Lens Care Solutions Research Articles

Contact lens, case and solution related microbiological evaluation in health care workers and medical students

: To assess the microbial contamination in different types of contact lenses, their storage case, and lens case solutions of healthcare workers: This is a cross-sectional study, conducted over 2 months. 100 contact lenses, their cases, and case solutions were collected from 50 healthcare professionals and students. Individuals filled out a questionnaire on the duration of use, care, and compliance. The samples were subjected to gram staining, KOH mount, and culture with blood and potato dextrose agar.: Out of the 300 collected samples, 30 lenses, 30 lens cases, and 6 lens care solutions showed positive growth. Among these 100 lenses and lens cases, 56 yielded bacterial growth and 4 fungal growth. Predominant bacteria isolated from lenses, lens cases, and their lens care solutions were followed by . 4 lenses and lens cases showed candida albicans. Polymicrobial growth was observed in 2 contact lenses. were isolated from only lenses, and cases, and not solutions. Most of the healthcare workers followed the recommended lens care regimen. The most common organism isolated was followed by , and with few showing the presence of . A similar profile was also noted in the general population. From observations made in our study and similar studies, care on lens case and lens solution hygiene must be emphasized.

Unveiling Generally-ignored Co-substrate Effect of Catalase-inherent Peroxidase Mimic for Self-verifiable Detection of High-concentration Hydrogen Peroxide.

One nanoparticle possessing both peroxidase (POD) and catalase (CAT) activities is a prevalent co-substrate nanozyme system, distinct from the extensively researched cascade nanozyme system. During the sensing of hydrogen peroxide by POD, the impact of CAT is actually ignored in most studies. In this study, the CAT effect on hydrogen peroxide detection is thoroughly investigated based on POD catalysis by finely tuning the relative activity of POD and CAT. It is discovered that the CAT effect can be changed by delaying the injection of chromogenic substrate after adding hydrogen peroxide and that the linear range grows with the delayed time. Then, a theoretical mechanism showed that the time-delay mediated CAT effect magnification does not change the Vmax, but it causes Km to linearly increase with delayed time, consistent with the experiment results. Furthermore, the detection of high concentrations of hydrogen peroxide is successfully realized in contact lens care solutions by utilizing time-delay-mediated POD/CAT nanozyme. On the other hand, its linear range-tunable characteristic is used to produce multiple standard curves, then enabled self-verifying hydrogen peroxide detection. Overall, this work investigates the role of CAT in CAT-inherent POD nanozymes both theoretically and experimentally, and confirms POD/CAT nanozyme's priority in developing high-performance sensors.

Microbial Contamination in Contact Lenses, Lens Care Solutions, and Accessories Among Asymptomatic Soft Contact Lens Users.

Objective This study aimed to evaluate microbial contamination of contact lenses (CL) and their accessories among asymptomatic lens users and identify behavioral risk factors that might exacerbate the said contamination. Methodology Ninety-five asymptomatic soft CL users were recruited. In total, 380 samples were collected from the inner surface of lenses, the base of lens cases, the tip of the multipurpose solution bottle, and the solution itself. All swabs with samples were inoculated onto Columbia 5% sheep blood agar, MacConkey agar, Pseudomonas agar with cetrimide, and Sabouraud dextrose agar. Blood agar, MacConkey agar, and Pseudomonas agar with cetrimide were incubated at 37 °C for 24-48 hours. Fungal growth was investigated on Sabouraud dextrose agar, incubated at 25 °C, and examined daily for three weeks. Microscopic examination, culture-based methods, and biochemical tests were used to identify isolated microorganisms. A self-administered questionnaire on compliance with care and hygiene procedures was completed by each participant. Results The overall microbial contamination of tested samples was 38.7%. The most frequently contaminated items were lens cases (59, 62.1%), followed by bottles (44, 46.3%) and lenses (35, 36.8%). Meanwhile, the lowest incidence of contamination was seen in lens multipurpose solutions (9, 9.5%). The predominant microorganisms recovered were Coagulase-negative Staphylococci (CoNS) (94, 64%) and Gram-positive rods (29, 19.7%). Other identified potential pathogens were Staphylococcus aureus(11, 7.5%), Pseudomonas aeruginosa(5, 3.4%), Escherichia coli(1, 0.7%), andCandida albicans(2, 1.4%). The questionnaire revealed that contact lens users aged 18 to 20 showed a lack of compliance with proper hygienic care for contact lens maintenance. Risk factors such as male gender, smoking, showering, or swimming while wearing CL were related to microbiological contamination in at least one of the samples (P > 0.05). Conclusions The highest degree of contamination with highly virulent pathogens was determined in lens cases owing to insufficient lens care practices among study participants. Noncompliance with the lens cleaning procedures can lead to microbial colonization of the lens and its accessories, prompting inflammatory events in the eyes in the future.

