Pharmacologic prevention of posterior capsule opacification: in vitro effects of preservative-free lidocaine 1% on lens epithelial cells

Comparative histomorphologic study of basement membrane side staining and additional epithelial side staining of the anterior lens capsule with Trypan Blue

PURPOSE

To compare the histomorphologic changes on the anterior lens capsule by both epithelial and basement membrane side staining to those of only basement membrane side staining of the anterior lens capsule with Trypan Blue (TB).

METHODS

A cross-sectional study was done on 72 samples from patients who underwent cataract surgery between April 2021 and September 2022. After capsulorhexis of the TB-stained capsule, it was made into two halves externally and one half labeled as controls (sample A). The other half was immediately stained further with TB on the epithelial side and was taken as cases (sample B). Samples were analyzed for lens epithelial cells and basement membrane changes.

RESULTS

The loss of intactness of lens epithelial cells, partial or complete detachment of lens epithelial cells, degeneration of lens epithelial cells, and basement edema were significantly higher in cases compared to controls, whereas intactness of the basement membrane did not show any statistical significance between the two groups. There was a statistically significant decrease in cell density in cases compared to controls.

CONCLUSION

Staining the epithelial side of the capsular bag with TB is more detrimental to lens epithelial cells and paves the way for a further study of staining the capsular bag before intra-ocular lens implantation to reduce the incidence of posterior capsule opacification.

Statistical optimization of hyaluronic acid enriched ultradeformable elastosomes for ocular delivery of voriconazole via Box-Behnken design: in vitro characterization and in vivo evaluation

Voriconazole (VCZ) is a well-known broad spectrum triazole antifungal, mainly used orally and intravenously. The study aimed to formulate VCZ into ultradeformable elastosomes for the topical treatment of ocular fungal keratitis. Different formulae were prepared using a modified ethanol injection method, employing a 3³ Box-Behnken design. They were characterized by measuring their entrapment efficiency (EE%), particle size (PS), polydispersity index (PDI) and zeta potential (ZP). The optimized formula was subjected to further in vitro investigations and in vivo evaluation studies. The prepared vesicles had satisfactory EE%, PS, PDI and ZP values. The numerical optimization process suggested an optimal elastosomal formula (OE) composed of phosphatidyl choline and brij S100 at the weight ratio of 3.62: 1, 0.25%w/v hyaluronic acid and 5% (percentage from phosphatidyl choline/brij mixture) polyvinyl alcohol. It had high EE (72.6%), acceptable PS and PDI (362.4 nm and 0.25, respectively) and highly negative ZP of −41.7 mV. OE exhibited higher elasticity than conventional liposomes, with acceptable stability for three months. Transmission electron microscopy demonstrated the spherical morphology of vesicles with an external transparent coat of Hyaluronic acid. OE was expected to cause no ocular irritation or blurring in vision as reflected by pH and refractive index measurements. The histopathological study revealed the safety of OE for ocular use. The fungal susceptibility testing using Candida albicans demonstrated the superiority of OE to VCZ suspension, with greater and more durable growth inhibition. Therefore, OE can be regarded as a promising formula, achieving both safety and efficacy.

Posterior Capsule Opacification: A Review of Experimental Studies

Posterior capsule opacification (PCO) is the most common complication of cataract surgery. It causes a gradual deterioration of visual acuity, which would otherwise improve after a successful procedure. Despite recent advances in ophthalmology, this complication has not been eradicated, and the incidence of PCO can be as high as 10%. This article reviews the literature concerning the pathomechanism of PCO and examines the biochemical pathways involved in its formation and methods to prevent this complication. We also review the reported tests performed in cell cultures under laboratory conditions and in experimental animal models and in ex vivo human lens capsules. Finally, we describe research involving human eyes in the clinical setting and pharmacological methods that may reduce the frequency of PCO. Due to the multifactorial etiology of PCO, in vitro studies make it possible to assess the factors contributing to its complications and search for new therapeutic targets. Not all pathways involved in cell proliferation, migration, and contraction of the lens capsule are reproducible in laboratory conditions; moreover, PCO in humans and laboratory animals may be additionally stimulated by various degrees of postoperative reactions depending on the course of surgery. Therefore, further studies are necessary.

