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This study aims to compare the levels of intrinsic protein disorder within the human lens and zonule proteomes and investigate the role of aging as a potential influencing factor on disorder levels. A cross-sectional proteomic analysis was employed, utilizing a dataset of 1466 proteins derived from the lens and zonule proteomes previously published by Wang et al. and De Maria et al. Bioinformatics tools, including a composition profiler and a rapid intrinsic disorder analysis online tool, were used to conduct a comparative analysis of protein disorder. Statistical tests such as ANOVA, Tukey's HSD, and chi-squared tests were applied to evaluate differences between groups. The study revealed distinct amino acid compositions for each proteome, showing a direct correlation between aging and increased protein disorder in the zonular proteomes, whereas the lens proteomes exhibited the opposite trend. Findings suggest that age-related changes in intrinsic protein disorder within the lens and zonule proteomes may be linked to structural transformations in these tissues. Understanding how protein disorder evolves with age could enhance knowledge of the molecular basis for age-related conditions such as cataracts and pseudoexfoliation, potentially leading to better therapeutic strategies.

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BACKGROUND/AIMS: Population surveys are required to measure the prevalence of cataract blindness in the community. We conducted simultaneous surveys in two regions in Malaysia in 2023 to estimate the prevalence of untreated cataract, measure the visual outcomes after cataract surgery and compare the results with the survey in 2014. METHODS: The surveys were done in Eastern and Sarawak administrative regions using the rapid assessment of avoidable blindness technique. It involved a multistage cluster sampling method, each cluster comprising 50 residents aged 50 years and older. The prevalence of cataract was determined through a visual acuity (VA) check and eye examination. The VA of those who had undergone cataract surgery was measured, and the findings were compared with the previous survey. RESULTS: A total of 9709 subjects, 50 years old and older, were examined (percentages of response were 94.5% and 96.2% for Eastern and Sarawak, respectively). Comparing the current to the previous survey in 2014, the prevalence of cataract at all levels of surgical thresholds (except unilateral VA <6/60 and <6/18 in the Eastern) was reduced. The percentages of cataract surgery visual outcomes with good VA (6/12) were improved, and those with poor VA (<6/60) were reduced in both regions. CONCLUSION: There was a reduction in cataract prevalence and improved visual outcomes in both regions. These favourable results could be attributed to the surgical performance monitoring initiatives and the community cataract programme implemented soon after the survey in 2014.

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AIMS: To assess the association between statin use and cataract surgery according to different statin treatment durations in patients with different cardiovascular risk profiles. METHODS AND RESULTS: We performed a nested case-control study using Danish registries, covering the period from 1 January 1996 to 31 December 2020. We defined cases as surgically treated cataract patients, matched in a 1:1 ratio by sex and age with controls not undergoing cataract surgery. The exposure of interest was statin use in different durations (1, 5 and 10 years) compared with never use of statins. Conditional logistic regression provided adjusted HRs and corresponding 95% CIs in subgroups defined by established atherosclerotic cardiovascular disease, diabetes, hypertension and individuals without these comorbidities. We identified 505 150 cataract surgery cases and found no increased HR of cataract surgery with statin treatment at any duration in any of the subgroups with established atherosclerotic cardiovascular disease, diabetes or hypertension. CONCLUSION: Our findings do not support a possible association between long-term statin use and cataract in patients with established atherosclerotic cardiovascular disease, diabetes or hypertension. Although we found an association between statin use and cataract in individuals without these comorbidities, increasing durations of statin use did not yield higher cataract surgery rates.

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BACKGROUND/AIMS: The aim of this study was to develop and evaluate digital ray, based on preoperative and postoperative image pairs using style transfer generative adversarial networks (GANs), to enhance cataractous fundus images for improved retinopathy detection. METHODS: For eligible cataract patients, preoperative and postoperative colour fundus photographs (CFP) and ultra-wide field (UWF) images were captured. Then, both the original CycleGAN and a modified CycleGAN (C2ycleGAN) framework were adopted for image generation and quantitatively compared using Frechet Inception Distance (FID) and Kernel Inception Distance (KID). Additionally, CFP and UWF images from another cataract cohort were used to test model performances. Different panels of ophthalmologists evaluated the quality, authenticity and diagnostic efficacy of the generated images. RESULTS: A total of 959 CFP and 1009 UWF image pairs were included in model development. FID and KID indicated that images generated by C2ycleGAN presented significantly improved quality. Based on ophthalmologists' average ratings, the percentages of inadequate-quality images decreased from 32% to 18.8% for CFP, and from 18.7% to 14.7% for UWF. Only 24.8% and 13.8% of generated CFP and UWF images could be recognised as synthetic. The accuracy of retinopathy detection significantly increased from 78% to 91% for CFP and from 91% to 93% for UWF. For retinopathy subtype diagnosis, the accuracies also increased from 87%-94% to 91%-100% for CFP and from 87%-95% to 93%-97% for UWF. CONCLUSION: Digital ray could generate realistic postoperative CFP and UWF images with enhanced quality and accuracy for overall detection and subtype diagnosis of retinopathies, especially for CFP.\ TRIAL REGISTRATION NUMBER: This study was registered with ClinicalTrials.gov (NCT05491798).

