Purpose: To analyze the characteristics and factors associated with intraocular lens (IOL) tilt and decentration after uneventful phacoemulsification with IOL implantation. Setting: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China. Design: Cross-sectional study. Methods: All patients underwent a general ophthalmologic examination and anterior segment photography. IOL tilt and decentration were measured with a second-generation anterior segment optical coherence tomography (Casia2). Univariate and multivariate regression analyses were performed to assess the association between IOL tilt and decentration with ocular biometric and systemic parameters, and the visual acuity. Results: A total of 196 eyes of 196 patients were enrolled in this study. IOLs showed a mean tilt of 4.8 degrees toward the inferotemporal direction, and the mean decentration was 0.21 mm. Both eyes presented a mirror symmetry relationship. Twenty-two eyes (11.22%) had a tilt greater than 7 degrees, and 21 eyes (10.72%) had a decentration more than 0.4 mm. Multivariate regression analysis showed previous pars plana vitrectomy (PPV) and short axial length (AL) were associated with greater IOL tilt (P = .014 and P < .001). In addition, long AL, thicker lens, and less capsulorhexis–IOL overlap were positively correlated with decentration (P < .001, P = .029, and P = .026). Corrected distance visual acuity did not directly correlate with IOL tilt and decentration (P = .417 and P = .550). Conclusions: PPV history and short AL were associated with greater IOL tilt, whereas longer AL, thicker lens, and overlarge capsulorhexis contribute to greater decentration. Implantation of toric and multifocal IOLs in these patients should be cautious.

Background: The COVID-19 pandemic has led to worldwide school closures, with millions of children confined to online learning at home. As a result, children may be susceptible to anxiety and digital eye strain, highlighting a need for population interventions. Objective: The objective of our study was to investigate whether a digital behavior change intervention aimed at promoting physical activity could reduce children’s anxiety and digital eye strain while undergoing prolonged homeschooling during the COVID-19 pandemic. Methods: In this cluster randomized controlled trial, homeschooled grade 7 students at 12 middle schools in southern China were recruited through local schools and randomly assigned by the school to receive (1:1 allocation): (1) health education information promoting exercise and ocular relaxation, and access to a digital behavior change intervention, with live streaming and peer sharing of promoted activities (intervention), or (2) health education information only (control). The primary outcome was change in self-reported anxiety score. Secondary outcomes included change in self-reported eye strain and sleep quality. Results: On March 16, 2020, 1009 children were evaluated, and 954 (94.5%) eligible children of consenting families were included in the intention-to-treat analysis. Children in the intervention (n=485, 6 schools) and control (n=469, 6 schools) groups were aged 13.5 (SD 0.5) years, and 52.3% (n=499) were male. The assigned interventions were completed by 896 children (intervention: n=467, 96.3%; control: n=429, 91.5%). The 2-week change in square-root–transformed self-reported anxiety scores was greater in the intervention (–0.23, 95% CI –0.27 to –0.20) vs control group (0.12, 95% CI 0.09-0.16; unadjusted difference –0.36, 95% CI –0.63 to –0.08; P=.02). There was a significant reduction in square-root–transformed eye strain in the intervention group (–0.08, 95% CI –0.10 to 0.06) compared to controls (0.07, 95% CI 0.05-0.09; difference –0.15, 95% CI –0.26 to –0.03; P=.02). Change in sleep quality was similar between the two groups. Conclusions: This digital behavior change intervention reduced children’s anxiety and eye strain during COVID-19–associated online schooling. Trial Registration: ClinicalTrials.gov NCT04309097; http://clinicaltrials.gov/ct2/show/NCT04309097

In humans, the lens is the organ with the ability to change morphology and refractive power, designated as accommodation, to focus light from various distances and obtain clear retinal image. The accommodative ability of the lens depends on its structure and biological parameters. The lens grows throughout the life, forming specific lens sutures and a unique gradient refractive index, and possesses regenerative ability under certain circumstances. Minimally invasive lens surgery that preserves endogenous lens epithelial stem/progenitor cells (LECs) can achieve functional lens regeneration in humans. The lens is the main source of intraocular aberration, especially intraocular higher-order aberrations (IHOAs) which is found to be binocularly symmetrical in phakic eyes. There is a compensation mechanism between corneal aberrations and lens aberrations. Therefore, the structure and the biological parameters of the lens, the binocular relationship of the lens and the correlation between the lens and cornea affect visual quality. This paper summarises the above findings and their current and potential applications in refractive surgeries, providing a comprehensive understanding of the lens as a strong determinant of visual quality in the optical system.

Background/aims Quantity of cataract surgery has long been an important public health indicator to assess health accessibility, however the quality of care has been less investigated. We aimed to summarise the up-to-date evidences to assess the real-world visual outcomes after cataract surgery in different settings. Methods A systematic review was undertaken in October 2021. Population-based cross-sectional and longitudinal studies reporting vision-related outcomes after cataract surgery published from 2006 onward were included. A meta-analysis was not planned. Results Twenty-six cross-sectional studies from low-income and middle-income countries (LMICs) and five cross-sectional studies from high-income countries (HICs) were included. The proportions of participants with postoperative presenting visual acuity (VA) ≥0.32 (20/60) were all over 70% in all HICS studies, but mostly below 70% in LMICS studies, ranging from 29.9% to 80.5%. Significant difference in postoperative VA was also observed within countries. The leading causes for postoperative visual impairment (defined mostly as presenting VA <20/60) mainly included refractive error, ocular comorbidities and surgical complications including posterior capsule opacification, except for one study in Nigeria wherein the leading cause was aphakia. Only four population-based cohort studies were included with 5–20 years of follow-up time, generally demonstrating no significant changes in postoperative visual outcomes during the follow-up. Conclusions We observed large inequality in the visual outcomes and principal causes of visual impairment after cataract surgery among different countries and regions. Structured quality control and enhancement programmes are needed to improve the outcomes of cataract surgery and reduce inequality.

Background: To identify the main determinants of intraocular lens (IOL) tilt and decentration after cataract surgery using a novel anterior segment optical coherence tomography (AS-OCT) method. Methods: Fifty-six patients who underwent phacoemulsification with IOL implantation in one eye were continuously enrolled in this cohort study. Axial length (AL) was measured with IOL Master 700. The tilt and decentration of patients’ preoperative crystalline lenses and postoperative IOLs, as well as crystalline lens thickness (LT), were measured using AS-OCT before surgery and 1 week after surgery. Results: The mean tilt and decentration of the patients’ preoperative crystalline lenses were 4.90°±1.81° and 0.21±0.02 mm, and the mean tilt and decentration of IOLs were 4.75°±1.66° and 0.21±0.02 mm, respectively. There were no significant differences in magnitude, direction of tilt, or decentration between crystalline lenses and IOLs. The strongest determinant of IOL tilt was preoperative crystalline lens tilt (R²=0.512, P<0.001), followed by AL (R²=0.154, P=0.003). Additionally, crystalline lens decentration and AL explained 54.6% of the variability in IOL decentration. AL was the factor most highly associated with IOL decentration (R²=0.332, P<0.001), rather than crystalline lens decentration (R²=0.214, P<0.001). Conclusions: The position of the preoperative crystalline lens and AL were the critical determinants of IOL tilt and decentration. The tilt and decentration of IOLs will be greater in patients with larger tilt and decentration of crystalline lenses, or shorter and longer AL.