Lens Care Solutions Research Articles

Antimicrobial Efficacy of Multipurpose Solutions Paired with Five Lens Materials Against Clinical Strains of Fusarium

Purpose: To evaluate the antimicrobial effectiveness of multipurpose lens care solutions (MPS) paired with five commercially available contact lens materials according to ISO 18259 and ISO 14729. Solution and lens pairings were challenged with clinical strains of the fungal pathogen Fusarium isolated from microbial keratitis according to ISO 18259. Solution efficacy with lenses in cases was compared to baseline efficacy in test tubes at the recommended disinfection time (DT) per ISO 14729.

Edge design and Contact Lens Care Solutions influence in contact lenses wear

Purpose: The purpose of this study was to evaluate the impact of edge design and contact lens care solutions (CLCS) in comfort, vision, fitting and ocular health on contact lenses (CLs) wear.

Antimicrobial Efficacy of Multipurpose Solutions Paired with Five Lens Materials Against Clinical Strains of Bacteria and Fungi

Purpose: To evaluate the antimicrobial effectiveness of multipurpose lens care solutions (MPS) paired with five commercially available contact lens materials according to ISO 18259:2014 and ISO 14729:2001. Solution and lens pairings were challenged with bacteria and fungi isolated from microbial keratitis according to ISO 18259. Solution efficacy with lenses in cases was compared to baseline efficacy in test tubes at the recommended disinfection time (DT) per ISO 14729.

Self-assembly and cleaning and wettability of a polysaccharide-surfactant system formed from the cationic hydroxypropyltrimethyl ammonium chloride chitosan and nonionic sucrose lauric acid ester

Contact lens care solution was prepared via hydroxypropyltrimethyl ammonium chloride chitosan (HACC) and sucrose lauric acid ester (SML) via self-assembly in borate buffer solution (BBS). The elution efficiency of lipids, micellization, and wettability properties of HACC-SML in BBS was studied systematically using high-performance liquid chromatography (HPLC), dynamic light scattering (DLS), zeta potential, surface tension, and contact angles methodologies. The elution efficiency of the lipid increased from 46.98% to 65.68%, whereas DLS and zeta potential data varied with the addition of SML. These caused the shrinkage of micelles, and the system became stable, and further revealed that SML was a non-ionic biosurfactant with excellent performance. The result of surface tension at water-air and contact angles on silicone hydrogel lens at 25 °C showed that SML has outstanding adsorption capacity with an increased degree of wetting, ensuring the comfort and safety of wearing.

Phytochemical, anti-Acanthamoeba, and anti-adhesion properties of Garcinia mangostana flower as preventive contact lens solution

Acanthamoeba keratitis infection extends due to the growing number of contact lens users. Indigenous plants including Garcinia mangostana play a vital role in human health and well being. Many species of this plant have been reported with myriads of potent medicinal properties. However, the aims of this study were, for the first time, to isolate compounds from the flower of G. mangostana and to test their anti-Acanthamoeba and anti-adhesion activity against Acanthamoeba triangularis. Powdered flowers of G. mangostana were extracted and chromatographed on a silica gel column. The structures of the compounds were established with the aid of 1H NMR. More so, the anti-Acanthamoeba and anti-adhesion properties were tested on a 96-well polystyrene microtiter plate and soft contact lenses. Scanning electron microscope (SEM) was used to determine the features of A. triangularis on contact lenses. Eight pure compounds were obtained, namely 9-hydroxycalabaxanthone, tovophillin A, garcinone E, garcinone B, α-mangostin, gartinin, 8-deoxygartinin and γ-mangostin. The extract and pure compounds exhibited anti-Acanthamoeba activity with MIC values in the range of 0.25–1 mg/mL. In addition, the extract and α-mangostin displayed significant activity against the adhesion of A. triangularis trophozoites both in polystyrene plate and in contact lenses at 0.5 × MIC (0.25 mg/mL). Furthermore, α-mangostin has the potential to remove A. triangularis adhesion in contact lenses similar to a commercial multipurpose solution (MPS). SEM study confirmed that crude extract and α-mangostin are effective as solutions for contact lenses, which removed A. triangularis trophozoites within 24 h. Alpha-mangostin was non-toxic to Vero cells at a concentration below 39 μM in 24 h. Crude extract of G. mangostana flower and its α-mangostin serve as candidate compounds in the treatment of Acanthamoeba infection or as lens care solution, since they can be used as a source of natural products against Acanthamoeba and virulence factor associated with the adhesion of A. triangularis.