Voriconazole Ternary Micellar Systems for the Treatment of Ocular Mycosis: Statistical Optimization and In Vivo Evaluation

Voriconazole (VRC) is a broad spectrum, second generation triazole antifungal. The main use of VRC is via the oral and intravenous route. The study aimed to formulate VRC into ternary micellar systems (TMSs) for the topical treatment of ocular mycosis. TMSs were successfully prepared by water addition/solvent evaporation method, applying a 3-factor D-optimal design. The numerical optimization process suggested an optimal formula (OTMS) composed of total Pluronics to drug weight ratio of 22.89: 1, 1:1 weight ratio of Pluronic® P123 and F68, and 2% w/v of Labrasol. OTMS had high solubilization efficiency of 98.0%, small micellar size of 21.8 nm and suitable zeta potential and polydispersity index values of -9.0 mV and 0.261, respectively. OTMS exhibited acceptable stability for 3 months. Transmission electron microscopy demonstrated the spherical morphology of micelles. OTMS was expected to cause no ocular irritation or blurring in vision as reflected by pH and refractive index measurements. The histopathological study revealed the safety of OTMS for ocular use. The fungal susceptibility testing using Candida albicans demonstrated the superiority of OTMS to VRC suspension, with greater and more durable growth inhibition. Therefore, ocular application of optimized VRC-loaded TMSs can be a promising treatment for ocular mycosis.

Research Progress of Drug Prophylaxis for Lens Capsule Opacification after Cataract Surgery

Phacoemulsification combined with intraocular lens (IOL) implantation is the international standard operation procedure for cataract and has been generalized worldwide. However, lens capsule opacification, one of the common complications after cataract surgery, impacts the recovery of patients' visual function to a large extent. Lens capsule opacification has two types, anterior capsule opacification (ACO) and posterior capsule opacification (PCO), according to the location. There is not an accepted approach to treat ACO. Nd : YAG laser capsulotomy, the common treatment of PCO, can effectively improve the vision, but may cause a series of complications and is inappropriate for children who are too young to cooperate with this treatment. It is generally known that the responses of lens epithelial cells (LECs) after cataract surgery, including cell proliferation, migration, and epithelial-mesenchymal transition (EMT), play a key role in the pathogenesis of lens capsule opacification. Scholars found that substantial drugs can reduce the occurrence of lens capsule opacification by inhibiting, clearing, or killing LECs, and made great efforts as well as innovations on the exploration of drug species or modes of administration. This article is a systematic interpretation and elaboration about how to prevent lens capsule opacification after cataract surgery via different drugs.

Effect of anterior capsule polish on visual function: A meta-analysis

PURPOSE

To investigate the relationship between anterior capsule polish and visual function.

METHODS

Data were obtained from Pubmed, Embase, Web of Science, WanFang, VIP and CNKI up to the end of May 2018, without any date or language restrictions for trials. The modified Jadad scale and the newcastle-ottawa scale were used to assess the quality of included studies. Uncorrected visual acuity (UCVA) and posterior capsule opacification (PCO) were used as outcome variables. Data on anterior capsule polish were pooled using weighted, random-effect meta-analysis.

RESULTS

One randomized controlled trial and 4 observational cohort studies involving 2533 patients were included in the analyses. There was a statistically significant difference of UCVA (OR 1.92, 95% CI 1.41-2.61) between the polish group and the control group, indicating that anterior capsule polish improved UCVA. Further studies with continuous data also suggested that anterior capsule polish was associated with good UCVA (MD 0.11, 95% CI 0.06-0.16). Posterior capsule opacification rate for 1-year or longer follow-up were extracted for 2561 eyes in 3 studies. Posterior capsule opacification rate was lower in the anterior capsule polish group according to summary odds ratio on PCO rate (OR 0.42 95% CI 0.24-0.73).

CONCLUSIONS

Anterior capsule polish prevents complication of modern cataract surgery and benefits on visual function in short term follow-up period.

