Please use the archived list on the right to look at past peer-reviewed articles.
Bajgrowicz,M., Phan,C. -M, Subbaraman,L. N., Jones,L. Release of ciprofloxacin and moxifloxacin from daily disposable contact lenses from an in vitro eye model. Investigative Ophthalmology and Visual Science 2015;56,4:2234-2242. [ Show Abstract ]
Purpose. To analyze the release of two fluoroquinolones, ciprofloxacin and moxifloxacin, from conventional hydrogel (CH) and silicone hydrogel (SH) daily disposable contact lenses (CLs), comparing release from a fixed-volume vial and a novel in vitro eye model. Methods. Four CH CLs (nelfilcon A, omafilcon A, etafilcon A, ocufilcon B) and three SH CLs (somofilcon A, narafilcon A, delefilcon A) were used. The lenses were incubated in drug solutions for 24 hours. After the incubation period, the lenses were placed in two release conditions: (1) a vial containing 4.8 mL PBS for 24 hours and (2) an in vitro eye model with a flow rate at 4.8 mL over 24 hours. Results. Release in the vial for both drugs was rapid, reaching a plateau between 15 minutes and 2 hours for all lenses. In contrast, under physiological flow conditions, a constant and slow release was observed over 24 hours. The amounts of ciprofloxacin released from the lenses ranged between 49.6 Â±0.7 and 62.8 Â± 0.3 Âµg per lens in the vial, and between 35.0 Â± 7.0 and 109.0 Â± 5.0 Âµg per lens in the eye model. Moxifloxacin release ranged from 24.0 Â± 4.0 to 226.0 Â± 2.0 Âµg per lens for the vial, and between 13.0 Â± 2.0 and 151.0 Â± 10.0 Âµg per lens in the eye model. In both systems and for both drugs, HEMA-based CLs released more drugs than other materials. Conclusions. The parameters of the release system, in particular the volume and flow rate, have a significant influence on measured release profiles. Under physiological flow, release profiles are significantly slower and constant when compared with release in a vial. Â© 2015, The Association for Research in Vision and Ophthalmology, Inc.
Chang,J. M. L., McCanna,D. J., Subbaraman,L. N., Jones,L. W. Efficacy of antimicrobials against biofilms of achromobacter and pseudomonas. Optometry and Vision Science 2015;92,4:506-513. [ Show Abstract ]
Purpose. Achromobacter xylosoxidans and Pseudomonas aeruginosa biofilms can develop in ophthalmic products and accessories such as contact lens cases, leading to the development of ocular infections. This study evaluated the efficacy of the antimicrobials polyaminopropyl biguanide (PAPB) and benzalkonium chloride (BAK) against A. xylosoxidans and P. aeruginosa biofilms. Methods. Biofilms of A. xylosoxidans and P. aeruginosa used as a comparative control were formed by incubating the bacteria on contact lens cases and on coverslips in phosphate-buffered saline. The biofilms were then exposed to PAPB and BAK for 5 minutes and 4 hours. After exposure, alginate swabs were used to remove the biofilms from the lens cases and the bacteria were plated on tryptic soy agar for determination of survivors. Also, after exposure to these disinfectants, the A. xylosoxidans and P. aeruginosa biofilms were stained with SYTO 9 and propidium iodide. Using a confocal microscope with a 488-nm laser, the number of cells with damaged cell membranes was determined. Results. After 5 minutes of exposure to BAK or PAPB, A. xylosoxidans biofilms were more resistant to the antimicrobial effects of these disinfectants than P. aeruginosa biofilms. After 4 hours, both organisms were reduced by more than 3 logs after exposure to either BAK or PAPB. Confocal microscopy studies revealed that BAK was more effective at damaging A. xylosoxidans and P. aeruginosa cell membranes than PAPB at the concentrations used in ophthalmic products. Conclusions. Biofilms of the emerging pathogen A. xylosoxidans were more resistant to the disinfectants PAPB and BAK than biofilms of P. aeruginosa. Because of the emergence of A. xylosoxidans and the demonstrated greater resistance to the common ophthalmic preservatives BAK and PAPB than the standard Gram-negative organism P. aeruginosa, A. xylosoxidans biofilms should be assessed in antimicrobial challenge tests to assure the safety of multiuse ophthalmic products. Copyright Â© 2015 American Academy of Optometry.
