Myopic Astigmatism Research Articles (Page 1)

To investigate the changes in posterior corneal elevation within 6mo after small incision lenticule extraction (SMILE) surgery for myopia and myopic astigmatism in patients with thin corneas. A prospective study included patients with thin corneas (preoperative thinnest corneal thickness ranging from 480 to 520 µm) who underwent SMILE for myopia or myopic astigmatism. Corneal topography and posterior corneal elevation were assessed using Pentacam HR at three time points: preoperatively, 1mo, and 6mo postoperatively. The measured parameters included thinnest point elevation (PTE), posterior maximal elevation (PME), posterior central elevation (PCE), and 24 additional reference points. A total of 106 eyes from 106 patients (age range: 18-34) were included in the study. Uncorrected distance visual acuity (UDVA) improved significantly, with a mean logMAR value of -0.07±0.06 at the final follow-up visit. Measurements of posterior corneal elevation showed no significant changes in most points, hemispheres, and meridians at 6mo postoperatively. Notably, only two points, ∆E2mm-45° and ∆E2mm-90°, exhibited statistically significant elevation changes: the elevation of ∆E2mm-45° increased from -2.3±4.99 to -1.0±5.9 µm (P=0.0037), and that of ∆E2mm-90° increased from -16±7.53 to -15±7.4 µm (P=0.016). However, these changes were within the measurement error range of the Pentacam HR (±5 µm in a 5 mm area). SMILE surgery is a safe and stable procedure for correcting myopia or myopic astigmatism in patients with thin corneas, as evidenced by the stability of posterior corneal elevation.

Objectives: The objective is to investigate the percentage of different types of refractive errors in school-going children aged 5–14 years at a tertiary eye care centre in Western India. Primary objective: To determine the percentage of different types of refractive errors in school-going children aged 5–14 years. Secondary objectives: (1) To determine demographic variation of types of refractive error based on gender and geographical location. (2) To determine the family history of refractive error as a risk factor for the development of refractive error. Materials and Methods: A descriptive cross-sectional study was done in a tertiary eye care centre in Western India after obtaining ethical approval from the institutional ethics committee. A convenience sampling method was used. Data from 402 eyes of 201 children with refractive error satisfying the selection criteria were collected and analysed. Results: The mean age of the children was 11.01 years, with a standard deviation of 2.44 years. Of 402 eyes examined, the frequency of simple myopia was 28.61%, simple myopic astigmatism was 11.94%, compound myopic astigmatism was 40.05%, simple hypermetropia was 3.73%, simple hypermetropic astigmatism was 5.47%, compound hypermetropic astigmatism was 4.48% and mixed astigmatism was 3.98%. Out of 402 eyes examined, 7 eyes did not have any refractive errors, which constituted 1.74% of the total eyes. The prevalence is higher in the Central Zone of Ahmedabad and among the 9–12 age group. In our study, we found out that compound myopic astigmatism is more prevalent. The secondary outcomes of our study are as follows: The maximum number of patients was seen in the age group of 9–12 years (198/402 i.e. 49.25%). This result was statistically significant at P = 0.001. The most common refractive error in this age group was found to be myopia (<−3D) (all categories), which is 50.5% of the total children seen in the 9–12 years age group (P = 0.001). This result can be explained by the use of electronic devices in children for online classes, etc. The result was not statistically significant for gender. In our study, the maximum number of children with refractive errors was from the central zone of Ahmedabad (138/402, i.e., 34.32%). The P value was statistically significant at 0.005. This can be explained by the fact that our hospital is located in the central zone of Ahmedabad; thus, the patients from the catchment area were more. In our study, the family history was positive in 129 out of 333 myopic eyes, which is 38.73%, and 6 out of 62 hypermetropic eyes, i.e., 9.67%. This result was statistically significant at a P = 0.001 Conclusion: Regular screening of refractive error is recommended among school-going children, especially in children with a positive family history of refractive error.

