Accuracy of 10 MHz ultrasonography for evaluation of posterior lens capsule in traumatic cataract.

PURPOSE: To investigate the performance of 10 MHz ultrasonography in detecting posterior lens capsule defects before traumatic cataract surgery. METHODS: This retrospective analysis includes patients with traumatic cataracts who underwent cataract surgery. Preoperative 10 MHz ultrasonography was performed to evaluate whether the posterior lens capsule was defective or intact, and the results were compared to the intraoperative findings. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and kappa were calculated. RESULTS: The study included 140 eyes of 140 patients. There were 68 eyes with closed-globe injuries and 72 eyes with open-globe injuries. The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and kappa of 10 MHz ultrasonography was 86.76%, 90.28%, 89.39%, 87.84%, 88.57% and 0.771, respectively. The accuracy was 86.11% and 91.18% in open-globe and closed-globe injury groups, respectively. CONCLUSION: The accuracy of 10 MHz ultrasonography in evaluating the posterior lens capsule in traumatic cataracts is high. Preoperative 10 MHz ultrasonography would help to make an appropriate surgical plan.

A modified anatomical posterior cruciate ligament reconstruction technique using the posterior septum and posterior capsule as landmarks to position the low tibial tunnel.

BACKGROUND: Lowering the exit position of the tibial tunnel can improve the clinical efficacy of posterior cruciate ligament (PCL) reconstruction, however, there is no unified positioning standard. This study aimed to use novel soft tissue landmarks to create a low tunnel. METHODS: A total of 14 human cadaveric knees and 12 patients with PCL injury were included in this study. Firstly, we observed the anatomical position between the PCL, posterior septum, and other tissue, and evaluated the relationship between the center of the low tibial tunnel (SP tunnel) and posterior septum and distal reflection of posterior capsule, and using computed tomography (CT) to evaluate distance between the center of the SP tunnel with bony landmarks. Then, evaluated the blood vessels content in the posterior septum with HE staining. Finally, observed the posterior septum and distal reflection of the posterior capsule under arthroscopy to explore the clinical feasibility of creating a low tibial tunnel, and assessed the risk of surgery by using ultrasound to detect the distance between the popliteal artery and the posterior edge of tibial plateau bone cortex. RESULTS: In all 14 cadaveric specimens, the PCL tibial insertions were located completely within the posterior medial compartment of the knee. The distance between the center of the SP tunnel and the the articular surface of tibial plateau was 9.4 ± 0.4 mm. All SP tunnels retained an intact posterior wall, which was 1.6 ± 0.3 mm from the distal reflection of the posterior capsule. The distances between the center of the SP tunnel and the the articular surface of tibial plateau, the champagne glass drop-off were 9.2 ± 0.4 mm (ICC: 0.932, 95%CI 0.806-0.978) and 1.5 ± 0.2 mm (ICC:0.925, 95%CI 0.788-0.975) in CT image. Compared with the posterior capsule, the posterior septum contained more vascular structures. Last, all 12 patients successfully established low tibial tunnels under arthroscopy, and the distance between the posterior edge of tibial plateau bone cortex and the popliteal artery was 7.8 ± 0.3, 9.4 ± 0.4 and 7.4 ± 0.3 mm at 30°, 60° and 90° flexion angels after filling with water and supporting with shaver in posterior-medial compartment of knee joint. CONCLUSIONS: A modified low tibial tunnel could be established in the PCL anatomical footprint by using the posterior septum and posterior capsule as landmarks.

Investigation of Optimal Needle Position for Radiofrequency Ablation-Based Blockade of Interspace between the Popliteal Artery and the Posterior Capsule of the Knee: A Cadaveric Study.

Background and Objectives: The interspace between the popliteal artery and the posterior capsule of the knee (iPACK) block has been widely used in perioperative settings to control posterior knee pain and can additionally be used for chronic knee pain. In this cadaveric study, we aimed to investigate the needle tip position and its proximity to the articular branch of the tibial nerve (ABTN) during an iPACK-targeted radiofrequency procedure. Materials and Methods: An ultrasound-guided iPACK block was performed on 20 knees of 10 cadavers. We injected 0.1 mL each of blue and green gelatinous dye near the tibial artery (point A) and posterior knee capsule (point B), respectively, and evaluated the spread of both around the ABTN. For a hypothetical conventional radiofrequency ablation (RFA) lesion (diameter, 2.95 mm) and cooled RFA lesion (diameter, 4.9 mm), we counted the number of specimens in which the ABTNs would be captured. Results: The percentage of specimens in which the ABTN would be captured by a cooled RFA lesion was 64.71% at point A and 43.75% at point B (p = 0.334). Meanwhile, the percentage of specimens in which the ABTN would be captured by a conventional RFA lesion was 58.82% from point A and 25% from point B (p = 0.065). Conclusions: When performing an RFA-based iPACK block, the needle tip may be positioned either lateral to the tibial artery or in the space between the posterior knee capsule and the tibial artery. However, more studies with larger samples are needed to verify these results before the clinical use of this procedure can be recommended.

