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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.

To determine the antimicrobial efficacy of a povidone-iodine system (PVP-I; cleadew, OPHTECS Corporation, Kobe, Japan), a peroxide system (AOSEPT Plus with HydraGlyde, Alcon, Fort Worth, TX), and a chemical multipurpose system (renu fresh, BauschLomb, Rochester, NY) on contact lens case surfaces that are both in contact and not in contact with the solutions during lens disinfection.The surfaces of the inner walls, underside of the lid, and lens holder (if applicable) of the cases were inoculated with P. aeruginosa ATCC 27853. The cases were disinfected with the solutions as per their manufacturer instructions. After disinfection, the inoculated surfaces were swabbed and the amount of surviving P. aeruginosa was determined. Following this experiment, separate cases were inoculated and disinfected as before. This time the cases were agitated after recommended disinfection time and the amount of P. aeruginosa in the disinfecting solution was quantified immediately, and again after resting for 7 days. Experiments were conducted in triplicate (n = 3).Units are expressed in log CFU. All three solutions significantly reduced P. aeruginosa on direct-contact surfaces (all p0.039). On non-contact surfaces, the reduction of P. aeruginosa in the PVP-I system (pre-disinfection: 6.8 ± 0.5, post-disinfection: 1.0 ± 0.0; p0.001) was significant, but not for the hydrogen peroxide system (pre-disinfection: 6.3 ± 0.6, post: 5.5 ± 0.5; p = 0.194) and the chemical multipurpose system (pre-disinfection: 6.6 ± 0.1, post-disinfection: 5.6 ± 0.8; p = 0.336). After 7 days post-disinfection, no P. aeruginosa regrowth was observed in the PVP-I system (Day 1: 1.0 ± 0.0, Day 7: 1.0 ± 0.0; p = 1) and the chemical multipurpose system (Day 1: 4.2 ± 0.2, Day 7: 1.8 ± 0.9; p = 0.012), however regrowth was observed in the hydrogen peroxide system (Day 1: 3.4 ± 0.6, Day 7: 6.1 ± 0.4; p = 0.003).The PVP-I system was more effective against P. aeruginosa on non-contact surfaces than the hydrogen peroxide system or the chemical multipurpose system and is capable of inhibiting regrowth of P. aeruginosa for at least 7 days post-disinfection.

Purpose this survey aimed to assess levels of compliance with contact lens wear and care among university student’s population in Jordan. Methods An 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. Results 210 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. Conclusion High 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.

Purpose : As inflammation is suggested as a core drive factor for dry eye, in this study the effects of contact lens wear and corneal refractive surgery on inflammatory dry eye were investigated in Korean twenties. Methods : Eighty-one adults (162 eyes) in their twenties who had no ocular disease were evaluated by 'Matrix Metalloproteinase-9 (MMP-9)' test as known biomarker for inflammatory dry eye and 'OSDI/conjunctival hyperemia' test for screening of inflammatory dry eye. We analyzed prevalence and risk factors of inflammatory dry eye based on two inflammatory dry eye tests, and analyzed them using Chi-square test and logistic regression. The statistical significance level was p＜0.050. Results : The prevalence of inflammatory dry eye evaluated by MMP-9 and OSDI/conjunctival hyperemia tests in all subjects was shown 77.15% and 64.31%, respectively. The prevalence of inflammatory dry eye in contact lens wearer group with two tests was 85.23% and 75.00%, respectively, and that in the non-wearer group was 67.57% and 52.70%, respectively. The risk of inflammatory dry eye in contact lens wears was 2.77 times (OR 2.77, 95% CI 1.29~5.99), and 2.69 times (OR 2.69, 95% CI 1.39~5.23) higher than non contact lens wearers, respectively. The prevalence of inflammatory dry eye in corneal refractive surgery group compared with non operative group was not significantly different (p=0.682 and p=0.370, respectively). Conclusion : It was confirmed that the prevalence of inflammatory dry eye in Korean twenties was very high, and the odds ratio of inflammatory dry eye was 2 times higher than contact lens wearers. Therefore, the contact lens care education for contact lens weareres would be necessary to prevent inflammatory dry eye.

