Contact Lens Solutions Research Articles

Place du pharmacien de ville dans la prise en charge des patients en ophtalmologie

To assess the role of community pharmacists in ophthalmology, to evaluate the frequency of giving patients advice, and to report their difficulties in daily practice. An anonymous questionnaire consisting of 13 questions was sent to 620 community pharmacists of Burgundy (France). Pharmacists were asked about their ophthalmic products, their ophthalmic activity in giving patients advice on ocular symptoms, and patients' expectations. For analysis, community pharmacies were separated into three groups: pharmacies in rural areas (under 2000 inhabitants), pharmacies in an urban zone with fewer than 10,000 inhabitants, and pharmacies in an urban zone with more than 10,000 inhabitants. The response rate was 46.9%. Ophthalmic products were mainly glasses for presbyopia (84.5%), eye care hygiene products (76.0%), and contact lens solutions (55.3%). Ophthalmic vitamin supplements were sold by 36.8% of pharmacists, mainly in urban areas. On average, the pharmacist was consulted for ocular problems seven times a week. Acute benign symptoms were most frequent. Advice on prescriptions came next. Then, information on contact lenses and chronic ocular disease were given (cataract, glaucoma, visual acuity loss, age-related maculopathy). Finally, the pharmacist either sold the patient an ocular treatment or oriented the patient to an ophthalmologist when needed. The pharmacist and his staff are active players in providing advice on ocular diseases and taking care of patients. Moreover, pharmacists have to manage ocular therapeutics, urgent symptoms, and chronic diseases. However, in our study, 46.0% of pharmacists felt confident with their knowledge on ophthalmology, 36.4% did not give their opinion, and 7.0% were uncomfortable with some questions. Most community pharmacists mentioned a lack of continuing education from pharmaceutical companies and postgraduate education on ocular diseases and treatment, mainly for age-related maculopathy.

Effects of Ionic and Surfactant Agents on the Antimicrobial Activity of Polyhexamethylene Biguanide

Polyhexamethylene biguanide (PHMB) exhibits broad-spectrum antimicrobial activity and is included in multipurpose solutions for contact lenses as a disinfectant. Both cationic and hydrophobic features of PHMB are believed to support its association with microbial cell membranes through electrostatic and hydrophobic interactions. We now evaluated the effects of ionic and surfactant agents on the antimicrobial activity of PHMB. The antimicrobial activity of PHMB (1 ppm) against various bacteria and fungi was measured with the stand-alone procedure (ISO 14729, 2001). The effect of NaCl as an ionic isotonic agent on such an activity was determined in comparison with that of propylene glycol as a nonionic isotonic agent. The effect of the nonionic surfactant Poloxamer 407 (Px407) was similarly examined in the absence or presence of NaCl. The antimicrobial activity of PHMB increased with time, being especially pronounced after 60 min. This activity was inhibited by NaCl in a concentration-dependent manner but was not affected by propylene glycol. Poloxamer 407 (4%) alone slightly increased the activity of PHMB toward Staphylococcus aureus and fungi. Although Px407 prevented the inhibitory effect of NaCl on PHMB activity against bacteria, it enhanced that observed with Candida albicans. The antimicrobial activity of PHMB was inhibited by adjustment of osmolality with the ionic agent NaCl but not by that with the nonionic agent propylene glycol. The surfactant Px407 exhibited complex effects on PHMB activity in the presence of NaCl. These findings indicate that the electrostatic interaction with the cell membrane is a dominant factor in the antimicrobial activity of PHMB.