Hydrodissection and femtosecond laser assisted surgery in posterior polar cataract.

PURPOSE: To present our clinical experience using femtosecond laser-assisted cataract surgery (FLACS) and cortical cleavage hydrodissection in eyes with posterior polar cataract. METHODS: Medical records of consecutive10 eyes of 6 patients with clinical diagnosis of posterior polar cataract (PPC), were retrospectively reviewed. All surgeries were done by using femtosecond laser-assisted cataract surgery. In all cases careful hydrodissection was done to separate the lens material from the posterior capsule. RESULTS: There were 3 males and 3 females, ages 39-73 years (average 52.5 years), two of them were implanted with toric lenses. In all eyes hydrodissection was successfully performed and the lens material was separated from the lens capsule. The posterior capsule remained intact during nucleus removal in all cases. In one eye the posterior capsule broke during cortical cleaning and the tear was converted to posterior capsulorhexis (PCCC). No postoperative complications were recorded during follow-up in all eyes. CONCLUSIONS: Hydrodissection can be safely performed in combination (but not exclusively) with FLACS, in eyes with posterior polar cataract with no evidence of a preexisting posterior capsule rent. Hydrodissection is regarded by most surgeons as contraindicated in these eyes however apparently it is more gentile to the capsule than any other surgical maneuver and allows clean and efficient separation of the lens material from the thinned posterior capsule. Femtosecond laser capsulotomy and lens fragmentation is effective and may further assist surgery by pneumo-separation of the lens material. Anterior chamber maintainer may further aid to the stability of the chamber and safety of surgery.

Vascular endothelial cell-derived exosomal miR-1246 facilitates posterior capsule opacification development by targeting GSK-3ß in diabetes mellitus.

Posterior capsule opacification (PCO) is a serious complication after cataract surgery. Diabetes could increase the occurrence of PCO, but the mechanism is still unclear. The purpose of this study is to investigate the role of small extracellular vesicles (sEVs) derived from diabetic aqueous humor in PCO process. Intraoperatively-derived aqueous humor sEVs from patients with diabetic related cataract (DRC) promoted the epithelial-mesenchymal transition (EMT) and metastasis of human lens epithelial cells (LECs). Via mouse PCO surgical model and DiI labeled fluorescence detection of sEVs, the sEVs derived from vascular endothelium were discovered directly contacting with LECs. Furthermore, we demonstrated that high-glucose-cultured human umbilical vein endothelial cells (HUVEC) -derived sEVs facilitated EMT process of HLE-B3 using co-culture model in vitro. miRNA-seq data and GEO datasets analysis revealed that miR-1246 was essential in EMT process with diabetes. The miR-1246 was highly expressed in diabetic aqueous humor sEVs and high-glucose-treated vascular-endothelial-cell-derived sEVs. Moreover, miR-1246 promoted the metastasis and EMT process of HLE-B3 cells by directly targeting GSK-3ß. Inhibiting miR-1246 could negatively regulated EMT. This finding might serve as a potential therapy for diabetic PCO.

Glutaredoxin 2 protects lens epithelial cells from epithelial-mesenchymal transition by suppressing mitochondrial oxidative stress-related upregulation of integrin-linked kinase.

Glutaredoxin 2 (Grx2), a mitochondrial glutathione-dependent oxidoreductase, is crucial for maintaining redox homeostasis and cellular functions in the lens. The oxidative stress-induced epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) is related to posterior capsule opacification. In this study, we investigated the effects of Grx2 on oxidative stress-induced EMT in LECs during posterior capsule opacification. We found that Grx2 expression was substantially decreased during the EMT of LECs and in a mouse model of cataract surgery. Deletion of Grx2 aggravated the generation of reactive oxygen species, including those that are mitochondria-derived, and promoted the proliferation and EMT of the LECs. This was reversed by Grx2 overexpression. In vivo, proteomic liquid chromatography-mass spectrometry analysis showed that integrin-linked kinase (ILK) was significantly upregulated in the lens posterior capsule of a Grx2 knockout (KO) mouse model. Compared with that of the wild-type group, the expression of ILK and EMT markers was increased in the Grx2 KO group which was reversed in the Grx2 knock-in group. Inhibition of ILK partially blocked Grx2 knockdown-induced EMT and prevented the increased phosphorylation of Akt and GSK-3ß and the nuclear translocation of ß-catenin in the Grx2 KO group. Finally, inhibition of the Wnt/ß-catenin pathway partially blocked the Grx2 knockdown-induced EMT. In conclusion, we demonstrated that Grx2 protects LECs from oxidative stress-related EMT by regulating the ILK/Akt/GSK-3ß axis.

