Search

Purpose: To investigate the physical properties of commercially available multipurpose soft contact lens solutions in Ghana. Methods: pH (Kelilong ICL-099 pH meter, China), osmolality (OSMOMAT 3000, GONOTEC, Germany), surface tension (Sigma 700 Tensiometer, Sweden), and viscosity (CFOC-200 Viscometer, Cannon Company, USA) of various soft contact lens multipurpose solutions (MPS) were measured in triplicates at room temperature. Viscosity measurements were also taken at 34 °C ocular surface temperature. The solutions examined were Opti-Free Replenish (OFR), Trufresh (TF), Avizor (AV), Freshlook (FL), and Refresh (RF). Results: Several solutions were largely hypo-osmotic in the range of 108–231 mOsm/kg, the exception being Avizor, which had osmolality values that were closer to human tears (301 ± 0.58 mOsm/kg). The range of pH values of the solutions (6.33–8.24, mean (SD) = 7.53 ± 0.18) fell within the reported tolerable range for the ocular surface (6.20–9.00). Surface tension values ranged from 35.86 to 42.27 mNm with a mean of 38.49 ± 2.32 mNm. The average viscosity of most solutions at room temperature (25 °C) was 1.44 ± 0.49 cP with a range of 1.04–2.15 cP. Significantly lower values ranging from 0.79 to 1.58 cP were obtained at ocular surface temperature (34 °C), p = 0.0001). Conclusions: The physical properties of many of the solutions used as MPS in Ghana are markedly variable. Nevertheless, pH, surface tension, and viscosity fall within the acceptable limits of ocular physiological tolerance; except for osmolality, which majority were outside the reported tolerable range for the ocular surface. This information may partly explain the reason some patients exhibit strong preferences for certain care systems and should aid clinical decision-making when prescribing eye care systems to patients.

Objective: Despite the increasing prevalence of contact lens (CL) wear, knowledge and compliance with proper care remain suboptimal. This study aims to assess the level of knowledge and compliance with lens care practices in patients attending a third-level institution in Northeast Mexico., Methods: A cross-sectional study using a self-administered online survey was conducted. Patients at the Instituto Tecnolgico de Monterrey were invited to participate. The questionnaire consisted of three sections: demographic data and CL information, CL practices, and CL care knowledge. Participants responding correctly to 6/7 questions from the second and third sections were classified as having good compliance and good knowledge, respectively. Predictive factors for good compliance and knowledge were calculated using a logistic regression model., Results: A total of 287 users participated in the study. The median age was 25 (14-78) years with a female (n = 221, 77 %) predominance. Good knowledge was observed in 215 (74.9 %), whereas only 42 (14.6 %) presented good compliance. Failing to replace CL as prescribed (n = 199, 69.3 %) and sleeping with the devices (n = 198, 69 %) were the most frequent practices causing non-compliance. Whereas prohibition of swimming with CL was the least known practice (n = 74, 25 %). Users with recent (≤5 years) wearing experience were more likely to present good knowledge (OR 2.19, p = 0.014) and compliance (OR 3.15, p < 00.01). No statistical correlation was established between knowledge and compliance., Conclusion: Non-compliance and lack of knowledge of proper CL care were prevalent among in this population. Long-term CL users were at higher risk of non-compliance and lack of knowledge. Moreover, knowledge was not related to compliance; therefore, different strategies must be implemented to reduce CL misconduct., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: Biofilm formation caused by infrequent contact lens case replacement and the ineffectiveness of multi-purpose solutions (MPS) on biofilm removal is associated with high rates of bacterial keratitis infections. This study demonstrated biofilm elimination from the contact lens case by microwave irradiation., Methods: Staphylococcus aureus biofilms indicative of 3-9 months of contact wear were cultured in contact lens cases and visualized with crystal violet (CV) staining. Biofilms in contact cases were then exposed to four treatment regimens: No treatment (n = 8), 45 s microwave irradiation (n = 8), tap water (n = 6), and MPS (n = 9). Bacterial survival was assessed by colony forming unit (CFU) assay using streak dilutions., Results: Visualization of the biofilms through CV staining revealed that biofilms coalesce between ribs of the contact case. In 5/8 cases no CFU were cultivated from the case after treatment with microwave irradiation. In tap water and MPS the first dilution averaged 6 ± 2 and 31 ± 13 CFUs per plate, respectively, while microwave irradiation averaged < 1 CFU per plate. In Dilution 2, the average reduced to 0.7 ± 0.7 and 6 ± 5 CFUs per plate for tap water and MPS, respectively, while microwave irradiation had 0 CFUs in Dilution 2., Conclusion: Biofilms that coalesce between the ribs of the contact case pose a threat because this area is difficult to thoroughly scrub and could act as a basis for infection through fouling of contact lenses. Of the four treatment regimens, microwave irradiation displayed the most consistent and highest rate of bacterial eradication. Tap water was less effective compared to microwave irradiation, and poses other harmful side effects, but greatly reduced CFU count compared to no treatment. MPS displayed the poorest bacterial eradication of the treatments. Thus, microwave irradiation is worth further investigation as a viable in-home disinfecting option., (Copyright © 2021 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To document contact lens prescribing trends in the United Kingdom over the past quarter of a century., Methods: An 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., Results: Over 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., Conclusions: This 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., (Copyright © 2021 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

