Effects Of Multipurpose Solutions Research Articles

Effect of multipurpose solutions on in vivo surface wettability of a silicone hydrogel lens.

To compare the in vivo surface wettability of silicone hydrogel (SiHy) contact lenses pre-soaked overnight in different multipurpose solutions (MPS) and normal saline. In this double-blinded, randomized and self-controlled study, 36 subjects were fitted with three pairs of contact lenses (senofilcon A) pre-soaked overnight in five different MPS and saline in a randomized order. Each pair of lenses (pre-soaked in two different solutions the night before) were worn for 15min before assessment of pre-lens non-invasive tear break-up time (PL-NITBUT) using the Medmont corneal topographer (video recording). Corneal integrity was assessed using a slit lamp and a resting interval of 20min was allowed between each pair of lenses to ensure post-lens wear corneal integrity. Thirty subjects completed the study. The median PL-NITBUT ranged from 2.84s to 3.08s with lenses pre-soaked in different MPS, compared to 2.78s with lenses pre-soaked in saline. No significant differences in PL-NITBUT were found among lenses pre-soaked in different solutions (p=0.647). In vivo surface wettability, in terms of PL-NITBUT after 15min of lens wear, of senofilcon A contact lenses pre-soaked overnight in different MPS were not significantly different from those pre-soaked in saline.

Effects of multipurpose solutions on the adhesion of Acanthamoeba to rigid gas permeable contact lenses.

To evaluate the effect of multipurpose contact lens care solutions (MPSs) on the adhesion of Acanthamoeba to rigid gas permeable (RGP) contact lenses. Acanthamoeba castellanii (AC) trophozoites were inoculated onto untreated RGP contact lenses (FP, Extra, or Menicon Z), and numbers of trophozoites adhering to lenses were counted under a phase contrast microscope at 18h post-inoculation (controls). Similarly, adhering trophozoites were counted at 6h post-inoculation on each of the three RGP lens types with one of three MPSs (Boston Simplus, Menicare Plus, and O2 Care). Scanning electron microscopic examinations were performed to compare lens surfaces. Adhesion of AC trophozoites to untreated FP was greater than to untreated Extra or Menicon Z. Surfaces of Extra and Menicon Z lenses were waxier, smoother, and more homogeneous than those of FP lenses. After treatment with Boston Simplus, adhesion of AC trophozoites was significantly reduced for all lens types as compared with controls (p<0.0001). Treatments with Menicare Plus or O2 Care reduced the number of adherent AC trophozoites significantly on FP lenses only as compared with controls (p<0.0001). The adhesion rates of AC trophozoites to RGP lenses depended on lens surfaces. Boston Simplus reduced the adhesion rate of AC trophozoites more than Menicare Plus or O2 Care. Appropriate RGP lens and MPS selection could decrease the prevalence of Acanthamoeba keratitis.

Effect of Multipurpose Solutions against Acinetobacter Carrying QAC Genes

Acinetobacter has low virulence but causes infections in subjects with reduced immunity. It has been reported in ocular infections including those of patients using contact lenses. Treatment is difficult because Acinetobacter is frequently multidrug resistant. Antibiotic-resistant strains frequently also harbor genes for antiseptic resistance (quaternary ammonium compound [QAC]) genes. Because Acinetobacter is part of the normal flora, it may contaminate contact lens and accessories. This study aims to investigate carriage rates of QAC genes in household and clinical isolates of Acinetobacter and to determine the effectiveness of two multipurpose solutions (MPSs) for soft lenses against organisms carrying QAC genes. DNA was extracted from 11 bathroom isolates and 15 clinical isolates and amplified by polymerase chain reaction to determine the presence of qacEΔ1. Gene-positive and gene-negative control strains were used to challenge the two MPSs, and minimum inhibitory concentrations (MICs) of these organisms to benzalkonium chloride and chlorhexidine gluconate were determined. More than 90% of isolates carried qacEΔ1. The MICs of clinical isolates were higher than those of isolates of bathrooms. Both MPSs were able to produce a 3-log reduction in the numbers of all isolates. Although most isolates carried qacEΔ1 and elevated MICs to benzalkonium chloride and chlorhexidine gluconate were observed, all were susceptible to both MPSs tested. However, if there were to be poor compliance with care procedures, it is probable that such organisms could survive in the presence of diluted or expired solutions.

