Association of polymorphisms in the HTRA1 gene with myopia.

PURPOSE: To evaluate the associations of single-nucleotide polymorphisms (SNPs) in the high-temperature requirement protease A 1 (HTRA1) gene with myopia. METHODS: 25 SNPs in HTRA1 were selected, including 23 haplotype-tagging SNPs, SNP rs2142308 from a previous genome-wide association study (GWAS) of myopia and rs11200638, a SNP strongly associated with age-related macular degeneration (AMD). All SNPs were genotyped in a Hong Kong Chinese cohort of 533 myopia subjects (including 175 high myopia, 189 moderate myopia and 189 mild myopia) and 280 non-myopic controls. The association of individual SNPs were evaluated in overall myopia and different subgroups of myopia using logistic regression. RESULTS: A tagging SNP, rs11200647, was significantly associated with myopia (p=2.17×10-4, OR=0.67). Nominal associations were detected for the AMD-associated SNP rs11200638 (p=0.0042, OR=1.37) and tagging SNPs rs12266322 (p=0.0048, OR=0.59) and rs17103569 (p=0.047, OR=1.34). The association of rs11200647 with myopia remained significant after adjusting for rs11200638, rs12266322 and rs17103569. In sub-group analysis, two tagging SNPs, rs11200647 (p=2.24×10-4, OR=0.58) and rs12266322 (p=8.31×10-4, OR=0.39), showed significant association with moderate myopia. In haplotype association analysis, haplotypes AT (p=1.00×10-4, OR=1.77) and haplotype GT (p=0.0019, OR=0.64), defined by rs11200647 and rs66884382, were significantly associated with myopia. CONCLUSIONS: This study provided new evidence to support HTRA1 as an associated gene for myopia, especially moderate myopia. The findings suggested that myopia and AMD may have shared genetic components.

Paediatric staphyloma classification: new perspectives via ultrawide field three-dimensional swept-source optical coherence tomographic angiography.

AIM: To employ ultrawide field three-dimensional swept-source optical coherence tomographic angiography (UWF 3D SS-OCTA) modality, integrating novel strategies, posterior eye curvature maps and posterior eye height maps, in characterising the features and disease associations of posterior staphyloma in paediatric patients. This study seeks to compare paediatric staphylomas to established adult classifications, identify distinct paediatric patterns and introduce a new classification system for paediatric staphyloma using advanced multimodal imaging. METHODS: UWF 3D SS-OCTA imaging, integrating posterior eye curvature maps and posterior eye height maps strategies, was employed to analyse staphyloma presentations in the paediatric cohort. These data were then set against the traditionally established adult classifications. Additionally, the aetiology of staphylomas was investigated. RESULTS: The UWF 3D SS-OCTA modality, when integrated with posterior eye curvature maps and posterior eye height map, showcased superior imaging detail and better classification compared with UWF scanning laser ophthalmoscope, offering a more nuanced view of staphyloma patterns in paediatric patients. Specifically, only 54.7% of the paediatric cohort fit into previously recognised categories. The paediatric group displayed prominent temporal and inferior temporal staphylomas, likely linked to the high prevalence of peripheral vascular diseases. The study led to the proposal of five unique paediatric staphyloma classifications. CONCLUSIONS: The UWF 3D SS-OCTA modality with posterior eye curvature maps and posterior eye height maps offers unparalleled insights into staphyloma patterns, especially in paediatric patients. Paediatric staphylomas exhibit a unique presentation, divergent from adults, with two novel types identified. The findings underline the importance of updating classification systems, ensuring they reflect the realities observed in paediatric pathology and diagnostics.

Analysis of factors influencing refractive error in Fuchs eyes undergoing Descemet membrane endothelial keratoplasty triple procedure.

