Cataract: Advances in surgery and whether surgery remains the only treatment in future

Nontraditional approaches to sedation for anterior segment surgery: a narrative review

PURPOSE OF REVIEW

Surgical and anesthetic technological advancement have made both cataract and noncataract anterior segment surgery significantly less invasive and time-intensive, facilitating the transition of some of these procedures from the operating room under monitored anesthesia care (MAC) to the office-based setting without MAC. This transition has been aided by the popularization of nonintravenous approaches to achieving patient sedation for these procedures. In this review, we discuss the literature surrounding traditional and nontraditional methods of achieving patient sedation for anterior segment surgery.

RECENT FINDINGS

Our survey of the literature suggests that nonintravenous (IV) approaches to sedation for these procedures may be just as safe, effective, and satisfactory to patients as traditional IV approaches.

SUMMARY

As anterior segment surgery becomes less invasive and less time-intensive, providers considering transitioning their cataract and anterior segment surgery out of the operating room and into the office-based setting without MAC anesthesia should consider the non-IV sedation options outlined in this review to achieve adequate patient sedation and comfort.

Plasma miR-19b, miR-34a, and miR-146a expression in patients with type 2 diabetes mellitus and cataract: A pilot study

Cataract is among the most common ocular complications in diabetes mellitus (DM). While microRNA (miRNA) dysregulations in DM have been previously reported, consensus is still lacking concerning miRNA expression in cataract. Furthermore, the miRNA profile in diabetic cataract patients remains largely unexplored, and data on plasma expression levels are limited. Our study aimed to assess the plasma levels of three distinct miRNA species (hsa-miR-19b, hsa-miR-34a, and hsa-miR-146a) implicated in the development of cataract and/or DM.We investigated the circulating miRNA expression in DM patients diagnosed with cataract, compared to a non-DM cataract group. We employed qRT-PCR for relative quantification experiments and subsequently conducted a correlation analysis between miRNA expression levels and clinical characteristics. Our findings reveal that hsa-miR-34a and hsa-miR-146a are differentially expressed in the two cohorts. However, no significant correlation was observed between the clinical variables and miRNA levels. In summary, our results suggest a potential role for hsa-miR-34a and hsa-miR-146a in the biology of diabetic cataract.

Incidence and analysis of intraoperative complications in femtosecond laser-assisted cataract surgery: a large-scale cohort study to establish the learning curve

AIMS

To assess the safety of femtosecond laser-assisted cataract surgery (FLACS) based on surgical parameters and intraoperative complications analysis and to determine the length of the learning curve for FLACS.

METHODS

A prospective consecutive cohort study was conducted on Chinese patients who underwent either FLACS (3289 cases) or contemporaneous conventional phacoemulsification cataract surgery (2130 cases). The laser group was divided into four subgroups in chronological order. We recorded intraoperative complication incidences and compared with surgical parameters between groups. Subgroup analysis was conducted to explore the learning curve of FLACS.

RESULTS

The laser group had a 4.93% incidence of incomplete capsulotomies and a 1.22% incidence of anterior capsule tears. Subgroup analysis showed significant differences in 8 aspects between the first 250 cases (50 cases per surgeon) and the last 2539 cases, but only 2 aspects differed between the second 250 cases (50 cases per surgeon) and the last 2539 cases. There were no significant differences between the third 250 cases (50 cases per surgeon) and the last 2539 cases.

CONCLUSIONS

The intraoperative complications of FLACS were reported, and the learning curve is associated with a significant reduction in the incidence of intraoperative complications. The length of the basic learning curve of FLACS is 100 cases, and the length of the advanced learning curve was 150 cases. This study demonstrated that FLACS is characterised by a relatively straightforward and secure operative technique.

Association between dietary inflammation index and cataract: a population-based study from NHANES 2005-2008

Importance

Various studies have widely explored the association between index of dietary inflammation (DII) and occurrence of diseases. Accumulating evidence have revealed that a lower DII seems to be protective against a variety of diseases. Nevertheless, the association between DII and age-related cataract remains unclear.

Objective

To investigate the correlation between DII and age-related cataract in a representative sample of the American population.