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With over a billion adults worldwide currently affected, presbyopia remains a ubiquitous, global problem. Despite over a century of study, the precise mechanism of ocular accommodation and presbyopia progression remains a topic of debate. Accordingly, this narrative review outlines the lenticular and extralenticular components of accommodation together with the impact of age on the accommodative apparatus, neural control of accommodation, models of accommodation, the impact of presbyopia on retinal image quality, and both historic and contemporary theories of presbyopia.

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BACKGROUND: Retinal imaging, including fundus autofluorescence (FAF), strongly depends on the clearness of the optical media. Lens status is crucial since the ageing lens has both light-blocking and autofluorescence (AF) properties that distort image analysis. Here, we report both lens opacification and AF metrics and the effect on automated image quality assessment. METHODS: 227 subjects (range: 19-89 years old) received quantitative AF of the lens (LQAF), Scheimpflug, anterior chamber optical coherence tomography as well as blue/green FAF (BAF/GAF), and infrared (IR) imaging. LQAF values, the Pentacam Nucleus Staging score and the relative lens reflectivity were extracted to estimate lens opacification. Mean opinion scores of FAF and IR image quality were compiled by medical readers. A regression model for predicting image quality was developed using a convolutional neural network (CNN). Correlation analysis was conducted to assess the association of lens scores, with retinal image quality derived from human or CNN annotations. RESULTS: Retinal image quality was generally high across all imaging modalities (IR (8.25±1.99) >GAF >BAF (6.6±3.13)). CNN image quality prediction was excellent (average mean absolute error (MAE) 0.9). Predictions were comparable to human grading. Overall, LQAF showed the highest correlation with image quality grading criteria for all imaging modalities (eg, Pearson correlation±CI -0.35 (-0.50 to 0.18) for BAF/LQAF). BAF image quality was most vulnerable to an increase in lenticular metrics, while IR (-0.19 (-0.38 to 0.01)) demonstrated the highest resilience. CONCLUSION: The use of CNN-based retinal image quality assessment achieved excellent results. The study highlights the vulnerability of BAF to lenticular remodelling. These results can aid in the development of cut-off values for clinical studies, ensuring reliable data collection for the monitoring of retinal diseases.

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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.

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Una mujer de raza negra de 62 años de edad que presentaba glaucoma crónico de ángulo estrecho no controlado en tratamiento con tres fármacos fue sometida a faco-esclerectomía profunda no perforante (facoEPNP) de su ojo izquierdo (OI). Durante la cirugía se puso de manifiesto que presentaba rasgo de zónula larga. Precisó goniopunción y desbridamiento de la ampolla posteriormente, presentando una sinequia de iris en la goniopunción que pudo ser reducida de forma conservadora. Este rasgo debe sospecharse en aquellos pacientes que presentan un ángulo estrecho combinado con un síndrome de dispersión pigmentaria. El manejo de la hipertensión ocular y el glaucoma que puede aparecer asociado a este rasgo no está protocolizado. En esta comunicación se reflexiona acerca de la mejor actuación ante esta infrecuente forma de glaucoma.(AU)

A 62-year-old black woman with uncontrolled chronic narrow-angle glaucoma on 3-drug therapy underwent phaco-non-perforating deep sclerectomy of her left eye. During surgery it was revealed that she had long zonule trait. She later required goniopuncture and conjuntival needling, presenting an iris synechia on the goniopuncture that could be reduced conservatively. Long anterior zonule trait should be suspected in those patients presenting with a combination of narrow angle and pigment dispersion syndrome. The management of ocular hypertension and glaucoma associated to this trait is not protocolized. This communication discusses on the best action in this rare form of glaucoma.(AU)

