Contact Lens Solutions Research Articles

Contact Lens Solution Pulled in Wake of Infections

Contact Lens Solution Pulled in Wake of Infections

Efficacy of Contact Lens Storage Solutions against Different Acanthamoeba Strains

This study was undertaken in order to determine the susceptibility of acanthamoebae to various contact lens disinfecting systems, with respect to type of disinfectant and exposure time. Ten contact lens solutions, including one new system, were tested for their effectivities against cysts of three Acanthamoeba strains. Of main interest was an incubation time of 8 hours (overnight disinfection) and cyst quantities of 10 and 10, respectively. Boston Advance (polyaminopropyl biguanide 0.0005%, chlorhexidine 0.003%) for the storage of rigid gas permeable contact lenses destroyed the cysts of all strains at either concentration within one hour of exposure. Meni Care Plus (polyhexamethylene biguanide 0.0005%) also destroyed 10 cysts of all strains, however, 10 cysts only of two strains within one hour; after an exposure time of 8 hours all cysts were killed. The disinfecting solutions for soft contact lenses did not kill 10 cysts of either strain after 8 hours of incubation time. Two of the tested contact lens solutions (the ones for rigid gas permeable lenses) destroyed the cysts of all strains. One of these, containing a combination of two amoebicidal ingredients even after only one hour of exposure time.

Evaluation of povidone-iodine as a disinfectant solution for contact lenses: Antimicrobial activity and cytotoxicity for corneal epithelial cells

Povidone-iodine (PVP-I) possesses broad-spectrum antimicrobial activity and is used clinically as a disinfectant. We evaluated the disinfectant properties and safety of PVP-I for use as a contact lens solution. The concentrations of PVP-I required to reduce the number of Staphylococcus aureus or Candida albicans by 3 log units were lower than were those of hydrogen peroxide, polyhexamethylene biguanide (PHMB), and benzalkonium chloride (BAK). The cytotoxicity of PVP-I for cultured human corneal epithelial (HCE) cells was less than that of the other three agents. The safety margin for PVP-I was thus greatest among the tested compounds. PVP-I appears suited for use as a contact lens disinfectant.

Disinfecting Solutions for Soft Contact Lenses Using Different Color Indicators

The color change reached in two commercial disinfecting solutions for soft contact lenses using new color indicators has been analyzed, and its relationship with the temporal evolution of the hydrogen peroxide concentration, responsible for the disinfection process, has been examined. The results are compared with another commercial solution using a different color indicator. Color measurements of the disinfecting solutions were performed at 2-minute intervals for over 2 hours using a Photo-Research PR-704 spectroradiometer with horizontal optical axis. Samples were placed at the floor of a VeriVide CAC 120 light booth with a Munsell gray mask behind them. Two different standard light sources, representative of outdoor and indoor illumination, were used. The hydrogen peroxide concentration during the disinfection process was measured for each commercial solution using a Beckman DU-7 spectrophotometer. The temporal evolutions of color for the two new disinfecting solutions were qualitatively different. CIELAB color differences induced in these two new disinfecting solutions were 1.5 and 2.2 times greater than that measured in the earlier comparative solution and occur in a more appropriate direction of color space for users with defective color vision. Although the earlier solution generated color changes close to the deutan confusion line, the changes produced by the new solutions are close to the tritan confusion line. After 2 hours, the hydrogen peroxide concentration for the two new solutions was approximately one-third the one reached by the earlier solution. There are statistically significant correlations (p < 0.01) between color change and hydrogen peroxide concentration for the two new solutions (r = -0.878 and r = -0.990). Color changes in these hydrogen peroxide systems can be used as a safe and useful tool by contact lens wearers. The two new disinfecting solutions analyzed in this article show noteworthy improvements over the earlier solution.