Design setting and participants

This cross-sectional population-based study comprised 6,395 participants from the National Health and Nutrition Examination Survey (NHANES) conducted in cycles from 2005 to 2008. DII was calculated using dietary recall information, with higher scores indicating greater inflammatory potential of the diet. Age-related cataract was evaluated using cataract surgery as a surrogate measure. Covariates included sociodemographic factors, lifestyle factors, physical measures, and comorbidities. Logistic regression models were employed to assess the association between DII and cataract. The presence of a non-linear relationship was examined using restricted cubic spline analysis. Subgroup analysis was conducted to explore potential interaction effects. Data analysis was performed from September 1 to December 30, 2022.

Main outcomes and measures

Age-related cataract assessed through cataract surgery information obtained from a self-reported questionnaire.

Results

A total of 6,395 participants were included, with a mean (standard deviation, SD) age of 48.7 (15.3) years. Of these, 3,115 (48.7%) were male, 3,333 (52.1%) were non-Hispanic white, and 683 (10.7%) had cataract. The mean (SD) DII was -4.78 (1.74). After adjusting for all included covariates, DII showed a positive association with cataract, both as a continuous variable (odds ratio (OR): 1.054, 95% confidence interval (CI): 1.007-1.103, p = 0.023) and in quartiles, with the highest quartile compared to the lowest (OR: 1.555, 95% CI: 1.233-1.967, p < 0.001). Restricted cubic spline analysis revealed no evidence of a non-linear relationship (p for non-linearity 0.085). Subgroup analysis indicated no interaction effects among the studied covariates.

Conclusions and relevance

These findings suggest that a pro-inflammatory diet serves as a risk factor for the occurrence of cataracts.

Association between amiodarone use and risk of cataract: a population-based active-comparator study

BACKGROUND

Despite previous concerns about ocular side effects related to amiodarone, the relationship between amiodarone and cataract remains uncertain. Therefore, this study aimed to assess the potential association between amiodarone use and the subsequent risk of cataract, taking into account potential confounders.

METHODS

This population-based, active comparator-controlled cohort study utilized the data from the Taiwan National Health Insurance program and involved adults over 40 years old between 2001 and 2013. We analyzed 12 055 new amiodarone users and contrasted them with a propafenone user cohort. The primary outcome was the incidence of cataract. Inverse-probability treatment-weighting (IPTW) was further used to eliminate the potential confounding effects, and Cox proportional-hazard regression analyses were performed to calculate the risk of cataract. Serial subgroup analyses were also performed.

RESULTS

In the main analysis, amiodarone users did not exhibit a significant causal relationship in both full cohort [adjusted hazard ratio (aHR): 0.994, 95% confidence interval (CI): 0.913-1.082] and IPTW cohort (IPTW-aHR 0.977, 95% CI: 0.900-1.060). Furthermore, it is important to highlight a significantly reduced risk of cataract among patients with heart failure (IPTW-aHR 0.708, 95% CI: 0.554-0.905) and during the 2-year follow-up period (IPTW-aHR 0.889, 95% CI: 0.794-0.996), implying potential advantages linked to the use of amiodarone.

CONCLUSIONS

The study found no increased risk of cataract with amiodarone, one of the most frequently used antiarrhythmic medications, compared to the use of propafenone. Future research is recommended to explore potential mechanisms and their implications for clinical practice.

A review of using Traditional Chinese Medicine in the management of glaucoma and cataract

Traditional Chinese Medicine has a long history in ophthalmology in China. Over 250 kinds of Traditional Chinese Medicine have been recorded in ancient books for the management of eye diseases, which may provide an alternative or supplement to current ocular therapies. However, the core holistic philosophy of Traditional Chinese Medicine that makes it attractive can also hinder its understanding from a scientific perspective - in particular, determining true cause and effect. This review focused on how Traditional Chinese Medicine could be applied to two prevalent ocular diseases, glaucoma, and cataract. The literature on preclinical and clinical studies in both English and Chinese on the use of Traditional Chinese Medicine to treat these two diseases was reviewed. The pharmacological effects, safety profile, and drug-herb interaction of selected herbal formulas were also investigated. Finally, key considerations for conducting future Traditional Chinese Medicine studies are discussed.