NIR-triggered thermosensitive polymer brush coating modified intraocular lens for smart prevention of posterior capsular opacification.

Posterior capsule opacification (PCO) is the most common complication after cataract surgery. Drug-eluting intraocular lens (IOLs) is a promising concept of PCO treatment in modern cataract surgery. However, the large dose of drugs in IOL leads to uncontrollable and unpredictable drug release, which inevitably brings risks of overtreatment and ocular toxicity. Herein, a low-power NIR-triggered thermosensitive IOL named IDG@P(NIPAM-co-AA)-IOL is proposed to improve security and prevent PCO by synergetic controlled drug therapy and simultaneous photo-therapy. Thermosensitive polymer brushes Poly(N-isopropylacrylamide-co-Acrylic acid) (P(NIPAM-co-AA)) is prepared on IOL via surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization. Then, Doxorubicin (DOX) and Indocyanine green (ICG) co-loaded Gelatin NPs (IDG NPs) are loaded in P(NIPAM-co-AA) by temperature control. The IDG NPs perform in suit photodynamic & photothermal therapy (PTT&PDT), and the produced heat also provides a trigger for controllable drug therapy with a cascade effect. Such functional IOL shows excellent synergistic drug-phototherapy effect and NIR-triggered drug release behavior. And there is no obvious PCO occurrence in IDG@P(NIPAM-co-AA) IOL under NIR irradiation compared with control group. This proposed IDG@P(NIPAM-co-AA)-IOL serves as a promising platform that combines phototherapy and drug-therapy to enhance the therapeutic potential and medication safety for future clinical application of PCO treatment.

Objective quantification of posterior capsule opacification after cataract surgery with swept-source optical coherence tomography.

PURPOSE: To evaluate the application of swept-source optical coherence tomography (SS-OCT) and pentacam scheimpflug tomography in posterior capsule opacification (PCO) severity assessment. METHODS: The posterior capsule image region segmentation and adaptive threshold algorithm are used to process the SS-OCT scanned image to obtain the posterior capsule thickness (PCT). Scheimpflug tomography reconstructed and analysized by image J software can obtain the average gray value and evaluate the effectiveness with the two methods. RESULT: One hundred sixty-two IOL eyes of 101 patients were divided into two groups, laser group (65 eyes) with the mean PCT was 8.0 ± 2.7 pixel unit and the mean gray value of the eyes was 66 ± 33 pixel unit. However, these figures in the control group (97 eyes) were 5.0 ± 0.9 and 11 ± 17. The sensitivity, specificity and area under curve(AUC) of SS-OCT PCT were 85%, 74% and 0.942,the sensitivity, specificity and AUC of Pentacam gray value were 91%, 76% and 0.947, respectively. After using the multivariable model of generalized estimation equation to corrected the dependence of subjects' eyes, it was found that SS-OCT PCT, Pentacam gray value, low vision quality of life questionnaire (LVQ questionnaire) for distance vision, and mobility and lighting dimension were significantly correlated with the PCO score (P = 0.012, P = 0.001, P = 0.005, respectively). CONCLUSION: The region segmentation and adaptive threshold algorithm of posterior capsule image will accurately quantify the posterior capsule. Computer aided quantifications of posterior capsule are of great significance in the early surgical decision-making of PCO. The average occurrence time of most PCO was around 34 months, and the severity of PCO worsened with increasing postoperative time.

Influence of the CleaRing intraocular open capsule device on refractive predictability in cataract surgery.