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 1 H 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., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: Ocular manifestations and ocular transmission of SARS-CoV-2 in contact lens (CL) wearers may be fostered by non-compliance with care and maintenance instructions which, in turn, may be aggravated by inadequate patient-practitioner communication. The purpose of this research was to determine CL use, compliance and patient-practitioner communication during a 3-month long COVID-19 lockdown in Spain., Methods: An online survey (developed using Google Forms) retrospectively evaluated CL compliance during the 3-month lockdown (responses captured between 15th July and 10th August, 2020), with particular emphasis on patient-practitioner communication, handwashing practices and CL case hygiene and replacement., Results: A total of 247 responses were collected and analysed. Most participants used monthly replacement soft lenses (64.8 %) and multipurpose solutions (75.7 %), with 86.6 % of them owning a storage case for their lenses. During lockdown, a significant percentage of participants ceased lens wear (28.4 %) or reduced wearing time (49.2 %). Regarding patient-practitioner communication, 54.3 % of respondents received specific instructions, mostly about handwashing (93.3 %) and storage case hygiene (48.5 %). The most frequent non-compliant practices were inadequate handwashing (36.4 %), and overextending monthly or two-weekly replacement lenses (35.2 %). Many respondents never cleaned (23.0 %) nor replaced (16.3 %) their storage case, and 27.8 % of them reported not having been informed about case hygiene by their practitioners., Conclusion: Contact lens compliance, particularly in terms of handwashing and storage case hygiene, was poor during a prolonged COVID-19 lockdown, thus stressing the need to foster patient-practitioner communication strategies to curtail the possibility of ocular transmission and the risk of virus tropism., (Copyright © 2021 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To compare lens cleaning routines using a povidone iodine-based rigid lens disinfecting solution and its effect on conjunctival colonisation, and lens and lens case contamination., Methods: Participants, aged 6-10 years, receiving orthokeratology treatment were randomised to four lens cleaning routines: with and without the use of daily and/or weekly cleaners, which were performed by their parents. Conjunctival colonisation was compared before lens wear and at 1-, 3-, and 6-month after commencement of lens wear. Contamination of lenses and lens cases was investigated at these times. Organisms were identified using MALDI-TOF mass spectrometry., Results: Of the 76 participants who completed the study, conjunctival colonization was present in 24 (32 %) at baseline. Of the remaining 52 participants, 34 consistently yielded no growth. Participants positive at baseline were statistically more likely to be colonized after commencement of lens wear (p = 0.020). Overall, colonization rate was reduced to 15 % (11/72) after 6-month lens wear, which reached significance for initially colonized participants (p < 0.001). Few cultures yielded potential ocular pathogens, with notably no Pseudomonas aeruginosa. Contamination rates of both lenses and lens cases were also low, with few isolations of ocular pathogens. No significant differences were observed between cleaning regimes for conjunctival colonization or contamination of lenses or cases., Conclusions: Disinfection for rigid and ortho-k lens wearers may be effectively achieved with the use of povidone iodine-based solution, apparently regardless of cleaning routine adopted in the current study. The absence of pathogens in the conjunctiva, lenses, and lens cases in the great majority of samples indicates that it can improve the safety of overnight lens wear., (Copyright © 2021 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: Investigate changes in optical properties of contact lenses materials (transmittance and reflectance) and lens care solutions (absorption and fluorescence) resulting from its interaction., Methods: From 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., Results: All 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., Conclusion: The 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., (Copyright © 2021 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Reusable soft daily wear contact lenses (CLs) remain popular and were fit to just over half of all wearers in the most recent international CL prescribing survey. Unlike daily disposable CLs, reusables require cleaning and disinfecting after every use, along with storage in a CL case. These additional requirements add a number of steps to the daily wear and care routine, increasing the opportunities for CL wearers to exhibit non-compliant behaviour. The impact of non-compliance ranges from poor lens comfort through to potentially sight-threatening infective keratitis. The coronavirus pandemic has refocused the profession on the importance of hand hygiene in particular, and the need for promoting safe CL wear in general. This review summarises typical non-compliant behaviour related to reusable CLs, and examines strategies and opportunities to better support wearers. Patient education has a central role in encouraging compliant behaviour, although patient recall of information is low, and personal belief systems may result in continuation of non-compliant behaviour despite awareness of the risks. CL care solutions are required for the daily disinfection of lenses, however misuse of multipurpose solutions (MPS) and hydrogen peroxide (H 2 O 2 )-based care systems can challenge their ability to be fully efficacious. Standard efficacy testing is reviewed, with consideration of how well current protocols model real-world use of CL solutions. Although some recommendations are in place for the inclusion of additional variables such as lens cases, CL materials, organic soil and efficacy against Acanthamoeba, opportunity still exists to reevaluate global standards to ensure consistency of testing in all markets. Finally, potential future innovations are discussed which may further support increased safety in reusable lens wear through novel antimicrobial additions to both CL materials and cases., (Copyright © 2021 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Aim: To establish contact lens wear and care practices during the COVID-19 pandemic in Spain., Method: A 58-item anonymous online survey was distributed during the period 30th April to 10th May via Qualtrics. The survey explored: a) demographic characteristics (age, sex, general health and where they were living during lockdown), b) changes in their contact lens use during lockdown, c) hygiene and contact lens compliance and d) concerns associated with contact lens wear and ways to support wearers during the pandemic., Results: Two hundred and sixty responses were analysed (38.8 ± 11.4 years old, 75% female). Three-quarters