PurposeEvaluation of the incidence and variability of ocular manifestations in children with neurofibromatosis type 1.MethodsIn this study, the files of 71 children aged 0-18 years with neurofibromatosis type 1 were retrospectively analyzed. Child age groups were categorized as 0-6, 7-12, and 13-18 years. In cycloplegic refractive examination, ≥-0.50 Diopter (D) values in spherical equivalents were recorded as myopia, ≥+2.0 D as hypermetropia, and ≥±1.0 D cylindrical values as astigmatism. Patients with a difference of ≥1 D in spherical or cylindrical equivalents between the 2 eyes were considered anisometropic. Amblyopia was defined as a best-corrected visual acuity ≤0.8 with Snellen chart and a difference of at least 2 lines between both eyes. The presence of 2 or more iris Lisch nodules (iris hamartoma) was considered positive.ResultsOf the 71 patients whose ocular findings were evaluated, 32 (45.1%) were boys and 39 (54.9%) were girls. According to age and gender, myopia (P = .878), hypermetropia (P = .329), myopia astigmatism (P = .761), hypermetropia astigmatism (P = .457), mixed astigmatism, anisometropia (P = .836), amblyopia (P = .551), emmetropia (P = .234), optic glioma (P = .598), strabismus (P = .219), and ptosis (P = .099) showed no significant difference (P > .05). A statistically significant difference was observed in the Lisch nodule, one of the ocular examination findings, according to age and gender (P < .05).ConclusionsPediatric patients with neurofibromatosis type 1, with common ocular manifestations, should undergo a comprehensive ophthalmologic examination. Early diagnosis and treatment are crucial for improving the clinical course of the disease and preserving vision.

To evaluate refractive and topographic outcomes following photorefractive keratectomy (PRK) with 75% angle kappa (P-Dist) compensation in myopic eyes. This retrospective study included 127 right eyes of patients with myopia and/or myopic astigmatism, who underwent wavefront-optimized PRK, incorporating 75% P-Dist compensation. Visual, refractive, topographic, aberrometric, and point-spread function (PSF) measurements were recorded preoperatively and at 1, 3, and 6 months postoperatively. The mean P-Dist was 232.13±121.78 μm (range: 31.69-769.84 μm). Eyes were grouped by mean P-Dist: group-1 (<232.13 μm, small-angle kappa, n=67) and group-2 (>232.13 μm, large-angle kappa, n=60). Preoperative P-Dist correlated with root-mean-square of higher-order aberrations (RMS-HOAs) (r=0.24, P =0.01) and coma (r=0.381, P <0.001). Group-2 had higher preoperative coma ( P =0.001). At 6 months, the percentage of eyes within ±0.50 diopters (D) spherical equivalent and≤0.50 D astigmatism, visual acuity, asphericity, mean pupil power, HOAs, and PSF were similar between the groups ( P >0.05 for all). No correlation was found between preoperative P-Dist and postoperative HOAs or PSF changes ( P >0.05 for all). PRK with 75% angle kappa compensation yields comparable refractive and topographical outcomes in myopic eyes with small- and large-angle kappa. In eyes with a significant angle kappa, aligning ablation with P-Dist may not induce additional corneal refractive or topographical changes.