Care practices of contact lens solutions and microbial contamination among wearers in Ghana

PurposeThis study sought to assess contact lens solutions care practices, and their microbial contamination among contact lens wearers in Ghana and to profile their antibiotic susceptibility pattern. MethodsThe study employed a biphasic approach which involved a cross-sectional design that investigated participants’ habits related to care for the solutions with a two-part questionnaire and a microbiological analysis of samples of contact lens care solutions of the participants for microbial contamination. A snowball sampling method provided access to 32 different contact lens wearers in four care facilities in Ghana. In most cases, the participants had no pre-existing familial relationship with each other or with the care facilities. ResultsOut of 32 samples of contact lens solutions, 30 were tested for microbial contamination. A total of 23 (76.67 %) samples of contact lens solution were found to be contaminated with Enterobacter sp. (34.80 %), Pseudomonas sp. (21.70 %), Bacilli sp. (21.70 %), Klebsiella sp. (17.20 %), and Escherichia coli (4.60 %). The duration of solution storage in the open bottle and nonadherence to manufacturer instructions for solution storage showed a statistically significant association with microbial contamination (p ≤ 0.05). ConclusionContact lens care solutions have been found to harbour multiple antibiotic-resistant bacteria that are potentially pathogenic to the corneal surface. The contamination is associated with some unhealthy solution-care practices among wearers.

Electrochemical high sensitive detection of hydrogen peroxide based on platinum-palladium nano-enzyme modified microelectrode

Hydrogen peroxide (H2O2) is widely distributed in living organisms and the environment, and its concentration is closely associated with human health. Therefore, the development of an efficient and sensitive detection method for H2O2 is imperative. In this study, a PtPd nano-enzyme composite was electrodeposited onto a platinum wire microelectrode (ME) using a one-step electrochemical deposition method to fabricate an H2O2 electrochemical sensor (PtPd/ME) with exceptional performance. The successful modification of PtPd on the electrode surface was confirmed by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). Chronoamperometry (i-t) was employed to investigate various technical parameters including sensitivity, detection limit, detection range, reproducibility, and anti-interference capability. The results demonstrate that the sensor exhibits a sensitivity of 11.94 mA M-1 cm-2 with a detection limit of 0.034 μM and a wide linear range from 31.25 μM to 4.15 mM while also demonstrating excellent anti-interference properties. These superior performances can be attributed to the strong catalytic activity towards H2O2 provided by PtPd nanoparticles as well as the fast electron transfer rate facilitated by microelectrodes. Furthermore, this sensor effectively enables real-time monitoring of H2O2 released by ascorbic acid-stimulated vascular endothelial cells and demonstrates its potential for detecting H2O2 in contact lens care solutions. These findings provide valuable insights for food and drug testing, and demonstrate great potential for monitoring key pathological processes within living cells.

Impact of in vitro lens deposition and removal on bacterial adhesion to orthokeratology contact lenses