of participants reported that they were self-isolating or rigorously following social distancing advice. Sixty-seven percent of participants reported using their contact lenses less during the pandemic. Respondents were found to be compliant with handwashing prior to inserting and removing contact lenses (in both cases 97% doing this 'most times' or 'every time'). However, only 44 % complied with the '20 s rule' and 48 % used a shared towel to dry their hands. A higher proportion of hydrogen peroxide users replaced the lens case monthly compared to multi-purpose users (64% vs.49%; p < 0.001). Twenty-four percent admitted wearing lenses whilst showering and 16% did not consider ceasing lens wear if feeling unwell with flu/cold symptoms., Conclusion: Eye care practitioners should continue to educate contact lens wearers to ensure safe contact lens wear to minimise the chance of developing contact lens related complications during the pandemic. Modifiable factors that need particular attention in Spain include: handwashing for at least 20s before lens handling, drying hands with single use paper towels, including a rub-and-rinse step for reusable lenses, lens case cleaning and renewal, avoidance of water exposure and when to cease lens wear during the pandemic., (Copyright © 2020 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

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 < 0.001)., 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., (Copyright © 2020 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Aim: Contact lens wearers need to maintain optimal hygiene practices during the COVID-19 pandemic to minimise contact-lens complications including microbial keratitis and corneal infiltrative events. This online survey (UK and Ireland) explored contact lens wearers' compliance behaviours, attitudes and concerns during the pandemic., Method: The 60-item anonymous online survey was distributed during a 1-month period via Qualtrics (starting on 14/04/20). The survey captured: a) demographic information, b) type of lenses worn and compliance with lens wear and care procedures, c) adherence to recommendations and d) concerns associated with contact lens wear during the pandemic., Results: Two hundred and forty seven responses were received (34.3 ± 11.7 years old, 79% female). Seventy nine percent of participants reported that they were self-isolating or rigorously following social distance advice. Fifty-six percent of participants reported using their lenses less during the pandemic. Eighty-seven percent of respondents reported following the recommended 20-second rule most times/every time and 96% used soap and water during handwashing. Eleven percent of respondents admitted not following recommendations regarding disposal of lenses and 18% would not consider ceasing lens wear if unwell (with flu/cold) during the pandemic., Conclusion: Respondents reported wearing their contact lenses less than usual. Good compliance with handwashing was observed but soft reusable lens wearers showed a statistically significant lower compliance with lens wear and care compared to daily disposable lens wearers (p=<0.001)., (Copyright © 2020 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: This study examined the rate and level of microbial contamination of silver and non-silver (control) barrel contact lens storage cases in vivo., Methods: A prospective, single-centre, randomized, double blinded, crossover study was conducted to evaluate the efficacy of silver and control barrel cases used with an Oxipol™-based disinfecting solution over a two-month period. Lens cases were collected, and the frequency, type and level of microbial contamination evaluated using viable culture and standard identification methods. Questionnaires were used to assess the contact lens-related hygiene compliance of the participants., Results: Forty eight daily contact lens wearers completed the study. Overall, 27 % of silver and 35 % control lens cases (P > 0.05) were contaminated, predominantly with Gram-positive bacteria. Only, 12 % of participants had good compliance, with 46 % having average compliance and 43 % poor compliance. Compliance score was not associated with level of microbial contamination. However, the use of hydrogel lenses in combination with silver cases compared to non-silver barrel cases resulted significantly greater numbers of bacteria colonising cases., Conclusion: The present investigation demonstrated that the use of silver barrel cases does not reduce the overall rate and level of bacterial contamination, but that using hydrogel lenses in combination with silver cases resulted in higher numbers of bacteria isolated from cases., (Copyright © 2020 British Contact Lens Association. All rights reserved.)

Purpose: To investigate the interaction of a novel low molecular weight hyaluronic acid derivative containing hydrophobic groups with soft contact lenses and its effect on lens hydrophilicity compared with a conventional form of hyaluronic acid., Methods: This investigation studied the uptake of fluorescently-labelled hyaluronic acid and a low molecular weight hyaluronic acid derivative to four types of contact lenses using fluorescent microscopy and confocal laser scanning microscopy. Further, the four lens types were used to compare efficacy in improving hydrophilicity, as well as maintenance of contact angle measurements, in commercially available multipurpose solutions that contained either hyaluronic acid, the low molecular weight hyaluronic acid derivative, or an alternative wetting agent., Results: The low molecular weight hyaluronic acid derivative was found to sorb more readily to silicone hydrogel lenses and exhibit a greater accumulation over time than conventional hyaluronic acid. Multipurpose solutions containing the low molecular weight hyaluronic acid derivative showed an increase in lens hydrophilicity through decreases in contact angle measurements when compared with those obtained from lenses treated with multipurpose solutions containing conventional hyaluronic acid or alternative wetting agents. This increase in lens hydrophilicity associated with the low molecular weight hyaluronic acid derivative was also maintained over multiple cycles in phosphate buffered saline, while alternative solutions with conventional hyaluronic acid did not., Conclusion: Overall, lens treatment using a low molecular weight hyaluronic acid derivative-based solution lead to improved in vitro lens hydrophilicity., (Copyright © 2020 British Contact Lens Association. All rights reserved.)