Reducing ophthalmic surgical waste through electronic instructions for use: a multisociety position paper

Every ophthalmic surgical supply, including intraocular lenses (IOLs), IOL cartridges, and ophthalmic viscosurgical device syringes, is packaged with instructions for use (IFU). These pamphlets are printed in multiple languages and, in the case of an IOL, significantly increase the size and weight of the packaging. To eliminate this significant and unnecessary source of waste, we recommend that manufacturers move to Quick Response codes that link to online electronic IFU (e-IFU) as a sensible alternative. In addition to reducing carbon emissions and manufacturing costs, e-IFU can be updated more easily and accessed by surgeons in the clinic, where IOL models and powers are selected. Varying and inconsistent IFU requirements between different countries are a barrier to wider adoption of e-IFU by the ophthalmic surgical industry. Regulatory agencies in every country should allow and encourage e-IFU. This position paper has been endorsed by the 3 major societies that sponsor EyeSustain, a consortium of global societies dedicated to advancing sustainability in ophthalmology.

Using genetics to investigate the association between lanosterol and cataract

Background: Cataract is one of the most prevalent causes of blindness worldwide. Whilst surgery is the primary treatment for cataracts, it is not always an available option, particularly in developing countries. Non-surgical methods of treatment would increase treatment availability for more patients. Several studies have investigated how topical application of oxysterols, such as lanosterol, may break down aggregated proteins and restore lens transparency. However, the results are conflicting and inconclusive. Aim: In this study, we focus on combining genetic evidence for associations between lanosterol related genetic variation and cataract to explore whether lanosterol is a potentially suitable drug treatment option. Method: Using data from 45,449 available cataract cases from the UK Biobank, with participant ages ranging from 40-69, we conducted a genetic association study (GWAS) to assess the risk of cataract. Cataract cases were defined using diagnostic and operation codes. We focused on genetic variants in the lanosterol synthase gene region. We also compared our results with previously published genetic associations of phytosterol-to-lanosterol ratios. Finally, we performed a genetic risk score analysis to test the association between lanosterol within the cholesterol synthesis pathway and the risk of cataract. Results: No statistically significant single nucleotide polymorphisms (SNPs) associations with cataract were observed in the gene region of lanosterol synthase at a multiple testing adjusted significance threshold of p < 0.05/13. The comparison between cataract risk and genetic association of 8 phytosterol-to-lanosterol GWAS results also showed no evidence to support lanosterol's protective properties for cataract risk. No statistically significant association was found between the lanosterol within the cholesterol synthesis pathway genetic risk score and cataract outcomes (OR = 1.002 p = 0.568). Conclusion: There was no evidence observed for genetic associations between lanosterol and cataract risk. Our results do not support lanosterol's potential role in treating cataracts. Further research may be needed to address the effect of lanosterol on specific cataract subtypes.

Chitosan and Anionic Solubility Enhancer Sulfobutylether-β-Cyclodextrin-Based Nanoparticles as Dexamethasone Ophthalmic Delivery System for Anti-Inflammatory Therapy

Cataract surgery interventions are constantly increasing, particularly among adult and elderly patients. This type of surgery can lead to inflammatory states of the ocular anterior segment (AS), usually healed via postoperative treatment with dexamethasone (DEX)-containing eye drops. The application of eye drops is challenging due to the high number of daily administrations. In this study, mucoadhesive nanoparticles (NPs) were formulated to improve the residence time of DEX on the corneal mucosa, enhancing the drug's solubility and bioavailability. The NPs were generated using an ionotropic gelation technique, exploiting the interaction between the cationic group of chitosan (CS) and the anionic group of sulfobutylether-β-cyclodextrin (SBE-β-CD). The formation of the inclusion complex and its stoichiometry were studied through phase solubility studies, Job's plot method, and Bi-directional transport studies on MDCKII-MDR1. The obtained NPs showed good chemical and physical characteristics suitable for drug loading and subsequent testing on animal mucosa. The DEX-loaded CS/SBE-β-CD NPs exhibited a prolonged residence time on animal mucosa and demonstrated enhanced drug permeability through the corneal membrane, showing a sustained release profile. The developed NPs posed no irritation or toxicity concerns upon local administration, making them an optimal and innovative drug delivery system for inflammatory AS diseases treatment.

A meta-analysis of topical Ketorolac's effect on surgical site wound healing post-cataract surgery

This meta-analysis evaluates the impact of topical ketorolac on surgical site wound healing and scar formation after cataract surgery. A thorough literature search, adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, identified eight relevant studies from 2348 articles. The selected studies were analysed for wound healing efficacy, using the redness, edema, ecchymosis, discharge and approximation (REEDA) scale, and scar formation, assessed by the Manchester scar scale (MSS). Results indicated that ketorolac significantly improved wound healing, with lower REEDA scores 1 week post-surgery (I2  = 97%; Random: standardised mean difference (SMD): -10.93, 95% CI: -13.85 to -8.00, p < 0.01), and reduced scar formation, evidenced by lower MSS scores 3 months post-surgery (I2  = 74%; Random: SMD: -9.67, 95% CI: -11.03 to -8.30, p < 0.01). The findings suggest that topical ketorolac is beneficial in post-cataract surgery care, enhancing wound healing and reducing scarring.