BACKGROUND: The marked improvement in cataract surgery and intraocular lens (IOL) quality has led to a decline in posterior capsular opacification (PCO) incidence; however, PCO remains a common complication of cataract surgery. The CleaRing intraocular capsule open device (IOCD) decreases PCO incidence. We aimed to investigate the influence of the CleaRing IOCD on refractive predictability in cataract surgery. METHODS: We conducted this prospective pilot study at the Wolfson Medical Center, Holon, Israel. Ten eyes of patients who underwent cataract surgery and insertion of an IOL after IOCD implantation into the capsular bag were included. All patients completed 12 months of follow-up, including refraction, measurement of uncorrected (UDVA) and best-corrected distance visual acuity (CDVA), slit-lamp biomicroscopy, and ultrasound biomicroscopy. RESULTS: All the surgeries were uneventful, with no postoperative complications. The IOL was centred in the device and bag in all cases. The mean prediction error at 1 and 12 months postoperatively was +0.28 ± 0.32 D and +0.50 ± 0.32 D, respectively. The mean UDVA was 0.17 ± 0.13 and 0.15 ± 0.11 logMAR, and the mean CDVA was 0.04 ± 0.10 and 0.04 ± 0.06 logMAR, respectively. The manifest refractive cylinders at 12 months postoperatively were compatible with corneal astigmatism. CONCLUSIONS: Implantation of the IOCD resulted in a slight, predicted, and stable hyperopic shift with a low standard deviation. The standard deviation of the prediction error demonstrated excellent refractive accuracy and predictability using the IOCD, which was as low as 0.32 D at the 12-month follow-up.

Posterior lens capsule rupture in non-diabetic canine cataracts: Pre-operative, intra-operative, and post-operative findings.

PURPOSE: To describe clinical features of non-diabetic canine cataracts with presumed pre-existing posterior capsule rupture (PLCR) and their surgical outcomes. METHODS: Clinical records of 497 non-diabetic canines that underwent elective cataract surgery were reviewed. Twelve canines met the inclusion criteria indicative of PLCR pre-dating surgery. RESULTS: The incidence of presumed pre-existing PLCR was 12/497 (2.4%). Cataracts included were unilateral in 10 out of 12 canines (83.3%) and bilateral in the remaining two (16.7%). Four eyes (28.6%) had clinically detectable pre-operative lens-induced uveitis. The mean age at cataract diagnosis for cases included was 6.6 years, and golden retrievers were the most common breed affected (28.6%). Phacoemulsification surgery was performed at a median time of 110 days (range 17-403 days) after presentation. Pre-existing PLCR was found intra-operatively as a large ellipse spanning the posterior capsule from equator to equator centrally in 12 eyes and peripherally in two eyes. The capsular defect in all eyes with PLCR incorporated a distinct "pseudo-capsule" preventing vitreal presentation and ruling out intraoperative surgeon rupture. Ten eyes (71.4%) received an intraocular lens implant (IOL), and 13 eyes (92.9%) maintained vision throughout a mean follow-up period of 12 months. CONCLUSION: Posterior lens capsule rupture of blunt trauma origin and associated cataract formation, as reported in humans, may also be an infrequent but distinct cause of some cases of non-diabetic canine cataracts. Medical management of phacolytic uveitis and delayed phacoemulsification surgery may be beneficial by allowing time for "pseudo-capsule" development, increasing the likelihood of IOL placement and improved visual outcomes.

Comparison of the Incidence of Nd:YAG Laser Capsulotomy Based on the Type of Intraocular Lens.

Background and Objectives: Posterior capsular opacification (PCO) is the most common long-term complication of successful cataract surgery and can cause visual impairment. We aimed to investigate the effects of intraocular lens (IOL) characteristics on PCO by comparing the incidence of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy for different types of intraocular lenses. Materials and Methods: A retrospective analysis was performed on 2866 eyes that underwent cataract surgery between January 2010 and December 2017, with at least 5 years of follow-up. The IOLs used for surgery were the hydrophobic lenses SN60WF (Alcon, Fort Worth, TX, USA), ZCB00 (Johnson & Johnson Vision, Santa Ana, CA, USA), and MX60 (Bausch & Lomb, Rochester, NY, USA), and the hydrophilic lens MI60 (Bausch & Lomb, Rochester, NY, USA). We analyzed the incidence of Nd:YAG laser capsulotomy according to the type of IOL used. Results: The incidence of Nd:YAG laser capsulotomy was significantly higher with MI60 lenses (31.70%, 175/552 eyes) compared to SN60WF (7.90%, 113/1431 eyes), ZCB00 (10.06%, 64/636 eyes), and MX60 (10.57%, 13/123 eyes; p < 0.001) lenses. The incidence of Nd:YAG laser capsulotomy was significantly lower with the hydrophobic IOLs (8.68%, 190/2190 eyes) than with the hydrophilic IOL (31.70%, 175/552 eyes; p < 0.001). Over time, the rate of increase in the cumulative number of Nd:YAG laser capsulotomy cases was the highest with MI60. The cumulative rate of Nd:YAG laser capsulotomy during the first 3 years was 4.90% with SN60WF (70/1431 eyes), 6.76% with ZCB00 (43/636 eyes), 8.94% with MX60 (11/123 eyes), and 26.10% with MI60 (144/552 eyes) lenses. Conclusions: The incidence of PCO is influenced by the material of the IOLs. The hydrophilic IOL was associated with a higher rate of Nd:YAG laser capsulotomy than the hydrophobic IOLs, with a shorter time to Nd:YAG laser capsulotomy.