Study on All-Solid-State Chloride Sensor Based on Tin Oxide/Indium Tin Oxide Glass

An all-solid-state chloride electrode based on a tin oxide (SnO2)/indium tin oxide (ITO) glass was developed in this study. The sensing membrane of the electrode was prepared by mixing poly(vinyl chloride) (PVC), bis(2-ethylhexyl) sebacate (DOS), [4,5-dimethy-l-3,6-bis(dodecyloxy)-1,2-phenylene] bis(mercury chloride) (ETH9033), and tridodecylmethyl ammonium chloride (TDDMACl). The mixed solution was mixed with tetrahydrofuran (THF), and then dropped on the sensing window of SnO2/ITO glass. According to the experimental results, the optimal weight ratio were PVC:DOS:ETH9033:TDDMACl=33:66:2:5. At this optimum weight ratio, the sensitivity was 54 mV/dec while the range of linear concentrations of NaCl solutions was between 10-4 and 1 M. The lower detection limit of the sensor reached 8×10-5 M and the response time was less than 1 s. The selectivity coefficient was consistent with the theory of Hofmeister lipophilicity. The lifetime was over 60 days and the repeatability was over 50 times. Moreover, the chloride ion sensor was successfully applied to detecting chloride ions in rinsing solutions for contact lenses, and the experimental results revealed that the correlation coefficient was 0.99.

Fungal keratitis in France

Editor, Fungal keratitis is a sight-threatening corneal infection, which is common in tropical regions. Even if its incidence has increased over the last few years, its prevalence remains low in temperate countries (Rondeau et al. 2002). This study was conducted by retrospective analysis of the files of all patients attending to the Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts in Paris, who presented culture-proven fungal keratitis during a 16-year period (from January 1993 through December 2008). The characteristics of the population, clinical findings, etiologic organisms, treatments, predisposing factors and prognosis factors of fungal keratitis were analysed. Considering the response to medical treatment, eyes were divided in two groups: the group of ‘positive response to medical treatment’ (i.e. infection resolution with no surgical procedures) and the group of ‘no response to medical treatment’ (i.e. need for keratoplasty, evisceration or enucleation). During the study, 63 patients (64 eyes) with culture-proven fungal keratitis were followed up. The average age was 50.3 + 17.9 [37 men (59%) and 26 women (41%)]. Population characteristics at baseline are shown in Table 1. Before 2000, topical corticosteroids were the main predisposing factor for keratomycosis, representing 50% (10/20) of cases, whereas from 2001 to 2008 contact lens wear was the most frequent, representing 50% (22/44) of cases (p = 0.002). Concerning contact lens care practice and multipurpose solutions for cleaning, between January 2004 through November 2006, 14 contact lens wearers were diagnosed with Fusarium keratitis. Six patients reported using ReNu with MoistureLoc, and eight patients reported using other brands of contact lens cleaning solution. The risk factors included the continued use of contact lenses after the planned replacement date (35%), the overnight use of daily wear contact lenses (5%) and swimming with contact lenses in swimming pools (24%). Filamentous fungi (69%) were more common than yeast fungi (31%). The predominant fungal species was Fusarium spp (44%). Before 2000, Candida species were the most common fungi, representing 50% (10/20) of cases, whereas from 2001 to 2008 Fusarium species were the most frequent, representing 52% (23/44) of cases (p = 0.04). The patients were treated with topical amphotericin B 0.15% (97%) and/or topical natamycin 5% (25%), topical voriconazole 1% (16%) or topical caspofungin (13%). Systemic antifungal drugs (voriconazole or itraconazole or fluconazole) were administrated in 33 patients (52%). Clinical outcomes are listed in Table 1. A history of eye disease before infection (i.e. ocular surface diseases or keratoplasty) was significantly associated with no response to medical treatment (p = 0.01). Patient age older than 50 years (p = 0.03) was significant risk factor for low final visual acuity. In our study, soft contact lens wear and the use of the alexidine-containing contact lens cleaning solution ReNu with MoistureLoc were associated with Fusarium keratitis, consistent with previous observations (Chang et al. 2006; Gaujoux et al. 2008). Imamura et al. (2008) established an in vitro model of Candida and Fusarium biofilm formation on contact lenses, which reduced susceptibility against contact lens solutions. In France, there has been an increase in fungal keratitis and a change in the causative pathogens and risk factors for keratomycosis. Fusarium species are the most common species of fungi isolated, and contact lens wear is the main risk factor. Similar changes occurred in the Boston area (Jurkunas et al.2009). The results suggest that patients with a history of eye disease (i.e. ocular surface diseases or keratoplasty) and patients older than 50 years are at high risk of severe clinical outcome. Therefore, special care should be offered to these patients by the administration of intense dose of antifungals by topical and general route. This study was supported by the Paris VI University (Université Pierre et Marie Curie), Paris, France.