Optimization of β-cyclodextrin consolidated micellar dispersion for promoting the transcorneal permeation of a practically insoluble drug

Development of efficient ocular drug delivery system for antifungal drugs becomes a must nowadays to face and eradicate the widely spread ophthalmic fungal infections. Itraconazole, a triazole antifungal, is struggling to penetrate the cornea and subsequently, its efficacy is limited. The aim of this study was to enhance itraconazole corneal penetration through utilizing the minimum surfactant amount in presence of β-cyclodextrin which acted as a dissolution and permeation enhancer. β-Cyclodextrin consolidated micellar dispersions (CCMD) were prepared after an initial screening to select the composition of surfactant(s). The preparation was done according to a modified melt dispersion technique. The prepared CCMD were characterized through the analysis of their particle size, zeta potential and solubilization efficiency. The optimum formula was chosen based on a factorial response surface analysis and it was composed of 17:1 w/w surfactant/drug, 30:1 w/w cyclodextrin/drug ratios and 0.02% polyethylene oxide. This formula was subjected to in vitro characterization including release, imaging by transmission electron microscope, mucoadhesion, stability, in addition to the determination of the minimum inhibitory concentration. Moreover, the ex vivo/in vivo permeation, safety and efficacy profiles were determined. The optimized CCMD formula was found to be significantly safe, stable, mucoadhesive and efficient to permeate the drug through rabbits' corneas. Consequently, the optimized CCMD formulation can be a promising, safe and efficient platform for the transcorneal delivery of lipophilic drugs including most antifungals.

AIR/FLUID-DROPPING TECHNIQUE FOR INTRACAPSULAR DISTILLED WATER APPLICATION: A Vitrectomy Approach for Selective Targeting of Lens Epithelial Cells

PURPOSE

We describe a simplified technique of intracapsular distilled water application for targeting lens epithelial cells using vitrectomy approach of fluid-air exchange and to evaluate the reliability and safety of this technique.

METHODS

Consecutive patients with cataract were randomly assigned to treatment group and control group. After the nucleus removal and cortical aspiration, the space of anterior chamber and capsular bag were maintained with continuous infusion of sterile air by using fluid-air exchange technique through side-port incision. Distilled water was dropped into the capsular bag using a specially designed syringe. A concave air-fluid surface (a physical phenomenon) insured the contact of distilled water with the inner surface of the capsule without overflowing from the bag. The distilled water remained in place for 3 minutes and was then removed by the syringe.

RESULTS

No intraoperative surgical complication was observed, and no damage to adjacent intraocular structures was observed during the postoperative follow-up. There was no statistical difference of corneal endothelial cell loss between the treatment group and the control group. Histological study confirmed damage to the lens epithelial cells from anterior capsular specimens treated by the technique.

CONCLUSION

The simplified technique using vitrectomy approach is safe and specific for targeting lens epithelial cells without associated complications.

Prevention of posterior capsular opacification

Posterior capsular opacification (PCO) is a common complication of cataract surgery. The development of PCO is due to a combination of the processes of proliferation, migration, and transdifferentiation of residual lens epithelial cells (LECs) on the lens capsule. In the past decades, various forms of PCO prevention have been examined, including adjustments of techniques and intraocular lens materials, pharmacological treatments, and prevention by interfering with biological processes in LECs. The only method so far that seems effective is the implantation of an intraocular lens with sharp edged optics to mechanically prevent PCO formation. In this review, current knowledge of the prevention of PCO will be described. We illustrate the biological pathways underlying PCO formation and the various approaches to interfere with the biological processes to prevent PCO. In this type of prevention, the use of nanotechnological advances can play a role.

In vitro growth of lens epithelial cells from cataract patients - association with possible risk factors for posterior capsule opacification

AIM

Inter-individual differences in intrinsic proliferative capacity of lens epithelial cells may have importance for the risk of developing posterior capsule opacification (PCO) after cataract surgery. The purpose of the present study was to determine growth of human lens epithelial cells (HLEC) in culture and investigate possible associations with clinical characteristics of the donors, such as age, sex, pseudoexfoliation, uveitis and diabetes.

METHODS

Pieces of lens capsule and adhering lens epithelial cells were obtained through capsulorhexis at cataract surgery. Specimens were cultured in a humidified CO2-incubator using standard culture medium and 5% fetal calf serum for two weeks after which cultured cells were stained with carboxy-fluorescein diacetate succinimidyl ester. Image processing software was used to determine the area of the confluent epithelial cell layer in relation to the size of the original capsule specimen.

RESULTS

The increase in area of confluent HLEC showed a negative correlation with diabetes at the first week after surgery. Lower age and female sex showed border-line significant associations with a higher rate of cell proliferation. The presence of pseudoexfoliation in vivo did not significantly affect cell growth in culture postoperatively. Nor did installation of xylocain in the anterior chamber during surgery.

