Search Results (8)

The magnitude and short-term recovery of residual objective myopic bias after a brief, clinically plausible over-minus exposure during distance refraction remain insufficiently quantified. This study quantified the short-term residual objective myopic shift following 10 s of transient myopic overcorrection of 0.50 D or 1.00 D in young adults with myopia. Twenty healthy young adults with myopia and low astigmatism underwent open-field automated objective over-refraction (OR) while viewing a high-contrast 5 m target. After trial lenses induced a moderate myopic state, each participant completed three randomized 10 s lens conditions: 0.50 D undercorrection, 0.50 D overcorrection, and 1.00 D overcorrection. The primary endpoint was OR at 5 s after restoration of the objective neutral correction. Both overcorrection conditions produced significantly more negative OR than undercorrection at 5 s; exploratory analyses showed the same pattern at 10 s. The shift was evident at 5 and 10 s after restoration of the objective neutral correction and, by 30 s, was no longer statistically significant and appeared clinically negligible. This bias should be considered when OR measurements obtained shortly after over-minus lens exposure are used to inform subsequent subjective refinement. Full article

Transepithelial photorefractive keratectomy (Trans-PRK) offers superior re-epithelialization and visual recovery. This study evaluates the impact of preoperative refractive status on clinical outcomes and identifies prognostic factors across varying myopic severities. This retrospective observational study included 125 eyes [64 patients; age > 20 years; best-corrected visual acuity (BCVA) ≥ 20/25] that underwent Trans-PRK between March and December 2022. Patients were stratified into low myopia (LM: > −5.0 D), moderate-to-high myopia (MHM: −5.0 D to −8.0 D), and extremely high myopia (EHM: ≤ −8.0 D) groups. Analysis focused on preoperative refraction, intraoperative parameters, postoperative uncorrected visual acuity (UCVA), and corneal conditions of superficial punctate keratitis (SPKs) and haze. The mean age was 30.20 ± 6.34 years, with a mean initial manifest sphere (MS) of −6.42 ± 2.27 diopter (D) overall and −3.73 ± 0.15 D, −6.28 ± 0.13 D, and −9.17 ± 0.15 D in the LM, MHM, and EHM groups, respectively. At a mean follow-up of 6.69 ± 3.73 months, the overall mean final manifest spherical equivalent (MSE) was −0.12 ± 0.73 D, and the mean final UCVA was 0.01 [Snellen equivalent (SE), 205/200] ± 0.08 logMAR. Predictability was 94.4%, 88.88%, and 94.3% for the final MS ≤ −1.0 D, final MSE ≤ −1.0 D, and UCVA 0.8, respectively. In the LM and MHM groups, cycloplegic and subjective refractions showed the highest concordance with emmetropia, whereas initial manifest refractions were most accurate for the EHM group. Corneal SPK incidence declined from 32.2% (1 month) to 1.6% (6 months), primarily localized to EHM eyes. Corneal haze peaked at 28.2% at three months before receding to 9.4% by 6 months. Refractive and visual stability were achieved by the third month for the LM and MHM groups, whereas the EHM group (mean MSE: −9.59 ± 0.15 D) required six months to reach both refractive and visual plateaus. Despite transiently higher rates of corneal SPKs and haze in EHM eyes, final visual outcomes remained excellent, achieving a mean UCVA of 18/20. Full article