Hygiene compliance in contact lens wearers presenting to an ophthalmic casualty department

Abstract Poor compliance with contact lens care regimens is a factor considered important in the development of potentially sight-threatening microbial keratitis. The purpose of this study was to highlight particular areas of non-compliance in contact lens care. One hundred and sixty contact lens wearers, who presented to an ophthalmic casualty department over a period of six months, were surveyed using a self-administered questionnaire. Of the 142 patients who used daily wear lenses, 29 (20 per cent) did not clean/disinfect their contact lenses after every use. Soft contact lens wearers used a wide variety of care regimens, some of which would be ineffective in disinfecting the lenses. The care of the lens case was a particular problem, with only 10 patients (7 per cent) using a regular and effective method of case cleaning. Seventy-three patients (50 per cent) either rarely or never discarded their contact lens solutions 28 days after opening. Of the 128 patients wearing non-disposable lenses, 43 (34 per cent) either rarely or never used enzymatic cleaning tablets to remove protein from their lenses. Tap water, a potential source of microbial contamination, was used for rinsing contact lenses before or after cleaning by 36 patients (25 per cent). The results highlight specific areas where there was deviation from recognised standards of practice for contact lens care. There is a need for contact lens wearers to be re-educated in the care of their lenses. Since pharmacies are a major source of contact lens care products, pharmacy staff could have an important role to play in the counselling of contact lens wearers to help prevent serious ocular pathologies.

Epidemiology and Pathogenesis of Pseudomonas aeruginosa Infections

1. Nicholas M. Moore, MS, MLS(ASCP)[⇑][1] 1. Rush University, Department of Medical Laboratory Science, Chicago, IL 2. Maribeth L. Flaws, PhD, SM(ASCP)SI 1. Rush University, Department of Medical Laboratory Science, Chicago, IL 1. Address for Correspondence: Nicholas M. Moore, MS, MLS (ASCP), Department of Medical Laboratory Science, 600 S. Paulina St., Suite 1014, Chicago, IL 60612, 312-942-2111, Fax: (312) 942-6464, Nicholas_Moore{at}rush.edu Upon reading this article, the reader should be able to: 1. List the infections caused by Pseudomonas aeruginosa . 2. Compare and contrast between infections caused by P. aeruginosa in healthy hosts with those in compromised hosts. 3. Discuss the purpose of the National Healthcare Safety Network (NHSN). 4. Summarize the surveillance data reported by the NHSN and its predecessor National Nosocomial Infections Surveillance System (NNIS) with regards to P. aeruginosa infections. 5. Explain the mechanisms used by P. aeruginosa to evade host defense mechanisms and colonize its host. Pseudomonas aeruginosa is an opportunistic nonfermentive gram negative bacillus that is responsible for a wide variety of infections in humans ranging from relatively uncomplicated urinary tract infections (UTIs) to severe and life threatening infections including neonatal sepsis and chronic lung infections in patients with cystic fibrosis. P. aeruginosa produces a number of membrane bound and secreted virulence factors that aid in the attachment of the organism to host cells, the invasion of tissue, and the inhibition of the immune response. Epidemiology of P. aeruginosa It is almost impossible to prevent exposure to P. aeruginosa because it can be found anywhere. It is nonfastidious and requires little in terms of nutritional requirements, thus it can be found on inanimate objects such as hospital room sinks, toilets, showers and patient care equipment, especially respiratory ventilators. The surfaces of fresh fruits and vegetables may even harbor P. aeruginosa . The organism has a particular predilection for water and as a result, it has been isolated from soaps and disinfectants, contact lens solutions, cosmetics and hot tubs, all of which have been documented as sources of infection. Though not a major member of the human normal flora, it is most commonly found in small amounts in the gastrointestinal tract. It may transiently colonize a variety of moist skin surfaces including under the arm and on the perineum. The throat and nose have been shown to be sites that may be colonized with P. aeruginosa as well.1 P. aeruginosa can cause infection in almost any part… ABBREVIATIONS: HAI = Healthcare-associated infections, MRSA = methicillin resistant Staphylococcus aureus , NNIS = National Nosocomial Infection Surveillance System, CDC = Centers for Disease Control and Prevention, DSN = Dialysis Surveillance Network, NaSH = National Surveillance System for Healthcare Workers, NHSN = National Healthcare Safety Network Upon reading this article, the reader should be able to: 1. List the infections caused by Pseudomonas aeruginosa . 2. Compare and contrast between infections caused by P. aeruginosa in healthy hosts with those in compromised hosts. 3. Discuss the purpose of the National Healthcare Safety Network (NHSN). 4. Summarize the surveillance data reported by the NHSN and its predecessor National Nosocomial Infections Surveillance System (NNIS) with regards to P. aeruginosa infections. 5. Explain the mechanisms used by P. aeruginosa to evade host defense mechanisms and colonize its host. [1]: #corresp-1