Posterior capsule dynamics during femtosecond laser lens fragmentation.

PURPOSE: The dynamics of the posterior capsule during femtosecond laser lens fragmentation has received little attention in the literature. We analysed the movements of the posterior capsule to identify the rupture risk factors, if any, and to suggest possible modification of the laser spot energy pattern during fragmentation. MATERIALS AND METHODS: Posterior capsule ruptures during fragmentation were identified over a 10-year period of femtosecond laser use. In addition, the dynamics of the posterior capsule were identified through the real-time swept-source OCT lateral view available during the surgeries. RESULTS: Out of the 1465 laser cataract procedures performed, we recorded 1 case of posterior capsule rupture during lens fragmentation, which was caused by eye movement that was detected but ignored by the surgeon. Three types of posterior capsule dynamics were identified, all related to a gas bubble formation during the first part of the lens fragmentation. In eyes with a hard nucleus, the concussion of the posterior capsule was evident, however, with no capsule rupture. DISCUSSION: Maintaining good docking throughout the whole procedure seems important in avoiding a posterior capsule cut by the femtosecond laser. In addition, a Gaussian pattern of spot energy is suggested when fragmenting hard cataracts.

Passive CAP-VAC: a simple and safe technique to clean the posterior capsule.

PURPOSE: To describe a new and less risky technique for the cleaning of posterior capsule during phacoemulsification called passive cap vac. METHOD: Passive cap vac consisted in the removal of residual posterior capsule opacities using a disconnected 0.3 mm aspiration cannula. The hole of the aspiration cannula was faced toward posterior capsule and gently rubbed against it to achieve a complete cleaning of posterior capsule. The video of the technique is available online. RESULT: With this new technique, the aspiration was ruled by the gravity and by the height of the balanced saline solution (BSS), in addition the Venturi's effect and the absence of active aspiration beyond the cannula avoided an excessive aspiration of posterior capsule. CONCLUSION: Passive cap vac allowed to clean posterior capsule using softer forces than traditional way, minimizing the risk of capsular tear.

[Clinical features and treatment of endophthalmitis after cataract surgery]. / Klinicheskie osobennosti i lechenie endoftal'mita posle khirurgii katarakty.

PURPOSE: The study analyzes the frequency of acute endophthalmitis occurrence after cataract surgery, the risk factors, characteristic symptoms, and the effectiveness of peri-operative prevention measures. MATERIAL AND METHODS: The study retrospectively analyzed 59 670 cases of patients operated for cataract in 2017-2021. To prevent infections, patients received four instillations of third generation fluoroquinolone (quinolone antibiotic) in the course of two days prior to cataract phacoemulsification (PE), and two instillations immediately (1 hour and 30 minutes) before the surgery; three-minutes treatment of the cornea, conjunctival sac and periocular skin with 5% povidone iodine before the surgery; and as the last step of surgery, patients received subconjunctival injection of 0.05 g cefazolin with 2 mg dexamethasone. Follow-up after surgery included four injections of 0.5% levofloxacin in the course of 7-10 days, and 0.1% dexamethasone for two weeks, or fixed combination of tobramycin and dexamethasone four times per day for two weeks. The criteria for acute endophthalmitis are: loss of spatial vision, absence of red reflex, pronounced thickening of the choroid, suspended particulates in the retrovitreal space and the vitreous observed with ultrasonography in the early postoperative period (day 4-7 after surgery). RESULTS AND DISCUSSION: There were 32 patients (0.054%) diagnosed with acute endophthalmitis. Posterior capsule rupture was the main complicative risk factor of endophthalmitis development (OR=11.75, p=0.026). Main diagnostic criteria of acute endophthalmitis were hypopyon (OR=22.5, p=0.001) and absence of red reflex (OR=19.59, p<0.001). The use of the fixed combination of tobramycin and dexamethasone was associated with 5.8-times higher risk of acute endophthalmitis than separate application of levofloxacin and dexamethasone (p=0.042). CONCLUSIONS: Povidone iodine and third generation fluoroquinolone as a method of acute endophthalmitis prevention after cataract surgery demonstrate comparable efficacy to intracameral antibiotic injections.