The Royal College of Ophthalmologists' National Ophthalmology Database study of cataract surgery: report 16, influence of remuneration model on choice of intraocular lens in the UK

BACKGROUND/OBJECTIVES

Cataract surgery with intraocular lens (IOL) implantation is one of the most commonly performed surgeries worldwide. Within the UK, publicly funded cataract surgery is remunerated by two models: (1) "block contract" (BC), which commissions organisations to deliver whole service pathways without considering specific activity items; or (2) "payment by results" (PbR), which pays a tariff price for each procedure. This study aimed to examine the association between remuneration model and the cost and types of IOL used.

SUBJECTS/METHODS

Cataract operations recorded on the Royal College of Ophthalmologists' National Ophthalmology Database were included, with additional data collected for remuneration model from NHS England and cost of IOL from the NHS Spend Comparison Service.

RESULTS

We included 907,052 cataract operations from 87 centres. The majority of operations were performed in PbR centres (456 198, 50.3%), followed by BC centres (240 641, 26.5%) and mixed models centres (210 213, 23.2%). The mean price of hydrophobic (n = 7) and hydrophilic IOLs (n = 5) were £45.72 and £42.86, respectively. Hydrophobic IOLs were predominantly used (650 633, 71.7%) and were significantly more commonly used in centres remunerated by BC (96.5% vs. 3.5%) than those by PbR (65.7% vs. 34.3%) when compared to hydrophilic IOLs (p < 0.001).

CONCLUSIONS

This study demonstrated that the IOL choice may be perversely incentivised by the IOL cost and remuneration model. Although hydrophobic IOLs are more expensive at the point of surgery, their potential longer-term cost-effectiveness due to reduced requirement for YAG capsulotomy should be considered.

Heteromeric formation with βA3 protects the low thermal stability of βB1-L116P

BACKGROUND/AIMS

Congenital cataract is the leading cause of visual disability and blindness in childhood. βB1-crystallin (CRYBB1) comprises about 1/10th of crystallin structural proteins, forming heteromers to maintain lens transparency. We previously reported a CRYBB1 mutation (c.347T>C, p.L116P) affecting 16 patients in a congenital nuclear cataract family. In this study, we investigate the underlying pathogenic mechanism of βB1-L116P.

METHODS

Protein isolation, size-exclusion chromatography, spectroscopy, Uncle stability screens and molecular dynamics simulations were used to assess βA3- and βB1-crystallin thermal stability, structural properties and heteromer formation.

RESULTS

Cells that overexpressed βB1-L116P tended to form aggregates and precipitations under heat-shock stress. Thermal denaturation and time-dependent turbidity experiments showed that thermal stability was significantly impaired. Moreover, protein instability appeared to increase with elevated concentrations detected by the Uncle system. Additionally, βA3 had a relative protective effect on βB1-L116P after heteromers were formed, although βA3 was relatively unstable and was usually protected by basic β-crystallins. Molecular dynamic simulations revealed that L116P mutation altered the hydrophobic residues at the surface around the mutant site, providing solvents more access to the internal and hydrophobic parts of the protein.

CONCLUSIONS

Decreased βB1-crystallin thermal stability in the presence of the cataract-related L116P mutation contributes significantly to congenital cataract formation. Moreover, its formation of heteromers with βA3 protects against the low thermal stability of βB1-L116P.

Cataractogenesis and molecular pathways, with reactive free oxygen species as a common pathway

Slowing down or stopping the natural process of cataractogenesis is certainly a challenge for those who today propose an option other than surgery. Addressing the same problem in different ways constitutes a new approach to solving what is today the number one cause of reversible blindness worldwide. The technological revolution, as well as the advances in the biological sciences, allows us to conceive mechanisms never thought of before to stop the process that, as a common pathway, constitutes opacification of the crystalline lens. A new dawn for cataracts is coming through molecular, newly-discovered mechanisms. Cataractogenesis and molecular pathways have reactive free oxygen species as a common pathway. Surgical removal is today's gold standard, but perhaps not for much longer.