PURPOSE: To evaluate the accuracy of current intraocular lens (IOL) formulas and identify factors influencing mean error in eyes undergoing Descemet membrane endothelial keratoplasty (DMEK) triple procedure, that is, DMEK combined with cataract extraction and IOL placement for concurrent Fuchs endothelial corneal dystrophy (FECD) and cataracts. DESIGN: Retrospective cohort study. SUBJECTS: 90 eyes with FECD undergoing uncomplicated DMEK triple procedure at Wilmer Eye Institute. METHODS: We analysed tomographic features of oedema, including loss of regular isopachs, displacement of the thinnest point of the cornea and the presence of posterior surface depression, and assessed the correlation with the prediction error. MAIN OUTCOME MEASURES: We compared the mean error (±SD) for the Barrett Universal II (BU2), Hoffer QST, Haigis-L (HL) and Barrett True K (BTK) formulas and the percentage of eyes within 0.25, 0.5 and 1 diopter (D) of error. RESULTS: All formulas resulted in a mean hyperopic error, with the HL having the lowest mean error of 0.24 D (±0.97 D) and BU2 having the highest ME of 0.94 D (±0.97 D). For each additional tomographic feature of corneal oedema in the BU2 and Hoffer QST formulas, the mean hyperopic error increased by 0.38 D. For the BTK and HL formulas, the mean error increased by 0.35 D (p<0.001). CONCLUSION: The number of tomographic features of oedema can be useful in identifying eyes with higher errors in IOL calculation when performing the DMEK triple procedure for FECD.

Interaction of retinal electrophysiology and novel orthokeratology lens use on myopia control efficacy in children.

AIMS: The relationship between retinal electrophysiological function and myopia progression was evaluated in school-aged children wearing Breath-O-Correct Orthokeratology (OK) lenses compared with those wearing single vision (SV) lenses over 24 months. METHODS: In this randomised, single-blind, parallel controlled trial, children aged 8-12 years with -1.00 to -4.00 D of myopia were recruited. Retinal function was evaluated using global-flash multifocal electroretinography at baseline before OK or SV treatment. Axial length was evaluated at 6-month intervals up to 24 months. The main outcome measures were axial elongation (AE) between groups and the interactive effect of baseline retinal function. RESULTS: A total of 70 children (43 OK, 9.8±1.3 years; 27 SV, 9.5±1.4 years) completed the 2-year study and were included in the analysis. The 2-year normalised AE was 0.37±0.37 mm in the OK group and 0.60±0.41 mm in the SV group, respectively. For children in the SV group, the amplitude of the central inner retinal response was negatively correlated with axial length elongation (p=0.03). In contrast, this relationship between retinal electrophysiology and AE was not observed in OK group, indicating that they were independent of each other in children treated with OK (p=0.33). CONCLUSION: A weak retinal electrophysiological response was a risk factor for rapid AE in SV controls. However, OK treatment can lower this risk factor and significantly reduce AE in school-aged children.

Associations of genetic variants for refractive error and axial length in adults with ocular endophenotypes in children: a cross-sectional and longitudinal study.

AIMS: To investigate the associations of genetic variants previously linked to axial length (AL) and spherical equivalent refraction (SE) in adults with refractive error and related endophenotypes in children, at baseline and 3-year follow-up. METHODS: 15 candidate single-nucleotide polymorphisms (SNPs), selected from previous Genome-Wide Association Studies and meta-analyses, were genotyped in 2819 Chinese children, who had undergone baseline and 3-year follow-up cycloplegic refraction, ocular biometry and ocular health examinations. Linear regression analyses were conducted to assess the associations of the SNPs with baseline measurements and longitudinal changes in SE, spherical power (SPH), AL, corneal radius of curvature (CR) and AL/CR ratio. RESULTS: SNPs ZMAT4 rs7829127, ZMAT4 rs16890057, TOX rs7837791, GRIA4 rs11601239 and RDH5 rs3138142 were associated with SE (ß=0.233, p=4.21×10-4; ß=0.221, p=7.87×10-4; ß=0.106, p=0.0076; ß=0.084, p=0.041; ß=0.14, p=0.013, respectively) and SPH (ß=0.24, p=2.3×10-4; ß=0.232, p=3.8×10-4; ß=0.088, p=0.025; ß=0.086, p=0.034; ß=0.14, p=0.012, respectively). Among them, ZMAT4 rs7829127 and rs16890057, were also associated with AL (ß=-0.128, p=5.6×10-4; ß=-0.128, p=5.21×10-4) and AL/CR ratio (ß=-0.014, p=0.0028; ß=-0.014, p=0.0034), whereas TOX rs7837791 was associated with AL (ß=-0.062, p=0.0058) and GRIA4 11 601 239 with AL/CR ratio (ß=-0.0058, p=0.049). Additionally, CD55 rs1652333 and RDH5 rs3138142 were associated with 3-year longitudinal changes in AL (ß=0.062, p=0.018; ß=-0.079, p=0.029) and CR (ß=0.014, p=0.027; ß=-0.018, p=0.035). CONCLUSION: Among SNPs previously associated with AL and SE in adults, variants in ZMAT4, TOX and GRIA4 were associated with AL, SE, SPH, and/or AL/CR ratio, while variants in RDH5 and CD55 showed associations with AL and CR changes in children.