Guthrie,S. E., Jones,L., Blackie,C. A., Korb,D. R. A Comparative Study Between an Oil-in-Water Emulsion and Nonlipid Eye Drops Used for Rewetting Contact Lenses. Eye and Contact Lens 2015;41,6:373-377. [ Show Abstract ]
OBJECTIVES: The purpose of this study was to determine the clinical impact of using SYSTANE BALANCE Lubricant Eye Drops (Alcon, Fort Worth, TX), an oil-in-water emulsion, as a rewetting eye drop in symptomatic contact lens wearers. METHODS: Subjects who had previously experienced contact lens discomfort (CLD), with a mean lens wearing history of 18.6Â±12.8 years, were randomly assigned to use a Test (SYSTANE BALANCE Lubricant Eye Drops; n=76) or control (habitual nonlipid contact lens rewetting eye drop; n=30) drop over their contact lenses within 5 min of lens insertion and then subsequently at 2 hr intervals up to a maximum of 4 drops per eye daily for a 1-month period. Assessments of subjective comfort, comfortable wearing time, lid wiper epitheliopathy (LWE), and corneal staining were conducted at baseline and after 1 month, after 6 hr of lens wear. RESULTS: Comfort, wearing time, LWE, and corneal staining all showed statistically significant improvements in the test group using SYSTANE BALANCE Lubricant Eye Drops at the 1-month visit compared with baseline data (all P<0.01) and compared with the control group at the 1-month visit (P<0.01, P=0.01, P<0.01, and P=0.03, respectively). CONCLUSIONS: The use of SYSTANE BALANCE Lubricant Eye Drops as a rewetting drop in a group of wearers who experienced symptoms of CLD improved subjective comfort scores, increased comfortable wearing time, and reduced signs of LWE and corneal staining, when compared with the use of nonâ€“lipid-containing contact lens rewetting eye drops. Â© 2015 Contact Lens Association of Ophthalmologists, Inc.
Hagedorn,S., Drolle,E., Lorentz,H., Srinivasan,S., Leonenko,Z., Jones,L. Atomic force microscopy and Langmuir-Blodgett monolayer technique to assess contact lens deposits and human meibum extracts. Journal of Optometry 2015;8,3:187-199. [ Show Abstract ]
Purpose The purpose of this exploratory study was to investigate the differences in meibomian gland secretions, contact lens (CL) lipid extracts, and CL surface topography between participants with and without meibomian gland dysfunction (MGD). Methods Meibum study: Meibum was collected from all participants and studied via Langmuir-Blodgett (LB) deposition with subsequent Atomic Force Microscopy (AFM) visualization and surface roughness analysis. CL Study: Participants with and without MGD wore both etafilcon A and balafilcon A CLs in two different phases. CL lipid deposits were extracted and analyzed using pressure-area isotherms with the LB trough and CL surface topographies and roughness values were visualized using AFM. Results Meibum study: Non-MGD participant meibum samples showed larger, circular aggregates with lower surface roughness, whereas meibum samples from participants with MGD showed more lipid aggregates, greater size variability and higher surface roughness. CL Study: Worn CLs from participants with MGD had a few large tear film deposits with lower surface roughness, whereas non-MGD participant-worn lenses had many small lens deposits with higher surface roughness. Balafilcon A pore depths were shallower in MGD participant worn lenses when compared to non-MGD participant lenses. Isotherms of CL lipid extracts from MGD and non-MGD participants showed a seamless rise in surface pressure as area decreased; however, extracts from the two different lens materials produced different isotherms. Conclusions MGD and non-MGD participant-worn CL deposition were found to differ in type, amount, and pattern of lens deposits. Lipids from MGD participants deposited irregularly whereas lipids from non-MGD participants showed more uniformity. Â© 2014 Spanish General Council of Optometry. Published by Elsevier EspaÃ±a, S.L.U. All rights reserved.