Protective Effects of One 2,4-Dihydro-3H-Pyrazol-3-one Derivative against Posterior Capsular Opacification by Regulation of TGF-ß2/SMADs and Non-SMAD Signaling, Collagen I, and Fibronectin Proteins.

Many elderly individuals frequently experience cataracts that interfere with vision. After cataract surgery, the left lens epithelial cell (LEC) exhibited fibrosis and posterior capsule opacification (PCO). Sometimes, there is a need for a second surgery; nevertheless, people try other methods, such as a good pharmacological agent, to treat PCO to reduce transforming growth factor-ß2 (TGF-ß2) amounts to avoid secondary surgery. The aim of the present study was to explore the potential anti-PCO activity of five 2,4-dihydro-3H-pyrazol-3-one (DHPO) derivatives in a TGF-ß2-induced fibrogenesis SRA01/04 cell model. The 2-phenyl-5-propyl-DHPO (TSE; no. 2: TSE-2) compound showed the best activity of reduced expression levels of TGF-ß2 among five derivatives and therefore was chosen to evaluate the anti-PCO activity and molecular mechanisms on the Sma and mad protein (SMAD) signaling pathway (including TGF-ß2, SMADs, and the inhibition of nuclear translocation of SMADs), non-SMAD pathway proteins, including p-extracellular, regulated protein kinases (ERK) 1/2, or p-c-Jun N-terminal kinase (JUN) by Western blotting, PCR, or confocal immunofluorescence analyses. Following treatment with 10 µg/mL of the five compounds, the cells displayed great viability by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTT) assay. In this study, the result of lactate dehydrogenase (LDH) activity measurement did not affect the cytotoxicity of the five compounds. In TGF-ß2-induced fibrogenesis in SRA01/04 cells, treatment with the TSE compound decreased the TGF-ß2/SMAD signaling genes, including reduced mRNA or expression levels of TGF-ß2, SMAD3, and SMAD4, leading to inhibition of TGF-ß2-induced fibrogenesis. Our confocal immunofluorescence analyses demonstrated that TSE treatment displays a suppressive effect on SMAD2/3 or SMAD4 translocation to the nucleus. Furthermore, TSE treatment exhibits a reduction in the non-SMAD target gene expression levels of p- c-Jun N-terminal kinase (JUN), p- extracellular, regulated protein kinases (ERK)1/2, p- p38 mitogen-activated protein kinase (p38), p-phosphatidylinositol 3-kinase (PI3K), p-mammalian target of rapamycin complex (mTORC), p-Akt (Ser473), and p-Akt (Thr308). The overall effect of TSE is to reduce the expression levels of collagen I and fibrinogen (FN), thus contributing to antifibrotic effects in cell models mimicking PCO. Our findings reveal the benefits of TSE by regulating TGF-ß/SMAD signaling and non-SMAD signaling-related gene proteins to display antifibrotic activity in cells for the possibility of preventing PCO after cataract surgery.

Role of fibronectin and IOL surface modification in IOL: Lens capsule interactions.

Posterior Capsule Opacification (PCO) is one of the most common complications of cataract surgery. While studies have shown that IOL material properties and fibronectin adsorption may affect IOL-induced PCO in the clinical setting, the mechanism governing such interactions is not totally understood. Since strong adhesion forces between IOLs and posterior capsules (PCs) have been shown to impede cell infiltration and thus reduce PCO formation, this study was designed to assess whether fibronectin adsorption and IOL material properties would impact the IOL:PC adhesion force and cell infiltration using a PCO predictive in vitro model and a macromolecular dye imaging model, respectively. Our results showed that fibronectin adsorption significantly increased the adhesion forces and reduced simulated cell infiltration between acrylic foldable IOLs and the PC at physiological temperature in comparison to fibronectin-free controls. This fibronectin-mediated strong IOL: PC bond may be contributing to low PCO rates in the clinic for acrylic foldable IOLs. In addition, acrylic foldable IOLs coated with Di(ethylene glycol) (Diglyme), a hydrophilic coating known to reduce protein adsorption, was tested for its ability to alter adhesion force and cell infiltration. We observed that IOLs coated with Diglyme coating greatly reduced surface hydrophobicity and fibronectin adsorption of acrylic foldable IOLs. Furthermore, Diglyme coated IOLs showed significantly reduced adhesion force and increased simulated cell infiltration at the IOL:PC interface. The overall results support the hypothesis that IOL surface properties and their ability to adsorb fibronectin may have great impact on the IOL:PC adhesion force. A tight binding between IOLs and PC may contribute to the reduction of cell infiltration and thus the PCO incidence rate in the clinic.

