Posterior Capsule Opacification Research Articles

A Glistening Intraocular Lens: A Case Report

Introduction Cataract surgery with a posterior chamber intraocular lens (PCIOL) is one of the most performed surgeries in North America. A common complication of cataract surgery is the development of post-surgical opacities on the posterior lens capsule, known as posterior capsule opacification (PCO). When visually significant, PCO is treated with a YAG laser. Less commonly however, opacities can form within the lens implant itself known as lens glistening. Case Presentation An 86-year-old male patient with a history of macular retinoschisis and vitreoretinal traction in both eyes presented to the eye clinic with complaints of visual disturbance in the left eye over the course of 4 months. Clinical examination and diagnostic testing revealed stable retinal disease with new findings of PCIOLs with lens glistening, left eye greater than right eye. The patient was referred to the cataract surgeon and the decision was made to manage the lens glistening conservatively. Discussion Lens glistening can be managed with observation or intraocular lens (IOL) exchange depending on its impact on the patient’s quality of life or the degree to which the opacities preclude examination of the fundus.

A Study of the Relationship Between the Severity of Posterior Capsular Opacification Detected by Objective Detection Techniques and Visual Acuity.

To explore the severity of posterior capsule opacification (PCO) using objective detection techniques and its relationship with visual acuity. The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China. Prospective cohort study. All patients underwent slit-lamp examination, intraocular pressure measurement (IOP), best-corrected visual acuity (BCVA) before neodymium: yttrium aluminium garnet (Nd:YAG) laser capsulotomy, followed by examination after fully dilated, including IOLMaster 700, optical coherence tomography (OCT), Sirius anterior segment analysis system (Sirius), color fundus photography (CFP). Conducting BCVA and IOP post-treatment again. Recording the thickness and density of posterior capsule, color fundus photography quality (CFPQ) and OCT Signal Strength (OCTSS). Analysis using Spearman correlation analysis, heatmaps, and ROC curves. A total of 83 eyes in 78 patients were included in this study. Spearman correlation analysis revealed correlations between pre-treatment BCVA and IOLMaster 700 PCO thickness (MT), IOLMaster 700 cumulative effect (MCE), Sirius PCO thickness (ST), Sirius maximum density (SMD), Sirius cumulative effect (SCE), OCTSS, and CFPQ (correlation coefficients were 0.500, 0.484, 0.465, -0.256, 0.317, -0.442, -0.412, all P＜0.05). The improvement of Vision Acuity (ImpVA) showed correlations with MT, MCE, ST, SCE, OCTSS, and CFPQ (correlation coefficients were -0.452, -0.471, -0.346, -0.278, 0.320, 0.381, all P＜0.05). For ImpVA, the predictive ability of IOLMaster 700 was superior to Sirius, and the joint model was significantly better than single factors. Posterior capsule thickness and cumulative effect were reliable indicators for evaluating PCO. Compared to Sirius, IOLMaster 700 demonstrates superior predictive ability and higher correlation.

A 3D in vitro model for assessing the influence of intraocular lens: Posterior lens capsule interactions on lens epithelial cell responses

Posterior Capsule Opacification (PCO), the most frequent complication of cataract surgery, is caused by the infiltration and proliferation of lens epithelial cells (LECs) at the interface between the intraocular lens (IOL) and posterior lens capsule (PLC). According to the “no space, no cells, no PCO” theory, high affinity (or adhesion force) between the IOL and PLC would decrease the IOL: PLC interface space, hinder LEC migration, and thus reduce PCO formation. To test this hypothesis, an in vitro hemisphere-shaped simulated PLC (sPLC) was made to mimic the human IOL: PLC physical interactions and to assess their influence on LEC responses. Three commercially available IOLs with different affinities/adhesion forces toward the sPLC, including Acrylic foldable IOL, Silicone IOL, and PMMA IOL, were used in this investigation. Using the system, the physical interactions between IOLs and sPLC were quantified by measuring the adhesion force and interface space using an adhesion force apparatus and Optical Coherence Tomography, respectively. Our data shows that high adhesion force and tight binding between IOL and sPLC contribute to a small interface space (or “no space”). By introducing LECs into the in vitro system, we found that, with small interface space, among all IOLs, acrylic foldable IOLs permitted the least extent of LEC infiltration, proliferation, and differentiation (or “no cells”). Further statistical analyses using clinical data revealed that weak LEC responses are associated with low clinical PCO incidence rates (or “no PCO”). The findings support that the in vitro system could simulate IOL: PLC interplays and predict IOLs’ PCO potential in support of the “no space, no cells, no PCO” hypothesis.