Transparent and photochromic poly(hydroxyethyl acrylate–acrylamide)/WO3 hydrogel with antibacterial properties against bacterial keratitis in contact lens

AbstractThere have been numerous challenges in the incorporation of photochromic materials into hydrogel system due to the agglomeration of nanoparticles and non‐transparency of the hydrogel material. In this study, WO3 nanocomposites were prepared and incorporated into poly(hydroxyethyl acrylate) (pHEA) and polyacrylamide (pAAm) to fabricate poly(HEA‐AAm)/WO3 hydrogels with improved coloration efficiency and reversibility. The as‐prepared p(HEA‐AAm)/WO3 hydrogel displayed remarkable mechanical properties to sustain compressive and tensile stress up to 15.9 and 58.7 MPa with deformation ratios of 16.2 and 30.8, respectively. The hydrogels exhibited good transmittance (%T) and reflectance (%R) of ~47% and 64% at 829 and 408 nm respectively. The hydrogels also revealed visible spectroscopic absorbance at >781 nm after exposure to UV‐lamp and natural sunlight for 5 s and 0.5 h, giving rise to a blue coloration, however, the fading process of the hydrogels was achieved in 20 min and 2.0 h respectively in an open air. More so, the hydrogel solutions displayed a high antibacterial efficacy against bacteria pathogens associated with bacterial keratitis in contact lens care solutions. The observed excellent photochromic and antibacterial properties of the hydrogel show promising potentials for use in the construction of antibacterial contact lenses, optical and intelligent devices.

Correlation between surface friction and the hydrophobicity of structure-related side-chain exposure of albumin on contact lens

The management of contact lens discomfort remains a challenge leading to the increased contact lens dropout rates. Tear protein accumulates on the lens surfaces with different configurations observed are correlated to the lens friction, with the improved comfort experienced by reduced surface friction in the eye. However, protein adsorption is a complex process with the combined protein-protein interactions (PPI) and protein-surface interactions (PSI) involved, which is difficult to explain the complicated tribological behavior in terms of protein structural shifts alone on lens surfaces. On the other hand, the type of solvent-exposed side chains from specific protein conformations on lens surfaces should be more important to the lens friction involved. We aim to investigate the correlation between the structure-related side-chain exposure and corresponding lens friction of adsorbed tear proteins on lens surfaces under varied PPI and PSI. Albumin was the model protein adsorbed onto the conventional lens material. Such as polymethylmethacrylate (PMMA) or the poly-2-hydroxyethyl methacrylate (PHEMA) surfaces applied here. Adsorption was conducted under varying protein solution concentrations to saturate the model surface to change the PPI effects over a wide range. Our results indicate that PPI effects help stabilize protein structures on both surfaces. When PPI is minimized, a distinct correlation was observed between the surface friction and the hydrophobicity of structure-related side-chain exposure of albumin on lens surfaces depending on the different PSI involved. At a fundamental understanding, our results would provide insights for developing new lens materials or the lens care solution designs to reduce the lens discomfort.

Quarter of a century of contact lens prescribing trends in the United Kingdom (1996 – 2020)