To assess visual and refractive outcomes of 1,500 eyes that underwent small incision lenticule extraction (SMILE) with the VisuMax 800 femtosecond laser (Carl Zeiss Meditec AG). This retrospective study includes 1,500 eyes of 770 patients younger than 45 years with corrected distance visual acuity (CDVA) of 20/20 or better who were treated with SMILE using the VisuMax 800. The surgery was performed by an experienced surgeon using a standard technique and 3-month follow up data were analyzed. A total of 1,500 eyes of patients with a mean age of 27.25 ± 4.746 years (39.5% men and 60.52% women) were included in this study. At 3 months, 98% of eyes had uncorrected distance visual acuity (UDVA) of 20/20 or better with an efficacy index of 1.011. Mean preoperative spherical equivalent (SE) was -4.170 ± 1.860 and -0.025 ± 0.120 diopters (D) at 3 months (P < .001). A total of 18.4% gained one line of CDVA and 9.2% lost one line with a safety index of 1.085. Postoperative SE was within ±0.50 and ±1.00 D in 99% and 100% of eyes, respectively. A total of 98.4% and 100% of eyes showed astigmatism of 0.50 and 1.00 D or less, respectively. No eyes lost two or more lines of CDVA. At 3 months, the Objective Scatter Index score was 0.844 ± 0.486, which was close to preoperative values (0.733 ± 0.871), with a mean change of 0.11. Subgroup analysis was done based on grade of myopia and age. The VisuMax 800, with centration guidance (CentraLign) and cyclotorsion adjustment features (OcuLign), showed safe and effective outcomes for the treatment of myopia and myopic astigmatism in a large cohort of 1,500 eyes.

Prospective Intraindividual Comparison of Automated Customized Ray-Tracing-Guided versus Wavefront-Optimized LASIK.

Keratoconus in children has been diagnosed relatively recently, which is explained by the difficulties of examination (low compliance, concomitant diseases). The peculiarity of keratoconus in children is that it can develop unnoticed, often remaining unrecognized until adolescence, which creates additional difficulties in early diagnosis and treatment. The corneal collagen crosslinking (CXL) method, as a minimally invasive method, is a priority in the treatment of pediatric patients. Despite the confirmed effectiveness in short-term studies, long-term results remain a key aspect for assessing the sustainability of the therapeutic effect. This article presents a clinical case of a patient with keratoconus, observed for 5 years after crosslinking. Objective: To assess the condition of the cornea and ocular surface in a pediatric patient diagnosed with: OU High myopia, myopic astigmatism. OD Keratoconus stages 2-3 operated (corneal crosslinking was performed in 2020), OS Keratoconus stages 1-2. Results: Patient N., 17 years old, was observed with a diagnosis of keratoconus stages 2-3 in the right eye. Crosslinking was performed 5 years ago, currently showing stable remission. A standard and specialized ophthalmological examination was performed. Conclusion: Corneal cross-linking is an effective technique that allows for the stabilization of progressive keratoconus in children (5-year follow-up). The effectiveness of the method has been confirmed using modern high-tech methods, such as corneotopography and the Ocular Response Analyzer (ORA).

Soft toric contact lens correction of moderate astigmatism improves digital reading performance and oculomotor behaviour: An eye movement study.