Hall,B., Jones,L. W., Forrest,J. A. Competitive effects from an artificial tear solution to protein adsorption. Optometry and Vision Science 2015;92,7:781-789. [ Show Abstract ]
Purpose To compare the adsorption of lysozyme, lactoferrin, and albumin to various contact lens materials, between single-protein solutions and a multicomponent artificial tear solution (ATS). Additionally, extra steps were taken to distinguish loosely and tightly bound protein, the latter of which may be fully or partially denatured. Methods Using a previously described ATS, we measured the time-dependent adsorption of lys, lac, and alb onto one conventional hydrogel and four silicone hydrogel contact lens materials between the first minute and up to 1 week of protein interaction with the material surface. Proteins were quantified using I125 radiolabeling of each protein individually in ATS and buffered saline. Extra steps were taken to limit the amount of unbound I125 and to quantify the amount of reversibly bound protein. Results Comfilcon A, balafilcon A, and etafilcon A did not show any relevant competitive adsorption between the ATS components and lys, lac, or alb until after 1 week. Competitive adsorption effects for lys, lac, and alb were observed in as little as 1 minute on lotrafilcon B. Lotrafilcon B had no reversibly bound protein at any time points. The ionic materials balafilcon A and etafilcon A deposited significant amounts of reversibly bound lysozyme and lactoferrin in just 10 minutes. Senofilcon A apparent deposition was below our thresholds of confidence for this protein quantification method. Conclusions Both the competition between lys, lac, and alb and ATS components and the reversibility of these bound proteins is material specific. Coadsorption of lys, lac, and alb with ATS components can increase the reversibility of their adsorption. Â© 2015 American Academy of Optometry.
Hall,B., Jones,L., Forrest,J. A. Kinetics of competitive adsorption between lysozyme and lactoferrin on silicone hydrogel contact lenses and the effect on lysozyme activity. Current eye research 2015;40,6:622-631. [ Show Abstract ]
To determine the effect of competitive adsorption between lysozyme and lactoferrin on silicone hydrogel contact lenses and the effect on lysozyme activity. Methods: Three commercially available silicone hydrogel contact lens materials (senofilcon A, lotrafilcon B and balafilcon A) were examined, for time points ranging from 10s to 2h. Total protein deposition was determined by I125 radiolabeling of lysozyme and lactoferrin, while the activity of lysozyme was determined by a micrococcal activity assay. Results: Senofilcon A and balafilcon A did not show any relevant competitive adsorption between lysozyme and lactoferrin. Lotrafilcon B showed reduced protein deposition due to competitive adsorption for lactoferrin at all time points and lysozyme after 7.5min. Co-adsorption of lactoferrin and lysozyme decreased the activity of lysozyme in solution for senofilcon A and lotrafilcon B, but co-adsorption had no effect on the surface activity of lysozyme for all lens types investigated. Conclusions: Competition between lysozyme and lactoferrin is material specific. Co-adsorption of lysozyme and lactoferrin does not affect the activity of surface-bound lysozyme but can reduce the activity of subsequently desorbed lysozyme. Â© 2015 Informa Healthcare USA, Inc.
Liu,S., Chang,C. N., Verma,M. S., Hileeto,D., Muntz,A., Stahl,U., Woods,J., Jones,L. W., Gu,F. X. Phenylboronic acid modified mucoadhesive nanoparticle drug carriers facilitate weekly treatment of experimentallyinduced dry eye syndrome. Nano Research 2015;8,2:621-635.