Effect of a novel multipurpose contact lens solution on human corneal epithelial barrier function

Purpose To explore the effect of a novel multipurpose contact lens solution (MPS) on the junction protein distribution and barrier function of cultured human corneal epithelial cell monolayers. Methods Cultured human corneal epithelial cells (HCEpiC) were exposed to a novel MPS (MPS A; Biotrue™, Bausch & Lomb) at 50%, 75% and 100% for 10 or 30 min. Four commercially available MPS products, MPS B (AQuify, Ciba Vision), MPS C (COMPLETE MPS Easy Rub, AMO), MPS D (OPTI-FREE Express, Alcon) and MPS E (OPTI-FREE RepleniSH, Alcon) were tested in parallel. Tight junction structure and integrity were evaluated by confocal microscopy using ZO-1 antibody and scanning microscopy (SEM). Quantitative evaluation of MPSs on epithelial barrier function was determined by measuring transepithelial electrical resistance (TEER) across HCEpiC grown on Transwell Clear permeable supports and on electric cell-substrate impedance sensing (ECIS) electrode arrays. Results Overall after exposure to the three concentrations (50%, 75%, and 100%) of MPS A, ZO-1 distribution and fluorescent intensity on the cell surface appeared similar to the media control with continuous tight junctions and clear intercellular junctions. At all measured time points after exposure to MPS A (50% or 75%) there was also no effect on the TEER using both resistance methodologies, and SEM showed that MPS A appeared similar to the Hank's balanced salt solution (HBSS) control. In cells exposed to MPS D there was a dose-dependent change in the distribution of ZO-1, some cell detachment, and a decrease in monolayer resistance at all time points measured. Ultrastructurally, MPS D caused gross changes, including damage to cell junctions and plasma membranes. To a lesser extent, the remaining three commercial MPS products demonstrated some effects on tight junction ZO-1 distribution and/or TEER. Conclusions Based on the in vitro measurements of tight junction protein expression, monolayer integrity, and transepithelial electrical resistance, the novel multipurpose contact lens solution (MPS A) did not alter corneal barrier function as compared to media, PBS or HBSS control. Clinical significance of the observed differences in epithelial barrier function among the MPSs tested needs further investigation.

Accidental self-induced chemical eye injury in patients with low vision

Sir, Legislation introduced by the Medicines and Healthcare Products Regulatory Agency in 1995 requires Braille to appear on medication labels and in patient information leaflets.1 This legislation empowers blind persons with autonomy in the self-administration of drugs. Unfortunately, for those who have low vision but do not require Braille, the same safety provision does not exist. Contact lens users are often provided with two bottles of solution: one to clean the lenses, the main ingredient usually being hydrogen peroxide, and the other to rinse the lenses. Those with low vision rely on tactile information to differentiate such solutions; however, manufacturers frequently package them in similar sized and shaped bottles. We describe two low vision contact lens wearers with self-induced chemical eye injuries secondary to confusion with contact lens solutions.