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OBJECTIVE: To compare sustainability, financial implications and surgical efficiency of two phacoemulsification cassette systems for cataract surgery: a machine with single-use cassettes and another with daily, reusable ones. METHODS: Observational study involving retrospective cataract surgery data collection at the Centre Médical de l'Alliance, Braine-l'Alleud, Belgium, a tertiary eye care centre. Information on cassette weight, quantities and transport volume was obtained from routine procedures and purchasing records. The costs for each machine were calculated by reviewing the invoices received from the accounting department. RESULTS: We found significant differences across comparisons. The reusable cassette machine, when compared with the single-use machine, used 306.7 kg less plastic (75.3% reduction), required 2494 m3 less storage per 1000 surgeries (67.7% decrease) and cost €54.16 less per 10 procedures (16.9% reduction). The machine with daily reusable cassettes also exhibited a 7-minute priming time advantage for 10 procedures, reducing downtime between cases. CONCLUSIONS: Our findings underscore the benefits of adopting reusable cassette systems: reduced plastic consumption, storage volume and priming time, as well as enhanced efficiency and cost-savings. Healthcare professionals and institutions are encouraged to embrace environmentally conscious initiatives. The use of reusable cassette systems for cataract surgeries offers a pathway to sustainable practices.

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PURPOSE: To investigate the characteristics and associations of anterior lens zonules lengths in cataract patients via ultrasound biomicroscope (UBM) measurement. METHODS: Patients with age-related cataracts and high myopic cataracts who planned to undergo cataract surgery were included in the study. After routine ophthalmic examinations, the UBM was performed on both eyes to get images of the anterior lens zonules, and Image J software was used to measure the lengths of the lens zonules. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WTW) diameter of both eyes were obtained by IOL Master 700. Univariate and multivariate regression analyses were used to assess associated factors of anterior lens zonules lengths. RESULTS: Forty-nine patients with age-related cataracts and 33 patients with high myopic cataracts were enrolled. High myopic cataract patients were younger and had longer anterior lens zonules. Multivariate regression analysis showed that anterior lens zonules lengths were associated with axial lengths (temporal location: ß = 0.036, P = 0.029; nasal location: ß = 0.034, P = 0.011; superior location: ß = 0.046, P = 0.002) and ACD (inferior location: ß = 0.305, P = 0.016) in right eyes. In left eyes, anterior lens zonules lengths were associated with axial lengths (temporal location: ß = 0.028, P = 0.017; inferior location: ß = 0.026, P = 0.016; nasal location: ß = 0.033, P < 0.001) and ACD (inferior location: ß = 0.215, P = 0.030; superior location: ß = 0.290, P = 0.011). CONCLUSIONS: High myopic cataract patients have longer anterior lens zonules. AL and ACD contributed to the lengths of anterior lens zonules. Thus, for patients with long AL and deeper ACD, lens zonules measurement was crucial. CLINICAL TRIAL REGISTRATION: www.chictr.org.cn identifier is ChiCTR2300071397.

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Purpose:To describe the visual outcomes and problems that resulted from surgical treatment of nanophthalmic complete retinal detachment (RD) with retina-lens contact. Methods: A multicenter retrospective case series with deep sclerectomy as a treatment was performed. Results: Five cases had extensive deep sclerectomies, 3 with intended drainage of subretinal fluid (SRF). The RD resolved 1 week postoperatively in 4 cases and within 1 month in 1 case. The visual acuity improved from light perception to a median of 20/100. Three cases had longstanding lens touch beyond 1 year and improved VA to 20/100, 20/150, and hand motions, respectively. Complications included focal lens dialysis in 2 cases (passive drainage of SRF) and lens or intraocular lens dislocation in 1 case each (active drainage of SRF). Ultrasound biomicroscopy and anterior optical coherence tomography showed a very narrow angle and short zonules. Conclusions: Deep sclerectomy results in good anatomic and functional improvements in advanced cases of nanophthalmos exudative detachment, which is often considered to be incurable.