Luensmann,D., Yu,M., Yang,J., Srinivasan,S., Jones,L. Impact of cosmetics on the physical dimension and optical performance of silicone hydrogel contact lenses. Eye and Contact Lens 2015;41,4:218-227. [ Show Abstract ]
Objectives: To evaluate the impact of cosmetics on silicone hydrogel (SiHy) contact lens shape, lens power, and optical performance. Methods: In this in vitro experiment, 7 SiHy materials were coated with 9 marketed brands of cosmetics, including hand creams (HCs) (3), eye makeup removers (MRs) (3), and mascaras (3). Diameter, sagittal depth, and base curve were determined using the Chiltern (Optimec Limited), whereas lens power and optical performance were assessed using the Contest Plus (Rotlex). Six replicates were used for each lens and cosmetic combination.Measurements were repeated after a cleaning cycle using a one-step hydrogen peroxide solution. Results: Makeup removers had the greatest impact on diameter, sagittal depth, and base curve, resulting in changes of up to 0.5, 0.15, and 0.77 mm, respectively. The HCs and mascaras had little impact on these parameters; however, differences were observed between lens types. Optical performance was reduced with all mascaras, and a decrease of greater than 2 units on a 0 to 10 scale (10=uniform power distribution) was seen for 5 lens types exposed to waterproof mascara (P0.05). Lens cleaning resulted in some recovery of the lens parameters, and efficiency varied between cosmetics. Conclusion: Some eye MRs and waterproof mascaras changed the shape and optical performance of some SiHy lenses. Further research is needed to understand the clinical implications for SiHy lens wearers using cosmetics. Â© 2015 Contact Lens Association of Opthalmologists, Inc.
Menzies,Kara L., Srinivasan,Sruthi, Prokopich,C. Lisa, Jones,Lyndon Infrared Imaging of Meibomian Glands and Evaluation of the Lipid Layer in Sjögren's Syndrome Patients and Nondry Eye Controls. Investigative ophthalmology & visual science 2015;56,2:836-841. [ Show Abstract ]
Purpose. The purpose of this study was to evaluate meibomian gland dropout and lipid layer thickness (LLT) in patients with and without Sjögren's syndrome dry eye (SS).Methods. We recruited 11 participants with SS (males/females [M/F], 1:10; mean age = 56.0 ± 9.1 years) and 10 control subjects without dry eye (M/F, 3:7; mean age = 58.5 ± 4.7 years). All participants completed the Ocular Surface Disease Index (OSDI) questionnaire. The LLT was assessed using the Tearscope Plus based on the appearance of the lipid layer. Noninvasive tear break-up time (NITBUT) also was measured. The lower and upper lids were everted, and the meibomian glands were imaged using the infrared camera of the Keratograph 4. A meibomian gland dropout score due to gland loss was obtained. Statistical analysis was conducted using the Mann-Whitney U test and correlations were determined using Spearman rank correlations.Results. Of the SS participants, 100% reported ocular and oral dryness symptoms in the AECC questionnaire. The SS group recorded a higher OSDI score (median = 48.00, interquartile range [IQR] 23.0–56.2 vs. 2.1, IQR 0.0–2.6; P < 0.001), reduced LLT (median [IQR] = 15.0 [15.0–15.0] vs. 60.0 [45.0–100.0] nm; P = 0.001), and lower NITBUT (median [IQR] = 3.7 [2.5–4.2] vs. 9.5 [6.4–17.6] sec; P < 0.001) compared to the controls. Digital meibomian gland dropout score (% dropout) was significantly higher for the SS group (16.0% [IQR 12.1–40.0%] vs. 6.7% [IQR 1.5–12.7%]; P = 0.01). Subjective meibomian gland dropout score (0–6 score) was significantly higher for the SS group (median [IQR] = 1.5 [1.0–4.0] vs. 1.0 [0.0–1.25]; P = 0.03).Conclusions. Patients with SS showed higher meibomian gland dropout scores and reduced LLT and NITBUT, which likely contribute to the severe dry eye symptoms reported by SS subjects.