Contact Lens Solution–associatedAcanthamoebaandFusariumKeratitis

To the Editor: Verani et al. (1) detailed the 2004–2007 outbreak of Acanthamoeba keratitis (AK) in persons wearing soft contact lenses who used Complete MoisturePlus (CMP) multipurpose contact lens solution (Advanced Medical Optics, Santa Ana, CA, USA). They noted similarities between the AK outbreak and the Fusarium keratitis (FK) outbreak of 2004–2006, including the concomitant time frame and association with a particular solution, ReNu with MoistureLoc (Bausch & Lomb, Rochester, NY, USA). Both solutions were new products introduced within 1 year before the respective outbreaks. In neither outbreak was the solution contaminated; in both outbreaks, implicated bottles were from multiple lots, suggesting that each outbreak resulted from insufficient antimicrobial activity. However, in the FK outbreak, all reported cases involved bottles produced at 1 (Greenville, SC, USA) of 4 multinational Bausch & Lomb manufacturing plants (2). After a Food and Drug Administration inspection of the Greenville facility, Bausch & Lomb was cited for inadequacies in temperature control during production, storage, and transport of its products in and beyond the plant (3). We experimentally demonstrated that, when exposed to prolonged temperature elevation, ReNu with MoistureLoc loses more in vitro fungistatic activity than do other contact lens solutions. We concluded that improper temperature control of ReNu with MoistureLoc may have contributed to the FK outbreak (4). We are aware of no other theory that adequately explains why only ReNu with MoistureLoc from only 1 plant was implicated. CMP was manufactured and used internationally; AK has a much higher incidence in Europe and Hong Kong than in the United States (5), and CMP–associated AK has been reported internationally (6). Therefore, it would seem critical to know, and we would like the authors to comment on, whether the geographic pattern of the AK coincided with distribution of CMP solution from >1 Advanced Medical Optics manufacturing plants and, if so, the relevance of that information.

Propylene glycol and contact-lens solutions containing this diol induce pseudocyst formation in acanthamoebae

Propylene glycol used as an ophthalmic demulcent in certain contact-lens care systems has been included recently among factors responsible for increasing Acanthamoeba keratitis. In this study, we provide evidence that propylene glycol as well as examined contact-lens solutions containing it induce rapid differentiation of acanthamoebae into pseudocysts. The partial resistance of the pseudocysts and their reversibility to viable trophozoites even after 24-h exposure to the contact-lens solutions indicate a potential risk of infection to contact-lens users.

Removal of Biofilm from Contact Lens Storage Cases

Lens case hygiene practices are important in maintaining safe contact lens wear. However, the effectiveness of various lens case cleaning practices have not been evaluated and compared. This in vitro study aimed to evaluate and compare the efficacy of cleaning practices that are most commonly carried out by lens wearers and recommended by practitioners. Pseudomonas aeruginosa 122, Serratia marcescens ATCC 13880, and Staphylococcus aureus ATCC 6538 were the challenge bacteria for biofilm formation on unused lens cases from two different manufacturers. After establishment of the biofilm, each lens case was subjected to one of the six cleaning regimens: "rinsed," "rubbed and rinsed," "air-dried," "soaked in a multipurpose contact lens solution," "tissue-wiped," and "lids recapped." The level of residual biofilm was quantified at the end of each cleaning regimen. The efficacy of each cleaning regimen was then compared. Mechanical rubbing and wiping of lens cases were the most effective cleaning regimen tested in reducing biofilm. Soaking lenses in disinfecting solution for 6 hours removed the majority of biofilm from lens cases. Rinsing lens cases alone provided only minimal efficacy in reducing biofilm. Air-drying or recapping the cases with the lid without any other additional cleaning methods were the least efficient at removing biofilm. Based on this study, digital rubbing and rinsing and/or wiping the lens cases with tissue is recommended. Air-drying or recapping the lens case lids after use without any additional cleaning methods should be discouraged with non-antimicrobial lens cases.