Retinal curvature in Chinese children with myopia measured by ultra-widefield swept-source optical coherence tomography.

AIMS: To quantitatively measure retinal curvature (RC) in children with myopia and explore its association with refractive status. METHODS: This cross-sectional study included participants aged 5-18 years who underwent comprehensive ocular examinations, including cycloplegic refraction and macula 24×20 mm optical coherence tomography (OCT) scans. RC was derived from OCT data using a three-dimensional reconstruction system. Mean RC was assessed in concentric circles (RC I-VI) with diameters of 1, 3, 6, 9, 12 and 15 mm around the fovea, as well as in four orientations (RC S/I/N/T). RESULTS: A total of 443 eyes were included in the analysis. The values from RC I to RC VI were 0.51±0.19, 0.53±0.19, 0.62±0.19, 0.76±0.23, 0.86±0.23 and 0.81±0.18 10-2mm-2, respectively. RC I exhibited the smallest curvature, while RC V displayed the highest (p<0.001). High myopia (HM) group demonstrated larger RC I and smaller RC III/IV/V/VI compared with low myopia (LM) group (p<0.01). Significant differences among RC S/I/N/T were observed in HM group (pairwise comparison, p<0.001), but not in LM group. Multiple regression analysis revealed that age, sex, corneal curvature radius and subfoveal choroidal thickness (SFCT) were associated factors with foveal RC, while age, SFCT and axial length (AL) were associated factors of peripheral RC. CONCLUSION: RC can quantitatively characterise retinal shape and the morphological changes induced by myopia. Myopia progression results in a bulging macular retina accompanied by a flattening peripheral retina in children, and also increases the irregularity among the four quadrants. Age, AL and SFCT are associated factors of RC.

IOL decentration sensitivity according to spatial frequencies.

BACKGROUND/AIMS: Investigation of the decentration sensitivity of monofocal intraocular implants with a focus on different aberration corrections depending on different spatial frequencies. METHODS: Using an optical bench, the decentration sensitivities of an intraocular lens (IOL) with a high spherical aberration correction of -0.27 µm (ZCB00 Johnson & Johnson), an IOL with an aberration correction of -0.20 µm (Primus HD OphthalmoPro) and an IOL with an aberration neutral design (CT Asphina 409MP Carl Zeiss Meditec) were evaluated for Strehl ratio values and for 25, 50 and 100 lp/mm. Two different corneas with +0.13 µm and +0.28 µm were used. The lenses were tested in the best centration and up to a decentration of 0.5 mm. RESULTS: Decentration sensitivity affects high spatial frequencies more than lower ones. The possible decentration sensitivity is determined by the amount of spherical aberration of the cornea. The effective decentration sensitivity is determined by the extent to which these spherical aberrations are compensated. If these are not compensated, there is hardly any decentration sensitivity. CONCLUSION: High spatial frequencies are more affected by decentration sensitivity. The decentration sensitivity of an IOL is determined by the extent to which the spherical aberration of the cornea is corrected.

Quantitative assessment of colour fundus photography in hyperopia children based on artificial intelligence.