PurposeTo document contact lens prescribing trends in the United Kingdom over the past quarter of a century. MethodsAn annual survey of contact lens prescribing was conducted each year from 1996 to 2020, inclusive, by asking a random selection of optometrists and contact lens opticians to provide information relating to 10 consecutive contact lens fits between January and March. ResultsOver the 25 year survey period, 2,671 practitioners returned survey forms, reporting a total of 25,575 contact lens fits. The mean (± standard deviation) age of lens wearers was 35 ± 15 years, of which 64 % were female. Over the survey period, rigid lens new fits decreased from 22 % to 2%. The prescribing of silicone hydrogel lenses has increased steadily since their introduction towards the end of the 1990s, and now represent 80 % of soft lens fits. Soft toric lens prescribing has gradually increased to 47 % – a value at which astigmatism ≥ 0.75DC is theoretically corrected in all contact lens wearers. Daily disposable prescribing increased steadily over the survey period and now represents 63 % of lenses prescribed. Extended wear fits remain at very low levels, except for some prescribing for overnight orthokeratology. Multi-purpose lens care solutions are ubiquitous; peroxide and other systems are now seldom prescribed. Rigid lenses and monthly replacement soft lenses are predominantly worn on a full time basis, whereas daily disposable soft lenses are mainly worn part time. ConclusionsThis report documents the evolution of contact lens fitting in the United Kingdom over the past 25 years. The most likely lens fit is a spherical design silicone hydrogel daily disposable contact lens prescribed for a 35 year old female and worn on a part-time basis.

Contact Lens Care: Past, Present and Future (a Literature Review)

Introduction. The number of contact lens users continues to increase, exceeding the total of more than 125 million people in the world. The trend of modern vision correction with contact lenses is the creation of customized contact lenses and specialty lens care products that better meet the needs of patients of all age groups.Purpose. To study the evolution of contact lens care products, their properties, composition characteristics, reliability of cleaning and disinfection, advantages and disadvantages of multifunctional solutions and peroxide systems, compatibility with contact lens materials as well as the effct of contact lens care solutions on the eye microbiome based on a literature data review.Material and methods. The analysis of scientifi publications available on Pubmed, BCLA, Elibrary, Elsevier and Medline for the last 20 years was carried out; 48 sources of literature were analyzed.Results. The analysis of literature has shown that the evolution of both contact lenses and contact lens care products has tightened the control over the safety of wearing. We have studied not only the composition and characteristics of each component of contact lens care and disinfection systems, but also the properties of the eye microbiome and its changes whilst wearing contact lenses. It is noted that under otherwise equal conditions, peroxide systems for contact lens care provide more reliable protection against contamination of all types of lenses, as well as ensure a better disinfection, protecting the eye from possible microbial, toxic and allergic complications. We also analyzed patients’ behavior and identifid their concerns during the COVID-19 pandemic.Conclusion. The patient’s choice of a lens care product must be approved by contact lens specialist and ophthalmologist. Contact lens care products should ensure perfect cleaning, maximum disinfection, hydration and be compatible with lens materials; they should be selected taking into account the patient-specifi characteristics of the ocular surface, lifestyle and health condition. It is necessary to continuously educate and inform patients about the importance of lens care products, and special attention should be paid to care during a pandemic for the safe wearing of CL.

Interactions between contact lenses and lens care solutions: Influence in optical properties

PurposeInvestigate changes in optical properties of contact lenses materials (transmittance and reflectance) and lens care solutions (absorption and fluorescence) resulting from its interaction. MethodsFrom an experimental study, triplicate measurements of transmittance and reflectance of five contact lenses (Senofilcon A, Lotrafilcon B, Balafilcon A, Comfilcon A, and Omafilcon A), as well as UV-vis absorption and fluorescence of four lens care solutions (LCS) (ReNu MultiPlus, Biotrue, OPTI-FREE PureMoist, and AOSept Plus), were evaluated before and after 8 h, one day and one week in storage. The outcomes were provided by Shimadzu UV3101-PC UV–vis-NIR spectrophotometer equipped with an integrating sphere, between 200−700 nm, and SPEX-Fluorolog 2 FL3-22 spectrofluorometer. ResultsAll variables exhibited statistically significant differences over time. Comfilcon A showed the lowest ultraviolet radiation (UVR) A & B attenuation. Balafilcon A and Lotrafilcon B displayed a slight suppression of UVR. Senofilcon A was effective in UVR protection and showed less effect on the fluorescence of lens care solutions. Overall, the reflectance decreased after storage (p < 0.05). AOSept Plus absorbance and fluorescence demonstrated lower interactions than multipurpose solutions (MPS), and Lotrafilcon B induced more remarkable changes in optical properties of LCS than the other materials. ConclusionThe findings suggest that optical variables of lens care solutions and contact lenses changed mutually after storage, probably associated with biochemical and biophysical interactions between components and the release of some polymer compounds. These findings can provide additional information about the interaction of CL materials and LCS in clinical behavior.