International Travel with Children

International Travel with Children

Viability of Human Periodontal Ligament Fibroblasts in Tissue Culture After Exposure to Different Contact Lens Solutions

The viability of the periodontal ligament (PDL) cells is critical for successful healing of replanted avulsed teeth. Viability is primarily dependent on the duration of the extra-alveolar time and storage medium used to preserve teeth. Several storage media have been suggested but milk ranks highest. It would be desirable to evaluate other media as a suitable alternative for milk. The purpose of this study was to determine the viability of human PDL fibroblasts and their morphology after storage in different types of contact lens solutions. PDL fibroblasts were cultured from a healthy extracted impacted human tooth and exposed to Bausch and Lomb (Renu), Ciba Vision (Titmus), and Alcon (Opti-free) contact lens solutions. Eagle's minimal essential medium served as control. The experiment was performed in plastic tissue culture clusters containing 24 wells. The PDL fibroblasts were grown in each well for three days. On the day of the experiment the culture medium was decanted, the cells were washed with phosphate buffered saline solution (PBS), and 1 ml of the tested solution was placed in each culture well. All tissue culture clusters were incubated at 37 degrees C in 5% CO2 and 95% air for one, four, and 24 hrs. At the end of the incubation period, the cells were fixed and prepared for scanning electron microscope (SEM) examination. The results indicated Renu and Opti-free solutions were superior to Titmus solution in terms of their capacity to maintain the viability and normal morphology of PDL fibroblasts. Contact lens solution is a good storage medium to maintain the viability of PDL fibroblasts for a short-term period.

Artificial Tear Gel as a Gonioscopic and Contact Lens Ophthalmoscopy Fluid

An easy and convenient method of using a commercially available clear lubricant eye gel for diagnostic and therapeutic contact lens applications at the slit lamp is described. The authors used hydroxypropyl methylcellulose 0.3% as a medium for contact lens applications and compared it to the traditional hydroxypropyl methylcellulose 2.5%. Hydroxypropyl methylcellulose 0.3% as a contact lens solution is clear, viscous, and easy to apply; does not require irrigation after use; and has levels of convenience, safety, and visual recovery superior to the standard 2.5% solution characteristics. The 0.3% gel could be used as an effective and convenient gonioscopic and ophthalmoscopic contact medium.

Daytime Orthokeratology Associated With Infectious Keratitis by Multiple Gram-Negative Bacilli: Burkholderia cepacia, Pseudomonas putida, and Pseudomonas aeruginosa

To report a case of a corneal ulcer in a patient who wore orthokeratology contact lenses during the day. Case report. A 16-year-old girl who underwent orthokeratology treatment developed a corneal ulcer in her right eye. The refractive status of the affected eye was -5.75 -1.75 x 180, and the best-corrected visual acuity was 20/40. Corneal topography showed the temporal upper dislocation of a central flattened zone in the right eye. The patient had worn orthokeratology contact lenses during the day for more than 4 years. Her ulcer became worse after treatment with tobramycin and gentamicin for 1 day. After treatment with ciprofloxacin, the ulcer healed, and visual acuity returned to 20/20 with spectacle correction. Cultures of the cornea, contact lens, and lens solution all grew Burkholderia cepacia, Pseudomonas putida, and Pseudomonas aeruginosa. Improper fitting of lenses and contamination of lenses or solutions in orthokeratology therapy are risk factors for a corneal ulcer, even when patients wear orthokeratology lenses only during the day.

The Effect of Multipurpose Solutions on the Ocular Surface

We aimed to determine if multipurpose contact lens solutions could solely contribute to adverse ocular surface effects. Three specific multipurpose solutions were evaluated: Bausch & Lomb ReNu MultiPlus (ReNu with MoistureLoc was not evaluated in this study), Alcon No Rub Opti-Free Express, and Advanced Medical Optics Complete Moisture Plus. The impact that solutions have on the ocular surface, if negative, could be adverse. Nearly all recent studies examine the effects of solutions through the contact lens as a vehicle for delivery. The lens itself cannot be completely ruled out as a causal factor. 21 subjects were randomized to one of the three solution groups. Subjects self-administered a solution to their treatment eye four times daily, with the fellow eye serving as the control. Solutions and the test eye were masked to the subject and examiner. A battery of ocular surface testing was conducted at the baseline examination and at every week interval by masked examiner. Non-parametric data was analyzed by Friedman 1-way ANOVA and parametric data by the 1-way repeated measures ANOVA. A reduction in tear breakup time was found to be statistically significant for the ReNu group (P < 0.05). ReNu has frequently been cited as being more cytotoxic. We propose that when used at a high frequency, ReNu preservatives and additives are adverse. Contact lens dropout and/or clinical signs noted by the examiner may be linked to the use of ReNu.