Background. According to the literature, diffuse lamellar keratitis (DLK) develops in 4.3–37.5% of cases following excimer laser correction (ELC), with its pathogenesis modulated by the balance between proinflammatory interleukins and growth factors. Aim. To establish the prognostic role of interleukin-8 (IL-8) and transforming growth factor-β2 (TGF-β2) in the development of DLK after ELC using LASIK and Femto-LASIK methods. Material and methods. 180 patients (360 eyes) with myopia or myopia with myopic astigmatism were operated on. Patients in group 1 (182 eyes) underwent LASIK ELC, patients in group 2 (178 eyes) – Femto-LASIK. All patients were examined 1 week, 1 month, 1.5 and 2.5 years after ELC. In group 1, the number of cases with DLC at all observation periods was 29 (15.9%), in group 2 – 37 (20.8%). The control group included 10 patients from each group who did not develop DLC at any of the observation periods. The content of TGF-β2 and IL-8 in the tear fluid was determined by enzyme-linked immunosorbent assay. Results. In patients without DLC, the content of TGF-β2 and IL-8 in the tear fluid did not change significantly during the observation period. In patients with DLC, TGF-β2 was significantly increased (2.3-3.4 times compared to patients without DLC; p&lt;0.05) at all time points, which was more pronounced when using the Femto-LASIK technique than LASIK. The content of IL-8 in patients with DLC was increased (2.3-3.4 times compared to patients without DLC; p&lt;0.05), but only at early times (after 1 week – 3.1-3.2 times compared to control; p&lt;0.05). The content of IL-8 in the LASIK and Femto-LASIK groups did not differ. After 1 week, but not at other times, a strong correlation between TGF-β2 and IL-8 was noted (r=+0.73; p=0.04). Both markers were associated with the development of DLC (for TGF-β2 r=+0.84, for IL-8 r=+0.60; p&lt;0.001). Calculation of clinical Cut-Off thresholds for DLC development according to the Youden Index established a limit for TGF-β2 – 3237 pg/ml (sensitivity and specificity – 100%). The area under the ROC curve AUC=1.00 (95% CI 1.00-1.00), which indicated a very strong relationship between TGF-β2 content and DLC and the possibility of its use as a biomarker of DLC at all terms. Cut-Off for IL-8 was 4.02 pg/ml, the prognosis had satisfactory characteristics only at early terms. Conclusion. Thus, for the first time in the Ukrainian population, we have established the crucial importance of TGF-β2 accumulation for the development of DLC at different times (from 1 week to 2.5 years) after ELC by LASIK and Femto-LASIK methods.

Abstract: PURPOSE: Spectacles are a popular method for correcting refractive errors and provide optimal visual acuity for most wearers. However, spectacle intolerance remains a significant challenge in vision correction. The aim of this study is to identify the common causes of spectacle intolerance in Saudi wearers. METHODS: This cross-sectional, multi-optical center study was conducted across various regions of Saudi Arabia between August 2023 and April 2024. It included spectacle wearers aged 3–80 years who returned their new spectacles due to intolerance or discomfort. Spectacle prescriptions were compared to the dispensed lenses, and any discrepancies were corrected. Refraction was rechecked when necessary. RESULTS: The prevalence of spectacle intolerance was 3% of 101 participants who did not tolerate or found their new spectacles uncomfortable, with a mean age of 33.4 ± 15.3 years. The most common reasons for spectacle intolerances were incorrect prescription (38.6%), decentered lenses (21%), adaptation difficulties (20.8%), improper fitting of lenses compared to the prescribed ones (9.9%), and nonprescription-related issues: misunderstanding use of spectacle, antireflection coatings, frame fashion, material, tint problem, and hard coating (3%–15.9%). The most predominant refractive prescription was myopic astigmatism (44%), presbyopia (24%), and myopia (16%). CONCLUSION: The prevalence of spectacle intolerance in Saudi Arabia was 3%. The study found that myopic astigmatism, presbyopia, and myopia were the most frequently spectacle intolerances. The main reasons for spectacle intolerances were incorrect prescription, decentered lenses, adaptation difficulties, and improper fitting of lenses. Age and gender had no effect on spectacle intolerance.