OBJECTIVES: This study aimed to quantitatively evaluate optic nerve head and retinal vascular parameters in children with hyperopia in relation to age and spherical equivalent refraction (SER) using artificial intelligence (AI)-based analysis of colour fundus photographs (CFP). METHODS AND ANALYSIS: This cross-sectional study included 324 children with hyperopia aged 3-12 years. Participants were divided into low hyperopia (SER+0.5 D to+2.0 D) and moderate-to-high hyperopia (SER≥+2.0 D) groups. Fundus parameters, such as optic disc area and mean vessel diameter, were automatically and quantitatively detected using AI. Significant variables (p<0.05) in the univariate analysis were included in a stepwise multiple linear regression. RESULTS: Overall, 324 children were included, 172 with low and 152 with moderate-to-high hyperopia. The median optic disc area and vessel diameter were 1.42 mm2 and 65.09 µm, respectively. Children with high hyperopia had larger superior neuroretinal rim (NRR) width and larger vessel diameter than those with low and moderate hyperopia. In the univariate analysis, axial length was significantly associated with smaller superior NRR width (ß=-3.030, p<0.001), smaller temporal NRR width (ß=-1.469, p=0.020) and smaller vessel diameter (ß=-0.076, p<0.001). A mild inverse correlation was observed between the optic disc area and vertical disc diameter with age. CONCLUSION: AI-based CFP analysis showed that children with high hyperopia had larger mean vessel diameter but smaller vertical cup-to-disc ratio than those with low hyperopia. This suggests that AI can provide quantitative data on fundus parameters in children with hyperopia.

Shaping school for childhood myopia: the association between floor area ratio of school environment and myopia in China.

AIM: To investigate the association of floor area ratio (FAR), an indicator of built environments, and myopia onset. METHODS: This prospective cohort study recruited 136 753 children aged 6-10 years from 108 schools in Shenzhen, China at baseline (2016-2017). Refractive power was measured with non-cycloplegic autorefraction over a 2-year follow-up period. FAR was objectively evaluated using geographical information system technology. Mixed-effects logistic regression models were constructed to examine the association of FAR with a 2-year cumulative incidence of myopia among individuals without baseline myopia; multiple linear regression model, with a 2-year cumulative incidence rate of myopia at each school. RESULTS: Of 101 624 non-myopic children (56.3% boys; mean (SE) age, 7.657±1.182 years) included in the study, 26 391 (26.0%) of them developed myopia after 2 years. In the individual-level analysis adjusting for demographic, socioeconomic and greenness factors, an IQR in FAR was associated with a decreased risk of 2-year myopia incidence (OR 0.898, 95% CI 0.866 to 0.932, p<0.001). Similar findings were observed in the analysis additionally adjusted for genetic and behavioural factors (OR 0.821, 95% CI 0.766 to 0.880, p<0.001). In the school-level, an IQR increase in FAR was found to be associated with a 2.0% reduction in the 2-year incidence rate of myopia (95% CI 1.3% to 2.6%, p<0.001). CONCLUSIONS: Exposure to higher FAR was associated with a decreased myopia incidence, providing insights into myopia prevention through school built environments in China.

Short-term effects of sunlight exposure on fundus blood flow perfusion in children: a randomised controlled trial.

