Silicone oil adhesion to intraocular lenses: An experimental study comparing various biomaterials (original) (raw)
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Irreversible Silicone Oil Adhesion to Silicone Intraocular Lenses
Ophthalmology, 1996
To report a newly defined complication of foldable intraocular lenses (IOLs), namely silicone oil-silicone IOL interaction. This is a complication not generally seen by the implanting cataract surgeon but, rather, at a later stage in a patient's postoperative course, by a vitreoretinal surgeon.
A Preliminary Study of Silicone Hydrogel Lens Material and Care Solution Bioincompatibilities
Cornea, 2011
The study purpose was to evaluate corneal barrier function and staining relative to potential bioincompatibilities. Methods: This was a randomized double-masked study (n = 25 subjects). Three lens material-care solution combinations were tested: (1) lotrafilcon B/polyhexamethylene biguanide (PHMB)based multipurpose (MPS) solution (MPS-1); (2) lotrafilcon B/polyquaternium-1 and myristamidopropyl dimethylamine-based solution (MPS-2); and (3) lotrafilcon B and another PHMB-based solution (MPS-3). Saline served as the control. New lenses were soaked in the preserved solutions or saline and then worn for 2 hours before corneal measurements. Barrier function was characterized by the fluorescein penetration rate, corneal amount, both measured with an objective scanning fluorometer. The dye penetration rate ratio, test to control; amount ratio, test to control, and corneal staining were evaluated. Results: The mean rate ratios (6SD) for the combinations were 2.98 (63.04), 1.23 (61.01), and 1.83 (61.77) for MPS-1, MPS-2, and MPS-3 solutions, respectively. Significant ratio differences were found across regimens (P = 0.007); for MPS-1 compared with baseline (P = 0.031) and for MPS-1 compared with MPS-2 (P = 0.007). The statistical results for staining were similar. Conclusions: Use of an objective quantitative physiological method suggests that significant differences in lens solution bioincompatibilities occur that mirror corneal staining data relative to corneal compromise.
Impact of Silicone Hydrogel Lenses and Solutions on Corneal Epithelial Permeability
Optometry and Vision Science, 2013
Purpose. The primary purpose of this pilot study was to compare epithelial barrier function (EBF) and staining in a small group of participants using a silicone hydrogel (SH) lens worn on a daily basis with two different care regimens. Secondarily, the aim was to see if there was any correlation between corneal staining and EBF. Methods. The corneal EBF of 10 nonYlens wearers (control) and 15 age-matched asymptomatic SH contact lens wearers (test) were assessed using fluorophotometry. Biomicroscopy was performed to assess corneal staining after the EBF was measured. The lens wearers wore PureVision (FDA group V) SH lenses for two consecutive 1-month periods while using either Alcon Opti-Free Express or Renu Fresh using a randomized, investigator-masked, crossover design. Control subjects were assessed on one occasion, and lens wearers were examined before fitting with lenses and after 7, 14, and 28 days of lens wear, with each combination. Results. Compared with the control group, both study groups had an increase in epithelial permeability at baseline (p e 0.04). There were no changes in EBF during the treatment period for either solution (p = 0.87). A significant difference in EBF was found between the test groups during the treatment period (p = 0.02), with greater permeability in the Renu FreshYdisinfected lenses. There was poor correlation between corneal staining and EBF (r = 0.35, p 9 0.05) because of large individual variations. Conclusions. Daily wear of highly oxygen-permeable SH lenses increases corneal epithelial permeability to fluorescein probably because of increased mechanical effects. In addition, certain lens-solution interactions can add to this effect, as seen in this study. Despite having a low amount of central corneal staining in the Renu Fresh group, staining and EBF did not prove to be well correlated. The presence of central corneal staining is a confounding factor when measuring EBF. (Optom Vis Sci 2013;90:546Y556) FIGURE 4.
2010
Purpose: Although all contact lenses (CLs) are applied initially to the eye directly from a packaging solution, little is known about the effects of these solutions on human corneal epithelial cells (HCECs). Due to the porous nature of CL materials, they have the potential to sorb components of the packaging solution during storage, which could then be subsequently released upon insertion of the CL on the eye. The purpose of this study was to investigate the effect of various packaging solutions on HCECs, using an in vitro model. Methods: An in vitro assay was developed whereby various silicone hydrogels and conventional, poly-2hydroxyethylmethacrylate (polyHEMA)-based lens materials were removed directly from their packaging and then incubated for up to 24 h with HCECs. The effect of the retained and released packaging solution components on HCECs was assessed by measuring cell viability, adhesion phenotype, and apoptosis. Results: Incubation of HCECs with CLs stored in borate-buffered packaging solutions resulted in a significant reduction in cell viability. Adherent cells incubated with these CLs also exhibited reduced levels of β1 and α3 integrin. Soaking borate-buffered packaged CLs in PBS before cell incubation resolved viability and integrin expression in all cases, with the exception of galyfilcon A and balafilcon A, from which a 20% reduction in cell viability was still observed. In comparison, CLs stored in phosphate-buffered packaging solutions had cellular viability and expression of integrins similar to control cells (cells incubated in the absence of a lens). When incubated with cells at a 10% concentration in serum-free medium, borate-buffered packaging solutions and borate-containing saline (Unisol 4) significantly reduced cell viability and integrin expression. Neither caspase activation nor annexin V binding was observed on cells following exposure to borate buffer solution. However, a significant decrease in reactive oxygen species was observed at 24 h. These latter results suggest that in vitro exposure to low concentration of borate/boric acid results in cell dysfunction, leading to necrosis rather than apoptosis. Conclusions: Borate-buffered packaging solutions were shown to adversely affect the viability and integrin expression of HCECs in vitro. When used in ophthalmic packaging solutions, the antimicrobial properties of borate buffer may be outweighed by its relatively cytotoxic effects on cells. Molecular Vision 2010; 16:272-282 http://www.molvis.org/molvis/v16/a33
Journal of cataract and refractive surgery, 2015
To evaluate the adhesion of human lens capsule cells on hydrophilic acrylic intraocular lenses (IOLs) coated with polyethylene glycol (PEG). Department of Ophthalmology, Faculty of Medicine, Universidade Estadual Paulista-Botucatu, São Paulo, Brazil. Experimental study. Human anterior lens capsules obtained during cataract surgery were cultured and seeded (200 cells/IOLs) in triplicates on the surface of a copolymer comprising hydroxyethyl methacrylate, ethyl methacrylate, and methyl methacrylate IOLs (Loflex) treated or not treated with PEG. After 26 hours, the number of viable adherent cells was estimated by counting in a hemocytometer. The coating of hydrophilic acrylic IOLs with PEG was effective in inhibiting cell adhesion (P < .05). Cells showing 2 distinct morphologic patterns-epithelial and dendritic-like-were observed during the in vitro establishment of the cultures. A tendency toward greater adhesion of dendritic-like cells was observed in untreated IOLs compared with ...