Circ-POLR3A accelerates TGF-ß2-induced promotion in cell viability, migration, and invasion of lens epithelial cells via miR-31/TXNIP signaling cascade.

Posterior capsular opacification (PCO) is the major complication after cataract surgery and can result in secondary vision loss. Circular RNAs (circRNAs) are reported to play critical regulatory roles in multiple cell biological processes. The most common working mechanism of circRNAs is by acting as microRNA sponges. Here, we analyzed the role and mechanism of circRNA RNA polymerase III subunit A (POLR3A) in PCO. Cell viability was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell motility was assessed by transwell and wound healing assays. Dual-luciferase reporter and RNA-pull-down assays were performed to verify the interaction between microRNA-31 (miR-31) and circ-POLR3A or thioredoxin interacting protein (TXNIP). PCO cell model was established by treating SRA01/04 cells with transforming growth factor-ß2 (TGF-ß2). We found that TGF-ß2 enhanced SRA01/04 cell viability, migration, and invasion abilities. Circ-POLR3A expression was upregulated in PCO tissues and TGF-ß2-induced SRA01/04 cells. TGF-ß2 promoted the viability and motility of SRA01/04 cells largely by upregulating circ-POLR3A. Circ-POLR3A negatively regulated the miR-31 level by directly interacting with it. Circ-POLR3A absence-induced influences in TGF-ß2-induced SRA01/04 cells were partly reversed by silencing miR-31. miR-31 is directly bound to the 3'-untranslated region of TXNIP. TXNIP overexpression largely attenuated miR-31 overexpression-mediated effects in TGF-ß2-induced SRA01/04 cells. Circ-POLR3A could elevate the protein expression of TXNIP by sponging miR-31. Exosomes were involved in mediating the delivery of circ-POLR3A in SRA01/04 cells. In conclusion, circ-POLR3A contributed to TGF-ß2-induced promotion of cell viability, migration, and invasion of SRA01/04 cells by targeting miR-31/TXNIP axis.

Extracellular vesicles promote epithelial-to-mesenchymal transition of lens epithelial cells under oxidative stress.

Posterior capsule opacification (PCO), resulting from residual lens epithelial cell (LEC) epithelial-mesenchymal transition (EMT), abnormal proliferation, and migration, is the most common complication of cataract surgery. A recent study determined that extracellular vesicles (EVs) and reactive oxygen species (ROS) regulate the EMT process during cutaneous wound healing and tumour metastasis. However, their underlying mechanism in PCO is unclear. In this study, we examined the secreted EVs from a scratch model in vitro. We found that the production of ROS was increased after mechanical injury, especially at the wound edge, and there was an increased viability of LECs, which can be blocked by diphenyleneiodonium, an NADPH oxidase inhibitor. Cell viability and migration were increased upon treatment with 1 µM H2O2, but significantly reduced when the concentration of H2O2 increased to 100 µM. Transwell assay showed that both post-surgery LECs and LECs treated with 1 µM H2O2 significantly induced the migration of normal LECs by EV secretion. Extraction and quantification of EVs derived from injured and H2O2-treated LECs showed a similar increase in production. Co-incubation of EVs from both injured and H2O2-treated LECs with normal LECs and organ-cultured mouse lenses activated EMT, which was attenuated by a ROS inhibitor. These results suggest that EVs participate in ROS-induced lens EMT, making EVs a potential target for treating PCO.

Intravitreal Injection Is Associated with Increased Posterior Capsule Rupture Risk during Cataract Surgery: A Meta-Analysis.

