Purpose The aim of this study was to determine the age- and sex-specific incidence and prevalence of keratoconus (KC) in Taiwan and explore their association with the use of computerized corneal topography and tomography (TG). Design This nationwide retrospective study included the Taiwanese population (N = 27,540,859) from the National Health Insurance Research Database (NHIRD) between 2000 and 2018. Method We estimated the incidence of KC by identifying patients with newly diagnosed KC and estimated its prevalence by identifying patients who had the ICD9-CM code 371.6 or ICD-10-CM code H18.609 twice or more in NHIRD during 2000–2018. Results The incidence of KC in Taiwan during 2000–2018 was 7075, with the incidence rate being 1.56 (95% confidence interval [CI]: 1.53–1.60) per 100,000 person-years. The prevalence of KC was 4.29 (95% CI: 4.23–4.35) per 100,000 person-years. The KC incidence rate peaked in patients aged 21–25 (6.40 in males and 3.19 in females). The overall incidence rates in males and females were 2.01 and 1.35, respectively (incidence rate ratio: 1.46), indicating that KC had a significant male predisposition. Moreover, we noted a linear correlation (R² = 0.7488) between the proportion of the use of TG and the incidence of KC. Conclusion Estimates of nationwide population-based incidence and prevalence can contribute to a better understanding of the risk of ethnic groups and geographic locations in KC, and the trend can help physicians improve the general vision health of the population.

Introduction To evaluate the efficacy and safety of myopia control using a multifocal soft contact lens designed with high peripheral add power in schoolchildren. Methods This 1-year multi-center, prospective, randomized, double-blind, controlled study enrolled myopic schoolchildren aged 6–15 years with refractive errors between − 1.0 D and − 10.0 D. Each participant was randomly allocated to wear a daily disposable multifocal soft contact lens as the treatment in one eye and a single-vision soft contact lens as the control in the other eye. The primary endpoints were changes in the cycloplegic spherical equivalent (SE) and axial length at 1 year. Results Fifty-two of the 59 participants (88.1%) completed the study protocol. The mean change in SE was − 0.73 ± 0.40 D in the treatment group. and − 0.85 ± 0.51 D in the control group (mean difference: − 0.12 ± 0.34 D, p = 0.012). The mean change in axial length was 0.25 ± 0.14 mm in the treatment group, and 0.33 ± 0.17 mm in the control group (mean difference: 0.08 ± 0.10 mm, p < 0.001). The treatment was well tolerated, and no serious adverse events were observed. Conclusions Treatment with multifocal soft contact lenses with high peripheral add power was effective in controlling the progression of myopia and axial length elongation in myopic schoolchildren.

Anisometropia is a unique condition of both eyes and it is associated with vision problems such as amblyopia and reduced stereoacuity. Previous studies have not reported its change pattern by age and its correlation with the refractive condition of both eyes. This study aims to compare the changes in anisometropia by age in children with hyperopia, myopia, and antimetropia. In total, 156 children were included. Children aged 3–11 years with anisometropia ≥ 1.00 D were followed up for ≥ 1 year with ≥ 2 visits at two medical centers in Taiwan. Refractive errors by cycloplegic autorefractometry, best-corrected visual acuity, eye position, and atropine use were recorded. The children were divided into hyperopic, myopic, and antimetropic groups. The results showed that anisometropia decreased in children aged < 6 years (3.34–2.96 D; P = 0.038) and increased in older children (2.16–2.55 D; P = 0.005). In children aged 3, 4, 5, and 6 years, the mean anisometropia was higher in children with myopia and antimetropia than in those with hyperopia (P = 0.005, 0.002, 0.001, and 0.011, respectively). The differences were not significant in children aged > 6 years (all P > 0.05). The factors associated with changes in anisometropia were age, refractive group, amblyopia, and strabismus. Anisometropia decreased with age in children younger than 6 years, and the changes in anisometropia was found in children with myopia and antimetropia.

This study explores the utilization patterns of premium and nonpremium intraocular lenses (IOLs) under Taiwan's National Health Insurance, given the potential out-of-pocket expenses incurred by cataract surgery patients. A cross-sectional, population-based analysis was performed on patients who underwent IOL implantation between 2016 and 2020. IOLs were categorized into nonpremium and premium, with the latter further divided based on function. Logistic and multinomial logistic regression analyses were employed to identify factors influencing IOL implantation, with data stratified by medical institute type, ownership, and patient demographics. In total, 1,194,805 IOLs were implanted during the study period. The rate of premium IOL implantation was lower compared to non-premium IOL implantation. However, the adoption rate of premium IOLs increased more rapidly than that of non-premium IOLs. Specifically, the adoption rate for premium IOLs was 35.2% in 2016, rising to 42.6% in 2020. Patients receiving treatment in clinics were considerably more likely to use nonpremium IOLs than were those receiving treatment in medical centers (12.7% higher probability for clinics; P < 0.001). The implantation of higher-end premium IOLs was more prevalent in clinics than in other medical institutes. The prevalence of premium IOL implantation was higher in private hospitals than in public hospitals (odds ratio: 1.403; P < 0.001). Premium IOLs were more commonly implanted in younger patients with higher income levels and without relative contraindications. IOL selection is associated with both personal and institutional characteristics. These factors should be considered in public policy development aimed at regulating the IOL market within a universal health insurance framework.

Purpose: To analyze visual quality and contrast sensitivity in patients after intraocular lens (IOL) implantation with sutured scleral fixation. Setting: Chang Gung Memorial Hospital, Taoyuan, Taiwan. Design: Retrospective observational study. Methods: Data on the refractive outcome, visual acuity, and subjective visual symptoms in patients with scleral-fixated or in-bag IOL implantation were collected from September 2019 to March 2020. We also investigated patients’ postoperative higher-order aberrations (HOAs) and dysphotopsia using a wavefront aberrometer and glaretester, respectively. The following values were compared: corrected distance visual acuity, spherical equivalent, root mean square values for aberrations, and contrast sensitivity. Results: A total of 23 eyes implanted with scleral-fixated IOL and 74 eyes with in-bag IOL were studied. The mean postoperative spherical equivalent and logarithm of the minimum angle of resolution after scleral fixation were −1.09 ± 3.32 D and 0.20 ± 0.17, respectively. The ocular HOAs were higher in the scleral-fixation group than in the in-bag group (p = 0.001). Contrast sensitivity was negatively associated with age, and it was similar between the two groups after controlling for the age effect. Conclusions: Ocular HOAs and refractive errors were higher in the scleral-fixation group than in the in-bag group. However, no significant difference was noted in contrast sensitivity between advanced scleral fixation and in-bag IOL implantation.