Anatomy of a regimen: consideration of multipurpose solutions during non-compliant use.

Consumers are often non-compliant with instructions for contact lens care products. This study explores the antimicrobial capacity of multipurpose solutions using variable use conditions. Opti-Free Express (Alcon) Multi-Purpose Disinfecting Solution with Polyquad (Alcon) and Aldox (Alcon) antimicrobial system and products containing PHMB (ReNu MultiPlus, Solo-care, and Complete multipurpose solutions) were evaluated. Products were challenged with Fusarium solani, Candida albicans, Serratia marcescens, Pseudomonas aeruginosa, and Staphylococcus aureus. The antimicrobial activity and effectiveness of regimen steps, rinse volume, stored lenses and organic soil were evaluated. The results show that products using similar regimens can show different disinfection abilities. Opti-Free Express Multi-Purpose Disinfecting Solution retained effectiveness using variable and non-compliant conditions.     

Contribution of regimen steps to disinfection of hydrophilic contact lenses.

The effect of regimen steps on overall performance of contact lens disinfection processes was evaluated. Hydrophilic lenses were inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Candida albicans, or Fusarium solani. Contributions of regimen steps and rinse volumes to disinfection abilities of OPTI-FREE EXPRESS, Solo-care Plus (Ciba Vision), Complete (Allergan), and ReNu MultiPlus (Bausch & Lomb) multi-purpose solutions were examined. Numbers of surviving microorganisms were determined. Results showed that the number and timing of regimen steps was directly related to performance of products. OPTI-FREE EXPRESS solution showed fewer survivors than did other products. Minimizing regimen steps could adversely affect product efficacy.     

Comparative antimicrobial efficacy of multi-purpose hydrogel lens care solutions.

Ten single-bottle multipurpose hydrogel lens care solutions commercially available in the European market were evaluated for antimicrobial efficacy using the International Organization for Standardization's (ISO) Stand-Alone Procedure. The results of this study indicate that ReNu Multi Plus ReNu Multi Purpose, Complete and DUA meet the ISO Stand-Alone primary acceptance criteria for stand-alone disinfectants against all challenge organisms: Staphylococcus aureus, Serratia marcescens, Pseudomonas aeruginosa, Candida albicans, and Fusarium solani. Solo-Care Soft, All-In-One Light, Optiplus, Opti Free Express, UniCare and Combi Comfort do not meet the ISO Stand-Alone primary acceptance criteria for one or more test organisms within their respective labelled minimum disinfection times. In addition, although not a requirement of the guidance document, only ReNu MultiPlus and ReNu Multi-Purpose exceeded the minimum ISO Stand Alone primary acceptance criteria within 25% (1 h) of their labelled minimum disinfection time for all test organisms. This evaluation provides a direct comparison of antimicrobial activity for commercially available multipurpose lens care solutions at their labelled minimum disinfection times. The results of this study should be considered when selecting appropriate lens care systems for patients.     

A comparison of regimen methods for the removal and inactivation of bacteria, fungi and Acanthamoeba from two types of silicone hydrogel lenses

Purpose

To compare the antimicrobial efficacy of commercial contact lens solutions when used according to the manufacturers’ recommended regimens with two types of silicone hydrogel lenses.

Methods

Four multipurpose contact lens care solutions were examined, representing manufacturer recommended regimens of “rub & rinse”, “no rub, rinse” or “no rub, no rinse”. Test organisms were Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Fusarium solani, Candida albicans and Acanthamoeba castellanii (trophozoites and cysts). Organisms, in the presence of organic soil, were inoculated on to Acuvue Oasys or Air Optix lenses and subjected to the solution manufacturer's recommended regimen. The number of surviving organisms on the lenses and in the soak solution was enumerated in accordance with ISO 14729.

Results

ISO 14729 dictates that for a given organism the combined average number of surviving microbes from the lenses and disinfectant soaking solution must be ≤10 colony forming units (cfu)/ml. By this criterion, only Complete Easy Rub (“rub & rinse” regimen) gave satisfactory results for all bacteria, fungi and Acanthamoeba with both lens types. Solutions employing “no rub, rinse” were less satisfactory but significantly better than “no rub, no rinse”. Significant differences were found in organism survival on the lenses with greater numbers remaining on the Air Optix compared to Oasys (p < 0.01-0.0001).

Conclusion

The findings of this study demonstrate that the use of a manual rubbing step is more effective than rinsing or soaking alone in removing pathogenic microbes from silicone hydrogel lenses. Accordingly, it would seem prudent to recommend that contact lens care systems include a rub step as part of the hygiene regimen.     

Clinical performance of 'no rub' multi-purpose solutions.