PurposeThe purpose of this study was to explore the impact of several contact lens (CL) care solutions on the removal of proteins and lipids, and how deposit removal impacts bacterial adhesion and solution disinfection. MethodsLysozyme and lipid deposition on three ortho-k (rigid) and two soft CL materials were evaluated using an ELISA kit and gas chromatography respectively. Bacterial adhesion to a fluorosilicone acrylate material using Pseudomonas aeruginosa with various compositions of artificial tear solutions (ATS), including with denatured proteins, was also investigated. The impact of deposition of the different formulations of ATS on biofilm formation was explored using cover slips. Finally, the lysozyme and lipid cleaning efficacy and disinfection efficacy against P. aeruginosa and Staphylococcus aureus of four different contact lens care solutions were studied using qualitative analysis. ResultsWhile maximum lysozyme deposition was observed with the fluorosilicone acrylate material (327.25 ± 54.25 µg/lens), the highest amount of lipid deposition was recorded with a fluoro-siloxanyl styrene material (134.71 ± 19.87 µg/lens). Adhesion of P. aeruginosa to fluorosilicone acrylate lenses and biofilm formation on cover slips were significantly greater with the addition of denatured proteins and lipids. Of the four contact lens care solutions investigated, the solution based on povidone-iodine removed both denatured lysozyme and lipid deposits and could effectively disinfect against P. aeruginosa and S. aureus when contaminated with denatured proteins and lipids. In contrast, the peroxide-based solution was able to inhibit P. aeruginosa growth only, while the two multipurpose solutions were unable to disinfect lenses contaminated with denatured proteins and lipids. ConclusionBacterial adhesion and biofilm formation is influenced by components within artificial tear solutions depositing on lenses, including denatured proteins and lipids, which also affects disinfection. The ability of different solutions to remove these deposits should be considered when selecting systems to clean and disinfect ortho-k lenses.

Low molecular weight chitosan oligosaccharides form stable complexes with human lactoferrin.

Proteins in tears, including human lactoferrin (HLF), can be deposited and denatured on contact lenses, increasing the risk of microbial cell attachment to the lens and ocular complications. The surfactants currently used in commercial contact lens care solutions have low clearance ability for tear proteins. Chitosan oligosaccharide (COS) binds to a variety of proteins and has potential for use in protein removal, especially in contact lens care solutions. Here, we analyzed the interaction mechanism of COSs hydrolyzed from chitosan from different resources with HLF. The molecular weights (MWs) and concentrations of COSs were key factors for the formation of COS-HLF complexes. Lower MWs of COSs could form more stable COS-HLF complexes. COS from Aspergillus ochraceus had a superior effect on HLF compared with COS from shrimp and crab shell with the same MWs. In conclusion, COSs could bind to and cause a conformational change in HLF. Therefore, COSs, especially those with low MWs, have potential as deproteinizing agents in contact lens care solution.

The Role of Biofilms in Contact Lens Associated Fungal Keratitis.

Biofilm formation is an important microbial strategy for fungal pathogens, such as Fusarium, Aspergillus, and Candida, to establish keratitis in patients wearing soft contact lenses. Despite the well-documented 2006 outbreak of Fusarium keratitis that eventually led to the withdrawal of the Bausch & Lomb multipurpose lens care solution ReNu with MoistureLoc ("MoistureLoc") from the global market, contact lens care systems and solutions currently available on the market do not specifically target fungal biofilms. This is partially due to the lack of recognition and understanding of important roles that fungal biofilms play in contact lens associated fungal keratitis (CLAFK). This review aims to reemphasize the link between fungal biofilms and CLAFK, and deepen our comprehension of its importance in pathogenesis and persistence of this medical device-related infection.

Multi-Target Effect of Aloeresin-A against Bacterial and Host Inflammatory Targets Benefits Contact Lens-Related Keratitis: A Multi-Omics and Quantum Chemical Investigation.

Contact lens-mediated microbial keratitis caused by Pseudomonas aeruginosa and Streptococcus pneumoniae provokes corneal damage and vision loss. Recently, natural phytochemicals have become complementary medicines for corneal destruction. Herein, we aimed to identify multi-targeting Aloe vera-derived phytochemicals capable of inhibiting bacterial and host targets of keratitis through ADME (absorption, distribution, metabolism, and excretion), docking, molecular dynamics (MD) simulation, MMGBSA (molecular mechanics generalized Born surface area) and density functional theory (DFT) investigations. An extensive literature search revealed ExoU, ExoS, ExoT, ExoY, and PLY as virulent bacterial targets. Simultaneously, differential gene expression (DGE) and pathway enrichment analysis-specified host transcription factor (SPI1) influences keratitis pathogenesis. Molecular docking analysis uncovered aloeresin-A as a promising inhibitor against bacterial and host targets, demonstrating strong binding energies ranging from -7.59 to -6.20 kcal/mol. Further, MMGBSA and MD simulation analysis reflect higher binding free energies and stable interactions of aloeresin-A with the targets. In addition, DFT studies reveal the chemical reactiveness of aloeresin-A through quantum chemical calculations. Hence, our findings show aloeresin-A to be a promising candidate for effectively inhibiting keratitis. However, additional research is imperative for potential integration into lens care solutions.