Tannic acid-modified silver nanoparticles enhance the anti-Acanthamoeba activity of three multipurpose contact lens solutions without increasing their cytotoxicity

BackgroundFree-living amoebae of the genus Acanthamoeba are cosmopolitan, widely distributed protozoans that cause a severe, vision-threatening corneal infection known as Acanthamoeba keratitis (AK). The majority of the increasing number of AK cases are associated with contact lens use. Appropriate eye hygiene and effective contact lens disinfection are crucial in the prevention of AK because of the lack of effective therapies against it. Currently available multipurpose contact lens disinfection systems are not fully effective against Acanthamoeba trophozoites and cysts. There is an urgent need to increase the disinfecting activity of these systems to prevent AK infections. Synthesized nanoparticles (NPs) have been recently studied and proposed as a new generation of anti-microbial agents. It is also known that some plant metabolites, including tannins, have anti-parasitic activity. The aim of this study was to evaluate the anti-amoebic activity and cytotoxicity of tannic acid-modified silver NPs (AgTANPs) conjugated with selected multipurpose contact lens solutions.MethodsThe anti-amoebic activities of pure contact lens care solutions, and NPs conjugated with contact lens care solutions, were examined in vitro by a colorimetric assay based on the oxido-reduction of alamarBlue. The cytotoxicity assays were performed using a fibroblast HS-5 (ATCC CRL-11882) cell line. The results were statistically analysed by ANOVA and Student-Newman-Keuls test using P < 0.05 as the level of statistical significance.ResultsWe show that the NPs enhance the anti-Acanthamoeba activities of the tested contact lens solutions without increasing their cytotoxicity profiles. The activities are enhanced within the minimal disinfection time recommended by the manufacturers.ConclusionsThe conjugation of the selected contact lens solutions with AgTANPs might be a novel and promising approach for the prevention of AK infections among contact lens users.Graphical

Osmolality and pH of commercially available contact lens care solutions and eye drops

PurposeThe physical properties of contact lens care solutions and Eye Drops (ED) may affect initial comfort and dry eye symptomatology in contact lens wearers, although these properties are not always provided by manufacturers. The present study aimed to measure and compare the osmolality and pH of commercially available contact lens care solutions and ED. MethodsForty-four solutions were tested (17 lens care solutions and 27 ED) and classified by the presence and/or combination of the viscosity/lubrication-enhancing ingredients. Solution osmolality was obtained with the Fiske 110 osmometer and pH was measured with a micro-pH 2000. Each measurement was taken ten times, following the manufacturer's instructions, while controlling for room temperature and humidity. Differences between the values of the physical properties of the solutions were analysed by type and viscosity/lubrication-enhancing agent subclassification. ResultsOsmolality ranged from 192.6 ± 2.17 to 364.6 ± 2.88 mOsm/Kg, while pH ranged from 6.35 [6.35–6.26] to 7.99 [7.99–8.00]. A significant difference in the osmolality and pH values of contact lens care solutions and ED was found when classified by type or viscosity/lubrication-enhancing agent (ANOVA and Kruskal-Wallis respectively, both p < 0.001). ConclusionsThe physical properties of some contact lens care solutions and ED are not readily available. The osmolality and pH values of various commercially available lens care solutions and ED vary significantly both by type and viscosity/lubrication-enhancing ingredients.

Microbiome analysis of contact lens care solutions and tear fluids of contact lens wearers: Possible involvement of streptococcal antigens in allergic symptoms related to contact lens wear.