Lens regeneration in situ using hESCs-derived cells -similar to natural lens

Lens itself has limited regeneration functionality, thus we aimed to create regenerated lens with biological function to treat cataracts rather than the intraocular lens used in cataract surgery. We induced exogenous human embryonic stem cells to directionally differentiate into lens fate like cells in vitro, mixed these cells with hyaluronate, and then implanted the mixture into lens capsule to regenerate in vivo. We successfully achieved near-complete lens regeneration, and the thickness of the regenerated lens reached 85% of the contralateral eye, showing the characteristics of biconvex shape, transparency, and a thickness and diopter close to that of natural lenses. Meanwhile, the participation of Wnt/PCP pathway in lens regeneration was verified. The regenerated lens in this study was the most transparent, thickest, and most similar to the original natural lens that has thus far been reported. Overall, these findings offer a new therapeutic strategy for cataracts and other lens diseases.

Investigating the Role of TGF-β Signaling Pathways in Human Corneal Endothelial Cell Primary Culture

Corneal endothelial diseases are the leading cause of corneal transplantation. The global shortage of donor corneas has resulted in the investigation of alternative methods, such as cell therapy and tissue-engineered endothelial keratoplasty (TEEK), using primary cultures of human corneal endothelial cells (hCECs). The main challenge is optimizing the hCEC culture process to increase the endothelial cell density (ECD) and overall yield while preventing endothelial-mesenchymal transition (EndMT). Fetal bovine serum (FBS) is necessary for hCEC expansion but contains TGF-βs, which have been shown to be detrimental to hCECs. Therefore, we investigated various TGF-β signaling pathways using inhibitors to improve hCEC culture. Initially, we confirmed that TGF-β1, 2, and 3 induced EndMT on confluent hCECs without FBS. Using this TGF-β-induced EndMT model, we validated NCAM as a reliable biomarker to assess EndMT. We then demonstrated that, in a culture medium containing 8% FBS for hCEC expansion, TGF-β1 and 3, but not 2, significantly reduced the ECD and caused EndMT. TGF-β receptor inhibition had an anti-EndMT effect. Inhibition of the ROCK pathway, notably that of the P38 MAPK pathway, increased the ECD, while inhibition of the ERK pathway decreased the ECD. In conclusion, the presence of TGF-β1 and 3 in 8% FBS leads to a reduction in ECD and induces EndMT. The use of SB431542 or LY2109761 may prevent EndMT, while Y27632 or Ripasudil, and SB203580 or SB202190, can increase the ECD.

Comparison of endothelial cell loss in diabetic patients after conventional phacoemulsification and femtosecond laser-assisted cataract surgery

PURPOSE

This study aims to comparatively evaluate the morphological changes of the cornea after phacoemulsification (PHACO) and femtosecond laser-assisted cataract surgery (FLACS) without intercurrences in patients with type 2 diabetes mellitus.

METHODS

A total of 95 diabetic patients with moderate cataracts (N2 + and N3+), 47 undergoing PHACO and 48 undergoing FLACS, were selected randomly for the study. Surgeries were performed by a single surgeon between July 2021 and December 2021. Cumulative dissipated energy (CDE) and total balanced saline solution (BSS) data were obtained at the end of each surgery. Changes in corneal endothelial cell density (ECD) and central corneal thickness (CCT) at three months postoperatively were investigated.

RESULTS

After three months, evidence is lacking between groups in the CCT measures; the difference was neither statistically nor clinically relevant. However, for ECD, a significant and clinically significant difference was found; if all patients were treated with laser, the mean ECD would be 423.55 greater (RSE: 86.09; p-value < 0.001; 95% CI: 254.81-592.29) than the ECD potential means of 1656.423 among the conventional group (RSE: 74.90; p-value < 0.001; 95% CI: 1509.62-1803.23).

CONCLUSIONS

Diabetic patients under treatment with moderate cataracts may predispose themselves to a more significant loss of endothelial cells after conventional phacoemulsification than femtosecond laser-assisted cataract surgery.

TRIAL REGISTRATION

It was registered at The Brazilian Registry of Clinical Trials (ReBEC) with the code RBR-6d8whb5 (UTN code: U1111-1277-6020) on 17/05/2022.