To compare the U.S. Food and Drug Administration (FDA) premarket approval (PMA) trials of topography-guided laser in situ keratomileusis (TG-LASIK) and ray tracing-guided LASIK (RT-LASIK) for the treatment of myopia and myopic astigmatism. This comparative study was conducted between TG-LASIK (P020050/S012; Alcon Laboratories, Inc., Fort Worth, TX, USA) with Allegretto Wave Eye-Q laser and topography-guided custom ablation treatment planning software, and "WaveLight Plus" RT-LASIK (P020050/S043; Alcon Laboratories, Inc.) using the WaveLight EX500 excimer laser and InnovEyes Sightmap. Clinical outcomes were compared, including visual and refractive measures, astigmatic correction, mesopic contrast sensitivity, higher-order aberrations, and patient-reported outcomes. This analysis included 249 eyes (212 patients) that underwent TG-LASIK and 336 eyes (168 patients) that underwent RT-LASIK. At 12months, uncorrected distance visual acuity of 20/16 or better (64.8% TG-LASIK vs. 70.2% RT-LASIK) and 20/20 or better (92.6% TG-LASIK vs. 94.4% RT-LASIK) did not differ statistically between platforms. However, more TG-LASIK eyes had 20/10 or better (15.7% vs. 2.5%, P < 0.001) and 20/12.5 or better (34.4% vs. 26.4%, P = 0.044) than RT-LASIK eyes. Both platforms demonstrated comparable refractive predictability and stability (P > 0.05). For preoperative cylinder between - 1.00 to - 4.00 D, RT-LASIK showed greater astigmatic overcorrection (P < 0.05). At 3months, RT-LASIK showed higher mesopic contrast sensitivity at 3, 6, and 12 cycles per degree under glare, with more eyes achieving clinically significant gains compared to TG-LASIK (P < 0.001). Both platforms induced changes in total higher-order aberrations, although not clinically significant. RT-LASIK also reduced spherical aberration from baseline. Both procedures showed a reduction in symptom severity for glare, halos, starburst, double vision, and dry eye. While TG-LASIK showed superior visual acuity outcomes, RT-LASIK was associated with higher contrast sensitivity; however, both platforms demonstrate excellent visual and refractive outcomes. The majority of published studies are consistent with FDA PMA trends, showing potential reductions in spherical aberration and higher rates of 20/20 or better visual acuity with RT-LASIK.

myopia has been traditionally viewed as a consequence of the interplay between genetic, ethnic, and environmental risk factors. This disease affects people’s psychological development. The aim – is to assess the peculiarities of emotional, intellectual, and communicative character traits of the person left with myopia in various manifestations of anxiety and depression. 200 patients with moderate myopia and mild myopic astigmatism in both eyes were examined. The «Kettel Test» was used to study the characteristics of the patient’s character, and the Hospital Anxiety and Depression Scale was used to identify the levels of depression and anxiety. Methods of mathematical statistics were used for mathematical processing of the research results. The main characteristics of communicative features of patients with myopia are outgoing, supportive, somber, prudent, uninhibited, bold, docile, submissive, suspicious, private, shrewd, and self-sufficient. The main intellectual features of people with myopia are imaginative, close-minded, and traditional. The main emotional features of people with myopia are stable, calm, conscientious, apprehensive, organized, precise, stressed, and tough-minded. Patients with myopia and middle-level anxiety/depression were more close-minded, traditional, and tough-minded. Persons with a high level of anxiety/depression were more reserved, detached, somber, prudent, trusting, outgoing, social, and concrete thinkers. Determination of the prevalence of anxiety and depression, characterological features of patients with myopia if they are present, and compliance features of such patients should be the basis of their rehabilitation programs. Determination of emotional, intellectual, and communicative features of patients with myopia should be based on the study of etiopathogenetic factors of the formation of nosogenies of this pathology and the development of conceptual approaches to rehabilitation, improving their quality of life.

Background. Myopia is the most common refractive disorder of the eye globally. One of the methods for surgical correction of myopia is ReLEx® SMILE (Small Incision Lenticule Extraction). The impact of baseline myopia severity on postoperative outcomes remains debated due to inconsistent literature findings. Purpose: To assess the association between the outcomes of ReLEx® SMILE and baseline myopia severity. Materials and methods. This prospective study included 78 patients (156 eyes) aged 18 to 35 years who underwent refractive correction using the ReLEx® SMILE procedure. Patients were stratified into three groups by myopia severity: Group I – low myopia (n = 31 eyes), Group II – moderate myopia (n = 87 eyes), Group III – high myopia (n = 38 eyes). The follow-up period was six months. Results. Uncorrected visual acuity (UCVA) of 0.9–1.0 was achieved in 100% (Group I), 93% (Group II), and 82% (Group III) of eyes, with statistically significant differences between the groups (p &lt; 0.017). No statistically significant differences in the efficacy index were observed (p = 0.78): efficacy was 100% in Groups I and II, and 97.1% in Group III. The safety index was 100% in Groups I and III and 98% in Group II, with no statistically significant difference (p = 0.458). Refractive regression occurred in one case each in Groups I and III, while no cases of regression were observed in Group II. Conclusion. Refractive correction using the ReLEx® SMILE technique provides predictable and stable correction for all degrees of myopia and myopic astigmatism, with no significant differences in complication rates across severity groups.