AIM: To evaluate the short-term effects of different sunlight exposure on fundus blood flow perfusion (BFP) after near work. METHODS: In this parallel randomised controlled trial, 81 students aged 7-15 with spherical equivalent refraction between -2.00 and +3.00 diopters were randomly assigned to either a low-illuminance (4k lux) group (N=40) or high-illuminance (10k lux) (N=41). Following 1 hour indoor reading, participants had sunlight exposure matching their group's intensity for 15 minutes. BFPs in the superficial retina, deep retina and choroid were measured at four time points: pre-reading, post-reading, 5th-minute and 15th-minute sunlight exposure. RESULTS: Within the initial 5 minutes of sunlight exposure, the 10k lux group showed a tendency for decreased BFP, particularly in the choroid (superficial retina: -0.2, 95% CI -0.9 to 0.5; deep retina: -0.1, 95% CI -0.6 to 0.4; choroid: -0.4, 95% CI -0.8 to 0.0), while the 4k lux group exhibited an increase (superficial retina: 0.7, 95% CI 0.1 to 1.3; deep retina: 0.3, 95% CI -0.2 to 0.8; choroid: 0.1, 95% CI -0.2 to 0.5). From 5 to 15 minutes, BFP decreased in both groups. At the 5th-minute mark, the 10k lux group exhibited a greater decrease in choroid (10k -0.4 vs 4k 0.1, p=0.051). No significant difference was observed after 15 minutes of exposure. CONCLUSION: Higher illuminance sunlight exposure can restore fundus BFP more rapidly than lower; however, duration remains pivotal. To prevent myopia, continuous sunlight exposure for over 15 minutes is recommended to aid in reinstating the fundus BFP increased by near work. TRIAL REGISTRATION NUMBER: NCT05594732.

Association Between Myopia and Pupil Diameter in Preschoolers: Evidence from a Machine Learning Approach Based on a Real-World Large-Scale Dataset.

INTRODUCTION: Previous studies have explored the connections between various ocular biological parameters with myopia. Our previous study also found that pupil data can predict the myopic progression during the interventions for myopia. However, studies exploring the association between pupil diameter and myopia in preschoolers with myopia were lacking. Hence this study was aimed to investigate the association between pupil diameter and myopia in preschoolers with myopia based on a real-world, large-scale dataset. METHODS: Data containing 650,671 preschoolers were collected from a total of 1943 kindergartens in Shenzhen, China. Refraction and pupil parameters were collected. After data filtering, the occurrence of myopia and its association with age, gender, pupil diameter, and other variables, were analyzed. Random forest (RF) and eXtreme gradient boosting (XGBoost) were selected from seven machine learning algorithms to build the model. The mean decrease accuracy (MDA), mean decrease Gini (MDG), and gain feature importance (GFI) techniques were employed to quantify the importance of pupil diameter and other features. RESULTS: After the assessments, 51,325 valid records with complete pupil data were included, and 3468 (6.76%) were identified as myopia based on the calculated cycloplegic refraction. Preschoolers with myopia presented reduced pupil diameter and greater variation (5.00 ± 0.99 mm) compared to non-myopic preschoolers (6.22 ± 0.67 mm). A nonlinear relationship was found according to the scatterplots between pupil diameter and refraction (R2 = 0.14). Especially preschoolers with myopia had reduced pupil diameter compared to emmetropic preschoolers, but hyperope did not experience additional pupil enlargement. After adjusting for other covariates, this relationship is still consistent (P < 0.001). XGBoost and RF algorithms presented the highest performance and validated the importance of pupil diameter in myopia. CONCLUSIONS: Based on a real-world large-scale dataset, the current study illuminated that preschoolers with myopia had a reduced pupil diameter compared to emmetropic preschoolers with a nonlinear pattern. Machine learning algorithms visualized and validated the pivotal role of pupil diameter in myopia. TRIAL REGISTRATION: chictr.org Identifier: ChiCTR2200057391.

Ophthalmic quality of life in the adult Danish population: an epidemiological study.

BACKGROUND: Ophthalmic quality of life (OQoL) has been investigated in selected parts of general populations and in patients with ocular disease, but OQoL in unselected general populations has not been studied in detail. The present study reports OQoL obtained from a representative sample of the adult Danish population 2020-2022. METHODS: The FORSYN study invited 10 350 citizen representatives for the adult Danish population for a non-mydriatic eye examination and answer the National Eye Institute Visual Function Questionnaire with 39 items in the validated Danish translation. The results from the 3384 (32.7%) persons who participated in the study were weighted on the basis of relevant socio-economic factors, and data were projected to represent the total population. Binocular visual acuity was below 0.1 corresponding to legal blindness in 0.22% of this population. RESULTS: OQoL was positively correlated with binocular visual acuity up to better than 93 ETDRS letters, negatively correlated with age for persons younger than 60 years of age and again positively correlated with age for persons older than 60 years. OQoL was negatively correlated with increasing ametropia and refractive error above 1 dioptre and encompassed more OQoL parameters for hyperopic than for myopic persons. CONCLUSIONS: The study underlines the benefits of improving visual acuity even within the normal range and of adjusting uncorrected refraction errors in the general population. OQoL is positively correlated with age in older persons independently of visual acuity, sex, refractive power and previous cataract surgery.