Moezzi,A. M., Fonn,D., Varikooty,J., Simpson,T. L. Overnight corneal swelling with high and low powered silicone hydrogel lenses. Journal of Optometry 2015;8,1:19-26. [ Show Abstract ]
Purpose To compare central corneal swelling after eight hours of sleep in eyes wearing four different silicone hydrogel lenses with three different powers. Methods Twenty-nine neophyte subjects wore lotrafilcon A (Dk, 140), balafilcon A (Dk, 91), galyfilcon A (Dk, 60) and senofilcon A (Dk, 103) lenses in powers -3.00, -10.00 and +6.00 D on separate nights, in random order, and on one eye only. The contra-lateral eye (no lens) served as the control. Central corneal thickness was measured using a digital optical pachometer before lens insertion and immediately after lens removal on waking. Results For the +6.00 D and -10.00 D, lotrafilcon A induced the least swelling and galyfilcon A the most. The +6.00 D power, averaged across lens materials, induced significantly greater central swelling than the -10.00 and -3.00 D (Re-ANOVA, p < 0.001), (7.7 ± 2.9% vs. 6.8 ± 2.8% and 6.5 ± 2.5% respectively) but there was no difference between -10.00 and -3.00 D. Averaged for power, lotrafilcon A induced the least (6.2 ± 2.8%) and galyfilcon A the most (7.6 ± 3.0%) swelling at the center (Re-ANOVA, p < 0.001). Central corneal swelling with +6.00 D was significantly greater than -10.00 D lens power despite similar levels of average lens transmissibility of these two lens powers. Conclusions The differences in corneal swelling of the lens wearing eyes are consistent with the differences in oxygen transmission of the silicone hydrogel lenses. In silicone hydrogel lenses central corneal swelling is mainly driven by central lens oxygen transmissibility.
Muntz,A., Subbaraman,L. N., Sorbara,L., Jones,L. Tear exchange and contact lenses: A review. Journal of Optometry 2015;8,1:2-11. [ Show Abstract ]
Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses.
Ngo,W., Caffery,B., Srinivasan,S., Jones,L. W. Effect of lid debridement-scaling in sjÃ¶gren syndrome dry eye. Optometry and Vision Science 2015;92,9:e316-e320. [ Show Abstract ]
Purpose To evaluate the effect of lid debridement-scaling (LDS) on dry eye signs and symptoms in subjects with SjÃ¶gren syndrome (SS). Methods This prospective randomized controlled study enrolled 14 female subjects with SS. Seven subjects were randomized into the treatment group where they were selected to receive LDS; the remainder did not receive LDS and served as control subjects. Lid debridement-scaling was conducted using a stainless steel golf club spud (Hilco Wilson Ophthalmics, Plainville, MA) on both the upper and lower eyelids of both eyes. Outcome variables were assessed before LDS and again 1 month later. The outcome variables were the Ocular Surface Disease Index (OSDI), Symptom Assessment iN Dry Eye (SANDE) visual analog scores, ocular staining (SICCA OSS [SjÃ¶gren's International Collaborative Clinical Alliance Ocular Staining Score]), fluorescein tear breakup time (FLBUT), meibomian gland score (MGS), meibomian gland yielding liquid secretions (MGYLS) score, and line of Marx's (LOM) position. Results Thirteen subjects completed the study. Data from only the right eye were analyzed. For the control group (n = 6; mean [Â±SD] age, 62.3 [Â±11.6] years), the pre-LDS, post-LDS, and significance level (pre-LDS mean [Â±SD] vs. post-LDS mean [Â±SD]; p value) were as follows: OSDI (58.3 [Â±22.1] vs. 48.3 [Â±29.0]; p = 0.051), SANDE (77.4 [Â±22.1] vs. 89.6 [Â±32.6]; p = 0.20), SICCA OSS (7.0 [Â±4.5] vs. 8.2 [Â±3.5]; p = 0.25), MGS (1.3 [Â±1.5] vs. 1.0 [Â±0.9]; p = 0.75), MGYLS (0.3 [Â±0.5] vs. 0.0 [Â±0.0]; p = 0.50), FLBUT (2.99 [Â±1.54] vs. 2.85 [Â±1.79]; p = 0.63), and LOM (2.0 [Â±0.0] vs. 2.0 [Â±0.0]; p = n/a). For the treatment group (n = 7; mean [Â±SD] age, 58.0 [Â±8.1] years), the pre-LDS, post-LDS, and significance level were as follows: OSDI (63.2 [Â±13.3] vs. 46.9 [Â±19.4]; p = 0.04), SANDE (72.6 [Â±17.1] vs. 77.0 [Â±28.0]; p = 0.54), SICCA OSS (6.6 [Â±2.9] vs. 5.0 [Â±3.9]; p = 0.02), MGS (1.0 [Â±1.2] vs. 3.1 [Â±1.7]; p = 0.01), MGYLS (0.0 [Â±0.0] vs. 0.6 [Â±1.0]; p = 0.50), FLBUT (3.13 [Â±0.81] vs. 3.45 [Â±1.03]; p = 0.53), and LOM (0.9 [Â±0.9] vs. 1.0 [Â±1.0]; p = 1.00). Conclusions This pilot study showed that LDS improved symptoms, ocular staining, and meibomian gland function for the group that received LDS. This indicates that LDS can aid in the management of SS dry eye. Â© 2015 American Academy of Optometry.