Background/Objectives: The aim of this study was to compare the efficacy of correcting myopia and myopic astigmatism between small incision lenticule extraction (SMILE) surgery performed using VisuMax 500 and that using VisuMax 800. Methods: Patients who underwent myopia correction using either VisuMax 500 (493 eyes of 249 patients) or VisuMax 800 (169 eyes of 85 patients) employing the nomogram of VisuMax 500 were enrolled in this retrospective case–control study. At 2 months after the operation, the percentage of eyes achieving a postoperative uncorrected distance visual acuity (UDVA) of 20/20 and residual refractive error were compared between the two groups. Additionally, the percentage of eyes with refractive astigmatism angle of error within ±15° and the mean absolute angle of error were analyzed. Results: In the VisuMax 500 and 800 groups, 99% and 97% of eyes achieved a postoperative UDVA of 20/20, respectively. Postoperative residual astigmatism was similar between the two groups, but residual myopia was significantly lower in the VisuMax 800 group (−0.09 ± 0.50 cylinder diopters [CD]) compared to the VisuMax 500 group (−0.21 ± 0.49 CD; p-value = 0.005). Additionally, 84% of eyes in the VisuMax 800 group achieved astigmatism correction within ±15° of the intended meridian, significantly outperforming the 71% in the VisuMax 500 group (p-value = 0.002), with a significantly smaller mean absolute angle of error (8.3 ± 12.2° and 14.1 ± 20.1°; p-value < 0.001). Conclusions: Both VisuMax 500 and VisuMax 800 effectively corrected myopia. However, in terms of the accuracy of astigmatism axis correction, VisuMax 800 demonstrated superior precision compared to VisuMax 500. This study may be limited by perceived bias associated with evaluating two platforms from the same manufacturer.

To systematically investigate the safety and efficacy of photorefractive keratectomy (PRK) or transepithelial photorefractive keratectomy (transPRK) in patients with thin corneas. Concerns exist regarding the outcomes of refractive surgeries including PRK/trnasPRK in patients with thin corneas. This study was registered prospectively in PROSPERO with an ID of CRD42023457156. It was conducted according to the Cochrane Handbook for Systematic Reviews of Interventions and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 Consensus Statement. We searched six databases and three registries from January 1, 1985, until November 30, 2024: PubMed, Web of Science, Scopus, Google Scholar, Embase, ProQuest, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, and International Clinical Trials Registry Platform (ICTRP). Our primary outcomes include the safety index (SI), efficacy index (EI), and best-corrected visual acuity (BCVA) changes, while our secondary outcomes include predictability and the rate of complications (including corneal ectasia and haze). We included any observational or interventional study reporting data on the primary or secondary outcomes of PRK or transPRK in patients with a mean central corneal thickness (CCT) <500 μm, with no history of previous ocular pathology or surgery. The outcome estimates and 95% confidence intervals (CI) were derived from a random-effects model meta-analysis to account for possible heterogeneity. A total of 946 eyes from 10 studies were included. All included studies were case series, either retrospective (n=4) or prospective (n=6). Four studies (n=4) reported the SI and EI, with pooled estimates of 1.01 (95% CI: 0.73 to 1.29) and 1.01 (95% CI: 0.98 to 1.04) after sensitivity analysis, respectively. The mean post-operative change in BCVA was -0.01 (95% CI: -0.07 to 0.05). Compared to baseline values, a mild yet non-significant improvement in BCVA was observed (Standardized mean difference: -0.20 95% CI: -0.89 to 0.49). The pooled predictability within ±0.5 D of emmetropia, based on data from six studies, was 0.83 (95% CI: 0.98 to 1.04). No study reported any cases of corneal ectasia after surgery. PRK/transPRK appears to be a safe and effective refractive surgery for thin corneas with simple or astigmatic myopia and without any other ocular pathologies/topographic abnormalities. However, the power analysis and insufficient follow-up call for future studies to draw definitive conclusions about safety and efficacy.