Application of Convergent Science and Technology toward Ocular Disease Treatment

Eyes are one of the main critical organs of the body that provide our brain with the most information about the surrounding environment. Disturbance in the activity of this informational organ, resulting from different ocular diseases, could affect the quality of life, so finding appropriate methods for treating ocular disease has attracted lots of attention. This is especially due to the ineffectiveness of the conventional therapeutic method to deliver drugs into the interior parts of the eye, and the also presence of barriers such as tear film, blood-ocular, and blood-retina barriers. Recently, some novel techniques, such as different types of contact lenses, micro and nanoneedles and in situ gels, have been introduced which can overcome the previously mentioned barriers. These novel techniques could enhance the bioavailability of therapeutic components inside the eyes, deliver them to the posterior side of the eyes, release them in a controlled manner, and reduce the side effects of previous methods (such as eye drops). Accordingly, this review paper aims to summarize some of the evidence on the effectiveness of these new techniques for treating ocular disease, their preclinical and clinical progression, current limitations, and future perspectives.

Association between Healthy Eating Index-2015 and Age-Related Cataract in American Adults: A Cross-Sectional Study of NHANES 2005-2008

BACKGROUND

Healthy Eating Index-2015 (HEI-2015), a healthy eating pattern proposed by Dietary Guidelines for Americans, is proven to be protective against various diseases. However, whether it is associated with age-related cataracts is unknown.

METHODS

This population-based cross-sectional study included 6395 participants from the National Health and Nutrition Examination Survey (NHANES) in the cycles from 2005 to 2008. HEI-2015 was calculated from 24-h dietary recall interviews, ranging from 0 to 100, and higher HEI-2015 represents better diet quality. Age-related cataract was generated from the questionnaire. The association between HEI-2015 and cataract was assessed with logistic regression models. Propensity score weighting, restricted cubic spline, and subgroup analysis were conducted to further explore the relationship.

RESULTS

6395 participants were included in the study, with a mean [standard deviation (SD)] age of 48.7 (15.3) years and 3115 (48.7%) being male. HEI-2015 was negatively associated with cataracts after adjusting all covariates included, both as a continuous variable [odds ratio (OR): 0.991, 95% confidence interval (CI): 0.984-0.997, p = 0.006] and quartiles with the highest quartile compared to the lowest (OR: 0.739, 95% CI: 0.559-0.980, p = 0.035). After propensity score weighting, the association remained significant. Restricted cubic spline revealed no non-linear relationship (p for non-linearity 0.085). Subgroup analysis showed that there were no interaction effects.

CONCLUSIONS

Adherence to the healthy eating pattern, HEI-2015, was associated with a lower risk of age-related cataracts.

Postponement of the opacification of lentoid bodies derived from human induced pluripotent stem cells after lanosterol treatment—the first use of the lens aging model in vitro in cataract drug screening

Purpose: Our previous study observed that human induced pluripotent stem cell (HiPSC)-derived lentoid bodies (LBs) became cloudy with extended culture time, partially mimicking the progress of human age-related cataracts (ARCs) in a dish. In the present study, lanosterol, a potential anticataract drug, was used to further verify the value of this model in drug screening for cataract treatment.

Methods: Mature LBs on day 25, which were differentiated from HiPSCs using the “fried egg” method, were continually cultured and treated with either dimethyl sulfoxide (control) or lanosterol. The LBs’ shape and opacity alterations were examined using light microscopy and mean gray value evaluation. The soluble and insoluble proteins were examined through SDS-PAGE gel electrophoresis combined with Coomassie blue staining. The protein aggregations were examined with immunofluorescence.

Results: The mature LBs became cloudy with an extended culture time, and the opacification of the LBs was partially prevented by lanosterol treatment. There was less increase in insoluble proteins in the lanosterol-treated LBs than in the control group. There were also fewer cells containing aggregated protein (αA‐crystallin and αB‐crystallin) puncta in the lanosterol-treated LBs than in the control LBs.

Conclusion: It was found that the opacification of LBs could be delayed by lanosterol treatment, which could be achieved by reducing protein aggregation, suggesting a promising HiPSC-derived drug-screening model for Age-related cataract.

Recent Advances of Intraocular Lens Materials and Surface Modification in Cataract Surgery

Advances in cataract surgery have increased the demand for intraocular lens (IOL) materials. At present, the progress of IOL materials mainly contains further improving biocompatibility, providing better visual quality and adjustable ability, reducing surgical incision, as well as dealing with complications such as posterior capsular opacification (PCO) and ophthalmitis. The purpose of this review is to describe the research progress of relevant IOL materials classified according to different clinical purposes. The innovation of IOL materials is often based on the common IOL materials on the market, such as silicon and acrylate. Special properties and functions are obtained by adding extra polymers or surface modification. Most of these studies have not yet been commercialized, which requires a large number of clinical trials. But they provide valuable thoughts for the optimization of the IOL function.