Omali,N. B., Subbaraman,L. N., Coles-Brennan,C., Fadli,Z., Jones,L. W. Biological and clinical implications of lysozyme deposition on soft contact lenses. Optometry and Vision Science 2015;92,7:750-757. [ Show Abstract ]
Within a few minutes of wear, contact lenses become rapidly coated with a variety of tear film components, including proteins, lipids, and mucins. Tears have a rich and complex composition, allowing a wide range of interactions and competitive processes, with the first event observed at the interface between a contact lens and tear fluid being protein adsorption. Protein adsorption on hydrogel contact lenses is a complex process involving a variety of factors relating to both the protein in question and the lens material. Among tear proteins, lysozyme is a major protein that has both antibacterial and anti-inflammatory functions. Contact lens materials that have high ionicity and high water content have an increased affinity to accumulate lysozyme during wear, when compared with other soft lens materials, notably silicone hydrogel lenses. This review provides an overview of tear film proteins, with a specific focus on lysozyme, and examines various factors that influence protein deposition on contact lenses. In addition, the impact of lysozyme deposition on various ocular physiological responses and bacterial adhesion to lenses and the interaction of lysozyme with other tear proteins are reviewed. This comprehensive review suggests that deposition of lysozyme on contact lens materials may provide a number of beneficial effects during contact lens wear. Â© 2015 American Academy of Optometry.
Pucker,A. D., Jones-Jordan,L. A., Li,W., Kwan,J. T., Lin,M. C., Sickenberger,W., Marx,S., Srinivasan,S., Jones,L. W. Associations with meibomian gland atrophy in daily contact lens wearers. Optometry and Vision Science 2015;92,9:e206-e213. [ Show Abstract ]
Purpose To determine associations for contact lenses (CLs) and meibomian gland atrophy in a matched-pair study. Methods Contact lens wearers (case) and age- and sex-matched non-contact lens (NCL) wearers with no history of CL use (control) were recruited for a multicenter study. All subjects were administered the Ocular Surface Disease Index questionnaire and a comprehensive battery of clinical tests (e.g., tear breakup time, bulbar and limbal redness, meibography, etc.) were performed. Upper and lower eyelid meibomian gland atrophy were graded with both digital meibography (percent gland atrophy) and visual meiboscore methods. Conditional logistic regression analyses were then used to determine relationships among CL use, meibomian gland atrophy, and ocular surface signs and symptoms. Results A total of 70 matched pairs were analyzed. The mean (Â±SD) age of the CL group was 30.6 (Â±12.4) years, and that of the NCL group was 30.1 (Â±12.2) years. The subjects were 63% female. The association between CL wear and meiboscore was not significant univariately, but the best-fitting multivariate regression model showed that higher meiboscores were associated with being a CL wearer (odds ratio [OR], 2.45) in a model that included eyelid margin erythema (OR, 0.25) and lissamine green staining (OR, 1.25). Percent gland atrophy was not associated with CL wear in regression analysis (p = 0.31). Conclusions This study determined inconclusive associations with CLs and meibomian gland atrophy. This study also provided a comprehensive assessment of differences between CL and NCL wearers. Â© 2015 American Academy of Optometry.
