibrosis and microbial infection. CONCLUSIONS: Persistent epithelial defects are among the most feared complications of refractive surgery. Timely and aggressive treatment should be instituted to close the epithelium prior to the development of scarring fibrosis and/or microbial corneal infection. [J Refract Surg. 2024;40(2):e117-e124.].

Factors Predicting the Need for Re-treatment After Laser Refractive Surgery in Patients With Mixed Astigmatism.

PURPOSE: To identify risk factors that increase the likelihood of re-treatment following refractive surgery in patients with mixed astigmatism. METHODS: This was a retrospective study including patients who underwent either laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between 2000 and 2019 and had mixed astigmatism (spherical error of +0.50 D or greater and spherical equivalent of less than 0.00 diopters [D]). Patients were divided into two groups according to whether they underwent re-treatments during the study period. RESULTS: Overall, 785 eyes (785 patients) were included. In total, 5.2% of the eyes (n = 41) underwent re-treatment. The re-treatment group was more likely to have preoperative high astigmatism (80.5% vs 48.3%, P < .001), moderate to high hyperopia (36.6% vs 22.3%, P = .035), and to have undergone surgery earlier during the study period (P < .001). They were also more likely to have undergone surgery using the Wave-Light EX200 rather than the EX500 laser platform (Alcon Laboratories, Inc) (P < .001), have a treated optical zone of 6 mm rather than 6.5 mm (P < .001 for both), and their maximum ablation depth was greater (P < .001). There was no difference between the re-treatment and control groups regarding procedure type (PRK vs LASIK). Binary logistic regression found preoperative high astigmatism (odds ratio = 3.97, P < .001) and the type of laser platform used (EX200, odds ratio = 7.78, P < .001) as the only independent factors associated with re-treatment. CONCLUSIONS: Re-treatment rates following correction of mixed astigmatism were 5.2% over 20 years. Use of a sixth-generation laser platform significantly reduced the risk of re-treatment. Presence of high astigmatism is a significant risk factor for re-treatment. There was no difference in retreatment risk between PRK and LASIK. [J Refract Surg. 2024;40(2):e73-e78.].