A novel 3D high resolution imaging method using correlative X-Ray and electron microscopy to study Nd:YAG laser induced defects in intraocular lenses.

Cataract extraction is the most frequently performed ophthalmological procedure worldwide. Posterior capsule opacification (PCO) remains the most common consequence after cataract surgery and can lead to deterioration of the visual performance with cloudy, blurred vision and halo, glare effects. Nd:YAG laser capsulotomy is the gold standard treatment and a very effective, safe and fast procedure in removing the cloudy posterior capsule. Damaging the intraocular lens during the treatment may occur due to wrong focus of the laser beam. These YAG-pits may lead to a permanent impairment of the visual quality. In an experimental study, we intentionally induced YAG pits in hydrophilic and hydrophobic acrylic intraocular lenses (IOLs) using a photodisruption laser with 2.6mJ. This experimental study established a novel 3D imaging method using correlative X-Ray and scanning electron microscopy to characterize these damages. By integrating the information obtained from both X-ray microscopy and SEM, a comprehensive picture of the materials structure and performance could be established. It could be revealed that although the exact same energies were used to all samples, the observed defects in the tested lenses showed severe differences in shape and depth. While YAG pits in hydrophilic samples range from 100 to 180 µm depth with a round shape tip, very sharp tipped defects up to 250 µm in depth were found in hydrophobic samples. In all samples, particles/fragments of the IOL material were found on the surface that were blasted out as a result of the laser shelling. Defects in hydrophilic and hydrophobic acrylic materials differ. Material particles can detach from the IOL and were found on the surface of the samples. The results of the laboratory study illustrate the importance of a precise and careful approach to Nd:YAG capsulotomy in order to avoid permanent damage to the IOL. The use of an appropriate contact glass and posterior offset setting to increase safety should be carried out routinely.

Zwitterionic modified and freeze-thaw reinforced foldable hydrogel as intraocular lens for posterior capsule opacification prevention

Posterior capsule opacification (PCO) is a predominant postoperative complication, often leading to visual impairment due to the aberrant proliferation and adhesion of lens epithelial cells (LECs) and protein precipitates subsequent to intraocular lens (IOL) implantation. To address this clinical issue, a foldable and antifouling sharp-edged IOL implant based on naturally-derived cellulose hydrogel is synthesized. The mechanical strength and transparency of the hydrogel is enhanced via repeated freeze-thaw (FT) cycles. The incorporated zwitterionic modifications can remarkably prevent the incidence of PCO by exhibiting proteins repulsion and cell anti-adhesion properties. The graft of dopamine onto both the haptic and the periphery of the posterior surface ensures the adhesion of the hydrogel to the posterior capsule and impedes the migration of LECs without compromising transparency. In in vivo study, the zwitterionic modified foldable hydrogel exhibits uveal and capsular biocompatibility synchronously with no signs of inflammatory response and prevent PCO formation, better than that of commercialized and PEG-modified IOL. With foldability, endurability, antifouling effect, and adhesive to posterior capsule, the reported hydrogel featuring heterogeneous surface design displays great potential to eradicate PCO and attain post-operative efficacy after cataract surgery.