The present study elucidated the pathogenesis of allergic symptoms (AS) related to contact lens (CL) wear by assaying CL care solutions in lens storage cases and tears from subjects with AS using molecular biology techniques. A total of 15 CL storage cases were collected from subjects with AS (n=9) and healthy, asymptomatic control CL wearers (n=6). Bacterial populations in CL care solutions and tears were assayed by culture and 16S rDNA sequencing. Histamine levels in tears were measured by high-performance liquid chromatography. Western blot analysis was performed to identify the bacteria recognized by tear IgE from subjects with AS. No significant differences were found in the culture results between the subjects with AS and asymptomatic subjects. Histamine was detected in 2 subjects with AS. Meta-16S rDNA sequencing identified a cluster of 4 subjects with AS that were distinguished from others by principal coordinate analysis. Detailed population analysis revealed that the abundance of Gram-positive bacteria in the microbiomes of CL care solutions used by the subjects with AS were higher than those of asymptomatic subjects (42.24±9.47 vs. 16.85±22.76% abundance). Among these, Streptococcus was the dominant genus (12.1-18.3% abundance). Tear microbiome analysis revealed that the abundance of Streptococcus in the subjects with AS was significantly higher than that in other subjects (19.02±5.50 vs. 3.08±3.35%, P<0.01). Western blot analysis demonstrated that the tear IgE in all subjects with AS reacted with Streptococcus (100%), but not with Staphylococcus. On the whole, these results provide novel insight into the pathogenesis of AS and identify Streptococcus as an important factor in AS associated with CL wear.

KNOWLEDGE, COMPLIANCE AND COMPLICATION OF CONTACT LENS USAGE AMONG MEDICAL STUDENTS IN UNIVERSITI KEBANGSAAN MALAYSIA MEDICAL CENTRE

Non-compliance to hygienic practices in contact lens wear is regarded as a significant risk factor for contact lens-related complications. Non-compliant behaviour continues to prevent efforts to improve contact lens safety despite advancements in lens materials and care solutions. The objective of this study was to identify the association between knowledge, compliance and complications of contact lens wear. A cross-sectional design was used and contact lens users among medical faculty students were identified and recruited via convenience sampling throughout October 2013 to March 2014. A total of 36 close-ended questions that focused on knowledge level, compliance to standard contact lens practice, and experience of complications were administered. A total of 188 respondents, majority of females (89.4%; n=168) participated in this study. Although majority had good knowledge level (68.1%; n=128) on care and usage of contact lens while only a small number having moderate knowledge (26.6%; n=50) and poor knowledge (5.3%; n=10), most of them were partially compliant (74.5%; n=140) to the recommended contact lens practices. However, a small group was found to be fully compliant (24.4%; n=46) and the rest being non-compliant (1.1%; n=2). There was a significant association between knowledge on contact lens usage and compliance level to standard practices (p=0.0003). In addition, a significant association also existed between compliance level to recommended practices and risk of complications from contact lens usage (p=0.023). Findings of this study showed the positive association between knowledge of contact lens usage and compliance to recommended practices and negative association between knowledge of contact lens usage and complications experienced by contact lens users. By providing basic knowledge on contact lens care and usage via education, improvement on compliance and enhancement of safety of contact lens wear could invariably be achieved.

Different contact lens case treatment methods for the elimination of pathogen biofilms associated with contact lens related microbial keratitis

Objective To investigate the biofilm-forming abilities of pathogens associated with contact lens related microbial keratitis and to compare the efficacies of different treatments in eliminating biofilms in contact lens cases (CLCs). Methods Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans biolm formation in polypropylene CLCs was examined by using a static biofilm formation model, which was incubated at 37 ℃ for 24 hours.According to the CLC treatment methods, the experimental groups were divided into a control group, a room temperature air-drying group, a contact lens care solution soaking group, a heat-drying group and a soaking-heating group.A pathogen colony counting-based serial dilution micro-counting method was applied to evaluate the biofilm elimination efficacies and pathogen killing rates of treatments. Results All four tested strains formed biofilms on the inner walls of the CLC, and the biomasses of S. aureus, P. aeruginosa, E.coli and C. albicans biofilm were (10.78±2.12), (9.19±0.57), (8.03±0.30), and (7.50±0.07)lg CFU/ml, respectively.The S. aureus biofilm biomass was significantly higher than those of the other strains (P<0.05). The biofilm biomasses of all the tested strains in the heat-drying and the soaking-heating groups were significantly lower than those in the control group (all at P<0.05); and the biofilm biomasses of S. aureus and E. coli in the soaking group were significantly lower than that in the control group (all at P<0.05). The heat-drying treatment resulted in a killing rate of (51.76±16.75)% for S. aureus, (68.63±4.43)% for P. aeruginosa, (83.51±13.97)% for E. coli, and (97.13±5.19)% for C. albicans, respectively (F=31.806, P<0.001). Significant differences were observed between the killing rates for each bacterium (all at P<0.05). The E. coli and C. albicans killing rates of the soak-heating treatment were (100.00±0.00) % and (97.79±7.67)%, respectively, and were significantly higher than (81.13±14.86)% of S. aureus and (74.22±11.91)% of P. aeruginosa (all at P<0.05). Conclusions Heating alone or combined with the use of contact lens care solution treatment can improve the pathogen killing rates and effectively eliminate the bacterial and fungal contaminations in CLCs. Key words: Microbial keratitis; Contact lens cases; Biofilm; Heating