Uptake and Release Phenomena in Contact Lens Care by Silicone Hydrogel Lenses
Eye & Contact Lens: Science & Clinical Practice, 2013
Contact lens solutions are highly complex mixtures of biocides (preservatives), surfactants, and other agents designed to disinfect, clean, and wet contact lenses. The commercialization of silicone hydrogel (SiHy) lenses has resulted in unique challenges to the manufacturers of contact lens solutions, because the properties of these materials differ markedly from those seen previously with poly-hydroxyethyl methacrylate-based hydrogels. Historically, hydrogel lens uptake and release of low-molecular weight preservatives such as chlorhexidine and thimerosal were known to result in allergic reactions, resulting in corneal irritation, stinging, conjunctival hyperemia, development of corneal infiltrates, palpebral lid changes, and corneal staining. However, little is known about the interaction of modern care systems with modern soft lens materials. Factors to be considered when evaluating the uptake and release of care components include the water content, charge, relative hydrophobicity, surface treatment, and porosity of the lens material, in conjunction with the concentration, charge/molecule, ionicity in the product matrix, molecular weight, and hydrophobicity of the care component in question. These factors control the sorption of the solution components by lenses, resulting in a variety of differences in the amount of the component taken up into the lens material and the amount and rate of subsequent release onto the ocular surface. Because both natural (ocular) and environmental biota become part of the solution-lens system during regimen use of any lens care product, these extraneously introduced substances should also be considered regarding their potential for uptake and either subsequent release onto the ocular surface or functioning as a scaffold for the adhesion of microbes. This article will review current knowledge concerning these interactions and investigate what clinically observable complications may arise from these interactions. It also reviews whether current methods to determine these interactions could be improved on.
Colloids and surfaces. B, Biointerfaces, 2018
Although contact lenses are promising platforms for ocular drug delivery and have been extensively studied for that purpose, the influence of sterilization methods on these systems remains barely investigated. In this work, a silicone-based hydrogel was produced and loaded with different ophthalmic drugs: levofloxacin, chlorhexidine, diclofenac and timolol. The drug release profiles, along with several material properties, were evaluated before and after sterilization by three different methods steam heat, γ-irradiation and ozone gas. Independently of the sterilization method used, the results of the swelling and mechanical properties tests strongly indicate the occurrence of specific drug-polymer interactions promoted by the sterilization. In general, these interactions led to a decrease on the amount of drug released. It is shown that γ-irradiation and ozone led to significant degradation of all of the drugs used in this study. Thus, it was concluded that steam heat is the sterili...
Clinical observations of biofouling on PEO coated silicone hydrogel contact lenses
Biomaterials, 2010
Silicone hydrogel contact lenses, which have been a major advance in the field of vision correction, require surface modification or coatings for comfort and biocompatibility. While current coatings show adequate clinical performance, advanced coatings may improve the biocompatibility of contact lenses further by reducing biofouling and related adverse clinical events. Here, we have produced coatings on Lotrafilcon A contact lenses by deposition of a thin film of allylamine plasma polymer (ALAPP) as a reactive interlayer for the high density grafting of poly(ethylene oxide) dialdehyde (PEO(ALD) 2 ), which had previously shown complete resistance to protein adsorption in vitro. The performance of these contact lenses was evaluated in a controlled clinical study over 6 h using Focus Ò Night and DayÔ (also known as Air Optix Ò Night & Day Ò ) contact lenses as control lenses. Surface modified lenses were characterised by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) before and after wear. Clinical data showed a high level of biocompatibility of the PEO coated lenses equivalent to control lenses. Surface analysis of worn contact lenses demonstrated that the high density PEO coating is effective in reducing biofouling in vivo compared to control lenses, however small amounts of protein deposits were still detected on all worn contact lenses. This study highlights that elimination of biofouling in vivo can be much more demanding than in vitro and discusses issues that are important for the analysis of worn contact lenses as well as the design of improved contact lenses.