Samsom,M., Chan,A., Iwabuchi,Y., Subbaraman,L., Jones,L., Schmidt,TA In vitro friction testing of contact lenses and human ocular tissues: Effect of proteoglycan 4 (PRG4). Tribology International 2015;8927-33. [ Show Abstract ]
Contact lens friction was recently shown to correlate withÂ in vivoÂ comfort, with lower friction lenses providing improved comfort. Proteoglycan 4 (PRG4) is a recently discovered ocular surface boundary lubricant. The objectives of this study were to measure the friction of commercially available silicone hydrogel (SiHy) contact lenses against human cornea and eyelid tissues, and evaluate the ability of PRG4 to lubricate, and adhere to, SiHy contact lenses. TheÂ in vitroÂ friction test employed here effectively measured and distinguished the SiHy contact lens friction coefficients against human eyelid and cornea tissues, and PRG4 functioned as an effective boundary lubricant.
Srinivasan,S., Otchere,H., Yu,M., Yang,J., Luensmann,D., Jones,L. Impact of cosmetics on the surface properties of silicone hydrogel contact lenses. Eye and Contact Lens 2015;41,4:228-235. [ Show Abstract ]
Purpose: This study evaluated the impact of various cosmetics on the surface properties of silicone hydrogel (SiHy) contact lens materials. Methods: In this in vitro experiment, 7 SiHy contact lens materials were coated with 1 of 9 cosmetics, including common hand creams (3), eye makeup removers (3), and mascaras (3). Dark-field microscopy images were taken to determine pixel brightness (PB) after cosmetic exposure, which describes the visible surface deposition (n=6 for each lens type), with a higher PB indicating increased deposition. The sessile drop technique was used to determine the advancing contact angle (CA). Measurements were repeated for both methods after a single peroxide-based cleaning cycle. Results: Pixel brightness was significantly higher for mascara-coated lenses compared with the other cosmetic products (P,0.01). The peroxide-based lens care solution removed most deposits from the nonwaterproof mascara for 4 lens types, whereas deposits remained relatively unchanged for 1 waterproof mascara (P.0.05). Hand creams and makeup remover had minimal impact on PB. Changes in CA measurements after cosmetic application were highly lens dependent. Hand creams caused primarily a decrease in CA for 5 of the 7 lens types, whereas 1 of the waterproof mascaras caused a significant increase of 30 to 50Â° for 3 lens types. Conclusion: Some mascara-lens combinations resulted in increased CA and PB, which could have an impact on in vivo lens performance. Nonwaterproof mascara was mostly removed after a cleaning cycle. Further research is needed to understand the clinical implications for SiHy lens wearers using cosmetics. Â© 2015 Contact Lens Association of Opthalmologists, Inc.
Varikooty J., Srinivasan S., Subbaraman L., Woods C.A., Fonn D., Simpson T.L., Jones L.W. Variations in observable lid wiper epitheliopathy (LWE) staining patterns in wearers of silicone hydrogel lenses. Contact Lens and Anterior Eye 2015;38,6:471-476.