Background and Objectives: Myopia is a rapidly growing global health burden driven primarily by axial elongation, which exerts mechanical stress on the inner retina, leading to progressive thinning of the retinal nerve fiber layer (RNFL) and the ganglion cell complex (GCC). The sector-specific pattern of these changes across the full spectrum of myopia remains incompletely characterized. This study aimed to provide a comprehensive, sector-level analysis of RNFL and GCC changes across four myopia severity grades using optical coherence tomography angiography (OCTA), and to quantify their correlations with axial length (AL) and central foveal thickness (CFD). Materials and Methods: A total of 260 eyes of 130 participants were enrolled in a prospective cross-sectional study. Eyes were classified into four groups: emmetropia (EM, n = 74), low myopia (LM, n = 68), moderate myopia (MM, n = 64), and high myopia (HM, n = 54). All participants underwent cycloplegic refraction, AL measurement, and RTVue XR Avanti OCTA imaging. RNFL thickness was assessed across five peripapillary sectors, and GCC thickness across twelve macular zones. Between-group differences were analyzed using one-way ANOVA with Bonferroni post hoc correction or Kruskal–Wallis/Dunn-Bonferroni tests. Pearson correlations were used to assess associations among structural parameters, AL, and CFD. Results: Both the RNFL and GCC showed progressive, statistically significant thinning with increasing myopia severity. The superior RNFL was the only peripapillary sector that differentiated EM from LM (p = 0.039), with total thinning of 18.8 μm from EM to HM. The paratemporal GCC zone showed the earliest macular structural signal (EM vs. LM, p = 0.049). Temporal and nasal RNFL sectors showed relative preservation, with differences restricted to comparisons involving HM. AL correlated negatively with the RNFL and GCC across all sectors (r = −0.46 to −0.71), with the strongest correlation observed for the superior RNFL in HM (r = −0.71, p < 0.001). CFD demonstrated progressively stronger coupling with GCC thickness as myopia severity increased, peaking in HM (r = 0.72, p < 0.001). Conclusions: The RNFL and GCC thinning in myopia follows a progressive, sector-specific pattern driven by axial elongation. The superior RNFL and paratemporal GCC are the earliest structural indicators of inner retinal change, detectable already at the low-myopia grade. These findings support a neural-first model of myopia-related retinal remodeling and advocate for multiparametric, stage-targeted structural monitoring in clinical practice. Full article

Background: Refractive errors (REs) and amblyopia are the leading causes of visual impairment (VI) in children worldwide; however, national data for Mexico are scarce. Objective: We aim to estimate the clinical prevalence of RE, refractive amblyopia, and associated visual impairment (VI) in Mexican children aged 6–12 years. Methods: We analyzed 784,372 non-cycloplegic eye examinations from Salud Digna outpatient clinics across all 32 Mexican states (2021–2025). REs were classified as myopia (≤−0.50 D), hyperopia (≥+2.00 D), or astigmatism (≤ −1.00 D cylinder). Refractive amblyopia was defined as best-corrected visual acuity ≤ 20/30 in the most affected eye. The VI categories followed the WHO criteria. Results: Myopia was the most frequent (43.86%), followed by astigmatism (38.41%) and hyperopia (1.29%). Refractive amblyopia affected 4.94% of the children, predominantly due to astigmatic isoametropia (72.19%). VI related to refractive amblyopia occurred in 1.20% (mild), 0.37% (moderate), 0.01% (severe), and 0.01% (blindness) of children. Men showed a higher prevalence of RE and refractive amblyopia (p < 0.01). Geographic disparities were evident, with the central and southern states reporting the highest RA rates. Conclusions: Our outpatient-based study underscores REs, refractive amblyopia, and astigmatic ametropia as significant public health concerns in Mexican school-aged children. The high prevalence of uncorrected REs and refractive amblyopia highlights the need for nationwide school-based screening programs and early intervention strategies to mitigate long-term visual and developmental consequences. Full article

Background/Objectives: Although high myopia primarily affects the eyes, emerging evidence suggests that it is also associated with systemic inflammation and metabolic dysfunction. The liver plays a key role in metabolism and inflammation, and it may share pathological pathways with high myopia. However, no population studies have examined the relationship between high myopia and liver disease progression. This study used UK Biobank data to analyze the relationship between myopia severity and severe liver disease, as well as to determine whether inflammatory markers or metabolites mediate this link. Methods: A prospective cohort of 70,774 UK Biobank participants without severe liver disease at baseline was followed for 14.1 years. Myopia was categorized as emmetropia, low-to-moderate, or high based on refractive error. Cox proportional hazards models, stratified by aspartate aminotransferase (AST) level (≥40 vs. <40 U/L), were used to assess liver disease risk, and mediation analyses were used to evaluate inflammatory markers and metabolites. Results: Among participants with AST levels of at least 40 U/L, high myopia significantly increased liver fibrosis and cirrhosis risk (hazard ratio [HR] = 2.64, 95% confidence interval [CI] = 1.44–4.85, p = 0.002), exhibiting a dose-dependent trend (ptrend = 0.004). No association existed for AST < 40 U/L. C-reactive protein (CRP) partially mediated this link; no metabolites survived correction. Conclusions: High myopia is independently associated with an increased risk of liver fibrosis and cirrhosis in individuals with elevated AST, partially mediated by CRP-related inflammation. Refractive assessment may stratify liver disease risk in subclinical injury, warranting anti-inflammatory intervention research. Full article