MicroRNA-1225-5p Promotes the Development of Fibrotic Cataracts via Keap1/Nrf2 Signaling

Purpose Fibrotic cataracts, including anterior subcapsular cataract (ASC) as well as posterior capsule opacification (PCO), are a common vision-threatening cause worldwide. Still, little is known about the underlying mechanisms. Here, we demonstrate a miRNA-based pathway regulating the pathological fibrosis process of lens epithelium. Methods Gain- and loss-of-function approaches, as well as multiple fibrosis models of the lens, were applied to validate the crucial role of two miR-1225 family members in the TGF-β2 induced PCO model of human LECs and injury-induced ASC model in mice. Results Both miR-1225-3p and miR-1225-5p prominently stimulate the migration and EMT process of lens epithelial cells (LECs) in vitro as well as lens fibrosis in vivo. Moreover, we demonstrated that the underlying mechanism for these effects of miR-1225-5p is via directly targeting Keap1 to regulate Keap1/Nrf2 signaling. In addition, evidence showed that Keap1/Nrf2 signaling is activated in the TGF-β2 induced PCO model of human LECs and injury-induced ASC model in mice, and inhibition of the Nrf2 pathway can significantly reverse the process of LECs EMT as well as lens fibrosis. Conclusions These results suggest that blockade of miR-1225-5p prevents lens fibrosis via targeting Keap1 thereby inhibiting Nrf2 activation. The ‘miR-1225-Keap1-Nrf2’ signaling axis presumably holds therapeutic promise in the treatment of fibrotic cataracts.

High incidence of sebaceous gland inflammation in aldose reductase-deficient mice

Aldose reductase is a member of the 1B1 subfamily of aldo-keto reductase gene superfamily. The action of aldose reductase (AR) has been implicated in the pathogenesis of a variety of disease states, most notably complications of diabetes mellitus including neuropathy, retinopathy, nephropathy, and cataracts. To explore for mechanistic roles for AR in disease pathogenesis, we established mutant strains produced using Crispr-Cas9 to inactivate the AKR1B3 gene in C57BL6 mice. Phenotyping AR-knock out (ARKO) strains confirmed previous reports of reduced accumulation of tissue sorbitol levels. Lens epithelial cells in ARKO mice showed markedly reduced epithelial-to-mesenchymal transition following lens extraction in a surgical model of cataract and posterior capsule opacification. A previously unreported phenotype of preputial sebaceous gland swelling was observed frequently in male ARKO mice homozygous for the mutant AKR1B3 allele. This condition, which was shown to be accompanied by infiltration of proinflammatory CD3+ lymphocytes, was not observed in WT mice or mice heterozygous for the mutant allele. Despite this condition, reproductive fitness of the ARKO strain was indistinguishable from WT mice housed under identical conditions. These studies establish the utility of a new strain of AKR1B3-null mice created to support mechanistic studies of cataract and diabetic eye disease.

ESTIMATION OF ND:YAG LASER ENERGY FOR VARIOUS TYPES OF POSTERIOR CAPSULE OPACITY

Abstract
 Introduction & Objectives : Types of Posterior capsule opacity (PCO) are membranous, fibrotic, or fibro-membranous. Surgical capsulotomy has been replaced by Neodymium-doped Ytrium Aluminim Garnet (Nd:YAG) as a PCO management nowdays. The initial energy use of the laser is influenced by variations in PCO density. Utilizing initial energy effectively can help to use less total laser energy. This study is to estimate energy Nd:YAG laser levels to treat various types of PCO.
 Methods : This is a observational descriptive study with cross-sectional design. This study retrieved initial and total capsulotomy Nd:YAG laser as a main variable on various types of PCO. The best corrected visual acuity (BCVA) before and after laser, size of hole capsulotomy, and complications of each type of PCO were evaluated.
 Results : A total 59 eyes of 49 patients with pseudophakia who underwent capsulotomy laser were included. The mean values of initial energy levels were 1,45±0,31 mJ for membranous PCO, 1,51±0,29 mJ for fibrous PCO, and 1,68±0,23 mJ for fibro-membran PCO. The mean summated energy levels for membranous PCO was 51,86±28,19 mJ, 78,86±44,81 mJ for fibrous PCO, 86,88±60,51 mJ for fibro- membran PCO. Complications were iritis, oculi hypertension, hyaloid rupture and IOL pitting were occurred in this study.
 Conclusion : Fibro-membran PCO required more initial and total laser energy compared to membranous and fibrous PCO