Research Progress Concerning a Novel Intraocular Lens for the Prevention of Posterior Capsular Opacification

Posterior capsular opacification (PCO) is the most common complication resulting from cataract surgery and limits the long-term postoperative visual outcome. Using Nd:YAG laser-assisted posterior capsulotomy for the clinical treatment of symptomatic PCO increases the risks of complications, such as glaucoma, retinal diseases, uveitis, and intraocular lens (IOL) pitting. Therefore, finding how to prevent PCO development is the subject of active investigations. As a replacement organ, the IOL is implanted into the lens capsule after cataract surgery, but it is also associated with the occurrence of PCO. Using IOL as a medium for PCO prophylaxis is a more facile and efficient method that has demonstrated various clinical application prospects. Thus, scientists have conducted a lot of research on new intraocular lens fabrication methods, such as optimizing IOL materials and design, and IOL surface modification (including plasma/ultraviolet/ozone treatment, chemical grafting, drug loading, coating modification, and layer-by-layer self-assembly methods). This paper summarizes the research progress for different types of intraocular lenses prepared by different surface modifications, including anti-biofouling IOLs, enhanced-adhesion IOLs, micro-patterned IOLs, photothermal IOLs, photodynamic IOLs, and drug-loading IOLs. These modified intraocular lenses inhibit PCO development by reducing the residual intraoperative lens epithelial cells or by regulating the cellular behavior of lens epithelial cells. In the future, more works are needed to improve the biosecurity and therapeutic efficacy of these modified IOLs.

The effects of premium intraocular lenses on presbyopia treatments

Background

Presbyopia has become a global disease affecting the world's aging population. Among various treatments, cataract extraction and intraocular lens (IOL) implantation have become the most popular and common methods of presbyopia correction. During the twentieth century, IOLs have underwent significant innovation and advancements to meet the patients' high demands for functional vision at all distances.

Main Text

To meet the increasing needs for excellent near and intermediate vision for daily activities, some premium IOLs with more than one focus have been developed, for example, the refractive MfIOLs, diffractive MfIOLs, extended depth of field (EDOF) IOLs, and accommodating IOLs (AIOLs) were introduced to meet this need. In addition, the add-on MfIOLs have been explored as promising supplementary IOLs for pseudophakic presbyopia. When selecting the MfIOLs, the IOLs' features, patients' characteristics, preoperative eye conditions, and treatment expectations should be considered.

Conclusions

In this review, we focus on the multifocal IOLs (MfIOLs) commonly used for presbyopia correction and systematically summarized their optical designs and clinical outcomes. More evidence-based studies are required to provide guidelines for MfIOL selection, provide maximum visual benefits, and develop personalized visual solutions in the future.

Cataract-Causing S93R Mutant Destabilized Structural Conformation of βB1 Crystallin Linking With Aggregates Formation and Cellular Viability

Cataract, opacity of the eye lens, is the leading cause of visual impairment worldwide. The crucial pathogenic factors that cause cataract are misfolding and aggregation of crystallin protein. βB1‐crystallin, which is the most abundant water‐soluble protein in mammalian lens, is essential for lens transparency. A previous study identified the missense mutation βB1‐S93R being responsible for congenital cataract. However, the exact pathogenic mechanism causing cataract remains unclear. The S93 residue, which is located at the first Greek‐key motif of βB1‐crystallin, is highly conserved, and its substitution to Arginine severely impaired hydrogen bonds and structural conformation, which were evaluated via Molecular Dynamic Simulation. The βB1‐S93R was also found to be prone to aggregation in both human cell lines and Escherichia coli. Then, we isolated the βB1‐S93R variant from inclusion bodies by protein renaturation. The βB1-S93R mutation exposed more hydrophobic residues, and the looser structural mutation was prone to aggregation. Furthermore, the S93R mutation reduced the structural stability of βB1-crystallin when incubated at physiological temperature and made it more sensitive to environmental stress, such as UV irradiation or oxidative stress. We also constructed a βB1-S93R cellular model and discovered that βB1-S93R was more sensitive to environmental stress, causing not only aggregate formation but also cellular apoptosis and impaired cellular viability. All of the results indicated that lower solubility and structural stability, sensitivity to environmental stress, vulnerability to aggregation, and impaired cellular viability of βB1-S93R might be involved in cataract development.