Effects of Multipurpose Solutions on the Viability and Encystment of Acanthamoeba Determined by Flow Cytometry

To evaluate simultaneously the effects of multipurpose contact lens care solution (MPS) on the viability and encystment of Acanthamoeba using flow cytometry. Viability and encystment rate were evaluated using Acanthamoeba castellanii (ATCC 50514 and ATCC 50370) and three clinical strains of Acanthamoeba spp. isolated from patients with Acanthamoeba keratitis. Acanthamoeba trophozoites (1.0 × 10(5) cells/mL) were exposed to four kinds of commercially available MPSs for 24 hours. After dispensing the cell suspension into two portions, one portion was stained with 0.004% Congo Red (CR), a fluorescence dye to stain the inner cell wall of cysts, and the other portion was stained with a mixture of Congo Red and 3% sarkosyl (CRS), a detergent to lyse the trophozoites and pseudocysts. Flow cytometric analysis of the treated portions was then carried out on an EPICS ALTRA flow cytometer. The encystment rate and disinfecting efficacies (percentage of rounded trophozoites, "pseudocyst") were calculated by the rates of CR-stained, CR-nonstained, and CRS-stained populations, respectively. Ultrastructural features of resistant (mature or immature) cysts and pseudocysts were observed by transmission electron microscopy. Resistant cysts and rounded trophozoites (pseudocysts) were stained with CR, whereas native (unrounded) trophozoites were not. Resistant cysts were also stained with CRS unlike pseudocysts. Three clinical isolates showed higher resistance and higher encystment rates than two ATCC strains when treated with encystment-positive control solution. Disinfecting efficacy of each MPS was not directly related to each encystment rate. Transmission electron microscopy observations showed basic differences in the ultrastructure of pseudocysts produced by MPSs and resistant cysts. These results suggest that viability and encystment of Acanthamoeba are independent phenomena, and therefore disinfecting efficacy of MPS and encystment rates of Acanthamoeba should be evaluated, respectively. Thus, it is important to evaluate simultaneously the disinfecting efficacies and encystment rates of newly developed premarket MPS using the authors' novel flow cytometric methods.

Effect of Multipurpose Solutions on Cell Morphology and Cytokine Production by Corneal Epithelial Cells

We sought to determine whether human corneal limbal epithelial cells (HCLE) differ in their physiological response and production of inflammatory mediators during exposure to two multipurpose disinfecting solutions that differ in only four excipients. HCLE were exposed to dilutions (1%-20%) of OPTI-FREE Express and OPTI-FREE RepleniSH for 2, 6, or 18 h. Cell numbers were measured using CyQuant and metabolic activity assays. Morphology, viability, and apoptotic changes were examined by confocal microscopy after staining with Calcein AM/propidium iodide or Hoechst 33,342/propidiun iodide/YO-PRO-1. Cytokine responses and arachidonic acid metabolites were examined by enzyme-linked immunosorbent assay. OPTI-FREE Express showed greater reductions in corneal cell metabolic activity (up to 3-fold) than OPTI-FREE RepleniSH over 18 h. Cells exposed to OPTI-FREE Express were highly vacuolated, whereas those exposed to OPTI-FREE RepleniSH had morphology consistent with a presumed apoptotic response. OPTI-FREE Express elicited higher levels of interleukin (IL)-6 (maximum 4225 ± 300 pg/mL) and IL-8 (maximum 1094 ± 250 pg/mL) from cells than OPTI-FREE RepleniSH (maximum of 1717 ± 225 pg/mL and 930 ± 300 pg/mL, respectively) at all concentrations tested after 18 h. HCLE did not produce leukotriene B4 or prostaglandin E2 on stimulation, and IL-1β was produced in low levels, but its production was not different between multipurpose disinfecting solution types. The findings reported here are the first to describe the pattern of cytokine production produced in corneal epithelial cells in response to contact lens solutions. Alteration of only four excipients in the formulations had such effects on corneal epithelia; however, these differences do not explain differences in the incidences of corneal infiltrative events between these solutions. This might indicate that changes in the rates of infiltrative events result from interactions of the solutions with the contact lens surface, or directly with the corneal immune system, or as the result of gram-negative contamination of lens cases.

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.