Fusarium Keratitis Outbreak Due to Contact Lens Solution

Microbial keratitis is a well-known risk of contact lens use, although fungal infections in this setting have been considered quite rare. Thus, when three cases of contact lens–associated fusarium keratitis were reported to the CDC in March 2006 after similar cases had appeared in Singapore and Hong Kong, a national investigation was started. By June 30, 2006, the CDC had …

Effects of multipurpose contact lens solutions on the protein composition of the tear film

Objectives: To analyze the influence of multipurpose contact lens cleaning solutions on tear proteins. Changes in tear film protein profiles of contact lens wearers who used several marketed brands of multipurpose contact lens care solutions, were assessed by ProteinChip analysis. Methods: Three studies were conducted. Study I was a comparison of Complete and OptiFree multipurpose solutions. Study II was a study with Complete Moisture Plus solution, Study II was a comparison of Renu and Solocare contact lens solutions. Wearers of soft contact lenses were assigned to use the contact lens care solutions for 4 weeks. Non-contact lens wearing patients were used as controls. Tear samples of each participant were analyzed with the ProteinChip (SELDI–TOF) system. Multivariate statistical analysis and artificial neural networks were used to determine the tear protein profiles of each study group. Results: Before starting the use of the solutions, the tear protein composition in all contact lens wearers deviated from the tear composition of the non-contact lens wearing controls. After 4 weeks of using the different care regimens, the tear protein composition of the patients using Complete or Complete Moisture Plus solutions tended to move toward that of the non-contact lens wearing controls. The tear protein composition of patients using the OptiFree, Renu or Solocare solutions did not undergo a measureable change in the protein level. Conclusions: The ProteinChip system can analyze protein profiles for large-scale applications as in clinical studies. Two multipurpose solutions, Complete and Complete Mositure Plus, demonstrated a beneficial effect on the tear proteins in contact lens wearers.

Lessons in giving vaccines: soft tissue complications of vaccinations

Adverse reactions to vaccines vary from the mild to fatal.1 Systemic reactions can be attributed to the vaccine itself, but local reactions are often due to hypersensitivity to other agents in the vaccine. These include adjuvant (e.g. aluminium hydroxide), stabilizers (e.g. gelatin), antibacterial preservatives (e.g. mercury-based thiomersal) and antibiotics (e.g. neomycin). There are many other causes. Many of these substances are also found in other medicines, including anti toxins, contact lens solutions, allergy extracts, topical antibiotic agents and immunoglobulin.2 It has been suggested that alternative substances should be sought to prevent these problems but this has been difficult to achieve.3 Other reactions reported include urticaria, angiooedema, atopic eczema and granuloma annulare.4 Most of the hypersensitivity reactions settle on conservative treatment. Aluminium hydroxide is the main causative agent in granuloma formation at the site of vaccination.5 This has been previously reported in one case of tetanus toxoid injection, three cases of diphtheria, pertussis and tetanus (DPT) inoculation,6 one case of Q fever vaccination7 and three cases of the quadruple vaccine (tetanus, diphtheria, pertussis, polio).8 The illustrated case (Fig. 1) had each of the three DPT injections in the lateral thigh at the appropriate times. The second and third injections were given in spite of the discharging lesion. Aluminium was confirmed in the granulomata on electron microscopy. These discharging sinuses require surgery. Another significant problem is keloid scar formation at the site of BCG vaccination. This vaccine is traditionally given in the deltoid area (Fig. 2). This anatomical site has a bad reputation for scarring anyway but keloids occur more often if there is secondary bacterial infection or delay in healing. Problems can also arise when the vaccine is wrongly inserted in the superficial dermis. Keloid is also more common in some ethnic groups such as Afro-Caribbean and Chinese. Once a keloid (or even a hypertrophic reaction) has developed, it can be very difficult to treat. Repeat BCG should be given in a less conspicuous site, for example. the upper inner arm.9

Effect of a Multipurpose Contact Lens Solution on the Survival and Binding of Acanthamoeba Species on Contact Lenses Examined With a No-Rub Regimen

To determine the effect of a multipurpose contact lens solution (ReNu MultiPlus Multi-Purpose Solution [RMP]) on the relative survival and binding of trophozoites and cysts of Acanthamoeba on hydrogel lenses with a no-rub regimen. A stand-alone test procedure with RMP was conducted with and without the presence of organic soil (1 x 10(7) colony-forming units/mL heat-killed cells of Saccharomyces cerevisiae in heat-inactivated fetal bovine serum). Survival of amoebae on hydrogel contact lenses exposed to RMP was determined with a no-rub care regimen. ReNu MultiPlus Multi-Purpose Solution reduced the number of recoverable amoebae by more than 95% within 4 hours of inocula of 10(5) trophozoites and cysts, regardless of the presence or absence of an organic soil. Amoebae, particularly cysts, were readily rinsed from contact lenses, including silicone hydrogels, without rubbing after exposure to RMP. The efficacy of RMP for Acanthamoeba was not appreciably altered in the presence of organic soil in a no-rub protocol. The antimicrobial activity, in part, appeared to be a combination of reducing the capacity for binding of representative Acanthamoeba to the lens by alteration of morphology, often followed by lysis of the amoebae.