Background/Objectives: To evaluate the visual and refractive outcomes of keratorefractive lenticule extraction (KLEx) surgery and refractive lens exchange (RLE) surgery in moderate to high myopia patients. Methods: A retrospective cohort study was performed, and patients receiving KLEx or RLE surgeries with myopia within −3.00 to −10.00 diopter (D) were enrolled. A total of 19 and 35 patients were put into the RLE and KLEx groups after exclusion. The main outcomes are postoperative uncorrected visual acuity (UDVA), the spherical equivalent (SE), and residual astigmatism via vector analysis. Fisher’s exact test and the Mann–Whitney U test were utilized for the statistical analysis. Results: The percentages of patients who reached UDVA results of more than 20/25 and 20/20 were statistically similar between groups (both p > 0.05), and the percentages of patients who reached SE results within ±0.50 D and ±1.00 D were statistically similar between groups (both p > 0.05). The change in SE in the KLEx group was lesser compared to that in the RLE group (p = 0.021). The vector analysis showed a lower DV and ME and a higher CoI in the KLEx group than in the RLE group (all p < 0.05). The percentage of patients who reached specific UDVA and SE thresholds were statistically similar between groups with different myopia degrees (all p > 0.05). Conclusions: The postoperative visual and refractive outcomes between RLE and KLEx surgeries are grossly comparable, while the KLEx may have a slight advantage in astigmatism correction. Full article

Purpose: To evaluate the safety and efficacy of the transepithelial photorefractive keratectomy (TransPRK) performed using smart pulse technology (SPT) in myopic eyes with refractive error ranging from −5.25 D to −9.75 D. Methods: This retrospective study evaluated the outcomes of SPT-assisted TransPRK in 150 eyes performed using a 1050 Hz AMARIS excimer laser. Results: At 6 months postoperative, 98% of eyes achieved uncorrected distance visual acuity (UDVA) of 20/25 or better, and postoperative UDVA within one line of preoperative corrected distance visual acuity (CDVA). No eyes lost any line of CDVA. Residual spherical equivalent refraction and cylinder within ±0.50 D of intended correction were achieved in 72% and 67% of eyes, respectively. Ninety-seven percent of eyes reported no halos and glare. Conclusions: TransPRK using a 1050 Hz excimer laser with SPT showed excellent predictability, safety, and efficacy for moderate to high myopia correction. Full article

Previous studies have demonstrated safety and efficacy using 6.0 and 6.5 mm optical zones in the WaveLight EX500 Excimer Laser System but have not evaluated if differing optical zone sizes influence refractive outcomes. This study examines visual outcomes between two study populations undergoing LASIK with either a 6.0 mm (1332 patients) or 6.5 mm (1332 patients) optical zone. Outcomes were further stratified by severity of myopia (low, moderate, and high) and astigmatism (low and high). Patients were matched by age and preoperative manifest sphere and cylinder. Postoperative measurements were then compared. The 6.5 mm group demonstrated better postoperative manifest refractive spherical equivalent (MRSE), manifest sphere, and absolute value of the difference in actual and target spherical equivalent refraction (|∆ SEQ|), within the total population, moderate myopia, and low astigmatism groups, but this did not lead to improved postoperative uncorrected distance visual acuity (UDVA) or best corrected distance visual acuity (CDVA). Though astigmatic correction and postoperative angle of error were similar between optical zone sizes, they were significantly worse with high myopia. Overall, this study demonstrates differences in visual outcomes between the 6.0 and 6.5 mm optical zone sizes that may warrant consideration; however, essentially, the results are comparable between them. Full article