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Abstracts and Articles

PuriLens Performance Support Abstracts

Abstracts of articles and studies which support the performance of the PuriLens System are listed below. Abstracts can be viewed and/or printed by clicking on each study's title.

PuriLens Articles

Complete copies of the PuriLens Clinical Study and Proceedings from a Roundtable Discussion on the PuriLens System can be viewed and/or printed by clicking on each articles' title.

Click here to view or print the PuriLens Clinical Study.
This clinical study supports the safety and efficacy of the PuriLens System.

Click here to view or print the PuriLens Panel Discussion.
Clinical investigators discuss the PuriLens System, the first contact lens care system that cleans and disinfects soft contact lenses automatically.

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PuriLens® Lens Deposit Study
Hammack G, Edwards C. UAB School of Optometry.
March 7, 1999.

ABSTRACT: A blinded computer image processing quantification of visible light reflectance of hydrogel contact lens deposits was performed at the University of Alabama at Birmingham. Contact lenses to be tested were worn by patients for a three-month period, and cleaned in either the PuriLens® System (the TEST group) or Bausch and Lomb's ReNu® Multipurpose Solution (the CONTROL group). On a blind-basis, a total of 311 lenses were evaluated. The lenses were removed from the patient, rinsed with saline and then heated via a microwave oven to fix the deposits. The contact lens was placed in a test cell and was arranged with circular fluorescent lamp and black background to produce a dark-field stage in video microscopy. Video data acquisition consists of the mathematical average of 10 consecutive video frames. In order to accommodate variance in fluorescent tube illumination from day to day, data from the ground-glass standard measurements were analyzed. For each day, readings for each standard were averaged and compared to the overall mean for each standard to derive an adjustment factor for that day's data. This adjustment factor was applied to the lens data to arrive at adjusted lens data that was compensated for fluorescent tube brightness differences. The adjusted, non-excluded lens data was arranged to match patient and eye and comparison made between the TEST and CONTROL lenses for that eye from the different periods. Calculations were made to arrive at an "improvement" score for each patient and eye. A positive number indicated the improvement in "cleanliness" of the TEST lens over the CONTROL (i.e., the "improvement" score was positive where the reflectance of the TEST lens was lower than that of the CONTROL lens.) A total of 140 valid patient and eye consistent test-control cases were identified. The TEST group lenses measured 2.61 image brightness units (10.4%) lower (cleaner) than the CONTROL group lenses when matched for patient and eye, statistically SIGNIFICANT at p=0.02.

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Ultraviolet Disinfection of Contact Lenses
Harris M, Fluss L, Lem A, Leong H. Optom Vis Sci. 1998;70(10):839-842.

ABSTRACT: To evaluate the efficacy of ultraviolet (UV) radiation as a method of disinfecting contact lenses and their storage solutions, we contaminated soft lenses (Bausch & Lomb Optima 38), rigid gas permeable (RGP) lenses (Oxyflow F-30), and their storage solutions with three common bacteria, Escherichia coli (E.c.), Staphylococcus epidermis (S.e.), and Serratia marcescens (S.m.). The storage solutions used were saline solution and RGP conditioning solution. We determined the exposure times to 253.7-nm wavelength UV radiation necessary to disinfect the contact lenses and solutions. The decimal reduction values (D values) found for UV radiation were 10 to 200 hundred times shorter than reported for currently available disinfection systems. For E.c., sterilization was attained after 100 s of exposure. For S.e. and S.m., sterilization occurred after 300 s of exposure. Different contact lens solutions transmit UV radiation to various degrees, with saline solution passing more than 90% of the UV radiation. Thus, our results indicate that UV radiation is an effective and rapid method of disinfecting contact lenses and their storage solutions.

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Ultraviolet Radiation for the Sterilization of Contact Lenses
Gritz D, Lee T, McDonnell P, et al. CLAO J.1990:16
(4):294-298.