The Outcome of O-shape and Y-shape Nd:YAG Laser Capsulotomy in Patients with Posterior Capsule Opacification

Introduction & Objectives : Neodymium:yttrium-aluminium-garnet (Nd:YAG) laser capsulotomy is the method of choice in secondary cataract. Nd:YAG laser capsulotomy is a safe and effective method in treating decreased visual acuity. This study was conducted to determine the outcomes of Nd:YAG laser capsulotomy with O shape and Y shape in patients with posterior capsule opacification.
 Methods : This descriptive study was conducted in Siloam Karawaci General Hospital from February – March 2023. We included all patients with posterior capsule opacification who underwent Nd:YAG laser capsulotomy. The outcome included pre- and post-procedure uncorrected visual acuity (UCVA) after 1 week follow-up.
 Results : A total of six eyes from five patients (two men, three women) were included in this study. Three subjects underwent Nd:YAG laser with O-shape and three subjects with Y-shape. All subjects with O- shape had improved UCVA (0.7 to 1.0; 0.2 to 0.5; 0.5 to 0.8). Meanwhile, all subjects with Y-shape also had improved UCVA (0.2 to 0.5; 0.2 to 0.3; 0.5 to 0.7). No subjective symptoms reported following capsulotomy procedure in all patients.
 Conclusion : Nd:YAG laser posterior capsulotomy with O shape provided better UCVA than Y shape.

Impact of anterior capsule polishing on capsule opacification and capsule bend after age-related cataract surgery.

To investigate the effect of anterior capsule polishing on postoperative capsule opacification and capsular bend in patients with age-related cataract displaying normal axial length. University hospital. Prospective self-controlled trial. Patients with age-related cataracts aged 56 to 84 years displaying normal axial length were enrolled. Prior to surgery, a coin-toss method was used to randomly select one eye for intraoperative 360° anterior capsule polishing (polishing group); the contralateral eye received no treatment (control group). Capsular bend index (CBI), anterior capsule opacification (ACO), posterior capsule opacification (PCO), and anterior capsule opening area (ACOA) were recorded at 1 week, 1 month, 3 months, 6 months, and 12 months postoperatively using swept-source optical coherence tomography and slit-lamp examination. Twenty-one patients (42 eyes) were enrolled. Within-group comparisons showed that both groups had significant differences in CBI between 1 week and 1 month postoperatively, and between 6 months and 12 months postoperatively (P < .05). Between-group comparisons revealed a significant difference in CBI at 1 week postoperatively (P < .05); at 12 months postoperatively, there was a significant difference in ACOA (P < .05). There were no significant between-group differences regarding ACO or PCO at any time point (P > .05). For patients with age-related cataracts and normal axial length, 360° anterior capsule polishing can delay early capsular bag deformation without increasing the risks of ACO and PCO. This approach can also limit contraction of the anterior capsule opening.

Improvements to a GLCM-based machine-learning approach for quantifying posterior capsule opacification.

Posterior capsular opacification (PCO) is a common complication following cataract surgery that leads to visual disturbances and decreased quality of vision. The aim of our study was to employ a machine-learning methodology to characterize and validate enhancements applied to the grey-level co-occurrence matrix (GLCM) while assessing its validity in comparison to clinical evaluations for evaluating PCO. One hundred patients diagnosed with age-related cataracts who were scheduled for phacoemulsification surgery were included in the study. Following mydriasis, anterior segment photographs were captured using a high-resolution photographic system. The GLCM was utilized as the feature extractor, and a supported vector machine as the regressor. Three variations, namely, GLCM, GLCM+C (+axial information), and GLCM+V (+regional voting), were analyzed. The reference value for regression was determined by averaging clinical scores obtained through subjective analysis. The relationships between the predicted PCO outcome scores and the ground truth were assessed using Pearson correlation analysis and a Bland-Altman plot, while agreement between them was assessed through the Bland-Altman plot. Relative to the ground truth, the GLCM, GLCM+C, and GLCM+V methods exhibited correlation coefficients of 0.706, 0.768, and 0.829, respectively. The relationship between the PCO score predicted by the GLCM+V method and the ground truth was statistically significant (p<0.001). Furthermore, the GLCM+V method demonstrated competitive performance comparable to that of two experienced clinicians (r=0.825, 0.843) and superior to that of two junior clinicians (r=0.786, 0.756). Notably, a high level of agreement was observed between predictions and the ground truth, without significant evidence of proportional bias (p>0.05). Overall, our findings suggest that a machine-learning approach incorporating the GLCM, specifically the GLCM+V method, holds promise as an objective and reliable tool for assessing PCO progression. Further studies in larger patient cohorts are warranted to validate these findings and explore their potential clinical applications.