Stress-Induced Pseudocyst Formation - A Newly Identified Mechanism of Protection against Organic Solvents in Acanthamoebae of the T4 Genotype

Differentiation into highly resistant double-walled cysts is a major mechanism allowing amphizoic acanthamoebae to survive under long-lasting, unfavourable environmental conditions. We found that relatively low concentrations of methanol, acetone or DMSO stimulate promptAcanthamoebadifferentiation into a rounded cyst-like stage with a single envelope. To address whether this rapid response differs from the encystment, time-dependent changes in cell surface characteristics and cyst-specific gene expression were monitored in encystating cells and cells differentiating under methanol treatment using microscopic, lectin-binding, PCR and resistance studies. In contrast to the encystment: (1) a single-layered amorphous mannose/glucose coat was the only envelope assembled on the surface of the solvent-treated cells, (2) the cyst-specific protein (CSP21) was not expressed, (3) the coat did not protect cells against acidic pH and (4) in solvent-free encystment medium, the coated cells did not assemble the double-layered wall, thus indicating that these cells were not immature cysts. These findings lead us to specify a terminal stage of rapidAcanthamoebadifferentiation elicited by acute organic solvent stress as "pseudocyst", and to suggest that encystation and pseudocyst formation are distinct stress responses. Moreover, the possibility exists that pseudocysts might form in response to certain contact lens solutions thus increasing resistance of acanthamoebae to disinfecting agents.

Entire Contact Lens Imaged In Vivo and In Vitro With Spectral Domain Optical Coherence Tomography

To demonstrate the capability of directly visualizing the entire ocular surface and the entire contact lens on the eye using spectral domain optical coherence tomography (SD-OCT). A custom-built, high-speed, and high-resolution SD-OCT was developed with extended scan depth and width. The eye was imaged before and after wearing a toric soft contact lens (PureVision; Bausch & Lomb). A lubricant eye drop (Soothe; Bausch & Lomb) was instilled in the eye to enhance the image contrast on the lens. The same toric soft contact lens immersed in the contact lens solution was also imaged with a contrast enhancement medium (0.5% Intralipid). Cross-sectional OCT images of the entire ocular surface were acquired with high-resolution 2,048 x 2,048 pixels. Quantitative surface height map of the ocular surface was obtained from a radial scan data set containing 32 B-scans. With the contrast enhancement agent, the entire toric soft contact lens was clearly visualized, both in vitro and on the eye. The surfaces of the lens were detected and used to generate the thickness maps of the soft contact lens. Spectral domain optical coherence tomography with extended scan depth and width is a promising tool for imaging the entire ocular surface shape and soft contact lenses. This successful demonstration suggests that the extended depth SD-OCT is effective in studying ocular surface shape and its interaction with a soft contact lens. The novel method is helpful for the evaluation of contact lens fitting and lens design.

Concurrent Acanthamoeba and Fusarium Keratitis With Silicone Hydrogel Contact Lens Use

To report a case of simultaneous Acanthamoeba and Fusarium keratitis associated with no-rub multipurpose contact lens solution and silicone hydrogel contact lens use. Observational case report. A 39-year-old woman was referred for worsening of a presumed bacterial corneal ulcer in the setting of silicone hydrogellens wear with occasional overnight wear, no-rub multipurpose contact lens solution use, and combined topical antibiotic/corticosteroid treatment. Initial corneal scrapings and culture confirmed Acanthamoeba and Fusarium solani, corroborated by in vivo confocal microscopy findings, yet despite topical chlorhexidine 0.02%, propamidine 1%,neomycin/polymyxin B ointment, and natamycin 5% along with oral itraconazole, the ulcer worsened. Four days after amoebic and fungal therapy initiation, it was discovered that the pharmacy accidentally dispensed neomycin/polymyxin B/dexamethasone, and despite immediate discontinuation, therapeutic penetrating keratoplasty from corneal melting was ultimately required. Corneal histopathology confirmed the presence of amoebic cysts and fungal elements. Coexisting infection with Acanthamoeba and Fusarium species can occur in contact lens wear. Atypical infection must be considered in patients with corneal ulcers demonstrating poor therapeutic response in the setting of contact lens wear. Corticosteroids should be used with extreme caution in contact lens–related corneal infections, especially when the diagnosis remains unknown because they can lead to acceleration of active infection and keratolysis.