ABSTRACT: Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally affected by exposure to 300 hours of UV-B. Ultraviolet light is an effective germicidal agent but is injurious to soft lens polymers; its possible utility in the sterilization of RGP lenses and lens cases deserves further study.

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Evaluation of the PuriLens® Contact Lens Care System Incorporating UV Disinfection and Hydrodynamic Shear Cleaning
Choate W, Fontana F et al. CLAO J 2000 July; 26(3) 134-140

ABSTRACT: This study evaluated lens care using the PuriLens System, an advanced way to clean and disinfect soft hydrophilic lenses using subsonic agitation and UV radiation, respectively. A two-period crossover lens cleaning and safety investigation was conducted using 80 patients. Disinfecting efficacy was tested in accordance with standard FDA protocols. Lens compatibility was studied with Group I and Group IV lenses during the equivalent of a 6-month care regimen by measuring: lens power, base curve, wet diameter, refractive index, clarity, and tint. Safety was evaluated through slit-lamp findings, wearing time, comfort, and visual acuity. The mean wearing time of patients in the study was 13.79 hours. No slit lamp findings greater than grade 2 were noted. Visual acuity was 20/25 or better in 92.5% of examinations. None of the patients lost more than two lines of acuity. Lens surface evaluation showed no deposits (grade 0) to very slight deposits (grade 1) in 94.4% of examinations. Lenses cleaned with the PuriLens System were cleaner by a statistically significant margin (P=0.02) compared to lenses digitally cleaned with a leading multi-purpose solution (ReNu®, Bausch & Lomb). Overall, neither the Group I nor Group IV lenses were affected after 180 cleaning cycles. Conclusions: The PuriLens System provides automatic lens care compliance, superior antimicrobial efficacy, and eliminates the need for daily digital cleaning.

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Clinical Evaluation of PuriLens®, an Ultraviolet Light Contact Lens Care System
Bartolomei A, Alcaraz L, Bottone E et al. CLAO J 1994 Jan; 20 (1): 23-6.

ABSTRACT: PuriLens is a new contact lens care system that uses ultraviolet light and subsonic turbulence for lens cleaning and disinfection. In a single hands-off process using only preservative-free sterile saline, the lenses are ready to wear after a 15-minute cycle. This study was designed to test the safety of this contact lens care system. A total of 84 contact lens wearers from six centers were enrolled in the 3-month study, which comprised an initial visit and follow-up visits at 1, 2, 4, 8, and 12 weeks. At the end of the study, lenses and units were collected and a questionnaire was completed. Seventy-six of the 84 subjects (168 eyes) completed the study. No severe eye complications were reported, and no patients were removed from the study because of ocular problems or complications associated with the device or its use. Four patients were removed from the study for noncompliance with follow-up. Another four patients were active for 2 months, but were requested by the sponsor to complete the study 1 month early to complete data collection. Patient satisfaction was high. The study suggests that PuriLens may be considered as an alternative for contact lens cleaning and disinfection.

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Disinfection Efficacy Testing of the PuriLens® System
Elrashidy O, Roberts R, DeVoid S. Consumer Product Testing Co., Feb 16, 1999.

ABSTRACT: The study investigated the disinfection efficacy of the PuriLens System. The disinfection efficacy test challenged the System with a standard inoculum of a representative range of microorganisms and established the viability loss at predetermined time intervals comparable to those during which the product may be used. The preliminary portion of the protocol consisted of evaluating the disinfection adequacy of nine selected time points (1, 2, 3, 4, 5, 10, 15, 30 and 60 minutes) and a single challenge organism in organic soil. The use of organic soil addressed the worst-case scenario in which organic soil will increase the D-value. In the preliminary study, a 3-log reduction was observed after 1 minute with 99.958 % decrease in organisms. At subsequent time points, there was at least a 4 log reduction and a 99.999 % reduction in organisms at 15 minutes. For the Definitive portion of the study, five time points were selected based upon FDA guidance and the labeled use of the PuriLens system. The time points tested for the full panel of microorganisms (3, 4, 7, 10 and 15 minutes) include the intervals suggested by FDA (25, 50, 75 and 100 % of the recommended disinfection time for all organisms). The results show that the PuriLens System, under testing, is capable of reducing the population of microorganisms used in this study by at least four logs at the conclusion of it's full cycle of 15 minutes.