Self-assembled coating with a metal-polyphenolic network for intraocular lens modification to prevent posterior capsule opacification

Posterior capsule opacification (PCO) is a main complication after cataract surgery and intraocular lens (IOLs) implantation and is attributed to residual lens epithelial cells (LECs) migrating to the IOL surface and posterior capsules. IOL surface modification has been a newly-developing research filed in recent years; however, the applicability and economical acquisition of modified materials remain unsolved. In this study, we first applied a metal-polyphenolic network coating with a self-assembly technique on the IOL surface by using tannic acid (TA) combined with AlCl3, which are easily acquire and applying on the IOL surface to solve the IOL transmittance affair. Using wound healing and Transwell assay to verify AZD0364 inhibits cell migration ( P < 0.05), the lipopolysaccharide-induced macrophage inflammation model to verify pterostilbene (PTE) inhibits the inflammatory reaction ( P < 0.01). By optimizes its self-assembly coating parameters and calculating its drug release kinetics, we successfully loaded these two drugs on the coating, named TA (AZD0364/PTE) IOL. Its surface morphology characteristics were analyzed by scanning electron microscope, x-ray photoelectron spectrometer and water contact angle. The optical performance was carefully investigated by optical instruments and equipment (n= 3). The in vitro results showed that TA (AZD0364/PTE) IOL can significantly inhibit cell adhesion and acute inflammation (n= 3, P < 0.0001). Importantly, after in vivo implantation for 28 d with eight rabbits PCO models in two groups, the TA (AZD0364/PTE) IOL group maintained clear refracting media and decreased the inflammatory reaction compared with the original IOL group ( P < 0.05). This study provides a new applicable and economical strategy for preventing PCO and offers a reference for the next generation of IOLs that benefit cataract patients.

Are there sex-based disparities in cataract surgery?

To investigate sex-based differences in the occurrence of intra-operative and post-operative complications and associated visual outcomes following cataract surgery. This was a retrospective study of patients who had phacoemulsification cataract surgery at the University of Colorado School of Medicine. Data collected included the patient's health history, ocular comorbidities, operative and post-operative complications, and the post-operative best corrected visual acuity (BCVA). The data were analyzed using univariate and multivariable logistic regression with generalized estimating equations to account for the correlation of some patients having two eyes included in the study. A total of 11 977 eyes from 7253 patients were included in the study. Ocular comorbidities differed by sex, with males having significantly higher percentages of traumatic cataracts (males 0.7% vs females 0.1%), prior ocular surgery (6.7% vs 5.5%), and mature cataracts (2.8% vs 1.9%). Conversely, females had significantly higher rates of pseudoexfoliation (2.0% vs 3.2%). In unadjusted analysis, males had higher rates of posterior capsular rupture (0.8% vs 0.4%) and vitreous loss (1.0% vs 0.6%), but this difference was not significant after adjustment for confounders. Males had a significantly increased risk of post-operative retinal detachment, but in multivariable analysis this was no longer significant. Males were significantly less likely to undergo post-operative neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy for posterior capsule opacification (OR=0.8, 95%CI=0.7-0.9, P=0.0005). The BCVA was slightly worse for males pre-operatively; but post-operatively, both sexes exhibited similar visual acuity of Snellen equivalent 20/25. The study finds that in a cohort of patients presenting for cataract surgery, sex differences exist in pre-operative comorbidities and surgical characteristics that contribute to higher rates of some complications for males. However, observed surgical complication rates exhibit almost no difference by sex after adjusting for pre-operative differences and post-operative BCVA is similar between sexes.