This case report presents a comprehensive postural evaluation of a 9-year-old paediatric patient with unilateral right crossbite and an associated visual defect. Postural assessments were performed using a vertical laser line (VLL) and a baropodometric-stabilometric platform, revealing significant postural alterations, including cervical extension, increased dorsal kyphosis, pelvic rotation, and an asymmetrical distribution of plantar load. The Romberg test indicated a visual system dysfunction, confirmed by ophthalmologic and orthoptic examinations, which identified mild myopic astigmatism and convergence insufficiency. The patient underwent two years of treatment with the Mouth Slow Balance (MSB) functional appliance, combined with corrective lenses and orthoptic exercises. Post-treatment evaluations demonstrated substantial improvements, including correction of the crossbite, normalization of visual function, improved head and body posture, and balanced plantar load distribution. The Romberg Index returned to physiological values, confirming restored visual influence on postural control. This case underscores the importance of a multidisciplinary approach involving dental, postural, and ophthalmologic evaluations in addressing occlusal and visual dysfunctions. Early identification and intervention can prevent compensatory postural adaptations, optimise craniofacial growth, and enhance the overall quality of life in paediatric patients.

To discuss the technique and outcome of what the authors called the "flap-in-flap" technique and report its safety as a procedure for correction of post-laser in situ keratomileusis (LASIK) myopic regression. Seven eyes of 4 patients were included in this study. All patients had previously undergone LASIK for compound myopic astigmatism using the Moria M2 micro-keratome (Moria) 8 to 12 years prior to presentation. All had myopic refractive errors at presentation with a spherical equivalent ranging from -1.25 to -3.30 diopters. A new thinner femtosecond laser flap was created in the old LASIK flap and gently raised, and laser enhancement was performed. All patients were followed up 1 week, 1 month, and 3 months after the procedure. At these visits, the uncorrected distance visual acuity (UDVA), refraction, and corrected distance visual acuity (CDVA) were measured. Pentacam (Oculus Optikgeräte GmbH) and corneal anterior segment optical coherence tomography examinations were obtained on the third visit. All eyes underwent uneventful enhancement using the flap-in-flap technique. All patients showed an improvement in vision, with 100% of eyes reaching a postoperative UDVA equal to or better than the preoperative CDVA. None of the eyes showed intraoperative complications such as gas breakthroughs or difficult dissections, and no postoperative flap-related complications were seen. This study describes a technique for post-LASIK enhancement that is surgically safe and shows excellent visual outcomes with the potential to conserve the residual stromal bed and percentage of tissue altered, thus avoiding the risk of post-enhancement ectasia.

Refractive surgery enhances visual performance by reshaping the cornea. At the same time, optical aberrations typically increase, affecting visual quality. An essential factor for minimizing the induction of optical aberrations after refractive surgery is the preservation of corneal asphericity. To address this challenge, corneal lenticule extraction for advanced refractive correction (CLEAR) considers individual Q-values to generate an aspheric laser resection profile. This study aims to evaluate the effect of CLEAR on corneal asphericity, spherical aberration and optical zone diameter. Sixty eyes of 30 patients underwent refractive correction for myopia or compound myopic astigmatism with the CLEAR application. Three months postoperatively, the Q-value increased from − 0.13 ± 0.09 to 0.01 ± 0.27, resulting in an oblate shift of 0.14 ± 0.25 from the preoperative state. The preoperative SA was 0.24 ± 0.06 μm, remaining stable at 0.24 ± 0.13 μm postoperatively. The planned optical zone of 6.50 mm resulted in an achieved effective optical zone of 5.93 ± 0.40 mm, a mean reduction of −0.57 ± 0.40 mm. Therefore, myopia and compound myopic astigmatism correction with CLEAR resulted in minimal positive shift in Q-value, limited difference between planned and effective optical zone, and no overall induction of spherical aberration.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-16271-3.