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PuriLens® Lens Compatibility Testing
Bergbauer K, Wages S, Zeng M, Culley P. Technology Resource International Corporation, Jan 11, 1999.

ABSTRACT: A solution compatibility test, based on FDA solution compatibility test protocol guidelines, was conducted using the PuriLens Disinfection System with hydrophilic contact lenses in order to assess the effect of the disinfection system on the contact lens parameters. Group I and Group IV lenses were subjected to 180 disinfection cycles using the PuriLens device and PuriLens solution (buffered saline). At the start of the study, and for every 30 cycles up to 180, several parameters were measured for each contact lens, including refractive index (for lens water content), UV/Visible light absorbance and transmission (for determining lens clarity and color), and lens power, base curve and diameter. Under the conditions of this study, Group I lens base curves, diameters, lens powers, lens clarity and refractive indexes were unchanged by the cycling process. Overall, the color of the Group I lenses was somewhat lighter after 180 cycles as evidenced by the UV/Visible light absorbance spectra. Group IV lens color, clarity, refractive indexes and powers were not affected by 180 cycles with the PuriLens Disinfection System, while the average lens diameter and average base curve were increased slightly. Specifically, the average Group IV lens diameter was 14.3 mm and average base curve was 9.6 mm at the start of this study and, after 180 cycles, the average diameter was 14.4 mm and the average base curve was 9.7 mm.

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Profession Still Deciding Between Preservative-Free and Preserved-Chemical Disinfection
Andre M, Caroline P. Primary Care Optometry News.1997;2(6):32.

ABSTRACT: The ultimate challenge for lens care product engineers is the delicate balance between antimicrobial efficacy, ocular compatibility, and patient convenience. Because of this, the soft lens industry has been on a constant pendulum between preservative-free disinfection and preserved chemical disinfection for the past 30 years. Although effective, preserved soft lens care products, such as the popular multipurpose care regimens, are often associated with subtle adverse reactions such as multipurpose nonkeratitis. The single hallmark of multipurpose nonkeratitis is the patient's subjective complaint of ocular dryness while wearing soft lenses. Recent studies show three out of four soft lens wearers experience symptoms of ocular dryness during their wearing schedule. Furthermore, one patient in four is forced to significantly modify their wearing schedule to accommodate the dry eye symptoms. Dry eye is the number one complaint of soft lens wearers, yet practitioners often overlook the possible role of preserved disinfection symptoms as the cause of this condition. Several treatment options exist, including preservative-free systems and daily disposable lenses.

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Multipurpose Non-Keratitis
Campbell R, Caroline P. Contact Lens Spectrum. 1997; March;56.

ABSTRACT: Sensitivities to contact lens care products have many manifestations, such as diffuse punctate keratitis, conjunctival injection, subepithelial infiltrates, pseudodendritis and superior limbic keratoconjunctivitis. Modern chemical disinfection systems rarely cause this type of tissue disruption. More frequently, patients reacting to multipurpose lens care regimens present with completely normal external findings. Yet, many complain of only one symptom, ocular dryness. This chemically induced symptom is frequently overlooked or misdiagnosed as keratoconjunctivitis sicca. Delayed sensitivity to a multipurpose care regimen is commonly referred to as multipurpose nonkeratitis due to its lack of positive slit lamp findings. The condition may represent one of the leading causes of patient dissatisfaction with soft contact lenses today. Solution sensitivities can occur at any time during a patient's contact lens wearing history. When the reaction is delayed, the cause is frequently overlooked or misdiagnosed. This is especially true for multipurpose non-keratitis in which there may be no positive slit lamp findings. Fortunately, we can manage most solution sensitivities by either switching the patient to nonpreserved care products or prescribing one-day disposable lenses.

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