Varikooty,J., Schulze,M. M., Dumbleton,K., Keir,N., Woods,C. A., Fonn,D., Jones,L. W. Clinical performance of three silicone hydrogel daily disposable lenses. Optometry and Vision Science 2015;92,3:301-311. [ Show Abstract ]
Purpose. To determine the clinical performance of DAILIES TOTAL1 (DT1), Clariti 1Day (C1D), and 1-DAY ACUVUE TruEye (AVTE) silicone hydrogel daily disposable contact lenses (SiHy DDCLs). Methods. Eligible participants, subdivided into asymptomatic and symptomatic groups, wore each SiHy DDCLs for three consecutive days. Each participant attended three visits (on day 1 at 0 hours; on days 1 and 3 after 8 hours ofwear) per lens type. The order of lens wear was randomized, with at least 1 day washout between lenses. Lens-related performance was evaluated by assessing lens surface deposits, wettability, pre-lens noninvasive tear breakup time, lens movement, and centration; ocular response assessments included conjunctival redness, corneal staining, and conjunctival staining and indentation. Results. Fifty-one asymptomatic and 53 symptomatic participantscompleted the study. For all visits, themeannoninvasive tear breakup timewas about 1 second longer withDT1 than withC1DandAVTE (p < 0.01).Overall, thewettability of all three lenses was good; however, DT1 was graded marginally better than the other lenses (both p < 0.01). On day 3, eyes wearing AVTE had significantly more dehydration-induced corneal staining compared with DT1 (AVTE, 24%; DT1, 11%; p < 0.01). After 8 hours, conjunctival staining was different between lenses (greatest with C1D and least with DT1; all p < 0.01). Conjunctival indentation was more prevalent with the C1D lenses (n = 70) compared with DT1 (n = 1; p < 0.01) and AVTE (n = 11; p < 0.01). Therewere no differences between asymptomatic and symptomatic lenswearers for any of the clinical parameters (all p 9 0.05). Conclusions. Each of the three SiHy DDCLs performed well. Noninvasive tear breakup time was longest and wettability was greater with DT1. C1D had the most conjunctival staining conjunctival indentation. There was no difference between asymptomatic and symptomatic wearers with regard to ocular response and contact lensYrelated parameters. These results suggest that SiHy DDCLs may be an excellent contact lens modality for the symptomatic patient.
Verma,M. S., Chen,P. Z., Jones,L., Gu,F. X. Controlling "chemical nose" biosensor characteristics by modulating gold nanoparticle shape and concentration. Sensing and Bio-Sensing Research 2015;513-18. [ Show Abstract ]
Conventional lock-and-key biosensors often only detect a single pathogen because they incorporate biomolecules with high specificity. "Chemical nose" biosensors are overcoming this limitation and identifying multiple pathogens simultaneously by obtaining a unique set of responses for each pathogen of interest, but the number of pathogens that can be distinguished is limited by the number of responses obtained. Herein, we use a gold nanoparticle-based "chemical nose" to show that changing the shapes of nanoparticles can increase the number of responses available for analysis and expand the types of bacteria that can be identified. Using four shapes of nanoparticles (nanospheres, nanostars, nanocubes, and nanorods), we demonstrate that each shape provides a unique set of responses in the presence of different bacteria, which can be exploited for enhanced specificity of the biosensor. Additionally, the concentration of nanoparticles controls the detection limit of the biosensor, where a lower concentration provides better detection limit. Thus, here we lay a foundation for designing "chemical nose" biosensors and controlling their characteristics using gold nanoparticle morphology and concentration. Â© 2015 The Authors.
Verma,M. S., Rogowski,J. L., Jones,L., Gu,F. X. Colorimetric biosensing of pathogens using gold nanoparticles. Biotechnology Advances 2015;33,6:666-680. [ Show Abstract ]
Rapid detection of pathogens is crucial to minimize adverse health impacts of nosocomial, foodborne, and waterborne diseases. Gold nanoparticles are extremely successful at detecting pathogens due to their ability to provide a simple and rapid color change when their environment is altered. Here, we review general strategies of implementing gold nanoparticles in colorimetric biosensors. First, we highlight how gold nanoparticles have improved conventional genomic analysis methods by lowering detection limits while reducing assay times. Then, we focus on emerging point-of-care technologies that aim at pathogen detection using simpler assays. These advances will facilitate the implementation of gold nanoparticle-based biosensors in diverse environments throughout the world and help prevent the spread of infectious diseases. Â© 2015 Elsevier Inc.