CONCLUSION

Diabetes is associated with lower rate of proliferation of lens epithelial cells in culture. The lack of strong correlations between in vitro growth and known risk factors for PCO in the donors suggest that other factors than the proliferative capacity of the cells per se are important for PCO formation.

Long-term results of sealed capsule irrigation using distilled water to prevent posterior capsule opacification: a prospective clinical randomised trial

BACKGROUND

We investigated long-term safety and efficacy of sealed capsule irrigation (SCI) during cataract surgery to prevent posterior capsule opacification (PCO).

METHODS

One eye of each of 17 patients (mean age: 70.1+/-9.7 years) who presented with bilateral cataracts was randomly chosen for SCI treatment. After phacoemulsification, the capsular bag was vacuum sealed with the PerfectCapsule device (Milvella) followed by SCI using distilled water for two minutes. No vacuum loss occurred during irrigation. Each patient's fellow eye served as a control. One hydrophilic acrylic intraocular lens model was implanted in all eyes. Five patients had to be excluded due to deep anterior chamber, small pupil or unilateral surgery. Follow-up examinations took place one day and one, three, six, 12 and 24 months after surgery. We evaluated safety parameters, anterior capsule (AC) overlapping and PCO.

RESULTS

Postoperatively, mean best corrected visual acuity, pachymetry, endothelial cell count, intraocular pressure, AC overlapping and PCO showed no statistically significant difference between SCI and the control group (p>0.05, Wilcoxon test).

CONCLUSION

SCI is a safe procedure and enables the specific pharmacological targeting of lens epithelial cells inside the capsular bag. Using distilled water, however, it is not possible to reduce PCO development significantly. Thus, alternative substances should be evaluated.

Influence of three-piece and single-piece designs of two sharp-edge optic hydrophobic acrylic intraocular lenses on the prevention of posterior capsule opacification: a prospective, randomised, long-term clinical trial

BACKGROUND

Posterior capsule opacification (PCO) is still a major long-term complication of modern cataract surgery. We evaluated the impact of sharp-edged intraocular lenses (IOLs) with different haptic designs made from the same hydrophobic acrylic material on posterior and anterior lens capsule opacification.

SETTING

Eye clinic of Kaunas University of Medicine, Lithuania. Prospective randomised clinical study.

METHODS

Seventy-four eyes of 74 patients scheduled for cataract surgery were included in a prospective randomised clinical study. Thirty-seven eyes of 37 patients received a three-piece acrylic hydrophobic (AcrySof, MA3OBA, Alcon) IOL; and thirty-seven eyes of 37 patients received a one-piece acrylic hydrophobic (AcrySof, SA3OAL, Alcon) IOL. Visual acuity, anterior capsule opacification (ACO), capsular folds, capsulorrhexis/optic overlapping and posterior capsule opacification (PCO) were evaluated. ACO was assessed subjectively. PCO values in the entire IOL optic area and in the central 3 mm optic zone were assessed using a photographic image-analysis system (EPCO2000). Follow-ups were performed postoperatively at 1 day, 6 months, 1 year and 2 years.

RESULTS

There were no significant differences in best corrected visual acuity, grade of ACO and capsulorrhexis/optic overlapping between IOL types during the follow-up period. Patients in the one-piece acrylic hydrophobic IOL group more frequently presented with capsular folds behind the IOL optic area than those in the three-piece IOL group. In the three-piece acrylic hydrophobic IOL group, PCO values (mean (SD)) of the entire IOL optic area were significantly lower six months postoperative (three-piece: 0.002 (0.009); one-piece: 0.007 (0.017); p=0.04), one year postoperative (three-piece: 0.004 (0.016); one-piece: 0.026 (0.041); p=0.001) as well as one year postoperative in the central 3 mm optic zone (three-piece: 0.000 (0.0002); one-piece: 0.019 (0.049); p=0.001). However, two years postoperative, the PCO values of the groups did not show significant differences (entire IOL optic area: three-piece, 0.136 (0.223); one-piece, 0.154 (0.190); p=0.18; central zone: three-piece, 0.023 (0.065); one-piece: 0.020 (0.039); p=0.44).

CONCLUSION

The 2 year follow-up after cataract surgery showed no significant difference in ACO and PCO development between three-piece and one-piece acrylic hydrophobic intraocular lenses.