Purpose: To demonstrate an alternative to the rinse and rub (RR) method for cleaning pollutants from the exterior surface of soft contact lenses. This proposed technique is termed Polymer on Polymer Pollutant Removal (PoPPR), which utilizes the elastic properties of polydimethylsiloxane (PDMS) to physically remove contaminants from contact lens surfaces through non-adhesive unpeeling., Methods: Three different ratios of setting agent to polymer PDMS (1:30, 1:40, and 1:50) were evaluated using the PoPPR method against the control method of RR with a commercial multi-purpose lens cleaning solution. Three simulated pollutants of different sizes: pollen (25-40 μm), microbeads (1-5 μm), and nanoparticles (5-10 nm), were used to test the effectiveness of both cleaning methods. The fraction of pollutants removed from each contact lens was recorded and evaluated for significance., Results: PDMS 1:40 was found to be the optimal ratio for lens cleaning using the PoPPR method. For larger particles (>10 μm), no difference was observed between conventional RR and proposed PoPPR method (p > 0.05). However, the new PoPPR technique was significantly better at removing small PM 2.5 particles (<2.5 μm) compared to the RR method, specifically for microbeads (p = 0.006) and nanoparticles (p < 0.001)., Conclusion: This proof-of-concept work demonstrates that the PoPPR method of cleaning contact lenses is as effective as the conventional cleaning method for larger particles such as pollen. The PoPPR method is more effective at removing extremely fine particulate pollutants, including microplastics and nanoparticles. This method offers a potentially more efficient cleaning protocol that could enhance the safety, health, and comfort of contact lens users, especially those living in regions with significant air pollution., (Copyright © 2020 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: 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, Bausch & Lomb, Rochester, NY) on contact lens case surfaces that are both in contact and not in contact with the solutions during lens disinfection., Methods: 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)., Results: Units are expressed in log CFU. All three solutions significantly reduced P. aeruginosa on direct-contact surfaces (all p < 0.039). 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; p < 0.001) 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)., Conclusion: 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., (Copyright © 2020 British Contact Lens Association. All rights reserved.)

Purpose: To compare the sensitivity of two genotypes of P. aeruginosa to various disinfectant solutions and analyze the attached bacteria on worn cosmetic contact lenses (cosCLs)., Methods: In this prospective study, healthy volunteers wore etafilcon (brown), nelfilcon (gray), or hilafilcon (black) cosCLs and microbial adhesion analysis was performed. A rub-off test determined pigment dislodgement. Disinfectant sensitivity to Optifree Replenish (Alcon), Optifree Pure Moist (Alcon), Renu Fresh (Bausch & Lomb), and AoSept Plus (Ciba Vision) was tested at various disinfection times and compared between various genotypes and Type III secretion (T3S) system mutants., Results: Of the 1152 cosCLs collected, 364 were culture positive (32%). The highest rate of culture-positive lens was hilafilcon (chi square, P = 0.0001). Hilafilcon also had a significantly greater number of isolates than etafilcon (P < 0.0001). Hilafilcon was the only lens to fail the rub-off test. Cytotoxic strains were significant more resistant to Renu Fresh than were invasive strains, even at 100% of recommended disinfection time (P = 0.0005). Of the tested disinfectants, Renu Fresh was significantly less effective in killing both genotypes of P. aeruginosa compared to AoSept Plus at all time points (25%, 50%, 75%, and 100% recommended disinfection time, P = 0.0001, 0.0001, 0.0005, and 0.0005, respectively). When the T3S system was dysfunctional, mutant strains were all susceptible to disinfectants (P = 0.0001 for both invasive and cytotoxic strains)., Conclusion: Pseudomonas species is commonly found on cosCLs of asymptomatic individuals. Wearers of cosCLs that dislodge pigments may be predisposed to microbial contamination. Cytotoxic strains are more resistant to disinfectant solutions, especially to Renu Fresh. P. aeruginosa disinfectant resistance requires a functional T3S system., Competing Interests: Declaration of Competing Interest The authors have no proprietary or commercial interest in the research presented herein., (Copyright © 2019 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: This study investigated the efficacy of pre-conditioning lens cases on bacterial biofilm formation and removal., Methods: Silver impregnated (MicroBlock / ProGuard™ & i-Clean) and control storage cases were pre-conditioned for 24 h with their respective multipurpose solutions (MPDSs). Cases were then inoculated with 2 ml of 10 6 CFU/mL of ocular isolates of either P. aeruginosa or S. aureus and incubated for 48 h. Cases were subsequently disinfected (4-6 hours) as per the manufacturer's recommended disinfecting time (MRDT) followed by the recommended case hygiene procedures - recapping wet (MicroBlock / ProGuard™ cases only) or rinse and air-dry or rinse, tissue-wipe and air dry (mechanical disruption). Surviving bacteria were enumerated using standard techniques., Results: Pre-conditioning the MicroBlock / ProGuard™ cases with MPDS significantly reduced biofilm formation (-1.1 log 10 CFU, p < 0.01 for P. aeruginosa & -1.3 log 10 , p < 0.001, CFU for S. aureus) compared to the i-Clean lens cases. Maintaining the MicroBlock / ProGuard™ lens cases wet after the MRDT resulted in partial removal of bacterial biofilms (-2.9 log 10 CFU, p < 0.001 for P. aeruginosa and -2.6 log 10 CFU, p < 0.001 for S. aureus). Air-drying of all three types of lens storage cases after MRDT significantly reduced the bacterial biofilm (-5.4 log 10 CFU, p < 0.001 for P. aeruginosa and -3.5 log 10 CFU, p < 0.001 for S. aureus). Mechanical disruption produced the greatest reduction in the levels of bacterial biofilm in all 3 types of lens cases tested (-6.8 log 10 CFU, p < 0.001 for P. aeruginosa and -4.5 log 10 CFU, p < 0.001 for S. aureus). Synergi MPDS was significantly better than AQuify MPDS in removing bacterial biofilm from all 3 lens case types for case hygiene treatments with an air-drying step., Conclusion: Pre-conditioning of silver-impregnated ProGuard™ lens cases inhibited initial bacterial biofilm formation. Synergi MPDS was more effective than AQuify MPDS in removing bacterial biofilm in silver impregnated cases and tissue-wiping significantly improved biofilm removal., (Copyright © 2019 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2020 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