Doubtful Value of Patch Testing for Suspected Contact Allergy to Ophthalmic Products

Sir, Allergic contact dermatitis is the most common cause of peri-orbital eczema (1). It may be caused by allergens brought in contact with the eyelids by hand transfer (like toluene sulfonamide-formaldehyde resin in nail polishes), by airborne contact (like sesquiterpene lactones) or, most frequently, by direct application of cosmetics or topical ophthalmic medicaments. The percentage of sensitization due to cosmetics, such as moisturizing creams or eye-shadows, is estimated to range from 2.5% to 26% (2, 3). However, topical ophthalmic drugs, eye drops and contact lens solutions play a considerable role too. We studied 62 patients with eyelid dermatitis, closely related to the use of topical ocular products, with the aim of discerning the role of ophthalmic products in eyelid allergic contact dermatitis.

Effectiveness of Contact Lens Disinfectants After Lens Storage

To determine the effectiveness of multipurpose contact lens solutions after incubation with lenses for one week. Five multipurpose solutions, three lots each, were preincubated with contact lenses for one week. The solutions were removed and one of three microbes was added to a final concentration of l x l0(6)/mL. The inoculated solutions were incubated for 4 and 6 hours; aliquots were then neutralized, serially diluted, and plated. Plate counts were used to determine the approximate number of organisms that were killed effectively by the contact lens solution. Of the five solutions tested, only OPTI-FREE Express maintained full effectiveness after preincubation with lenses. The other solutions were effective only with Fusarium solani after the preincubation period. We propose that the active component was sufficiently reduced by absorption or inactivation during storage with contact lenses such that it was rendered effective only for F. solani and was no longer concentrated enough to be effective with the bacterial species.

Effect of storage temperatures and time on the efficacy of multipurpose solutions for contact lenses.

To determine the effect of storage time and temperature on the efficacy of four multipurpose solutions for soft contact lenses. Aliquots of multipurpose solutions (OPTI-FREE Express, ReNu MultiPlus, COMPLETE and SOLO-care) stored at different temperatures over a 3-month period, were challenged with contact lens-related ocular pathogens, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. The results showed that OPTI-FREE Express had the best activity against Ps. aeruginosa at all temperatures; ReNu MultiPlus performed well at 25 degrees C; COMPLETE barely achieved activity requirements at all temperatures, and lost efficacy after 2 months. SOLO-care maintained its activity best against Ps. aeruginosa at 30 degrees C. Storage at fridge temperature reduced activity of all solutions. Regardless of storage temperature, activities of all solutions against S. aureus markedly decreased by 2 months. Only OPTI-FREE Express met FDA requirements against C. albicans. Performance of multipurpose solutions is affected by time and temperature of storage. Contact lens users should be aware that the efficacy of opened solutions may not be sustained for as long as 3 months. Manufacturers should reconsider their recommendations to further safeguard the ocular health of contact lens wearers.

Survival of human periodontal ligament cells in media proposed for transport of avulsed teeth

Many solutions have been examined as possible storage media for avulsed teeth. In this report, human periodontal ligament (PDL) cells were exposed for 1 h to culture medium, milk, Hanks Balanced Salt Solution (HBSS), Soft Wear, Opti Free, and Solo Care contact lens solutions, Gatorade, and tap water, at room temperature and on ice. The number of viable cells was counted using the trypan blue exclusion technique, immediately after exposure (0 h) and at 24 and 48 h, to test the proliferative capacity of the cells after treatment. The results indicated that a significantly higher number of cells survived and proliferated when the exposures were performed at 0 degrees C. Water had a detrimental effect on the cells, whereas culture medium and HBSS preserved significantly more viable cells than the other experimental solutions. Within the parameters of this study, it appears that HBSS is the optimal storage medium for avulsed teeth. Low-fat milk could serve as an alternative if ice is available. Contact lens solutions or Gatorade on ice could serve as short-term (1 h) storage media if the other solutions are not readily available.

