Multipurpose Contact Lens Solutions Research Articles

Efficacy of multipurpose solutions against Acanthamoeba species

Aim The disinfection efficacy of contact lens multipurpose solutions (MPSs) against Acanthamoeba polyphaga (Ros) and Acanthamoeba castellanii (ATCC30868) cysts and trophozoites was determined by both biocidal and manufacturer-recommended no-rub/rinse regimen testing. Methods A biocidal assay using four MPSs (ReNu ® with MoistureLoc ®, Opti-free Express, Solo-care Plus, and Complete MoisturePlus) was conducted with or without the presence of organic soil. A second test procedure compared the ability of five MPSs (ReNu with MoistureLoc MPS, ReNu MultiPlus, Opti-free Express, Solo-care Aqua, and Complete MoisturePlus) to remove and kill Acanthamoeba species cysts and trophozoites from SofLens 38 and Surevue conventional hydrogel lenses, and Focus Night & Day silicone hydrogel lenses using the manufacturer-recommended regimen. Results In the biocidal assay, only ReNu with MoistureLoc successfully killed both trophozoites and cysts (>3 log) within the manufacturer-recommended soak time. A >3 log decrease in trophozoites, but not cysts, was reported for Opti-free Express; however, Solo-care Plus and Complete MoisturePlus did not reduce the number of cysts or trophozoites by >3 log during the manufacturer-recommended soak time. In the no-rub/rinse regimen tests, only ReNu with MoistureLoc removed an inoculum of 2 × 10 5 trophozoites or cysts from SofLens 38 and Surevue hydrogel lenses, as well as Focus Night & Day silicone hydrogel lenses. Less than 10 viable organisms were recovered from the lenses after the 10 s rinse and 4 h soak. Opti-free Express, Solo-care Aqua, and ReNu MultiPlus were effective at removing trophozoites and cysts from SofLens 38 and Surevue conventional hydrogel lenses, but not from Focus Night & Day silicone hydrogel lenses. In excess of 10 viable organisms were recovered from all lenses after the manufacturer-recommended regimen using Complete MoisturePlus. Conclusions These data suggest that some MPSs, when used as recommended by the manufacturer, are more effective at killing representative strains of Acanthamoeba than others.

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.

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.

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.

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.

Phagocytosis affects biguanide sensitivity of Acanthamoeba spp.

The incidence of Acanthamoeba keratitis, a disease associated with contact lens wear, has been in apparent decline with the advent of multipurpose contact lens solutions. The concentrations of the biguanides chlorhexidine digluconate (CHX) and particularly polyhexamethylene biguanide (PHMB) included in multipurpose solutions (MPSs) are sublethal for amoebae. We evaluated by flow cytometry the effects of these two biguanides on phagocytosis of particles and the survival of trophozoites of Acanthamoeba castellanii and A. polyphaga. Trophozoites of A. castellanii and A. polyphaga (10(6)/ml) were exposed to solutions of 5 and 50 microg of PHMB and CHX per ml in the presence and absence of particles (i.e., heat-killed yeasts and bacteria and latex beads). In addition, trophozoites were exposed to particles treated with these concentrations of the two biguanides. In the absence of particles, trophozoites of A. polyphaga appeared to be more resistant to the biguanides than those of A. castellanii. In the presence of particles, the rates of survival of both species were decreased. In most instances, particles treated with sublethal concentrations of both biguanides that were adsorbed onto the particles reduced the incidence of phagocytosis. Particles present in MPSs in contact lens cases may be involved in the decreased incidence of Acanthamoeba keratitis.

Amoebicidal activity of a preserved contact lens multipurpose disinfecting solution compared to a disinfectinn/neutralisation peroxide system

The amoebicidal activity of a contact lens multipurpose disinfecting solution (MPDS) containing polyquaternium-1 and myristamidopropyl dimethylamine was compared to a disinfection/neutralisation peroxide system against Acanthamoeba castellanii and Acanthamoeba polyphaga trophozoites and cysts. A quantitative microtitre method was used to evaluate the solutions. The MPDS showed similar amoebicidal activity to the disinfection/neutralisation peroxide system against the trophozoites of both species and equal or more rapid activity against the cysts of both species.

PH of multipurpose contact lens solutions over time

The pH of nine different brands of multipurpose contact lens solutions available in Spain was determined over a period of 32 days after opening the bottles. Five bottles of nine solutions were used, each of which was buffered and obtained from different manufacturers. The pH measurements were taken using a micropH 2002 Crison pH-meter (accuracy ±0.001 pH units). Each solution was measured three times daily over the test period using 10-ml samples taken from the same container. Fluctuations in pH over time were observed but these were within the range of ocular comfort. The average pH of all the solutions tested proved to be between 6.99 and 7.56.

Comparative study of pH for different saline and multi-purpose contact lens solutions

In this study, we determined the pH of different saline and multipurpose contact lens solutions available on the Spanish market. We examined 10 samples of 14 solutions, seven of which are saline solutions and seven multipurpose ones, from different manufacturers. Both types of solution were found to have significant variations in pH, with values ranging from 6.70 to 7.57 for the saline solutions and 6.84 to 7.63 for the multipurpose solutions. We concluded that the solutions should not affect the ocular physiological performance because their pH values are within the buffering capacity of the eye.

Clinical comparison of three polyhexanide-preserved multi-purpose contact lens solutions

This study investigated the clinical differences between three commercially available polyhexanide (PHMB) preserved disinfection systems containing varying percentages of PHMB, when used with FDA group II and group IV disposable contact lenses. After 1 month of wear the product with the highest concentration of PHMB (All-in-One) was graded as being less comfortable on insertion (P<0.003), had lower overall satisfaction (P<0.05) when compared with the other two products. Corneal staining was also significantly higher with this product after both 14 days (P<0.001 with group II and P<0.02 with group IV) and 28 days (P<0.00001 with group II and P<0.03 ith group IV).