Chelsea S Bradley,1 Lindsay A Sicks,1 Andrew D Pucker2 1Illinois College of Optometry, Chicago, IL, USA; 2School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USACorrespondence: Andrew D Pucker Email apucker@uab.edu View the original paper by Dr Bradley and colleagues This is in response to the Letter to the Editor

Nir Erdinest, 1 Naomi London, 2 Nadav Levinger 1, 3 1Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel; 2Private Practice, Jerusalem, Israel; 3Department of Ophthalmology, Enaim Refractive Surgery Center, Jerusalem, IsraelCorrespondence: Naomi LondonNaomi Vision Boutique, 5 Even Israel, Jerusalem, IsraelTel +972 545406646Fax +972 25004333Email imnl4u@gmail.com View the original paper by Dr Bradley and colleaguesA Response to Letter has been published for this article.

Acanthamoeba keratitis is a serious ocular infection which is challenging to treat and can lead to blindness. While this pathogen is ubiquitous and can contaminate contact lenses after contact with water, its habits remain elusive. Understanding this organism’s natural behavior will better inform us on how Acanthamoeba colonize contact lens care systems. Acanthamoeba trophozoites were allowed to adhere to either a glass coverslip or non-nutrient agar (NNA) within a flow cell with nutrients (Escherichia coli or an axenic culture medium (AC6)) or without nutrients (Ringer’s solution). Images were taken once every 24 s over 12 h and compiled, and videos were analyzed using ImageJ Trackmate software. Acanthamoeba maintained continuous movement for the entire 12 h period. ATCC 50370 had limited differences between conditions and surfaces throughout the experiment. Nutrient differences had a noticeable impact for ATCC 30461, where E. coli resulted in the highest total distance and speed during the early periods of the experiment but had the lowest total distance and speed by 12 h. The Ringer’s and AC6 conditions were the most similar between strains, while Acanthamoeba in the E. coli and NNA conditions demonstrated significant differences between strains (p < 0.05). These results indicate that quantifiable visual tracking of Acanthamoeba may be a novel and robust method for identifying the movement of Acanthamoeba in relation to contact lens care products. The present study indicates that Acanthamoeba can undertake sustained movement for at least 12 h with and without nutrients, on both rough and smooth surfaces, and that different strains have divergent behavior.

Despite their established disinfection and safety benefits, the use of hydrogen peroxide (H2O2) lens care systems among today's wearers of reusable contact lenses remains low in comparison with multipurpose solution (MPS) use. Multipurpose solution systems, however, present several potential drawbacks that may impact patient outcomes, including the use of chemical preservatives for disinfection, biocompatibility issues, and challenges with respect to lens care compliance. Given their unique composition and mechanism of action, one-step H2O2 systems offer the opportunity to avoid many of the challenges associated with MPS use. This article reviews the evolution of H2O2 lens care systems and examines the current scientific and clinical evidence regarding the relative ease of use, lens and tissue compatibility, disinfection efficacy, and ocular surface safety of H2O2 systems. Evaluation of the available data indicates that in comparison with MPS, one-step H2O2 systems tend to promote more favorable compliance, efficacy, comfort, and ocular surface outcomes for a wide range of contact lens-wearing patients. Based on the current published evidence, the authors recommend that eye care practitioners consider making one-step H2O2 systems their first-line contact lens care recommendation for most wearers of reusable lenses.

While the results of Acanthamoeba testing have been extensively published, laboratories conducting such testing are left to develop their own methods in the absence of a standardized methodology. The wide disparity of methods has resulted in equally inconsistent reported results for contact lens care (CLC) products. This study’s objective was to determine the source of these discrepancies by evaluating basic Acanthamoeba biology and their impact on antimicrobial efficacy testing, including the ability of a recovery method to stimulate a single trophozoite to proliferate. Antimicrobial efficacy testing was conducted using well-published Acanthamoeba strains, storage conditions, and growth-based recovery methods. To identify variables that influence results, test solutions with low Acanthamoeba disinfection rates were utilized to prevent differences from being masked by high log reductions. In addition, single-cell proliferation assays were executed to understand the growth requirements to stimulate trophozoite propagation in two recovery methods. These studies indicated that both nutrient density (>106 CFU) and the length of plate incubation (at least 14 days) could significantly influence the accurate recovery of trophozoites. Together, this study emphasizes the need to understand how Acanthamoeba trophozoites biology can impact test methods to create divergent results.