Knockout of TGF-β receptor II by CRISPR/Cas9 delays mesenchymal transition of Lens epithelium and posterior capsule opacification

Posterior capsule opacification (PCO) is the most common postoperative complication of cataract surgery. Transforming growth factor-β (TGF-β) is related to epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) that is proven to induce PCO formation in clinical and experimental studies. In this study, CRISPR sequences targeting exon of TGF-βRII were knocked out with lentiviral transfection in LECs. Rabbits' PCO model was established and recombinant adeno-associated virus (AAV) for transferring the gRNA of TGF βRII were intravitreally injected. SgRNA inhibited TGF-βRII expression and human LECs proliferation. In TGF-βRII knockout group, LECs motility and migration were suppressed, N-cadherin and vimentin expressions were significantly decreased, whereas E-cadherin was increased. The animal model showed that TGF-βRII knockout in vivo was effective in suppressing PCO. The current study suggested that the CRISPR/Cas9 endonuclease system could suppress TGF-βRII secretion, which participates in the EMT procedure of LECs in vitro and PCO in vivo. These findings might provide a new gene-editing approach and insight into a novel therapeutic strategy for PCO.

Fabrication of a 3D bioprinting model for posterior capsule opacification using GelMA and PLMA hydrogel-coated resin.

Posterior capsule opacification (PCO) remains the predominant complication following cataract surgery, significantly impairing visual function restoration. In this study, we developed a PCO model that closely mimics the anatomical structure of the crystalline lens capsule post-surgery. The model incorporated a threaded structure for accurate positioning and observation, allowing for opening and closing. Utilizing 3D printing technology, a stable external support system was created using resin material consisting of a rigid, hollow base and cover. To replicate the lens capsule structure, a thin hydrogel coating was applied to the resin scaffold. The biocompatibility and impact on cellular functionality of various hydrogel compositions were assessed through an array of staining techniques, including calcein-AM/PI staining, rhodamine staining, BODIPY-C11 staining and EdU staining in conjunction with transwell assays. Additionally, the PCO model was utilized to investigate the effects of eight drugs with anti-inflammatory and anti-proliferative properties, including 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), THZ1, sorbinil, 4-octyl itaconate (4-OI), xanthohumol, zebularine, rapamycin and caffeic acid phenethyl ester, on human lens epithelial cells (HLECs). Confocal microscopy facilitated comprehensive imaging of the PCO model. The results demonstrated that the GelMA 60 5% + PLMA 2% composite hydrogel exhibited superior biocompatibility and minimal lipid peroxidation levels among the tested hydrogels. Moreover, compared to using hydrogel as the material for 3D printing the entire model, applying surface hydrogel spin coating with parameters of 2000 rpm × 2 on the resin-based 3D printed base yielded a more uniform cell distribution and reduced apoptosis. Furthermore, rapamycin, 4-OI and AICAR demonstrated potent antiproliferative effects in the drug intervention study. Confocal microscopy imaging revealed a uniform distribution of HLECs along the anatomical structure of the crystalline lens capsule within the PCO model, showcasing robust cell viability and regular morphology. In conclusion, the PCO model provides a valuable experimental platform for studying PCO pathogenesis and exploring potential therapeutic interventions.