Effect of Contact Lens Solutions in Stabilizing the Activity of Tear Lysozyme.

Interactions between tear proteins and the interfaces of contact lenses can be complex and can influence contact lens wear success. Tear proteins, including lysozyme, function to maintain the balance of ocular surface homeostasis, as evidenced by the effects of its conformation relative to stabilizing the tear film and its potential impact on corneal epithelial cells. Contact lens manufacturers include components in lens care and blister package solutions to help stabilize the tear film and preserve homeostasis. This in vitro study was performed to evaluate the ability of daily disposable contact lens package solutions to stabilize lysozyme and preserve its native conformation under denaturing conditions. Lysozyme was added to contact lens solutions sampled from kalifilcon A, etafilcon A, senofilcon A, narafilcon A, nelfilcon A, verofilcon A, delefilcon A, somofilcon A, and stenfilcon A blister packages, then mixed with the protein denaturant sodium lauryl sulfate. Lysozyme activity was evaluated by adding test solutions to a suspension of Micrococcus luteus. Native lysozyme lyses the Micrococcus luteus cell wall, which decreases suspension turbidity. Stabilization of lysozyme activity was determined by comparing suspension turbidity before and after exposure to test solutions. Lysozyme stabilization was 90.7% for kalifilcon A solution, a statistically significant improvement (p < 0.05) compared to phosphate buffered saline (PBS, negative control). No significant improvement was observed with any other contact lens solution (all lysozyme stabilization < 5.00%). The representative tear protein lysozyme was significantly more stable in the novel kalifilcon A contact lens solution containing multiple moisturizers and osmoprotectants than in PBS or other daily disposable contact lens solutions. The lysozyme activity assay provides mechanistic evidence that the kalifilcon A contact lens solution can stabilize proteins under conditions that typically denature proteins, which may contribute to maintaining ocular surface homeostasis.

A Cascade Enzyme System Integrating Peroxidase Mimic with Catalase for Linear Range Expansion of H2 O2 Assay: A Mechanism and Application Study.

Peroxidase (POD) Nanozyme-based hydrogen peroxide (H2 O2 ) detection is popular, but hardly adapt to high concentration of H2 O2 owing to narrow linear range (LR) and low LR maximum. Here, a solution of combining POD and catalase (CAT) is raised to expand the LR of H2 O2 assay via decomposing part of H2 O2 . As a proof of concept, a cascade enzyme system (rGRC) is constructed by integrating ruthenium nanoparticles (RuNPs), CAT and graphene together. The rGRC-based sensor does perform an expanded LR and higher LR maximum for H2 O2 detection. Meanwhile, it is confirmed that LR expansion is closely associated with apparent Km of rGRC, which is determined by the relative enzyme activity between CAT and POD both in theory and in experiment. At last, rGRC is successfully used to detect high concentration of H2 O2 (up to 10mm) in contact lens care solution, which performs higher assay accuracy (close to 100% recovery at 10mm of H2 O2 ) than traditional POD nanozymes. This study brings up a kind of POD/CAT cascade enzyme system and provides a new concept for accurate and facile H2 O2 detection. Additionally, it replenishes a new enzyme-substrate model of achieving the same pattern with competitive inhibition in enzyme reactions.

Complete Recovery of Acanthamoeba Motility among Surviving Organisms after Contact Lens Care Disinfection