Lens capsule-related complications in femtosecond laser-assisted cataract surgery: a study based on video analysis

PURPOSE

To analyse the occurrence and potential causes of lens capsule-related complications during femtosecond laser-assisted cataract surgery (FLACS).

METHODS

This prospective consecutive cohort study included the first 1600 eyes (from 1140 consecutive patients) who received FLACS performed by the same surgeon from May 2015 to December 2018. The potential causes and characteristic signs of capsulotomy-related complications, including incomplete capsulotomies and radial anterior capsule (AC) tears, were summarised based on the agreement of two ophthalmologists after they analysed the surgical videos. Subgroup analysis was conducted to characterise the capsulotomy learning curve.

RESULTS

Of the 1600 eyes, 52 (3.25%) had incomplete capsulotomies and 22 (1.38%) had radial AC tears. The most common causes of incomplete capsulotomies were eye tilt (16 eyes, 30.77%), air bubbles or ocular secretions at the interface (14 eyes, 26.92%) and white cataracts (7 eyes, 13.46%). Additionally, 54.55% (12/22) of AC tears were due to incomplete capsulotomy and secondary capsulorhexis. A significant difference was noted between the first 200 eyes and subsequent groups in terms of the incidence of incomplete capsulotomies. No difference was observed in the incidence of AC tears after the initial 100 procedures.

CONCLUSION

The most common causes of incomplete capsulotomies were eye tilt and air bubbles or ocular secretions at the interface. Secondary capsulorhexis after incomplete capsulotomy is the main risk factor for AC tears. There was a steep learning curve for laser capsulotomy in the first 100 operated eyes, as evidenced by the higher complication rate, but this stabilised after 200 procedures.

Congenital cataract-causing mutation βB1-L116P is prone to amyloid fibrils aggregation and protease degradation with low structural stability

Congenital cataract, a common disease with lens opacification, causes blindness in the newborn worldwide and is mainly caused by abnormal aggregation of crystallin. As the main structural protein in the mammalian lens, βB1-crystallin has an important role in the maintenance of lens transparency. Recently, the L116P mutation in βB1-CRY was found in a Chinese family with congenital nuclear cataracts, while its underlying pathogenic mechanism remains unclear. In the current study, the βB1 wild-type protein was purified, and the mutated form, βB1-L116P, was examined for examining the effect on structural stability and susceptibility against environmental stresses. Our results reveal low solubility and structural stability of βB1-L116P at physiological temperature, which markedly impaired the protein structure and the oligomerization of βB1-crystallin. Under guanidine hydrochloride-induced denaturing conditions, βB1-L116P mutation perturbed the protein unfolding process, making it prone to amyloid fibrils aggregation. More importantly, the L116P mutation increased susceptibility of βB1-crystallin against UV radiation. βB1-L116P overexpression led to the formation of more serious intracellular aggresomes under UV radiation or oxidative stress. Furthermore, the βB1-L116P mutation increased the sensitivity to the proteolysis process. These results indicate that the low structural stability, susceptibility to amyloid fibrils aggregation, and protease degradation of βB1-L116P may contribute to cataract development and associated symptoms.

Phacoemulsification: Proposals for Improvement in Its Application

A cataract is defined as opacity of the crystalline lens. It is currently one of the most prevalent ocular pathologies and is generally associated with aging. The most common treatment for cataracts is surgery. Cataract surgery is a quick and painless process, is very effective, and has few risks. The operation consists of removing the opacified lens and replacing it with an intraocular lens. The most common intraocular lens removal procedure that is currently used is phacoemulsification. The energy applied in this process is generated by ultrasonic waves, which are mechanical waves with a frequency higher than 20 kHz. A great deal of research on the different ways to perform the stages of this surgical procedure and the analysis of the possible side effects of the operation has been published, but there is little information on the technical characteristics, the intensities applied, and the use of ultrasound-emitting (U/S) equipment for cataract removal. More studies on the method and depth of absorption of ultrasonic waves in our visual system when performing the phacoemulsification procedure are needed. It would be advisable for health authorities and medical professionals to develop guidelines for the handling and use of ultrasonic wave-emitting equipment, such as those that exist for ultrasound and physiotherapy. This could help us to reduce undesirable effects after the operation.