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AIMS: To establish and evaluate predictive models for glaucoma-related adverse events (GRAEs) following secondary intraocular lens (IOL) implantation in paediatric eyes. METHODS: 205 children (356 aphakic eyes) receiving secondary IOL implantation at Zhongshan Ophthalmic Center with a 3-year follow-up were enrolled. Cox proportional hazard model was used to identify predictors of GRAEs and developed nomograms. Model performance was evaluated with time-dependent receiver operating characteristic (ROC) curves, decision curve analysis, Kaplan-Meier curves and validated internally through C-statistics and calibration plot of the bootstrap samples. RESULTS: Older age at secondary IOL implantation (HR=1.5, 95% CI: 1.03 to 2.19), transient intraocular hypertension (HR=9.06, 95% CI: 2.97 to 27.67) and ciliary sulcus implantation (HR=14.55, 95% CI: 2.11 to 100.57) were identified as risk factors for GRAEs (all p<0.05). Two nomograms were established. At postoperatively 1, 2 and 3 years, model 1 achieved area under the ROC curves (AUCs) of 0.747 (95% CI: 0.776 to 0.935), 0.765 (95% CI: 0.804 to 0.936) and 0.748 (95% CI: 0.736 to 0.918), and the AUCs of model 2 were 0.881 (95% CI: 0.836 to 0.926), 0.895 (95% CI: 0.852 to 0.938) and 0.848 (95% CI: 0.752 to 0.945). Both models demonstrated fine clinical net benefit and performance in the interval validation. The Kaplan-Meier curves showing two distinct risk groups were well discriminated and robust in both models. An online risk calculator was constructed. CONCLUSION: Two nomograms could sensitively and accurately identify children at high risk of GRAEs after secondary IOL implantation to help early identification and timely intervention.

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AIMS: To predict high-risk factors for zonular complications during cataract surgery due to pre-existing severe zonular dehiscence in eyes with pseudoexfoliation (PXF) syndrome. METHODS: 315 eyes of 315 consecutive patients with PXF scheduled for phacoemulsification surgery underwent preoperative examination of various ocular parameters using an anterior segment-optical coherence tomography and other devices. When zonular complications occurred during surgery due to zonular dehiscence, scleral fixation of the intraocular lens (IOL) or implantation of a capsular tension ring (CTR) was performed. High-risk factors for these intraoperative zonular complications were examined using classification-tree and logistic regression analyses. RESULTS: Of the 315 eyes, 31 (9.84%) underwent scleral IOL fixation or CTR implantation. High-risk factors identified by classification-tree analysis were a small pupillary diameter after mydriasis <6.30 mm, a shallow anterior chamber depth <2.074 mm and lens decentration >0.260 mm. Based on exact logistic regression analysis, the OR was 4.81-fold higher for eyes with poor mydriasis than for eyes without poor mydriasis (p=0.006, 95% CI 1.49 to 18.23), 23.99-fold higher for eyes with poor mydriasis and a shallow anterior chamber (p<0.001, 5.92 to 109.02) and 287.39-fold higher for eyes with poor mydriasis, a shallow chamber and great lens decentration (p<0.001, 50.46 to infinity). CONCLUSION: In eyes with PXF, high-risk factors for zonular complications during cataract surgery due to pre-existing severe zonular dehiscence were poor mydriasis, shallow anterior chamber and large lens decentration, suggesting the importance of evaluating these conditions preoperatively.

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A 62-year-old black woman with uncontrolled chronic narrow-angle glaucoma on 3-drug therapy underwent phaco-non-perforating deep sclerectomy of her left eye. During surgery it was revealed that she had long zonule trait. She later required goniopuncture and conjuntival needling, presenting an iris herniation in the goniopuncture that could be reduced conservatively. Long anterior zonule trait should be suspected in those patients presenting with a combination of narrow angle and pigment dispersion syndrome. The management of ocular hypertension and glaucoma associated to this trait is not protocolized. This communication discusses on the best action in this rare form of glaucoma.