Purpose To assess the level of compliance related to contact lens (CL) wear in university students in Spain. Methods A web-based questionnaire was distributed to university students through their representatives to assess general demographic information, questions related to CL history, level of compliance with CL care and CL-related complications. Results A total of 266 participants with an average age of 22 (±4.5) years completed the online questionnaire. Only 39.1 % of respondents indicated that they always replace their CLs within the recommended schedule, and 63.6 % indicated that they usually wear their CLs more hours per day than recommended. Surprisingly, 64.9 % of participants reported that they had not been informed about the potential risks of CL wear, and only 20 % indicated that they always comply with follow-up visits, whereas 42.1 % of respondents expose their CL to water frequently. Participants who received proper CL education were more likely to attend aftercare visits (X2(2) = 9.104, p Conclusion A relatively high percentage of university CL wearers displayed some degree of non-compliance, which emphasises the importance of providing accurate and comprehensive CL care guidelines and attending aftercare visits to minimise potential CL-related complications. CL wearers should be provided with clear and unambiguous guidelines to avoid any exposure of CL’s and CL cases to water.

Purpose The 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. Methods Forty-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. Results Osmolality 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 Conclusions The 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.

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 (&gamma, PGA)-containing care solution, and it could reduce the high friction coefficient caused by lysozyme. However, the mechanism of how &gamma, PGA-containing care solution reduces the lysozyme-induced friction coefficient of contact lenses is unclear. We investigated the bio-tribological effect of &gamma, PGA on ionic contact lenses in the presence of lysozyme by testing load and velocity variations. The ability to remove lysozyme deposition by &gamma, PGA and viscosity analysis of &gamma, PGA-containing care solutions were also investigated to understand the potential mechanism. Our results showed that the friction coefficient of &gamma, PGA-containing care solution with lysozyme was the lowest in both load and velocity variations, and &gamma, PGA functions distinctly in the lysozyme-ionic contact lens system. We proposed a model of how &gamma, PGA could reduce the friction coefficient in these two conditions.

The population of soft contact lens wearers is increasing, thus the issues of feeling comfortable and contact lens-induced clinical symptoms are concerned. Both lysozyme deposition and mechanical friction among contact lens and the eye can induce discomfort and eye conditions. Therefore, we characterized our developed preservative-free contact lens care solution on lysozyme adsorption and lubrication. Two distinct lens materials were washed with the care solution after being soaked in lysozyme, as well as were rubbed against the glass in the presence of lysozyme and the care solution for measuring the friction coefficient. Our results demonstrated that the preservative-free contact lens care solution can be applied as a potential lubricant for a specific type of soft contact lenses.

With the increasing incidence of more pathogens that can cause microbial keratitis (MK), it is necessary to periodically reassess disinfection multipurpose solutions testing requirements to ensure that relevant organisms to challenge them are being used. Current testing protocols have included common pathogens such as Pseudomonas aeruginosa, Staphylococcus aureus, Serratia marcescens, Candida albicans, and Fusarium solani but have omitted less common pathogens such as Acanthamoeba. Specifically, Acanthamoeba sp. has recently been identified as a prevalent cause of MK in certain countries. Developing an appropriate protocol for this unique organism presents a challenge, given its two distinct life stages, methods to grow the organism, encystment techniques, and many other parameters that can affect testing outcomes. Therefore, the appropriate combination of these parameters is crucial to developing a protocol that ensures consistent, accurate results. The FDA has recognized the importance of establishing a standardized testing protocol for this pathogen and embarked on research efforts to provide a recommended testing protocol for testing contact lens care products.

Soft contact lenses provide perfect conditions for the breeding of pathogens. The study is a prospective, experimental study, conducted to know the antimicrobial ability of multipurpose contact lens solution against standard strains of Staphylococcus aureus and Pseudomonas aeruginosa by the stand-alone test. The test method is based on the procedures in the ISO 14729 standard primary stand-alone test. Three multipurpose contact lens care solutions commercially available in Mangalore markets, namely, Biotrue (Bausch & Lomb), Opti-Free Replenish (Alcon), and Aquasoft (Stericon Pharma), were tested for its antimicrobial effect in the microbiology lab at Kasturba Medical College, Mangalore. According to this study, the solutions named “Biotrue” and “Aquasoft” met the primary stand-alone and reached the 3log reduction and 5log reduction criteria in the manufacturer recommended time, respectively. No conclusion could be drawn for Opti-Free Replenish since the minimum recommended disinfection time was overnight, whereas it was noted for 6 hr only, and it should have been experimented further. The effectiveness of multipurpose solutions varies against different bacterial species. We have observed that the antimicrobial activity of different solutions varies with respect to time of incubation, and also there was a marked difference in the activity of some solutions against S. aureus and P. aeruginosa. So, it is necessary for the contact lens users to store their lenses in solutions for longer duration of hours. It is also recommended to use solutions that clear the ISO 14729 standards for better health conditions of the eye.