A novel coronavirus (CoV), the Severe Acute Respiratory Syndrome Coronavirus - 2 (SARS-CoV-2), results in the coronavirus disease 2019 (COVID-19). As information concerning the COVID-19 disease continues to evolve, patients look to their eye care practitioners for accurate eye health guidance. There is currently no evidence to suggest an increased risk of contracting COVID-19 through contact lens (CL) wear compared to spectacle lens wear and no scientific evidence that wearing standard prescription spectacles provides protection against COVID-19 or other viral transmissions. During the pandemic there will potentially be significant changes in access to local eyecare. Thus, it is imperative CL wearers are reminded of the steps they should follow to minimise their risk of complications, to reduce their need to leave isolation and seek care. Management of adverse events should be retained within optometric systems if possible, to minimise the impact on the wider healthcare service, which will be stretched. Optimal CL care behaviours should be the same as those under normal circumstances, which include appropriate hand washing (thoroughly with soap and water) and drying (with paper towels) before both CL application and removal. Daily CL cleaning and correct case care for reusable CL should be followed according to appropriate guidelines, and CL exposure to water must be avoided. Where the availability of local clinical care is restricted, practitioners could consider advising patients to reduce or eliminate sleeping in their CL (where patients have the appropriate knowledge about correct daily care and access to suitable lens-care products) or consider the option of moving patients to daily disposable lenses (where patients have appropriate lens supplies available). Patients should also avoid touching their face, including their eyes, nose and mouth, with unwashed hands and avoid CL wear altogether if unwell (particularly with any cold or flu-like symptoms)., (Copyright © 2020 British Contact Lens Association. All rights reserved.)

Purpose: To evaluate soft contact lens replacement, overnight (ON) wear, and contact lens case compliance in a non-clinical sample., Methods: Subjects (n = 297) were recruited at the Center for Science and Industry (COSI) in Columbus, Ohio. Adult (≥ 18 years) soft contact lens wearers completed a survey about contact lens replacement, ON contact lens wear, and contact lens case replacement habits., Results: Two-week replacement lenses (according to the manufacturer's replacement schedule [MRS]) were most common (45.5%), followed by monthly (34.3%) and daily replacement (20.2%). Non-compliance with replacement schedule was reported in 38.7% of subjects. Age (p = 0.02), years of lens wear (p = 0.02), and MRS (p <0.0001) affected replacement compliance. Post-hoc analysis showed daily replacement wearers were more compliant than two-week (p <0.0001) and monthly (p <0.0001) replacement wearers with prescribed lens replacement. Non-compliance with prescribed ON wear was reported in 23.9% of subjects. Subjects who were non-compliant with lens replacement were more likely to be non-compliant with ON wear (p = 0.02) and had worn contact lenses for less time (p = 0.02). Of the subjects who used contact lens cases, 74.6% were unsure when they should replace their case. Frequency of case replacement was not associated with age (p = 0.5), gender (p = 0.5), years of contact lens wear (p = 0.7), MRS (p = 0.4), replacement compliance (p = 0.3), or ON wear compliance (p = 0.7)., Conclusions: Daily replacement wearers were most likely to be compliant with contact lens replacement, but all subjects, including daily replacement wearers, had similar ON wear non-compliance. Non-compliant lens replacement was associated with non-compliant ON wear, but contact lens case replacement was not related to either compliance category. The majority of subjects had no knowledge of proper contact lens case replacement, despite compliance in other categories., (Copyright © 2019 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Medical devices are under strict regulatory oversight worldwide and such regulations prioritise patient safety and efficacy over anything else. Contact lenses fall under the medical device category - a result of direct contact with the eye. Equally regulated are the contact lens care product solutions, which include cleaning and maintenance solutions and lubricating and rewetting drops. In the USA, it is the FDA Centre for Devices and Radiological Health (CDRH) overseeing the regulations of medical devices, since 1976. In the European Union, it is the EU Commission responsible for regulating devices in Member States. The categorisation of contact lenses into medical devices is based on their inherent risk to the wearer. Contact lenses are subject to crucial regulatory oversight from concept to clinical evaluation, clinical investigations through to the finished lens product, and finally, strict conditions associated with their marketing approval including post-marketing surveillance. The physiochemical and manufacturing testing, such as biocompatibility testing alongside pre-clinical stability, sterility and microbiological testing are just some of the essential testing lenses must endure. Only through understanding the inherent risks and potential complications that can arise from contact lens wear, can one truly appreciate the need to adhere to strict regulations. The challenge however, lies in the need for more standardised regulations and flexible approaches, ensuring innovative device technologies reach patients in a timely manner without compromising public health and safety. This review highlights some key requirement, differences and similarities between the FDA and EU administrations in the approval of contact lenses., (Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To review contact lens prescribing trends in Japan between 2003 and 2016., Methods: An annual survey of contact lens prescribing trends was conducted each year between 2003 and 2016. Japanese ophthalmologists were asked to provide information relating to ten consecutive contact lens fittings between January and March every year., Results: Over the 14 years of the annual survey, data from a total of 64,122 contact lens fits were returned by ophthalmologists. The mean age (±SD) of lens wearers was 30 ± 13 years, and 68% were female. The proportion of rigid lens fits decreased over time, from 35.4% in 2003 to 14.7% in 2016. Across this period, daily disposable lens fits increased, representing 46% in 2016. The proportion of toric lenses and multifocal lenses gradually increased, from 6.6% and 1.9% to 12.3% and 5.8%, respectively. Silicone hydrogel material use grew from 0% to 43.2%, while mid and low water content lens materials declined from 54.1% and 28.2% to 36.1% and 8.3%, respectively. Multi-purpose lens care solutions dominated the market over the 14 year survey period., Conclusions: This survey has revealed prescribing trends and preferences in Japan over the past 14 years, with the main changes observed being a decrease in rigid lens use and an increase in the use of silicone hydrogel materials and daily disposable lenses., (Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To ascertain the effect that four contact lens (CL) multipurpose solutions (MPS) have on the viability and release of pro-inflammatory cytokines from human corneal epithelial cells (HCEC)., Methods: HCEC were exposed to four different MPS at various concentrations for 18 hours. The cells were also exposed to phosphate buffer, borate buffer, and PHMB. The cell viability was evaluated using the alamarBlue assay. The release of pro-inflammatory cytokines was measured using a Multiplex electrochemiluminescent assay., Results: MPS-A, MPS-B and MPS-C all reduced cell metabolic activity p < 0.05 from control with MPS-A showing the greatest cytotoxic effect (maximum reduction, 90.6%). In contrast, MPS-D showed no significant reductions in cytotoxicity except at the highest concentration tested (19% reduction at 20% MPS concentration). Of the four cytokines evaluated MPS-C showed a substantial increase in the release of IL-1β, IL-6, IL-8, and TNF-α at higher concentrations when compared to control p < 0.05. At the 20% concentration of MPS-A and MPS-B the release of IL-1 β increased p < 0.05 but the release of IL-6, IL-8, and TNF-α decreased. MPS-D did not cause a change in the release of cytokines IL-1β, IL-6, IL-8 and TNF-α p > 0.05. Exposing the cells to borate buffer and PHMB caused an increase in the release of TNF-α p < 0.05., Conclusions: This investigation demonstrates that at different concentration levels, several of the MPS tested showed a decrease in viability and an increase in the release of inflammatory cytokines from HCEC. The borate buffer component as well as PHMB appears to contribute to this pro-inflammatory reaction., (Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To understand long-term contact lens prescribing habits of Canadian optometrists., Methods: One thousand optometrists were surveyed annually from 2000 to 2015. Information was requested on the first ten patients examined after receiving the survey., Results: Over the 16-year survey period, 1987 optometrists provided information on 19,143 patients. Mean age of the patients was 32.7±14.4years. Ratio of females to males was 2:1, the ratio of new fits to refits was 2:3. Soft contact lenses represented 94.5% of all fits. Rigid lenses were more often used as a refit compared to a new fit. Over the 16 years, market share for silicone hydrogel materials grew from 0% to 69.6%, mid-water content materials declined from 75.7% to 14.1%. The multifocal market share grew at the expense of spherical designs, with no change in toric lens fitting. Monthly soft lens replacement remained the preferred option at 48.2%, followed by daily disposable at 40.8%; two-weekly replacement declined to less than10% of patients by 2015. Extended wear was likely used to refit and only to a small proportion of wearers, representing 2.6% of SCL by 2015. The lens care system of choice throughout the period was multipurpose solutions, although the proportion for peroxide systems more than doubled by 2015 from 9.6%, to 21.1%., Conclusions: Over the 16-year period, SCL material preference changed to silicone hydrogels with monthly replacement being preferred; daily disposables replacing 2-weekly as the alternate. Lens care preference continued to be multipurpose solutions. Rigid lenses appear to be sustained for specialist fitting., (Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To evaluate contact lens prescribing trends among optometrists in Jordan., Methods: Optometrists from 173 practices in Jordan were surveyed about prescribing contact lenses in their practice. Practitioners were required to record information for the last 10 patients that visited their practice. Demographic data such as age and gender was obtained for each patient. In addition, data relating to lens type, lens design, replacement methods and the care regime advised to each patient were recorded. Practitioners were required to provide information relating to their education and years of experience. The influence of education and experience with respect to lens prescribing trends was explored using linear regression models for the proportions of lens types fitted for patients., Results: A total of 1730 contact lens fits were analyzed. The mean (±SD) age of lens wearers was 26.6 (±7.9) years, of whom 65% were female. Conventional hydrogel lenses were the most prescribed lenses, accounting for 60.3% of the fits, followed by silicone hydrogel lenses (31.3%), and rigid lenses (8.4%). In terms of lens design, spherical lenses appeared to be most commonly prescribed on monthly basis. Daily disposable lenses were second most prescribed lens modality, accounting for 20.4% of the study sample. Multi-purpose solution (MPS) was the preferred care regimen, with a prevalence of 88.1% reported in the study sample, compared to hydrogen peroxide (1-step and 2-step), which represented only 2.8% of the patients in this study. A relationship was established between the two educational groups for rigid lens prescribing (F=17.4, p<0.0001), while the experience of the optometrist was not a significant factor (F=0.4, p=0.54)., Conclusion: This work has provides an up-to-date analysis of contact lens prescribing trends among optometrists in Jordan. Contact lens prescribing in terms of lens type, lens design, modality of wear and care regimen agree with global market trends with small variations. This report will help practitioners and the industry to detect any deficiencies in the contact lens market in Jordan, which will ease implementing current and future plans in developing contact lens practice and patient eye care in the region., (Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Objective: To investigate the antibacterial activity of cinnamon oil alone and in combination with a multipurpose contact lens disinfectant solution (MPS) as well as tobramycin against multi drμg resistant conjunctival bacteria both in planktonic and sessile forms., Methods: Minimum inhibitory concentrations (MIC) of tobramycin and cinnamon oil against 19 bacterial strains were investigated against planktonic and sessile cells by micro-dilution methods. Synergistic effects were determined by well diffusion and micro-dilution tissue culture plate methods for planktonic and sessile cells respectively. Time kill assay was performed to study the bactericidal effect of cinnamon oil in concentrations ranging from 5% to 0.312% combined with an MPS with respect to time., Results: MICs of cinnamon oil against planktonic bacteria ranged from 0.04% to 1.25% versus 0.156% to 5% for sessile cells. Combination of cinnamon oil with tobramycin had a synergistic