Advances in myopia control strategies for children.

Myopia has long been a global threat to public health. Timely interventions are likely to reduce the risk of vision-threatening complications. There are both established and rapidly evolving therapeutic approaches to slow myopia progression and/or delay its onset. The effective methods for slowing myopia progression include atropine eye-drops, defocus incorporated multiple segments (DIMS) spectacle lenses, spectacle lenses with highly aspherical lenslets target (HALT), diffusion optics technology (DOT) spectacle lenses, red light therapy (RLT), multifocal soft contact lenses and orthokeratology. Among these, 0.05% atropine, HALT lenses, RLT and +3.00 peripheral addition soft contact lenses yield over 60% reduction in myopia progression, whereas DIMS, DOT and MiSight contact lenses demonstrate at least 50% myopia control efficacy. 0.05% atropine demonstrates a more optimal balance of efficacy and safety than 0.01%. The efficacy of 0.01% atropine has not been consistent and requires further validation across diverse ethnicities. Combining atropine 0.01% with orthokeratology or DIMS spectacles yields better outcomes than using these interventions as monotherapies. Increased outdoor time is an effective public health strategy for myopia prevention while recent studies suggest that 0.05% low-concentration atropine and RLT therapy have promising potential as clinical myopia prevention interventions for high-risk groups. Myopia control spectacle lenses, being the least invasive, are safe for long-term use. However, when considering other approaches, it is essential to ensure proper instruction and regular follow-ups to maintain safety and monitor any potential complications. Ultimately, significant advances have been made in myopia control strategies, many of which have shown meaningful clinical outcomes. However, regular use and adequate safety monitoring over extended durations are imperative to foster confidence that can only come from extensive clinical experience.

Trio-based whole-exome sequencing reveals mutations in early-onset high myopia.

PURPOSE: Myopia, especially high myopia (HM), represents a widespread visual impairment with a globally escalating prevalence. This study aimed to elucidate the genetic foundations associated with early-onset HM (eoHM) while delineating the genetic landscape specific to Shaanxi province, China. METHODS: A comprehensive analysis of whole-exome sequencing was conducted involving 26 familial trios displaying eoHM. An exacting filtration protocol identified potential candidate mutations within acknowledged myopia-related genes and susceptibility loci. Subsequently, computational methodologies were employed for functional annotations and pathogenicity assessments. RESULTS: Our investigation identified 7 genes and 10 variants associated with HM across 7 families, including a novel mutation in the ARR3 gene (c.139C>T, p.Arg47*) and two mutations in the P3H2 gene (c.1865T>C, p.Phe622Ser and c.212T>C, p.Leu71Pro). Pathogenic mutations were found in syndromic myopia genes, notably encompassing VPS13B, TRPM1, RPGR, NYX and RP2. Additionally, a thorough comparison of previously reported causative genes of syndromic myopia and myopia risk genes with the negative sequencing results pinpointed various types of mutations within risk genes. CONCLUSIONS: This investigation into eoHM within Shaanxi province adds to the current understanding of myopic genetic factors. Our results warrant further functional validation and ocular examinations, yet they provide foundational insights for future genetic research and therapeutic innovations in HM.

Light exposure profiles differ between myopes and non-myopes outside school hours.