Bacterial Contamination of Stock Solutions in Storage Cases for Contact Lens, and the Disinfectant-Resistance of Isolates

To investigate the bacterial contamination of preservative solutions for contact lenses, contact lens cases were swabbed and the swabs were cultured. Various bacteria were isolated from 26 of 100 samples (26.0%). By preservative solution, the bacterial presence was low (16.7%) in the 30 samples from cases using ReNu, which was the most frequently employed solution, and 27.3% in 11 samples from cases using Complete, which was the second most frequently employed solution. Of 34 strains isolated and identified, gram-negative bacilli-glucose non-fermenting bacteria were the most frequently isolated, accounting for 61.8% (21 strains); particularly, 10 isolates were Stenotrophomonas maltophilia, accounting for 29.4%. The biofilm-forming ability of these isolates was investigated by staining. The mean absorbance of the gram-negative rods was 0.369, which was about 3 times higher than that (0.107) of the Staphylococcus group, confirming marked biofilm-forming ability. In addition, the bactericidal effects of the preservative solutions on the isolates were investigated. The effect varied among the preservative solutions in the suspension experiment, but the highest disinfection rate, which was achieved by Complete, was 99.9->99.99%, showing a favorable bactericidal effect. In contrast, none of the 3 test preservative solutions showed any bactericidal effect in the adhesion experiment.

MoisturePlus Contact Lens Solution as a Source of Acanthamoeba Keratitis

MoisturePlus Contact Lens Solution as a Source of Acanthamoeba Keratitis

National Outbreak of Acanthamoeba Keratitis Associated with Use of a Contact Lens Solution, United States

National Outbreak of Acanthamoeba Keratitis Associated with Use of a Contact Lens Solution, United States

Contact Lens–Related Adverse Events and the Silicone Hydrogel Lenses and Daily Wear Care System Used

To investigate the incidence of adverse events related to the use of varying silicone hydrogel contact lens and lens solution combinations. Individuals with myopia (N = 558) participated in 1 or more of approximately 40-participant trials in a matrix of 20 silicone hydrogel contact lens and lens-solution combinations. Visits were at baseline, 2 weeks, 1 month, and 3 months. The mean study completion rate was 90% of the expected participant-months (final data set: 840 lens-solution combinations and 2271 participant-months). Adverse events were reported as the first occurrence of each type per 100 participant-months for each lens-solution combination. The rate of all corneal infiltrative events (CIEs) was 3.1 per 100 participant-months (range, 0-10.5), and the rate of symptomatic CIEs was 1.7 per 100 participant-months (range, 0-10.5), including 1 case of microbial keratitis (0.04 per 100 participant-months). Rates for CIEs differed substantially among solution groups, with hydrogen peroxide having the lowest rate (0.6 per 100 participant-months; range, 0-0.9). The rate was 0.8 per 100 participant-months (range, 0-8.0) for superior epithelial arcuate lesions, which varied by lens type, 0.04 per 100 participant-months (1 case only) for corneal erosion, and 0.4 per 100 participant-months (range, 0-2.0) for contact lens papillary conjunctivitis, which was modified by type of solution. The rate of solution-induced corneal staining for all lens-solution combinations was 4.7 per 100 participant-months (range, 0-23) and varied significantly based on lens-solution combination (P < .001). The frequency of adverse events varied with silicone hydrogel contact lens and lens solution combinations, with hydrogen peroxide having the lowest incidence of CIEs and solution-induced corneal staining, indicating that lens material and design, type of solution, and solution-lens interactions are likely contributing factors in this mode of lens wear.