effect against most tested organisms. The MIC values of cinnamon oil in combination with tobramycin was significantly lower than cinnamon oil alone against biofilm production (P=0.004). Time kill assay revealed that combination of cinnamon oil and disinfectant successfully eradicated the tested microorganisms at all tested concentrations within 2h contact time except for 0.312% concentration (3h) versus 24h for MPS alone., Conclusion: Cinnamon oil has a promising antimicrobial effect. It could be a probable candidate for contact lens disinfection., (Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To determine the ease with which children and youths without previous soft contact lens (SCL) experience were able to handle, care for, adapt and be fitted with SCLs., Methods: 179 children aged 8-16 were recruited. Study visits included: screening and training visits, 1-week and 3-month follow-ups. During the training visit, the time taken to demonstrate proficiency in lens insertion and removal and care was recorded. A second training visit was scheduled if necessary., Results: Nine children did not complete the screening visit and eight discontinued during the study. Of those eight, seven discontinued during the first week and one before the 3-month visit. Of those recruited, 90.5% (162/179) were successfully fitted and completed the study. A majority of children were dispensed with lenses at the first training visit (94.6%, 162/171). The mean training time for all children was 30 min. There were no statistically significant differences in the number of lenses required to fit or instruction time by age group (p > 0.05) or gender (p > 0.05). Nine participants (5.3%, 9/171) required a second training visit with four still unable to handle lenses (2.3%, 4/171). By the 1-week visit 13.2% (22/167) of participants either lost or tore lenses, no subsequent lost or torn lenses occurred. No serious adverse events occurred during the study., Conclusion: Children and youths with no previous contact lens experience were easily fitted, able to successfully wear and care for lenses. The results of this study should encourage practitioners to recommend SCLs as a vision correction option., (Copyright © 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purposes: To determine the level of compliance and major non-compliant behaviors in contact lens (CL) wearing medical doctors (MDs) and to compare it with age matched CL wearing normal subjects with no medical background (NS)., Methods: Thirty-nine current CL wearing MDs, who were prescribed CLs in Nepal Eye Hospital, Kathmandu, Nepal, between 2007 and 2011, were interviewed on ten modifiable compliant behaviors regarding lens care and maintenance. The level of compliance and the rate of non-compliance for each behavior were determined and compared with NS., Results: Level of compliance was good, average and poor in 35.9%, 48.7% and 15.4% of MDs, respectively. There was no significant difference in compliance between MDs and NS (p=0.209). Level of compliance was not associated with age, gender and duration of lens wear (p>0.05). Compliance rate varied according to different behaviors, achieving a good compliance level of 95% for hand hygiene, avoidance of water contact and not sleeping with lenses. There was poor compliance for topping up solution (53.8%) and lens case replacement (15.4%)., Conclusion: About one third of MDs had a good level of compliance. Level of compliance and compliance rate of different behaviors were similar in MDs and NS. Periodic lens case replacement was the most neglected behavior in CL wearers for this region., (Copyright © 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: To determine the rates of microbial contamination and identify contaminants associated with contact lens (CL) care accessories. To investigate self-reported compliance levels with care of CL accessories and its association with contamination level., Methods: A total of 46 CL cases and care solutions from asymptomatic soft contact lens wearers were collected. Samples from the CL cases and care solutions were cultured for microbiological identification and enumeration. A questionnaire regarding compliance to care and hygiene procedures were administered to each subject on their visit., Results: The percentage of microbial contamination for CL cases and care solutions was 50% and 10.9%, respectively. All the contaminants were bacterial. Staphylococcus aureus (37.0%, 17 of 46 cases) and Escherichia coli (8.7%, 4 of 46 cases) were the most common microorganisms detected in CL cases. In care solutions, S. aureus (8.7%, 4 of 46 samples), Pseudomonas aeruginosa (2.2%, 1 of 46 samples) were common contaminants. CL cases and care solutions that were used for <3 months were significantly less contaminated than those used for >3 months (10.9% versus 39.1%, p<0.05). Polyquad and Aldox based MPS solution showed no contamination. Subjects with medium or low compliance had highly significant rates of contaminations both in CL cases and solutions than for subjects with high compliance (p<0.05)., Conclusions: Nepalese Soft CL wearers are at high risk of developing ocular complications due to high CL case and solution contamination. Frequent replacement of CL cases and solutions, as well as good compliance is recommended to reduce risk of contamination., (Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Introduction: This study investigated the modality, type and duration of contact lens wear as well as compliance and hygiene related issues (hand and case hygiene, use of tap water, dozing and overnight wear) in the UK and Germany. Questionnaires were collected anonymously from 417 UK and 767 German patients attending optometric practices for contact lens appointments. It is the seventh of a series of contact lens wearer profiles conducted since 2000., Results: The proportion of rigid gas permeable lenses worn was significantly higher at 55.4% in Germany, compared to 16.1% in the UK. Overall, a significantly larger proportion of German participants used tap water to rinse their lenses and cases (P<0.001). Also, German respondents changed their lens cases less frequently (p<0.001). Fewer UK than German respondents stated they washed their hands before lens insertion (p=0.009), removal (p=0.01), before eating (p<0.001). German participants were less likely to wash their hands before preparing food (p=0.042) and after using the toilet (p=0.002). The two sample groups differed significantly regarding the care regimens they used for their CLs (p<0.001)., Conclusion: The differences between Germany and the UK highlighted in this study were caused by differences in legal regulations, plumbing and practitioners' guidance. Although many of the questions relating to hygiene differed statistically between the two participating sample groups, the absolute differences in figures were not considered to be large.