BACKGROUND: Although observational studies have suggested that prior intravitreal therapy may predict posterior capsule rupture (PCR) during cataract surgery, this finding is still controversial. OBJECTIVE: This study aimed to summarize current evidence on the association between prior intravitreal injection (IVI) and PCR during cataract surgery. METHODS: A systematic literature search was performed up to October 27, 2021. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random-effects models. The potential association between IVI and PCR in future cataract surgeries was assessed using the following two models: "pooling the ORs of PCR in eyes with and without previous IVI(s)" and "pooling the ORs for PCR relative to each increase in the number of prior injections." The quality of included studies was appraised using the Newcastle-Ottawa Scale. RESULTS: Six cohort studies were included in this meta-analysis, with a total of 1,051,097 eyes that underwent cataract surgery. Of these, 7,034 eyes were associated with previous IVI. The pooled odds of PCR in eyes with prior IVI was 2.01 (95% CI: 1.35-3.00) times higher than that of eyes without an IVI history. An increase in the number of previous IVI conferred increased odds of PCR of 1.03 (95% CI: 1.01-1.06). After excluding studies that failed to account for confounders, the significantly increased risk was not altered, and the significant heterogeneity was minimized in both models. CONCLUSION: This meta-analysis provides evidence that previous IVI significantly increases the risk of PCR during future cataract surgery. The risk of PCR should be discussed preoperatively with patients. Further studies are required to validate our findings and explore the underlying mechanisms.

Short Term Visual and Refractive Outcome following Surgical Intervention for Posterior Capsule Opacification (PCO) in Children in a Tertiary Eye Hospital.

BACKGROUND: PCO occurs commonly postoperatively following cataract extraction in children, obscuring vision as did the initial cataract. It may require a second surgical procedure when it is dense. It is expected that this results in restoration of vision and it is important to ascertain that this is the case as well as to examine any significant changes in refraction thereafter. METHODS: A retrospective observational study extracting demographic and clinical information from case notes of patients who had membranectomy and/or capsule polishing between October 2017 and September 2018. RESULTS: 57 eyes of 51 patients were enrolled. There was a 2:1 male: female ratio. Mean age at cataract surgery was 6.33± 3.59years whilst that for PCO surgery was 9.68±3.89years. Postoperative visual acuity (by WHO definition) was good (between 6/6 and 6/18) in 33.3%, compared to 8.8% preoperatively. Whereas presenting visual acuity was poor (<6/60) in 61.4% preoperatively, this reduced to 30% postoperatively. Visual outcome was influenced by age at cataract surgery, age at PCO surgery, interval between cataract and PCO surgery and type of cataract. Children >8 years of age at time of PCO surgery had a greater proportion of good post-operative best corrected visual acuity (BCVA) (52.6%), whilst 75% of children younger than 8years at time of surgery turned out with poor BCVA after surgery. Developmental cataracts proportionately had the best outcome of visual acuity. There was a range of refractive shift of +0.25D to - 5.25D with a mean myopic shift of -1.51D following membranectomy. CONCLUSION: There was a good proportion of children with significant improvement in visual acuity on the short term, and a mild myopic shift following membranectomy.

CONTEXTE: Résultats visuels et réfractifs à court terme à la suite d'une intervention chirurgicale pour l'opacité de l'axe visuel (PCO) chez des enfants dans un hôpital ophtalmologique tertiaire. METHODES: Une étude d'observation rétrospective extrayant des informations démographiques de cas de patients ayant subi une membranectomie et / ou un polissage de gélule entre octobre 2017 et septembre 2018. RESULTATS: 57 yeux de 51 patients ont été inclus. Il y avait un ratio hommes / femmes de 2: 1. L'âge moyen à la chirurgie de la cataracte était de 5,9 ans alors que celui de la chirurgie du VAO était de 9,2 ans. L'acuité visuelle postopératoire était bonne (entre 6/6 et 6/18) dans 33,3% des cas, contre 8,8% en préopératoire. Alors que l'acuité visuelle était faible (<6/60) dans 61,4% des cas en préopératoire, elle était réduite à 30% en postopératoire. Les enfants de plus de 8 ans au moment de la chirurgie PCO présentaient une plus grande proportion de BCVA postopératoires satisfaisants (52,6%), tandis que 75% des enfants de moins de 8 ans au moment de la chirurgie avaient un BCVA médiocre après la chirurgie PCO. Les résultats visuels étaient influencés par l'âge au moment de la chirurgie de la cataracte et de la PCO, l'intervalle entre les chirurgies de la cataracte et de la PCO et le type de cataracte. Il y avait une plage de décalage de réfraction de +0,25 à -5,25 avec un décalage myopique moyen de 1,51D après la membranectomie. La cataracte développementale avait proportionnellement le meilleur résultat en acuité visuelle. CONCLUSION: Il y avait une bonne proportion d'enfants présentant une amélioration significative de l'acuité visuelle à court terme malgré un léger déplacement de la myopie après une membranectomie. Mots-clés: opacification de l'axe visuel, cataracte, changement myope, résultat visuel.