Contact Lens Solutions: Part of the Problem

FTER EFFORTS TO IMprove comfort, reducetoxicity,andfacilitate compliance regarding multipurposecontactlenssolutions,thetime has come to enhance their antimicrobial efficacy. It had been hoped that the ease of use of multipurpose solutions would enhance compliance, but noncompliance remains common, and even compliant patients have developed serious infections. In 2006 and 2007, there were voluntary recalls of 2 specific multipurpose solutions owing to their association with Fusarium and Acanthamoeba corneal infections. Since thistimecontactlens–associatedFusarium infections appear to have decreased, but Acanthamoeba infections remain a serious problem. Standards for multipurpose solutions need to be modified to include cidal action against Acanthamoeba cysts. Instructions for contact lens careneedtoincludedirectionstoresume rub-and-rinse steps and avoid exposure of contact lenses and lens cases to water. Afterextensivecarefulinvestigation,theFusariumoutbreakin2005 and 2006 associated with the use of ReNu with MoistureLoc solution (Bausch & Lomb, Rochester, New York) was determined to be caused by a failure in clinical use, despite in vitro efficacy and a lack of manufacturingproblems. 1,2 Inviewofthe geneticdiversityandthespecificFusarium solani species complex groupsisolated,theCentersforDiseaseControlandPrevention(CDC) study concluded that sink and shower water were the most likely sourcesofinfection. 1 Patientsinthe CDC study were more likely than controls to reuse solution by topping off their cases. Investigators at Bausch & Lomb did studies that simulated the reuse and evaporation of different types of solution without the disinfectant alexidine. 2 Withreuse,theconcentrationofthe disinfectantalexidinedecreasedowing to lens uptake, and with evaporation the concentration increased. They reported that under both conditions, ReNu MoistureLoc became less effective against Fusarium, although in stand-alone testing it caused a 3.3-log reduction of Fusarium, which surpassed the 1-log requirement. Ideally, solutionefficacyshouldbelessdependentontheconcentrationofthedisinfectant, as this may vary with use. It is also noteworthy, in these studies, that when MoistureLoc solution evaporated and left a polymer film that contained 2 strains of Fusarium, the strain from a clinical infectionsurvivedMoistureLocdisinfection, but the strain specified in the Food and Drug (FDA) test did notsurviveinthefilm.TheFDAtest isolates may need to be updated becausethereisanotherreportofclinical isolates of Serratia marcescens that are more resistant to multipurposesolutionsthanthestandardtest strain. 3 Other studies have also shown that clinical isolates of Fusariumsurviveinthedryingfilmsof

Non-Compliance and Microbial Contamination in Orthokeratology

To determine the rates of microbial contamination of solutions and lens accessories of existing ortho-k lens wearers and the effect on contamination rates of monthly replacement and warnings. To investigate self-reported levels of compliance with care of the lenses and lens accessories and correlation of these levels with the rates of microbial contamination. Asymptomatic ortho-k lens wearers with at least 6-month successful use were requested to bring their lenses, solutions, and accessories to their next aftercare visit. All items, except the lenses, were replaced at each data collection visit. Samples collected from the lens surface, solution, and accessories were cultured for pathogens. These procedures were repeated twice at 1-month intervals. At the first visit, each subject and/or parent was interviewed about the care/use of the lens and accessories. Thirty-eight subjects completed the study. Initial contamination rates of the lenses, lens cases, and tweezers were 29, 34, and 46%, respectively. Rates of contamination dropped for lenses, suction holders, and tweezers during the three-visit intervention. Contact lens solutions, except lens cleaner were contaminated on all occasions with the most contaminated product being artificial tears [33% (n = 18)]. There was no improvement in the contamination rate of the lens cases. The most common pathogens isolated were Staphylococcus aureus and Serratia marcescens. Compliance was lowest for care of lens cases and highest for care of lenses. However, correlation between reported compliance and presence of pathogens failed to reach significance. Subjects' awareness of the importance of lens cleanliness is high and can be improved by regular reinforcements. However, attitudes toward cleaning of accessories was far less satisfactory and while replacement and warnings resulted in significant improvements of contamination rates of tweezers and suction holders, more emphasis should be placed on educating patients on correct care of lens accessories.