A variety of approaches are available for cleaning, rinsing, disinfecting and storing reusable soft contact lenses. As demonstrated in this report of the results of annual UK prescribing surveys conducted over the past 12 years, there has been a steady increase in the use of multi-purpose solutions, which in 2007 represented 93% of all lens care systems prescribed. This increase is attributed to factors such as simplicity, reduced cost and enhanced compliance with these products. The apparent reversal of this trend in 2008 is probably due to an undermining of patient and practitioner confidence in multi-purpose solutions relating to withdrawals of some multi-purpose solutions from the market, and controversies concerning corneal staining with some lens-solution combinations.

Objective: To assess the relative risks (RR) of microbial keratitis (MK) for contemporary contact lens (CL) types and wearing schedules., Design: A 2-year prospective case-control study begun in December 2003., Participants: Cases were 367 CL wearers attending Moorfields Eye Hospital with proven or presumed MK. Controls were 1069 hospital controls, who were CL wearers with a disorder unrelated to CL wear, and 639 population-based controls who were CL wearers randomly selected from the Moorfields catchment area. Hospital patients completed a self-administered questionnaire; population-based controls were interviewed by telephone., Testing: Multivariate analysis was done both for all cases of MK, and for the moderate and severe MK subgroups alone., Main Outcome Measures: The RR for developing MK, and vision loss, for all lens types compared with planned replacement soft lenses (the referent)., Results: Compared with planned replacement soft lenses (the referent), the RR of MK was significantly increased with daily disposable (DD) CLs (RR, 1.56x [95% confidence interval (CI), 1.1-2.1]; P = 0.009) and differed between different brands of DD lens, was reduced for rigid lenses (RR, 0.16x [95% CI, 0.06-0.4]; P<0.001), and no different for silicone hydrogel or other types of soft lens. Although the risk of MK was higher overall among DD lens users, the risk of vision loss was less than for planned replacement soft CL users (P = 0.05); no DD lens users lost vision to the level of >or=20/40. The RR for overnight wear, for any lens type, was 5.4 times higher (95% CI, 3.3-10.9; P<0.001). Comparison of the DD soft CL types with planned replacement soft lenses (the referent), showed significant differences between brands for the risk of MK., Conclusions: The risk of MK has not been reduced in users of DD and silicone hydrogel CLs. However, vision loss is less likely to occur in DD than in reusable soft CL users. Different brands of CL may be associated with significantly different risks of keratitis; understanding these differences should lead to the development of safer soft lenses. These findings suggest that lens/ocular surface interactions may be more important in the development of corneal infection than oxygen levels and CL case contamination.

Objective: To analyze commercially available bottled water as a possible source of microbial contamination of contact lenses., Methods: Two different lots of 23 brands of noncarbonated bottled water were tested for coliforms, total bacteria, fungi, and free-living amebae. A sample consisted of three separate 100-ml aliquots from one lot of each brand (46 samples). Aliquots were vacuum-filtered using a 0.45-microm Nalgene analytical filter unit, and the membrane filter was placed on a filter pad in a Petri dish containing test medium. Plates were examined under a stereomicroscope, and the number of colony-forming units (CFUs) was calculated for each sample. To test for the presence of free-living amebae, three aliquots totaling approximately 3800 ml were concentrated using 8-microm filters, and the filters were placed on non-nutrient agar with live Enterobacter aerogenes. To assess the possibility of contaminating contact lenses, etafilcon lenses were rinsed in 2-ml aliquots of four brands of bottled water and then cultured., Results: Seventeen (37%) of 46 samples, representing 11 (48%) of 23 brands, contained viable micro-organisms. Bacteria, including coliforms, were recovered from 12 samples of 8 brands. Yeasts or molds were recovered from seven samples of five brands. Free-living amebae were isolated from two samples, and fresh-water algae were found in both samples of one brand. Nine (20%) of 46 samples, representing 7 (30%) of the 23 brands, had more than 500 CFUs per ml or contained coliforms. Sterile contact lenses became contaminated when exposed for 1 minute to two of four brands of water from which micro-organisms were recovered., Conclusion: Some bottled waters contain high numbers of potential ocular pathogens. Bottled water is not safe for routine use with contact lenses.

Periodontal ligament (PDL) cells cultured from healthy extracted human teeth were exposed to milk, Alcon Opti-Free contact lens solution, K-Mart contact lens solution, saline, and Hank's balanced salt solution. The appearance and rate of loss of the cells from the culture dishes were recorded over time at both room temperature (20 degrees C) and 4 degrees C. The results indicated that saline was superior to either of the contact lens solutions in its ability to maintain the vitality of the PDL cells. Milk at 4 degrees DC provided good short-term viability , but cells did not remain attached after 48 h. At 20 degrees C, however, milk resulted in a 24.4% retention of cells after 72 h. Hank's balanced salt solution was the best storage media, with 46.8% of sells remaining attached after 72 h of exposure. This study supports milk as a good short-term storage medium for maintaining the vitality of PDL cells in vitro.