Acanthamoeba polyphaga strain age and method of cyst production influence the observed efficacy of therapeutic agents and contact lens disinfectants.

The effects of age in culture and the type of medium used for induction of Acanthamoeba polyphaga (Ros) cysts on susceptibilities to polyhexamethylene biguanide (PHMB; 3 micro g/ml), chlorhexidine digluconate (30 micro g/ml), myristamidopropyl dimethylamine (20 micro g/ml), H(2)O(2) (3%), and two multipurpose contact lens solutions (MPS-1 and MPS-2, based on 1 micro g of PHMB per ml) were examined. Strain Ros-02 was cryopreserved on isolation in 1991, while strain Ros-91 had been in continuous axenic culture. Significant differences in susceptibilities to the disinfectants were found depending on the medium used for cyst preparation and the age of the test strain, with Ros-02 generally being more resistant. For example, the killing of Ros-91 cysts produced from an axenic culture of trophozoites in the presence of 50 mM MgCl(2) by MPS-2 was 4 logs, but the killing of Ros-02 by MPS-2 was only 2 logs (P < 0.05) and killing of both strains with cysts obtained from monoxenic cultures with Escherichia coli was only 1 log (P < 0.001). Assays repeated with different batches of the various cyst types gave consistent results. A batch of Ros-91 cysts stored at 4 degrees C and tested over an 8-week period with MPS-1 showed progressively increasing susceptibility to disinfection, although there was no loss of viability during storage (P < 0.01). These observations have important implications for the standardization and interpretation of Acanthamoeba disinfectant and therapeutic agent testing.

Preliminary evaluation of several disinfection/sterilization techniques for use with microdialysis probes

This study evaluated the suitability of some disinfection and sterilization methods for use with microdialysis probes. Disinfection or sterilization should minimize the tissue inflammatory reaction and improve the long-term health of rats on study and ensure the quality of data obtained by microdialysis sampling. Furthermore, the treatment should not negatively impact probe integrity or sampling performance. The techniques chosen for evaluation included two disinfection methods (70% ethanol and a commercial contact lens solution) and two sterilization methods (hydrogen peroxide plasma, and e-beam radiation). Linear microdialysis probes treated by these processes were compared to untreated probes removed from the manufacturer's packaging as if sterile (the control group). The probes were aseptically implanted in the livers of rats and monitored for 72 hours. The parameters chosen to evaluate probe performance were relative sample mass recovery and the relative in vivo extraction efficiency of the probe for caffeine. Post mortem bacterial counts and histopathology examination of liver tissue were also conducted. The probes remained intact and functional for the entire study period. The methods tested did not acutely alter the probes although hydrogen peroxide plasma and contact lens solution groups showed reduced extraction efficiencies. Minimal tissue damage was observed surrounding the probes and acute inflammatory reaction was mild to moderate. Low numbers of bacterial colonies from the implantation sites indicates that the health of animals in this study was not impaired. This was also true for the control group (untreated probe).

Effect of a chitin derivative in combination with cleaning and preservation solutions for contact lenses on adherence of fungi.

The objective of the study was to evaluate the effect of supplementation of a chitin soluble extract (CSE) to clinically used commercial contact lenses' cleaning/preservation solutions on adherence of Aspergillus niger and Candida albicans to contact lenses. CSE (25 mg ml-1) was added to Solocare or Oxysept. Adherence of A. niger or C. albicans to contact lenses was assessed by exposing lenses to fungi in test solutions and enumeration of fungal colony forming unit. The study included three parts: (i) the disinfecting and adherence-inhibiting effect of Solocare and Oxysept: (ii) the adherence-inhibiting effect of CSE; (iii) the effect of Solocare + CSE or Oxysept + CSE on the fungal adherence to contact lenses. The experiments showed that: (i) Solocare had a significant disinfecting effect on A. niger and C. albicans while that of Oxysept was only minimal. (ii) Neither Solocare nor Oxysept had an inhibitory effect on the fungal adherence. (iii) CSE inhibited significantly the adherence of A. niger and C. albicans. (iv) Addition of CSE to Solocare or Oxysept resulted in almost complete inhibition of adherence Supplementing CSE to lenses' maintenance solutions increases their antifungal potential by adding anti-adherence activity to the disinfecting effect of these solutions, bearing the potential to serve as a prophylactic means.