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BACKGROUND: The crystalline lens is a transparent structure of the eye to focus light on the retina. It becomes muddy, hard and dense with increasing age, which makes the crystalline lens gradually lose its function. We aim to develop a nuclear age predictor to reflect the degeneration of the crystalline lens nucleus. METHODS: First we trained and internally validated the nuclear age predictor with a deep-learning algorithm, using 12 904 anterior segment optical coherence tomography (AS-OCT) images from four diverse Asian and American cohorts: Zhongshan Ophthalmic Center with Machine0 (ZOM0), Tomey Corporation (TOMEY), University of California San Francisco and the Chinese University of Hong Kong. External testing was done on three independent datasets: Tokyo University (TU), ZOM1 and Shenzhen People's Hospital (SPH). We also demonstrate the possibility of detecting nuclear cataracts (NCs) from the nuclear age gap. FINDINGS: In the internal validation dataset, the nuclear age could be predicted with a mean absolute error (MAE) of 2.570 years (95% CI 1.886 to 2.863). Across the three external testing datasets, the algorithm achieved MAEs of 4.261 years (95% CI 3.391 to 5.094) in TU, 3.920 years (95% CI 3.332 to 4.637) in ZOM1-NonCata and 4.380 years (95% CI 3.730 to 5.061) in SPH-NonCata. The MAEs for NC eyes were 8.490 years (95% CI 7.219 to 9.766) in ZOM1-NC and 9.998 years (95% CI 5.673 to 14.642) in SPH-NC. The nuclear age gap outperformed both ophthalmologists in detecting NCs, with areas under the receiver operating characteristic curves of 0.853 years (95% CI 0.787 to 0.917) in ZOM1 and 0.909 years (95% CI 0.828 to 0.978) in SPH. INTERPRETATION: The nuclear age predictor shows good performance, validating the feasibility of using AS-OCT images as an effective screening tool for nucleus degeneration. Our work also demonstrates the potential use of the nuclear age gap to detect NCs.

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PURPOSE: To evaluate the long-term visual acuity (VA) outcome of cataract surgery in inflammatory eye disease. SETTING: Tertiary care academic centres. DESIGN: Multicentre retrospective cohort study. METHODS: A total of 1741 patients with non-infectious inflammatory eye disease (2382 eyes) who underwent cataract surgery while under tertiary uveitis management were included. Standardised chart review was used to gather clinical data. Multivariable logistic regression models with adjustment for intereye correlations were performed to evaluate the prognostic factors for VA outcomes. Main outcome measure was VA after cataract surgery. RESULTS: Uveitic eyes independent of anatomical location showed improved VA from baseline (mean 20/200) to within 3 months (mean 20/63) of cataract surgery and maintained through at least 5 years of follow-up (mean 20/63). Eyes that achieved 20/40 or better VA at 1 year were more likely to have scleritis (OR=1.34, p<0.0001) or anterior uveitis (OR=2.2, p<0.0001), VA 20/50 to 20/80 (OR 4.76 as compared with worse than 20/200, p<0.0001) preoperatively, inactive uveitis (OR=1.49, p=0.03), have undergone phacoemulsification (OR=1.45 as compared with extracapsular cataract extraction, p=0.04) or have had intraocular lens placement (OR=2.13, p=0.01). Adults had better VA immediately after surgery, with only 39% (57/146) paediatric eyes at 20/40 or better at 1 year. CONCLUSIONS: Our results suggest that adult and paediatric eyes with uveitis typically have improved VA following cataract surgery and remain stable thereafter for at least 5 years.

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INTRODUCTION: To determine the effectiveness of music in allaying preoperative anxiety in patients scheduled for and undergoing surgery for age-related cataract. METHODS: This is a randomised interventional study of individuals aged 50 years and above who were scheduled for and undergoing cataract surgery under regional anaesthesia, with music (test group) randomly matched with similar individuals undergoing the same procedure but without music (control group). The surgeries were performed at the Ophthalmology Theatre of the University of Nigeria Teaching Hospital (UNTH), Ituku Ozalla, Enugu, Nigeria. Using a systematic random sampling method, a total of 98 patients were selected into two groups. Both groups completed the State-Trait Anxiety Inventory (STAI) Questionnaire at baseline, immediately on entrance into the preoperative room and 5 min after intervention. The first group listened to music while the second group did not listen to music. Results were analysed using the SPSS V.20 and analysis of variance was used to compare means of variables measured at baseline, preoperative before intervention and preoperative after intervention. Categorical variables were compared using the χ2 test. Student's t-test was used to analyse the continuous variables. RESULTS: There was an increase in the anxiety scores in the two groups on entrance into the preoperative room, however, 5 min into intervention, there was a significant decrease in the anxiety scores in the music group and a progressive increase in the anxiety scores in the group without music. CONCLUSION: Music has a positive effect on preoperative anxiety evidenced by the indirect effect of music on the STAI anxiety scores.