Indomethacin and bromfenac may be effective in the prevention of posterior capsule opacification

Posterior capsule opacification (PCO) is the most common long‐term postoperative complication of cataract surgery, leading to secondary vision loss. Optimized intraocular lens (IOL) structure and appropriate pharmacological intervention can provide physical barriers and biological inhibition, respectively, to block the migration, proliferation, and epithelial‐mesenchymal transition (EMT) of lens epithelial cells (LECs) for PCO prophylaxis. We demonstrated that non‐steroidal anti‐inflammatory drugs (NSAIDs) are effective in preventing posterior capsule opacification. Indomethacin (INDOM) not only suppresses cell migration and down‐regulates the expression of cyclooxygenase‐2 (COX‐2) and EMT markers, including alpha‐smooth muscle actin (α‐SMA) and cyclin D1, but also promotes autophagy activation in LECs. Autophagy was also verified as a potential therapeutic target for down‐regulating EMT in LECs. Bromfenac effectively inhibits cell migration, overexpression of EMT markers such as fibronectin (FN), matrix metalloproteinase 2 (MMP2), α‐smooth muscle actin (α‐SMA), and transcription factor Snail, and extracellular signal‐regulated kinase (ERK)/glycogen synthase kinase‐3β (GSK‐3β) signalling induced by transforming growth factor‐β2 (TGF‐β2) in vitro. Based on ultrasonic spray technology, we developed a drug‐eluting intraocular lens (IOL) using poly (lactic‐co‐glycolic acid) (PLGA) with sustained release ability of indomethacin/bromfenac for PCO prevention. The novel IOL, serving as a drug delivery platform, can carry an adjustable dose of drugs with sustained release ability for more than 28 days. In the rabbit PCO model, the novel IOL showed excellent anti‐inflammatory and anti‐PCO effects. In summary, indomethacin and bromfenac are effective pharmacological interventions for PCO prophylaxis, and the novel IOL we developed prevented PCO in vivo, providing a promising approach for PCO prophylaxis in clinical applications.

The human capsular bag model as a pre‐clinical evaluation tool for IOLs

Cataract affects the vision and well‐being of millions. At present the only means of treating cataract is through surgical intervention. Modern cataract surgery typically retains a ring of anterior lens capsule and the entire posterior capsule. This is known as a capsular bag, which can house an intraocular lens (IOL) implant. Initial surgical outcomes are excellent, but with time lens cells that remain following surgery undergo a wound‐healing response. In essence the trauma of surgery provokes cells to proliferate and migrate across the acellular capsular surfaces and in some case the IOL surface. Most importantly, cells ultimately grow within the visual axis, on the central posterior capsule, and undergo fibrotic events that are associated with transdifferentiation to myofibroblasts, matrix deposition and matrix contraction that can lead to a secondary loss of vision termed posterior capsule opacification (PCO). PCO affects a large proportion of patients and is one of the most common fibrotic conditions in the world. It is therefore of great importance to better understand this condition and thus strong experimental systems are required for this purpose. To this end cataract surgery can be performed on human donor eyes within a laboratory setting to provide a biological product that is configured in the same manner as in the patient. This is known as the human capsular bag model. Using this clinically relevant model it has been possible to tease our key regulatory molecules driving human lens growth and fibrosis. While the human capsular bag model has been a useful tool to identify therapeutic targets or test putative therapeutics no pharmacological treatment is currently in clinical use. As a result, the intraocular lens is currently the major tool employed to manage PCO progression. Characteristics required for an IOL include strong optical performance, stability within the lens capsular bag and anti‐PCO properties. To meet international standards for IOL manufacture a number of tests are performed to predict IOL behaviour when implanted. However, ISO guided tests take place in a non‐biological setting and are limited to assessing purely physical characteristics. Therefore, understanding how the IOL interacts with the capsular bag and how wound‐healing responses could influence IOL position and stability is an area of great importance. The human capsular bag model can address this shortfall in the IOL development pipeline to relate design features to IOL stability and anti‐PCO performance in a clinically relevant setting. The presentation will highlight the evolution of the model as a tool for IOL testing and development.