Ultrasmall CuS-BSA-Cu3(PO4)2 nanozyme for highly efficient colorimetric sensing of H2O2 and glucose in contact lens care solutions and human serum

This work reports on the synthesis of organic-inorganic hybrid nanoscale materials, CuS-BSA-Cu3(PO4)2. The developed nanoparticles were characterized by various techniques, such as X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis absorption spectrophotometry, Fourier transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The CuS-BSA-Cu3(PO4)2 were successfully applied as artificial colorimetric probes in sensing H2O2, the final outcome of glucose oxidation, and proved to be efficient peroxidase mimics for the catalytic conversion of a chromogenic substrate, 3,3′,5,5′-tetramethylbenzidine (TMB), into a blue colored oxidized product (oxTMB) which can be easily visualized by the naked eye and monitored by a great absorption peak at 654 nm in the UV–vis spectrophotometry. A highly efficient, rapid, sensitive, and selective determination of H2O2 and glucose have been achieved with very low detection limits of 22 nM, and 27.6 nM over 0–8 μM and 0–1000 μM linear ranges, respectively. Compared to CuS-BSA, CuS-BSA-Cu3(PO4)2 exhibited improved peroxidase-like catalytic activity. Based on these observations, the performance of this approach was successfully validated in contact lens care solutions and human serum samples.

Assessment of compliance with contact lens wear and care among university-based population in Jordan

Purposethis survey aimed to assess levels of compliance with contact lens wear and care among university student’s population in Jordan. MethodsAn interviewer-administered questionnaire was used to assess the extent of compliance among contact lens wearers toward contact lens care in a university population. The questionnaire included 12 questions regarding compliance with contact lens care, lens case/solution replacement, general hygiene procedures related to contact lens and adherence to aftercare visits. Results210 contact lens wearers were interviewed. Of the study population 187 (89 %) were females and 23 (11 %) were males. The average age of the study group was 22.35 (± 3.77) years and all the study population were students (undergraduate or postgraduate).The average compliance rate of the study population was 75 %. High level of compliance was noticeable in the following aspects; not sharing lenses with others, not sleeping while wearing lenses, hand washing before lens use and not using water to clean lenses. Moderate level of compliance was reported in the following aspects; showering/swimming with lenses, using lenses longer than recommended replacement schedule and all behaviours related to contact lens care solution. However, low levels of compliance were reported in relation to cleaning and rinsing lens case and adherence to aftercare visits. ConclusionHigh to moderate levels of compliance were reported generally by participants. However, better strategies are recommended to further increase levels of compliance among contact lens wearers in Jordan related to adherence to aftercare visits. While this study is targeted contact lens wearers from a university student’s population, a future study is recommended to include larger sample of contact lens wearers from the general lay population.

The Bio-Tribological Effect of Poly-Gamma-Glutamic Acid in the Lysozyme-Ionic Contact Lens System.