The rise in scleral contact lens (ScCL) use may increase the risk of complications including microbial keratitis. Patient understanding of hygiene as well as care and handling of ScCLs is crucial to prevent the increase of complications. This manuscript presents a review of the modalities and implications of the hygiene and the care of scleral lenses, storage case, and devices. Also, correct application and removal techniques are explained in detail and recommendations on instructions for ScCL wearers and verification of patient compliance are provided. Adverse events are rarely reported in literature but clinicians need to understand how to deliver appropriate information and instruction regarding basic rules of hygiene, contact lens care and handling to patients to prevent and minimize associated infections. It is fundamental that practitioners learn how to impart knowledge to their patients during every encounter including follow up visits regarding proper management and compliance with ScCLs. Also, a dialogue with the patient is essential to develop empathy allowing for greater collaboration and compliance raising the fitting rate, success and patient’s overall satisfaction.

Amac: Kontakt lens ile iliskili enfeksiyonlarin onlenmesi ve goz sagliginin korunmasi icin kontakt lenslerin uygun bakimi cok onemlidir. Cok amacli solusyonlar, yumusak kontakt lenslerin temizlenmesi, durulanmasi, dezenfekte edilmesi ve saklanmasi gibi cesitli amaclar icin kullanilmaktadir. Gerec ve Yontem: Calismamizda ticari olarak satilan cok amacli dort kontakt lens bakim solusyonunun (CAKLBS) etkinlikleri arastirilmistir. Bu amacla, bes bakteri ve bir maya olmak uzere alti mikroorganizma kullanilmis ve dort adet cok amacli kontakt lens bakim solusyonu; ReNu® MultiPlus, Opti-Free® Express, All in One Light, Biotrue ™ degerlendirilmistir. Test mikroorganizmasi olarak S. epidermidis ATCC 35948 (biyofilm olusturan), S. epidermidis ATCC 12228 (biyofilm olusturmayan), Pseudomonas aeruginosa ATCC 9027, Staphylococcus aureus ATCC 25923, S. aureus ATCC 43300 (metisilin direncli) ve Candida albicans ATCC 10231 kullanilmistir. Kantitatif suspansiyon testi yapilmis ve sonuclar EN ISO 14729 bagimsiz test birincil kriterlerine gore degerlendirilmistir. 6 saatlik temas suresi sonunda ortalama log indirgeme degerlerine gore, tum CAKLBS’ ler test mikroorganizmalarina karsi etkili bulunmustur. Sonuc ve Tartisma: Piyasada cesitli ticari CAKLBS tipleri bulunmaktadir. Bu urunlerin antimikrobiyal etkinlikleri, iceriklerinde bulunan antimikrobiyal maddelerin tipine ve konsantrasyonlarina baglidir. Bu calismada, tum CAKLBS' ler, ureticinin tavsiye ettigi temas suresinde test mikroorganizmalarina karsi etkili bulunmustur.

In order to perform the multiple functions of disinfection, cleansing, and storage, preservatives are often added to contact lens care solutions. The disadvantage of adding preservatives is that this often causes various eye conditions. However, lens care solutions would not be able to disinfect in the absence of such preservatives. In addition, comfort is an important issue for contact lens wearers due to the long periods of time they are worn. It has been shown that lower friction coefficients are correlated with increased comfort. We have previously developed a multipurpose contact lens care solution in which poly-gamma-glutamic acid (&gamma, PGA) was the main ingredient. In this study, we investigated the antimicrobial activity and lubricating property of our care solution. We showed that there was a synergetic effect of &gamma, PGA and chlorine dioxide on antimicrobial activity. We also demonstrated that &gamma, PGA functioned as a lubricating agent. Our results provided evidence of &gamma, PGA acting as a multi-functional polymer that could be applied in contact lens care solutions.