PURPOSE: Considering the putative role of light in myopia, and variations in socioeconomic, lifestyle, educational and environmental factors across ethnicities, we objectively investigated light exposure patterns in Indian school children. METHODS: The light exposure profile of 143 school children (9-15 years, 50 myopes) recorded using a validated wearable light tracker for six continuous days was analysed. Additional data for non-school days were available for 87 children (26 myopes). The illuminance exposure levels, time spent outdoors and epoch (number of times participant is exposed to a predefined range of lux level per day) were compared between myopes and non-myopes across different light conditions: ≥1000, ≥3000, ≥5000 and ≥10 000 lux. For school days, light exposure profiles during (1) before school, school and after school hours; and (2) class, break and transition (when a student travels to and from school) time were analysed. RESULTS: The overall median (IQR) daily illuminance exposure level, time spent outdoors and epochs at outdoors (≥1000 lux) were 807 (507-1079) lux/day, 46 (30-64) min/day and 9 (6-12) times/day, respectively. The daily illuminance exposure on non-school days was significantly higher in non-myopes than myopes (6369 (4508-9112) vs 5623 (2616-6929) lux/day, p=0.04). During transition time (school days), non-myopes had significantly higher illuminance exposure (910 (388-1479) vs 550 (263-1098) lux/day, p=0.04), spent more time outdoors (25 (10-43) vs 14 (4-29) min/day, p=0.01) and had higher outdoor epochs (6 (4-11) vs 5 (2-8) times/day, p=0.01) than myopes. CONCLUSIONS: A small but significant difference in illuminance exposure, time spent outdoors and epoch was noted between myopes and non-myopes during transition time, which may have implications in myopia control.

Effectiveness of repeated low-level red light in myopia prevention and myopia control.

BACKGROUND/AIMS: To compare the effects of repeated low-level red light (RLRL) treatment on axial length growth and refractive error changes in myopic and premyopic children. METHODS: Subjects were assigned randomly to four subgroups: myopia-RLRL group (M-RL), myopia-control group (M-C), premyopia-RLRL group (PM-RL) and premyopia-control group (PM-C). Subjects in the RLRL group completed a 12-month treatment composed of a 3 min RLRL treatment session twice daily, with an interval of at least 4 hours, for 7 days per week. Visits were scheduled before and at 1-month, 3-month, 6-month, 9-month and 12-month follow-up after the treatment. Repeated-measures analysis of variance was used to compare the spherical equivalent refractive errors (SE) and axial length (AL) changes between the groups across the treatment period. RESULTS: After 12 months of treatment, in the myopia group, SE and AL changes were -0.078±0.375 D and 0.033±0.123 mm for M-RL and -0.861±0.556 D and 0.415±0.171 mm for M-C; in the premyopia group, the progression of SE and AL was -0.181±0.417 D and 0.145±0.175 mm for PM-RL and -0.521±0.436 D and 0.292±0.128 mm for PM-C. PM-RL indicated a lower myopia incidence than PM-C (2.5% vs 19.4%). Additionally, the percentage of AL shortening in the M-RL was higher than that in the PM-RL before the 9-month follow-up. CONCLUSION: RLRL effectively delayed myopia progression in children with myopia and reduced the incidence of myopia in premyopic children. Moreover, RLRL exhibited a stronger impact on myopic children compared with premyopic individuals.

Femtosecond laser-assisted astigmatic keratotomy versus toric IOL implantation for correcting astigmatism in cataract patients: a systematic review and meta-analysis with trial sequential analysis.

AIMS: To compare the refractive and visual outcomes of femtosecond laser-assisted astigmatic keratotomy (FSAK) and toric intraocular lens (IOL) implantation for correcting astigmatism in cataract patients. METHODS: Studies were retrieved from the Ovid-Medline, EMBASE, Cochrane Central Register of Controlled Trials and Scopus which compared FSAK and toric IOL for astigmatism correction in cataract patients. Outcome measures included postoperative refractive cylinder, correction index, uncorrected distance visual acuity (UDVA), the proportion of patients achieving a residual refractive cylinder of 1.00 dioptre or less, target-induced astigmatism (TIA) and surgically induced astigmatism (SIA). The trial sequential analysis (TSA) was used to collect firm evidence supporting our conclusion. RESULTS: 9 studies encompassing 590 participants were analysed. The meta-analysis revealed that toric IOLs could result in less postoperative refractive cylinder and provide better UDVA compared with FSAK. The TSA disclosed strong evidence of lower postoperative refractive cylinder in the toric IOL group compared with that of the FSAK group. FSAK showed a smaller correction index and lower mean TIA and SIA compared with toric IOLs. CONCLUSIONS: For cataract patients, both FSAK and toric IOLs are effective methods for correcting astigmatism. However, toric IOLs offer less postoperative astigmatism and result in better postoperative UDVA compared with FSAK. In vector analysis of astigmatism, toric IOLs can also produce higher TIA and SIA. Additionally, neither method is associated with severe untreatable complications. Therefore, the conclusion is that toric IOLs are the preferred choice for astigmatism correction in cataract patients and FSAK serves as a viable alternative when toric IOLs are contraindicated.