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BACKGROUND/AIMS: To identify ocular determinants of iridolenticular contact area (ILCA), a recently introduced swept-source optical coherence tomography (SSOCT) derived parameter, and assess the association between ILCA and angle closure. METHODS: In this population-based cross-sectional study, right eyes of 464 subjects underwent SSOCT (SS-1000, CASIA, Tomey Corporation, Nagoya, Japan) imaging in the dark. Eight out of 128 cross-sectional images (evenly spaced 22.5° apart) were selected for analysis. Matlab (Matworks, Massachusetts, USA) was used to measure ILCA, defined as the circumferential extent of contact area between the pigmented iris epithelium and anterior lens surface. Gonioscopic angle closure (GAC) was defined as non-visibility of the posterior trabecular meshwork in two or more angle quadrants. RESULTS: The mean age of subjects was 62±6.6 years, with the majority being female (65.5%). 143/464 subjects (28.6%) had GAC. In multivariable linear regression analysis, ILCA was significantly associated with anterior chamber width (ß=1.03, p=0.003), pupillary diameter (ß=-1.9, p<0.001) and iris curvature (ß=-17.35, p<0.001). ILCA was smaller in eyes with GAC compared with those with open angles (4.28±1.6 mm2 vs 6.02±2.71 mm2, p<0.001). ILCA was independently associated with GAC (ß=-0.03, p<0.001), iridotrabecular contact index (ß=-6.82, p<0.001) or angle opening distance (ß=0.02, p<0.001) after adjusting for covariates. The diagnostic performance of ILCA for detecting GAC was acceptable (AUC=0.69). CONCLUSIONS: ILCA is a significant predictor of angle closure independent of other biometric factors and may reflect unique anatomical information associated with pupillary block. ILCA represents a novel biometric risk factor in eyes with angle closure.

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PURPOSE: To explore the synergistic function of the ligaments in eye, the zonular fibres, that mediate change in eye lens shape to allow for focussing over different distances. METHODS: A set of 3D Finite Element models of the anterior eye together with a custom developed pre-stress modelling approach was proposed to simulate vision for distant objects (the unaccommodated state) to vision for near objects (accommodation). One of the five zonular groups was cut off in sequence creating five models with different zonular arrangements, the contribution of each zonular group was analysed by comparing results of each specific zonular-cut model with those from the all-zonules model in terms of lens shape and zonular tensions. RESULTS: In the all-zonular model, the anterior and equatorial zonules carry the highest tensions. In the anterior zonular-cut model, the equatorial zonular tension increases while the posterior zonular tension decreases, resulting in an increase in the change in Central Optical Power (COP). In the equatorial zonular-cut model, both the anterior and posterior zonular tensions increase, causing a decreasing change in COP. The change in COP decreases only slightly in the other models. For vitreous zonular-cut models, little change was seen in either the zonular tension or the change in COP. CONCLUSIONS: The anterior and the equatorial zonular fibres have the major influence on the change in lens optical power, with the anterior zonules having a negative effect and the equatorial zonules contributing a positive effect. The contribution to variations in optical power by the equatorial zonules is much larger than by the posterior zonules.

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PURPOSE: The purpose of this study was to develop a concept for predicting the effects of both discrete intraocular lens (IOL) power steps (PS) and power labelling tolerances (LT) on the uncertainty of the refractive outcome (REFU). DESIGN: Retrospective non-randomised cross-sectional Monte Carlo simulation study. METHODS: We evaluated a dataset containing 16 669 IOLMaster 700 preoperative biometric measurements. The PS and the delivery range of two modern IOLs (Bausch and Lomb enVista and Alcon SA60AT) were considered for this Monte Carlo simulation. The uncertainties from PS or LT were assumed to be normally distributed according to ±½ the IOL PS or the ISO 11979 LT. REFU was recorded and analysed for all simulations. RESULTS: With both lenses the REFU from discrete PS ranged from 0.11 to 0.12 dpt. Due to the larger PS for low/high power lenses with the enVista/SA60AT, REFU is more dominant in initially myopic/hyperopic eyes. REFU from LT ranged from 0.18 to 0.19 dpt for both lenses. Since LT increases stepwise with IOL power, REFU is more prevalent in initially hyperopic eyes requiring high IOL power values, and for lenses with a wide delivery range towards higher powers. CONCLUSIONS: Since surgeons and patients are typically aware of the effect of discrete PS on REFU, these might be tolerated in cataract surgery. However, REFU resulting from LT is inevitable while the true measured IOL power is not reported on the package, leading to background noise in postoperative achieved refraction.