Acanthamoeba keratitis (AK) is a serious ocular infection caused by a ubiquitous free-living amoeba, Acanthamoeba. This infection often results in extensive corneal damage and blindness, and is notoriously difficult to cure. While Acanthamoeba is an abundant organism, AK is most associated with contact lens hygiene noncompliance and inadequate contact lens care (CLC) disinfection regimens. Thus, accurate and timely antimicrobial efficacy testing of CLC solutions is paramount. Published methods for antimicrobial efficacy testing of Acanthamoeba trophozoites requires 14 days for results. Presently, alternate and/or rapid methods for evaluating CLC products rarely demonstrate equivalent results compared to commonly-reported methods. Propidium iodide is a cellular stain that can only bind to cells with damaged outer membranes. We evaluated propidium iodide staining as an alternative method for determining the relative antimicrobial efficacy of 11 different CLC products against Acanthamoeba trophozoites. Following exposure to a CLC product, the fluorescence intensity of propidium iodide in an Acanthamoeba population demonstrated a strong correlation to the log reduction determined by established, growth-based Acanthamoeba testing used to evaluate the antimicrobial efficacy of CLC products. Thus, propidium iodide was found to be an effective rapid tool for determining cell death in Acanthamoeba trophozoites following exposure to CLC solutions.

Contact lens (CL) wear has been a viable alternative to spectacle wear for several decades. The interest and desire to wear CLs have been stable in recent years, evidenced by the consistency of new wearers into this category of refractive correction. CLs have become one of the most commonly used medical devices in the market, with more than 40 million wearers in the US. There are many activities in which patients report a preference of CL wear over spectacles (athletics for example). Nearly all patients (even presbyopic patients) have the option of contact lenses today given the expansion of powers and parameters in recent years. Patients eyes are getting dryer as factors of age and the environment. CL materials have improved in recent years in an attempt to meet the challenges of dryer eyes. Despite the improvements in CLs and their care, challenges persist. Patient education, handwashing, compliance with care, and wearing schedule are some of the challenges that providers face in the care of CL patients even today., Video abstract

To determine the efficacy of multipurpose solutions (MPSs) on the removal of cholesterol deposits from silicone hydrogel (SH) contact lens materials using an in vitro model.Five SH lens materials: senofilcon A, comfilcon A, balafilcon A, lotrafilcon A, and lotrafilcon B were removed from the blister pack (n=4 for each lens type), incubated for 7 days at 37°C in an artificial tear solution containing C radiolabeled cholesterol. Thereafter, lenses were stored in a preserved saline solution control (Sensitive Eyes Saline Plus) or cleaned with 1 of the 5 MPSs incorporating different preservatives (POLYQUAD/ALDOX, polyquaternium-1/alexidine, polyquaternium-1/PHMB, and 2 based on PHMB alone) using a rub and rinse technique, according to the manufacturer's recommendations, and stored in the MPS for a minimum of 6 hr. Lenses were then extracted with 2:1 chloroform:methanol, analyzed in a beta counter, and μg/lens of cholesterol was determined.Balafilcon A and senofilcon A lens materials showed the highest amounts of accumulated cholesterol (0.93±0.02 μg/lens; 0.95±0.01 μg/lens, respectively), whereas lotrafilcon A and lotrafilcon B deposited the lowest amounts (0.37±0.03 μg/lens; 0.47±0.12 μg/lens, respectively). For all lens materials, the MPS preserved with POLYQUAD/ALDOX removed more deposited cholesterol than any other test solution; however, the amount of removed cholesterol contamination from the individual contact lenses was only statistically significant for balafilcon A and senofilcon A (P=0.006 and P=0.042, respectively). Sensitive eyes and the other evaluated MPSs showed no significant effect on cholesterol removal (P0.05).Cholesterol-removal efficacy varies depending on the combination of lens material and solution. Only 1 MPS showed a statistically significant reduction of cholesterol deposit for only 2 of the 5 tested lens materials.

Growing number of contact lens discomfort (CLD) and CL dropout incidence rate afflict the development of CL industry. This article analyzes literatures of past 5 years’ on studies of CLD. It reviews the epidemiology and mechanism of CLD, analyzes different characteristics of CLD resulting from CL material, contact lens care system, and wearers. It sketches the relationship between CLD and ocular surface microenvironment, pointing out that CLD is an incompatible status between CL and the ocular surface microenvironment. Literature analysis also reveals that while high-quality optical effect of rigid lens came at the price of unwelcome initial discomfort, soft lens wearing continuously changes the balance of ocular surface microenvironment, leading to time-dependent discomfort. Different components or formulas of contact lens care systems could be transited by CL into ocular surface and induce CLD. Personal features of wearers such as age, gender, race, and psychological state also could be considered as potential CLD risks.