Acanthamoeba keratitis is a sight-threatening infection of the cornea which is extremely challenging to treat. Understanding this organism's responses during contact lens contact and disinfection could enhance our understanding of how Acanthamoebae colonize contact lens cases, better inform us on contact lens care solution (CLC) efficacy, and help us better understand the efficacy required of CLC products. To explore this gap in knowledge, we used Acanthamoeba ATCC 30461 and ATCC 50370 trophozoites to examine Acanthamoeba behavior during and after CLC disinfection. Amoebae were added to sterile aluminum flow cells and flow cell solutions were changed to Ringer's solution (control), or one of four CLCs based on biocides (PHMB, PAPB/Polyquad, Polyquad/Aldox, or Polyquad/Alexidine) for 6 h. Each flow cell solution was then changed to axenic culture media (AC6) for 12 h to determine the behavior of amoebae following disinfection. Distance, speed, and displacement were calculated for each organism. As compared to the control of one-quarter Ringer's solution, each CLC significantly impacted Acanthamoeba motility in both the CLC and AC6 conditions. However, the amoebae challenged with the PHMB CLC traveled a significantly greater total distance than with the other three CLCs, indicating differences in effectiveness between biocides. Furthermore, amoebae regaining motility post-disinfection by CLCs were observed to travel considerable distances and thus could be considered dangerous to ocular health. We determined that while all CLCs produced a substantial or complete cessation of movement vs. the control condition during disinfection, those which relied on the Polyquad biocides were the most effective, and that any amoebae which survived disinfection were able to recover motility. Future examinations of these findings should include direct correlations between motility and viability, and how infectivity and motility may be related.

EVALUATION OF THE EFFICACY OF ANTIMICROBIAL ACTIVITY OF CONTACT LENS CARE SOLUTION

Contact lens care solutions are necessary for proper hygiene of contact lenses. Numerous microorganisms can be transmitted through them, leading to serious eye infections, while blindness can occur in particularly severe cases. A direct link between ocular infections and contact lens care solutions has been proven. Commercial preparations must meet a number of safety and antimicrobial efficacy requirements. This paper presents examinations of antimicrobial efficacy of commercial preparation called LENS CARE. The examinations were carried out according to ISO 14729:2012 standard Stand-alone test. It has been found that commercial preparation LENS CARE within proscribed contact lens care regimen of 8h meets the primary criteria of the Stand-alone test for Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans with the results of 3.4, 3.6 and 1.0 log10 reductions, respectively. If used in accordance with the manufacturer's instructions, the tested preparation has the desired antimicrobial effect against the tested pathogens.

Contact Lens Wear Induces Alterations of Lactoferrin Functionality in Human Tears.

The tear film is a complex matrix composed of several molecular classes, from small metal ions to macromolecules. Contact lens (CL) wear can affect the protein homeostasis of the tear film, by accumulating deposits on the CL surface and/or altering their structural and functional properties. This work investigates the effect of CL wear on lactoferrin (Lf), one of the most abundant tear proteins, known as an unspecific biomarker of inflammation. Tears from eight volunteers were collected and analyzed after alternated periods of CL wear and without CL. The experimental approach is to probe Lf into unprocessed human tears by the peculiar fluorescence emission originating from complex formation of Lf with terbium (Tb3+) at the iron-binding sites. The experimental data indicate that CL wear does not significantly affect the total amount of Lf. On the other hand, Lf affinity for Tb3+ is reduced upon CL wear, suggesting relevant changes in Lf structure and possible alterations of protein functionality. Future studies based on this approach will help define CL features (material, lens-care solution, wearing time, etc.) with minimal effects on tear protein activity, in order to obtain more biocompatible and comfortable devices.

Porphyrin-Containing Metallacage with Precise Active Sites and Super Long-Term Stability as a Specific Peroxidase Mimic for Versatile Analyte Determination.

Inspired by the architecture of single-atom catalysts, where the monodispersed metal atoms are widely distributed but stabilized by various coordination circumstances, the biomimetic design and synthesis of metalloporphyrin-containing nanocages have been demonstrated in this study. The nanocages were fabricated through a coordination-driven self-assembly process, and the Mn(III) porphyrin-based one was found to have exclusively peroxidase-like activity at pH 6.0 with neither oxidase nor catalase-like activity under the routine conditions. Benefiting from this, we demonstrated the wide applicability and convenient usage of an Mn(III)-containing supramolecular nanocage (Mn-PC) in the one-step detection of H2O2, sarcosine, and glucose through various oxidase-involved reactions, with a satisfactory detection limit and eligible specificity. Real samples including H2O2 in lens care solution, sarcosine in human urine, and glucose in human serum were also assayed, showing an adequate recovery rate. Such a specific activity originates from the super-consistent microstructure of each catalytic unit, which means that the active site of manganese porphyrin was "protected" by the confinement of the nanocage. This also helps to sustain the super long-term activity even after 545 days of storage. Furthermore, the intrinsic electronic structure of the Mn(III)-containing supramolecular nanocage endows the ability in electrochemical detection of H2O2 and glucose. Our smart design toward the supramolecular nanocages with a defined structure and quantity contributes to the construction of the ingenious sensing platform and has guiding significance for architectural design of nanozymes.