This was a multi-site, 231-subject double-masked, bilateral crossover study to evaluate subjective comfort and satisfaction, corneal staining and lens deposits with two 'no rub' multi-purpose solutions (MPS) used with FDA Group II (alphafilcon A, SofLens 66, Bausch & Lomb) and Group IV (etafilcon A, SUREVUE, Johnson & Johnson Vision Care) soft contact lenses. Subjects used each of the two MPS, Regimen 1 (OPTI-FREE EXPRESS Multi-Purpose Disinfecting Solution No Rub Lasting Comfort Formula, Alcon Laboratories) and Regimen 2 (ReNu MultiPlus Multi-Purpose Solution, Bausch & Lomb), for 28 days. They wore the same lens type for the duration of the study and were evaluated on days 0, 14 and 28 of each treatment period. Subjective ratings of comfort and satisfaction were significantly different between regimens, with the majority of variables in favour of Regimen 1 (P < 0.05). Corneal staining was significantly greater with the Group II, Regimen 2 combination (P < 0.0001). Group IV lenses cared for with Regimen 1 had significantly less residual lysozyme on Day 28 (562 microg) than lenses cared for with Regimen 2 (1145 microg; P < 0.0001). While both products offer the convenience of a 'no rub' regimen, differences in performance should be considered when recommending these solutions to patients.     

Ultraviolet (UV) transmittance characteristics of daily disposable and silicone hydrogel contact lenses.

The ultraviolet (UV) transmittance spectra of daily wear hydrogel and disposable silicone hydrogel contact lenses were measured. Average transmittance percentages were calculated for each lens for the entire UV spectrum and individually for the UVC, UVB and UVA portions of the spectrum. The significance of the differences in transmittance spectra obtained for the lenses was analysed using a one-way ANOVA planned comparisons test (alpha=0.05). The transmittance data were then used to calculate a UV protection factor (PF) for each contact lens brand tested. The PFs for 1-DAY ACUVUE MOIST (6.22), ACUVUE ADVANCE (10.02) and ACUVUE OASYS (11.96) contact lenses show that these contact lenses have superior UV-blocking capabilities. The PFs for Focus DAILIES (1.79), SofLens 1-day disposables (1.72), NIGHT & DAY (1.84), O2 Optix (1.99) and Purevision (2.62) show that these contact lenses posses more modest UV-blocking characteristics. This paper reviews the importance of protection of the anterior ocular surface from UV damage and quantifies the protection afforded by selected commercially available disposable contact lenses.     

Use of silicone hydrogel material for daily wear.

Silicone hydrogel contact lenses were initially developed to optimise oxygen transmissibility for extended wear use. The concerns with such contact lenses have been their higher elastomeric and hydrophobic characteristics associated with the incorporation of silicone type monomers. The use of silicone hydrogel has most recently been suggested for daily wear to eliminate all hypoxic related problems. The primary aim of the investigation was to test in vivo wetting performance and subjective acceptance of the first silicone hydrogel contact lens developed for daily wear, ACUVUE ADVANCE with HYDRACLEAR (galyfilcon A), compared to a conventional hydrogel contact lens for the same application SofLens 66 (alphafilcon A). The investigation was a randomised, subject masked bilateral cross over investigation testing of the two contact lens materials over their approved replacement periods (galyfilcon A 2 weeks and alphafilcon A 2 weeks (USA) and 4 weeks (Europe)). In all cases ReNu Multiplus lens care system was used. The investigation carried out on 24 contact lens wearers showed that: (i) in vivo wettability was superior for galyfilcon A which had a thicker lipid layer (thin layer incidence: galyfilcon A 54%; alphafilcon A 70-86%, p<0.05), a thicker aqueous layer (thick layer incidence: galyfilcon A 88%; alphafilcon A 35-64%, p<0.05) and a more stable tear film (galyfilcon A 7.8s; alphafilcon A 2 weeks 5.6s, p=0.022; 4 weeks 7.4s, p=0.276); (ii) for the intended replacement period, comfort was better with galyfilcon A (2 weeks) compared to alphafilcon A (4 weeks) at insertion (p=0.001) and, throughout the day (daytime and evening p=0.008). Contact lenses made from galyfilcon A and replaced two weekly achieved better in vivo wettability than contact lenses made from alphafilcon A and replaced either two and four weekly; the better wettability was associated with an overall better comfort for galyfilcon A.     

Effect of multipurpose solutions for contact lens care on the in vitro drug-induced spoliation of poly(2-hydroxyethyl methacrylate) in simulated aqueous humour.

Drug-induced spoliation of hydrogels as contact lenses or as implants in the anterior eye is a frequent occurrence in clinical practice. This study explores the capacity of three commercial multipurpose solutions for contact lens care to reduce the spoliation of poly(2-hydroxyethyl methacrylate) (PHEMA) specimens exposed to a simulated aqueous humour formulation and to three topical drugs commonly administered after insertion of artificial corneas (Predsol, Optimol and Depo-Ralovera). ReNu MultiPlus (Bausch & Lomb), Complete Blink-N-Cleantrade mark Lens Drops (Allergan) and Complete Protein Remover Tablets dissolved in Complete ComfortPLUS (both from Allergan) were evaluated. All multipurpose solutions were able to dislodge passively the deposits formed on hydrogels in the simulated aqueous and in the presence of Predsol and Optimol, but none were effective against the deposits induced by Depo-Ralovera. A reduction of the calcium content in deposits caused by Predsol and Optimol was confirmed after treatment with the protein remover preparation, while the other multipurpose solutions caused the complete removal of the deposits. In experiments designed to evaluate the preventive action of the multipurpose solutions, no such effects were observed regardless of the drug involved. The prospect of using multipurpose solutions as eye drops following implantation of a hydrogel artificial cornea is a valid alternative for reducing device spoliation, however it appears to depend on the nature of the postoperative medication.