Purpose The aim of this study was to assess the antimicrobial effects of marketed contact lens disinfecting solutions. Methods Using ISO 14729 Stand-Alone Test for disinfecting solutions, bactericidal, fungicidal and amoebicidal assays of eight different contact lens solutions including: ReNu MultiPlus, DuraPlus, Ultimate Plus, OptiFree Express, Kontex Clean, Kontex Normal, Kontex Multisol extra+, Kontex Soak were performed. The efficacy of contact lens solutions was determined against keratitis-causing microbes, namely: Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Fusarium solani and Acanthamoeba castellanii. Results The results revealed that ReNu MultiPlus, DuraPlus and OptiFree Express were effective in killing bacterial and fungal pathogens as per manufacturer's minimum recommended disinfection time. Ultimate Plus was effective against F. solani and MRSA but ineffective against P. aeruginosa, S. marcescens and S. aureus. Of concern however, is that none of the locally formulated contact lens disinfecting solutions from Pakistan, i.e., Kontex Clean, Kontex Normal, Kontex Multisol extra+ and Kontex Soak were effective against any of the keratitis-causing organisms tested. All eight contact lens disinfecting solutions were unable to destroy Acanthamoeba cysts. Conclusions Because such ineffective contact lens disinfection solutions present a major risk to public health, these findings are of great concern to the health officials and to the manufacturers of the contact lens disinfection solutions and effective solutions are needed, along with emphasis on proper hygiene for contact lens care and special guidelines for developing countries regarding the manufacture and storage of contact lens disinfecting solutions.

Purpose Neutrophil-derived extracellular debris has been shown to accelerate bacterial biofilm formation on hydrogel and silicone hydrogel contact lens surfaces compared to lenses inoculated with bacteria alone. The purpose of this study was to evaluate the disinfection efficacy of four standard commercial contact lens cleaning regimens against neutrophil-enhanced bacterial biofilms formed on silicone hydrogel contact lenses. Methods Four reference strains were used: Pseudomonas aeruginosa, Serratia marcescens, Stenotrophomonas maltophilia, and Staphylococcus aureus. Human neutrophils were isolated from peripheral blood by venipuncture. Unworn Lotrafilcon B lenses were incubated overnight in each respective strain with stimulated neutrophils. Contact lenses were then cleaned using one of four contact lens care solutions according to manufacturer instructions. Bacterial viability was assessed by colony counts and confocal microscopy. Volume of residual debris on lens surfaces after cleaning was quantified using IMARIS software. Results All four solutions tested showed effective antimicrobial activity against each bacterial strain; however, substantial amounts of nonviable bacteria and cellular debris remained on the lens surface despite concomitant digital cleaning. Conclusions Necrotic cellular debris that accumulates under the posterior lens surface during wear of an inoculated contact lens is not fully removed during routine cleaning and disinfection. Translational Relevance The accumulation of residual cellular debris on the contact lens surface may contribute to new colonization of the lens and represents a significant risk factor for a contact lens–related adverse event. Additional studies are needed to correlate these findings with risk for corneal infiltrative and/or infectious events in a standard animal model.

Free-living, cosmopolitan amoebae of the Acanthamoeba genus may be the causative agents of Acanthamoeba keratitis (AK) – a progressive, vision-threatening infection of the human cornea described particularly among contact lens wearers. Use of contact lens care solutions, effective against these organisms, is important in preventing AK infections. 3 different strains of Acanthamoeba castellanii of the T4 genotype (Neff strain and two others, isolated from patients with AK) were exposed to 4 selected multipurpose contact lens care solutions available in Poland: Ciba Vision AoSept Plus, Bausch & Lomb ReNu MultiPlus, Alcon Opti-Free, Ciba Vision Solo Care Aqua. No amoebicidal effect was observed. The strongest amoebostatic effect was visible after 24 h of exposition to Opti-Free and ReNu solution and associated with percentage increase of rounded, motionless forms. This is significantly longer than minimum disinfection time recommended by manufacturers of all tested multipurpose solutions. Surprisingly, no clear induction of the encystation process was observed.