Feeling comfortable is an important issue for contact lens wearers as contact lenses are worn for an extensive period of time. It has been shown that the in vitro friction coefficient of contact lenses is correlated to the degree of in vivo comfort, thus many studies focus on establishing friction testing methods for investigating the friction coefficient of contact lenses or contact lens care solution. We have previously demonstrated the lubricating property of poly-gamma-glutamic acid (γ-PGA)-containing care solution, and it could reduce the high friction coefficient caused by lysozyme. However, the mechanism of how γ-PGA-containing care solution reduces the lysozyme-induced friction coefficient of contact lenses is unclear. We investigated the bio-tribological effect of γ-PGA on ionic contact lenses in the presence of lysozyme by testing load and velocity variations. The ability to remove lysozyme deposition by γ-PGA and viscosity analysis of γ-PGA-containing care solutions were also investigated to understand the potential mechanism. Our results showed that the friction coefficient of γ-PGA-containing care solution with lysozyme was the lowest in both load and velocity variations, and γ-PGA functions distinctly in the lysozyme-ionic contact lens system. We proposed a model of how γ-PGA could reduce the friction coefficient in these two conditions.

Effect of multipurpose care solutions upon physical dimensions of silicone hydrogel contact lenses.

Interactions between contact lens multipurpose solution (MPS) components and the contact lenses with which they are used are both lens and solution dependent. As such, lens dimensional changes may arise after cleaning and immersion cycling in different lens care solutions over different time courses. In this study, the dimensional stability of five planned-replacement silicone hydrogel lenses (lotrafilcon B, comfilcon A, senofilcon A, senofilcon C, and samfilcon A) over 30 cycles in three different MPSs (Biotrue, OPTI-FREE Express, and OPTI-FREE Puremoist) was evaluated. Measurements of diameter, sagittal depth, power, roundness, and center thickness were obtained prior to, during, and after 30 cycles of cleaning and storage. Diameters of all lenses increased when soaked in Express or Biotrue but held the International Standards Organization (ISO) tolerance over the full course of 30 disinfection cycles; however, the diameters of comfilcon A, senofilcon A, senofilcon C, and samfilcon A lenses soaked in Puremoist exceeded ISO tolerance after between 4 and 9 immersion cycles. In contrast, the diameter of lotrafilcon B held tolerance. Similarly, all lenses cycled in Express or Biotrue held tolerance for sagittal depth, while in Puremoist only lotrafilcon B held tolerance. All lenses became less round in all MPSs but held tolerance for both power and central thickness. Given the lack of reported clinical issues with Puremoist when used with lenses other than lotrafilcon B, we propose that it may be appropriate to revisit the ISO test methods and tolerances to determine if they are still applicable for silicone hydrogel lenses.

Prevention of Pseudomonas aeruginosa Biofilm Formation on Soft Contact Lenses by Allium sativum Fermented Extract (BGE) and Cannabinol Oil Extract (CBD).

Two natural mixtures, Allium sativum fermented extract (BGE) and cannabinol oil extract (CBD), were assessed for their ability to inhibit and remove Pseudomonas aeruginosa biofilms on soft contact lenses in comparison to a multipurpose Soft Contact Lens-care solution present on the Italian market. Pseudomonas aeruginosa (ATCC 9027 strain) and Pseudomonas aeruginosa clinical strains isolated from ocular swabs were tested. Quantification of the biofilm was done using the microtiter plate assay and the fractional inhibitory concentration index was calculated. Both forms of Pseudomonas aeruginosa generated biofilms. BGE at minimal inhibitory concentration (MIC) showed inhibition percentages higher than 55% for both strains, and CBD inhibited biofilm formation by about 70%. The care solution at MIC inhibited biofilm formation by about 50% for both strains tested. The effect of BGE on the eradication of the microbial biofilm on soft contact lenses at MIC was 45% eradication for P. aeruginosa ATCC 9027 and 36% for P. aeruginosa clinical strain. For CBD, we observed 24% biofilm eradication for both strains. For the care solution, the eradication MICs were 43% eradication for P. aeruginosa ATCC 9027 and 41% for P. aeruginosa clinical strain. It was observed that both the test soft contact lenses solution/BGE (fractional inhibitory concentration index: 0.450) and the test soft contact lenses solution/CBD (fractional inhibitory concentration index: 0.153) combinations exhibited synergistic antibiofilm activity against most of the studied bacteria. The study showed that BGE and CBD have good effect on inhibition of biofilm formation and removal of preformed biofilms, which makes them promising agents that could be exploited to develop more effective care solutions.