Far‐red, high‐resolution, reflection‐free images of the anterior segment in retroillumination

Aims/Purpose: Retroillumination observation of the anterior segment is a routine examination method as old as the slit lamp, but capturing good quality images is difficult because of patient glare, the presence of corneal and or lens reflections, and limited resolution. We have modified a slit lamp to overcome these limitations and present the first series of images obtained.Methods: On a Topcon SL‐D7 slit lamp, we replaced the light source with a far‐red LED (Thorlabs, M780L3, 200 mW, 800 mA at 780 nm) and added a monochrome camera with sufficient resolution (Baumer, VCXU‐123 M). Reflection suppression was achieved by modifying the optical path (patent pending). In a clinical trial validated by an ethics committee (IDRCB: 2021‐A01496‐35), we acquired images of 5 different diseases after pupillary dilation: cataract, posterior capsule opacification, hereditary stromal dystrophy, Fuchs' corneal endothelial dystrophy (FECD), Bowman's membrane dystrophy.Results: Our innovative prototype device made it possible to obtain images of 3000 × 4096 pixels for 13.3 × 9.7 mm (×40 magnification). In 100% of the cases, one or more clear images on the area of interest were obtained without glare, and without disturbing reflections in 90% of the cases. Some pseudophakic patients showed minimal to moderate light reflection. The images were sufficiently resolved to allow precise analysis of disease areas, such as each guttae of the FECD.Conclusions: Our retroilluminator prototype provides, for the first time to our knowledge, high‐resolution images of the different structures of the anterior segment, easy to acquire and likely to facilitate the diagnosis and follow‐up of patients. Improvements to the prototype are underway to remove some persistent reflections. One of the first applications will be the classification of the severity of endothelial damage in FECD.

IOL's material and PCO

Posterior capsular opacification (PCO) is the most common of late post‐surgery complications and can lead to reduced visual acuity, diplopia, or glare. The different types of material used in intraocular lenses (IOLs) plays a significant role in possible post‐surgery complications, such as anterior capsule opacification (ACO) and phimosis, posterior capsule opacification (PCO), and the formation of IOL opacification. PCO incidence increases with time and varies from 10% to 50%. The incidence of PCO will rise in the nearest future since IOLs will stay longer in the eye, as people's lifespans are increasing. It was shown that hydrophilic IOLs had significantly more and denser PCO than hydrophobic or silicone IOLs. The higher incidence of PCO formation in hydrophilic than in hydrophobic IOLs should be considered as an important medical and health economic issue when choosing the IOL for implantation.

Influence of Nd:YAG laser capsulotomy on toric intraocular lens rotation and change in cylinder power.

To investigate toric monofocal intraocular lens (TIOL) rotation and associated changes in cylinder power caused by Nd:YAG laser capsulotomy performed due to posterior capsule opacification (PCO). Ekol Eye Hospital, Izmir, Turkey. Prospective case series. 41 eyes of 20 women and 21 men were included in the study. Before and 1 month after Nd:YAG laser capsulotomy, TIOL tilt and decentration were determined with Scheimpflug camera, and TIOL axial rotation and the change in cylinder power induced by this rotation were measured by ray tracing aberrometry. The time interval between cataract surgery and Nd:YAG laser capsulotomy was noted. Rotational misalignment of the TIOL was measured as 4.65 ± 2.75 degrees (range 0 to 11 degrees) before vs 6.97 ± 2.92 degrees (range 0 to 13 degrees) after capsulotomy, and absolute rotation was 2.75 ± 1.94 degrees (range 0 to 7 degrees, P = .028). Before and after Nd:YAG laser capsulotomy, cylinder power was 0.24 ± 0.70 diopter (D) (range 0.00 to 0.63 D) vs 0.56 ± 0.77 D (range 0.02 to 0.91 D), respectively, with an absolute change in cylinder power of 0.34 ± 0.22 D (range 0.01 to 0.90 D, P = .001). After capsulotomy, there was a significant decrease in IOL tilt in the horizontal and vertical planes and an increase in decentration ( P < .05). Time interval (33.02 ± 12.9 months) and IOL horizontal decentration were independent factors affecting IOL rotation after capsulotomy ( P < .05). Nd:YAG laser capsulotomy may cause TIOL rotation as well as tilt and decentration, resulting in a change in the TIOL's corrective effect on corneal astigmatism. Although this change was clinically insignificant, it may be beneficial to consider that TIOL rotational misalignment may occur in patients undergoing early capsulotomy.