Influencing factors of effective lens position in patients with Marfan syndrome and ectopia lentis.

AIMS: The aim of this study was to analyse the effective lens position (ELP) in patients with Marfan syndrome (MFS) and ectopia lentis (EL). METHODS: Patients with MFS undergoing lens removal and primary intraocular lens (IOL) implantation were enrolled in the study. The back-calculated ELP was obtained with the vergence formula and compared with the theoretical ELPs. The back-calculated ELP and ELP error were evaluated among demographic and biometric parameters, including axial length (AL), corneal curvature radius (CCR) and white-to-white (WTW). RESULTS: A total of 292 eyes from 200 patients were included. The back-calculated ELP was lower in patients undergoing scleral-fixated IOL than those receiving in-the-bag IOL implantation (4.54 (IQR 3.65-5.20) mm vs 4.98 (IQR 4.56-5.67) mm, p<0.001). The theoretical ELP of the SRK/T formula exhibited the highest accuracy, with no difference from the back-calculated ELP in patients undergoing in-the-bag IOL implantation (5.11 (IQR 4.83-5.65) mm vs 4.98 (IQR 4.56-5.67) mm, p=0.209). The ELP errors demonstrated significant correlations with refraction prediction error (PE): a 1 mm ELP error led to PE of 2.42D (AL<22 mm), 1.47D (22 mm≤AL<26 mm) and 0.54D (AL≥26 mm). Multivariate analysis revealed significant correlations of ELP with AL (b=0.43, p<0.001), CCR (b=-0.85, p<0.001) and WTW (b=0.41, p=0.004). CONCLUSION: This study provides novel insights into the origin of PE in patients with MFS and EL and potentially refines existing formulas.

Role of lens in early refractive development: evidence from a large cohort of Chinese children.

AIMS: To document longitudinal changes in spherical equivalent refraction (SER) and related biometric factors during early refractive development. METHODS: This was a prospective cohort study of Chinese children, starting in 2018 with annual follow-ups. At each visit, children received cycloplegic autorefraction and ocular biometry measurements. Lens power (LP) was calculated using Bennett's formula. Children were divided into eight groups based on baseline age: the 3-year-old (n=426, 49.77% girls), 4-year-old (n=834, 47.36% girls), 6-year-old (n=292, 46.58% girls), 7-year-old (n=964, 43.46% girls), 9-year-old (n=981, 46.18% girls), 10-year-old (n=1181, 46.32% girls), 12-year-old (n=504, 49.01%) and 13-year-old (n=644, 42.70%) age groups. RESULTS: This study included right-eye data from 5826 children. The 3-year-old and 4-year-old age groups demonstrated an inflection point in longitudinal SER changes at a mild hyperopic baseline SER (+1 to +2 D), with children with more myopic SER showing hyperopic refractive shifts while those with more hyperopic SER showing myopic shifts. The hyperopic shift in SER was mainly attributed to rapid LP loss and was rarely seen in the older age groups. Axial elongation accelerated in the premyopia stage, accompanied by a partially counter-balancing acceleration of LP loss. For children aged 3-7 years, those with annual SER changes <0.25 D were all mildly hyperopic at baseline (mean: 1.23 D, 95% CI 1.20 to 1.27 D). CONCLUSION: Our findings suggest that during early refractive development, refractions cluster around or above +1.00 D. There is a pushback process in which increases in the rate of LP occur in parallel with increases in axial elongation.