[New methods for the prevention of posterior capsule opacification]

Even though tremendous advances have been made especially during the last 10-15 years in terms of surgical techniques and improvement of implant technology, posterior capsule opacification (PCO) still remains a serious long-term complication. New clinical and laboratory studies (especially of autopsy eyes) have improved our understanding of how IOL design and material influence PCO. Sharp edge optic designs of IOLs of various materials have been shown to significantly reduce secondary cataract. The application of pharmacological substances selectively into the capsular bag is now possible due to the development of the PerfectCapsule System for vacuum-sealed capsule irrigation. Major advances in other areas of biotechnology and immunology including gene therapeutic methods offer totally new approaches for the future in the elimination of lens epithelium cells from the capsular bag. This survey gives an update on current and future means and trends to reduce or prevent PCO formation.

Evaluation of the cataractogenic effect of viscoanesthetic solutions on the rabbit crystalline lens

PURPOSE

To evaluate the toxicity and cataractogenic effect of solutions combining sodium (Na) hyaluronate 1.0% and 1.5% with lidocaine 1.0% on the rabbit crystalline lens. The amount of pupil dilation provided by the addition of lidocaine to the Na hyaluronate solutions was also assessed.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

METHODS

Five solutions were injected into the anterior chamber of 18 pigmented rabbits in a randomized manner by the same surgeon, the intraocular component of VisThesia (Na hyaluronate 1.5%/lidocaine 1.0%), the intraocular component of VisThesia Light (Na hyaluronate 1.0%/lidocaine 1.0%), Ophthalin Plus (Na hyaluronate 1.5%), and a balanced salt solution; and both eyes of 2 other rabbits were injected with nonpreserved aqueous lidocaine 1.0%. The pupil diameter of each eye was measured before injection, immediately after, and 1 and 5 minutes after injection. After a follow-up of 3 months with slitlamp examinations, the rabbits were killed, and their eyes were enucleated. The crystalline lenses were evaluated from a posterior or Miyake-Apple view, and the eyes were fixated in 10% formalin for histopathologic analyses.

RESULTS

Pupil diameter was significantly larger 1 and 5 minutes after injection in the VisThesia (P = .01 and P = .007) and VisThesia Light (P = .008 and P = .007) groups, whereas the differences were not significant in the Ophthalin Plus (P = .317 and P = .102) and balanced salt solution groups (P = .317 and P = .180). Fast and large pupillary dilation was observed in the aqueous lidocaine group, starting during the injection. No differences in the transparency of the natural lens and the red fundus reflex were noted during slitlamp examinations. Postmortem analyses from a posterior view also showed no differences in the transparency of the crystalline lens. The histopathologic appearance of the lens capsule, anterior and equatorial lens epithelial cells, and epithelial lens bow was comparable in the eyes, without signs of cell vacuolization or disruption.

CONCLUSIONS

Intracameral injection of the solutions used in this study caused no localized opacity or overall change in the transparency of the crystalline lenses as observed during clinical and postmortem examinations as well as histopathologic analyses of the enucleated rabbit eyes. Viscoanesthesia may have application in phakic intraocular lens implantation.

Endothelial cell integrity after phacoemulsification with 2 different handpieces

PURPOSE

To investigate corneal endothelial cell loss in fresh phakic human autopsy cadaver eyes after phacoemulsification (PE) with a conventional handpiece or a new oscillatory handpiece.

SETTING

Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA.

METHODS

Twenty fresh phakic human autopsy globes were randomized to PE with a conventional handpiece (n = 10) or an oscillatory handpiece (n = 10). The main parameters evaluated were age, nucleus density, amount of ophthalmic viscosurgical device (OVD) used, and mean PE time and ultrasound (US) power. After surgery, the corneas were excised and the endothelia were vitally stained with trypan blue and alizarin red. Light microscopy was used to assess the endothelial cell loss.

RESULTS

The mean age, density of the nucleus, OVD used, and US power were similar between the groups. The mean PE time was less with the NeoSoniX handpiece (0.71 minutes +/- 0.39 [SD]) than with the conventional handpiece (1.05 +/- 0.53 minutes). The mean number of dead endothelial cells was significantly lower in the oscillatory handpiece group (31.3 +/- 24.2 cells/mm(2)) than in the conventional handpiece group (60.4 +/- 46.8 cells/mm(2)) (P<.001, Mann-Whitney rank sum test).

CONCLUSIONS

Less corneal endothelial cell loss occurred after PE with an oscillatory handpiece than with a conventional handpiece. Further randomized clinical trials are recommended to validate this study.