The Risk Factors and Clinical Features of Acanthamoeba Keratitis: First Time Detection of Acanthamoeba T5 Genotype from Keratitis Patients in Turkey.

The primary aim of this study is to investigate Acanthamoeba in clinical samples of keratitis cases (n = 60), in contact lens (CL) and lens care solutions of asymptomatic CL users (n = 41), and to identify the genotypes in positive samples. The secondary aim is to assess the risk factors and clinical features of Acanthamoeba keratitis (AK) patients. All samples from patients and asymptomatic CL users were examined by microscopy and inoculated in non-nutrient agar plates. PCR was performed using the DNA isolated from corneal scrapings, CL and lens care solution samples. Positive DNA samples were sequenced to determine the genotype of Acanthamoeba. In none of the samples, Acanthamoeba was identified by microscopy, while Acanthamoeba was detected in a patient with keratitis by culture method. However, Acanthamoeba was detected in 11.66% (7/60) of the keratitis patients by PCR. The genotypes of these isolates detected by sequencing were T4 (4), and T5 (3). Acanthamoeba was detected in none of the samples of asymptomatic CL users by any of the three methods. To best of our knowledge, this is the first study to detect T5 genotype in AK patients from Turkey. In addition, the CL use was found to be an important risk factor for AK.

Reduction of disinfection efficacy of contact lens care products on the global market in the presence of contact lenses and cases

ObjectiveSight-threatening infections can be caused by pathogenic micro-organisms colonising the cornea, leading to microbial keratitis (MK). These micro-organisms can be introduced to the eye via improper contact lens use and...

Antiviral Activity of Contemporary Contact Lens Care Solutions against Two Human Seasonal Coronavirus Strains.

Background: Given that reports have suggested SARS-CoV-2 can be transmitted via conjunctiva, the ability of contact lens (CL) care products to reduce the infectiousness of two seasonal human coronavirus (HCoV) (HCoV-229E and HCoV-OC43) surrogates for SARS-CoV-2 was investigated. Methods: Biotrue and Boston Simplus (Bausch&Lomb), OPTI-FREE Puremoist and Clear Care (Alcon), and cleadew and cleadew GP (Ophtecs) were tested. Their ability to inactivate HCoV was evaluated using contact times of 4 and 6 h as well as 1% and 10% of virus inoculum. Results: Non-oxidative systems (Biotrue, Boston Simplus, and OPTI-FREE) did not exhibit a significant log10 reduction compared to controls for the two viral strains for either incubation time (all p > 0.05) when 10% tests were performed. For the 1% test, while Boston Simplus and OPTI-FREE exhibited a significant log10 reduction of both HCoV-229E (after 6 h) and HCoV-OC43 (after either 4 or 6 h incubation), those products showed less than 1 log10 reduction of the two infectious viruses. Oxidative systems based on hydrogen peroxide or povidone-iodine showed a significant log10 reduction compared with the controls for both HCoV-229E and HCoV-OC43 in all tested conditions (all p < 0.01). Clear Care led to virus inactivation to below the limit of quantification for tests performed with 1% of inoculum after 6 h incubation, while cleadew and cleadew GP led to inactivation of the two viruses to below the limit of quantification in all tested conditions. Conclusion: Oxidative CL disinfection systems showed significant virucidal activity against HCoV-229E and HCoV-OC43, while non-oxidative systems showed minimal ability to inactivate the HCoV species examined.