To compare the visual and optical outcomes following femtosecond laser in situ keratomileusis (FS-LASIK) using an aberration neutral profile with asymmetric offset (AO) and pupil center (PC) treatments. In this randomized double-blind clinical trial study, 48 (24 cases) and 38 eyes (19 cases) underwent myopic astigmatism and hyperopic astigmatism LASIK. One eye of each individual was randomly assigned to AO centration and the fellow eye underwent the PC-centered method. The clinical outcomes including uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), safety and efficacy indexes, subjective spherical equivalent (SE) and corneal high-order aberrations (HOAs) were measured at baseline and 6mo postoperatively. In the myopic group, the mean preoperative SE and astigmatism were -4.12±0.87 (-2.88 to -6.00) diopter (D) and -0.88±0.79 (0 to -2.75) D, respectively. In the hyperopic group, the mean preoperative SE and astigmatism were 0.93±0.59 (-0.25 to 2.25) D and -0.73±1.00 (0 to -4.25) D, respectively. At 6mo postoperatively, the safety and efficacy indexes were similar for centration in myopic and hyperopic LASIK groups. In the myopic group, significant changes were found in horizontal trefoil (P=0.041) and oblique trefoil (P=0.031) in favor of AO centration treatment. Femtosecond-LASIK is a safe and efficacious procedure for treatment of myopic and hyperopic astigmatism. AO-centered and PC-centered approaches provide similar visual and refractive outcomes. Myopic astigmatism LASIK with AO centration leads to slightly better corneal aberration outcomes.

PurposeThis study aims to compare the initial three-month outcomes of a single-center experience with small incision lenticule extraction (SMILE) for correction of myopia and myopic astigmatism using the VisuMax 500 (Carl Zeiss Meditec, Jena, Germany) versus the VisuMax 800 (SMILE Pro®; Carl Zeiss Meditec, Jena, Germany). This experience is compared to the US Food and Drug Administration approval studies and published literature.Patients and methodsThe initial 45 eyes (23 patients) that underwent SMILE with the VisuMax 500 in 2018 were compared with the initial 42 eyes (21 patients) that underwent SMILE Pro® with the VisuMax 800 in 2024. These patients represent the first to be treated with SMILE or SMILE Pro® at a single institution in Draper, Utah. Data from postoperative visits up to three months of follow-up were collected and analyzed. Generalized estimating equations (GEE) were used in our analysis to account for inter-eye bias.ResultsBy three months, six eyes (13.3%) reported uncorrected distance visual acuity (UDVA) of 20/16 or better in the VisuMax 500 group compared to nine eyes (23.1%) in the VisuMax 800 group. All 87 eyes had a UDVA of 20/40 or better at three months. There was no statistically significant difference in the mean postoperative UDVA (logMAR) between platforms (0.02 ± 0.07 vs 0.04 ± 0.15; P = 0.315). Safety and efficacy indices were also comparable between platforms (P = 0.406 and 0.239, respectively). VisuMax 800 demonstrated less undercorrection of astigmatism compared to VisuMax 500; however, this was not statistically significant (P = 0.174).ConclusionBoth platforms remain safe and effective for the treatment of myopia with and without astigmatism. Despite the improved ergonomic technology of the VisuMax 800, its three-month visual outcomes are comparable to those of the VisuMax 500.