In Vivo Wettability of HydraGlyde® Silicone Hydrogel Lens With and Without HydraGlyde® Containing Lens Care Solution

Contact lens care solutions are readily available over-the-counter at any pharmacy, optical shop, or eye care specialist centers. The use of a non-compatible solution may damage or alter the material of the contact lens, and may cause changes in the efficiency of the lens, thereby reducing comfort of the wearer. Hence, this research was carried out to determine the wettability of HydraGlyde® Silicone Hydrogel lens with and without HydraGlyde® containing lens care solutions. The right eye of 25 subjects (mean age: 22.8 ± 1.3 years old) were studied. The subjects needed to come for two visits [1 week apart] at approximately the same time of the day. Each subject received the pre-soaked lenses with and without HydraGlyde® Moisture Matrix randomly. The subjects wore the lenses for 8 h. Non-Invasive Tear Breakup Time (NIKBUT) was measured using OCULUS® Keratograph 5M, followed by a subjective questionnaire response.Parametric paired t-test showed no significant differences in PLTF NIKBUT baseline (16.25 ± 3.75 s)and after 8 h of lens wear (15.02 ± 3.81 s) when lenses soaked in a solution with HydraGlyde® Moisture Matrix (p &gt; 0.05). However, a significant difference was found in PLTF NIKBUT baseline (16.16 ± 2.79 s), and after 8 h of lens wear (14.74 ± 3.73 s) when lenses were soaked in a solution without HydraGlyde® Moisture Matrix (p &lt; 0.05). The change in the PLTF NIKBUT baseline and after 8 h of lens wear for the solution with and without HydraGlyde® Moisture Matrix (−1.23 ± 3.89 s and 1.68 ± 3.58 s respectively) were not statistically significant (p &gt; 0.05). The subjective questionnaire revealed a preference towards a solution with HydraGlyde® Moisture Matrix with a mean score of 68.84 ± 15.36% compared to without HydraGlyde® Moisture Matrix with a mean score of 62.80 ± 14.00% (p &lt; 0.05). A lens care solution con-taining HydraGlyde® Moisture Matrix is advised to be prescribed along with HydraGlyde® silicone hydrogel lens to achieve optimum lens performance.

Bacterial isolates and their biofilm formation on contact lenses

Using contact lenses without proper care and sterilization measures can lead to eye infection like keratitis and other eye diseases. About 25-30% of cases with corneal ulcers are related to contacts lens use. Microbial agents after their entry, they further invade into corneal layers by their virulence factors and enzymatics secreted by the bacteria. Wearing contact lenses also increase stress on cornea so the cornea has less ability to defend against the bacteria which is invading. Some of the bacteria are also capable of biofilm formation. Biofilms formed on contact lens surfaces has increased resistance to common steriliants used in contact lens care solution. The main aim of this study is to identify the pathogens that can be grown on the contact lenses and contact lens cases, to identify the production of biofilm by the isolates obtained during this study and to bring awareness about proper sterilization of contact lenses and lens cases during their usage to prevent unnecessary eye infections. This cross sectional study was carried from October 2019 to June 2021 on MBBS and BDS students in Konaseema Institute of Medical Sciences and Research Foundation, who are using contact lenses and who are asymptomatic. Written consent from all students participating in this study was taken. The samples are collected using sterile swabs. Swabs from both the lens and lens cases are taken and immediately cultured and related biochemical tests are done to identify the organism. For the study of biofilm formation, the bacterial isolates obtained from the specimen are inoculated on to commercially available Congo red agar (CRA). The data was processed and arranged into distribution tables and cross tables using statistical package for the social sciences (SPSS) version 21. Total 200 samples were collected and processed for bacterial culture. Among them 145(72.5%) samples showed positive bacterial culures. The most common organisms obtained are which were 30 (20.6%), next common organism isolated were micrococci 24(16.5%), though ASB’s and micrococci are non pathogenic, these were included because the lens and lens cases are preferably to be sterile. The other organisms isolated are 21 (14.4%), 18 (12.4%), 16 (11.04%), 12 (8.2%), 10 (6.9%), 8 (5.5%) and 6 (4.2%). The isolated bacteria are then again streaked on Congo Red Agar to check for the ability of the bacterial isolates to form biofilms. Among 145 bacterial isolates obtained in this study 98 (67.5%) samples showed positive biofilm formation. The micro organisms can lodge in most of the contact lenses and contact lens cases… which in turn enter into eye due to improper sterilization of lens and lens cases. And most of the bacterial isolates obtained from these contact lenses and contact lens cases are capable of production of biofilm. To avoid infections caused by contact lens users the care of both the contact lenses and lens cases is very important.