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Peer-reviewed articles

2016

Dantam,J., McCanna,D. J., Subbaraman,L. N., Papinski,D., Lakkis,C., Mirza,A., Berntsen,D. A., Morgan,P., Nichols,J. J., Jones,L. W., Mathew,J. H., Cox,S. M., Bickle,K. M., Powell,D. R., Cox,J., Miller,W. L., Wallace-Tucker,A., Charrier,S., Chen,Y. -J, Cardenas,L., Huerta,S., Dionne,K., Maldonado-Codina,C., Plowright,A. J., Howarth,G. F., Chatterjee,N., Smith,S., Dumbleton,K., Schulze,M., Moezzi,A., Luensmann,D., Ngo,W., Paquette,L., Srinivasan,S., Varikooty,J., Johnson,J., Simpson,M., Voss,L., R Microbial contamination of contact lens storage cases during daily wear use. Optometry and Vision Science 2016;93,8:925-932. [ Show Abstract ]

Purpose. To evaluate contact lens (CL) storage case contamination when used with four different CL care solutions during daily wear of three different CL materials. Methods. A parallel, prospective, bilateral, randomized clinical trial (n = 38) was conducted. Subjects were randomly assigned to use one of three CL materials (etafilcon A, senofilcon A, or galyfilcon A) on a daily wear basis. Subsequently, each subject randomly used one of four different CL care solutions (Biotrue, OPTI-FREE PureMoist, RevitaLens OcuTec, and CLEAR CARE) for 2 weeks, along with their respective storage cases. After every 2-week period, their storage cases were collected and the right and left wells of each storage case were randomized for two procedures: (1) microbial enumeration by swabbing the storage case surface and (2) evaluation of biofilm formation (multipurpose solution cases only) using a crystal violet staining assay. Results. More than 80% of storage cases were contaminated when used in conjunction with the four CL care solutions, irrespective of the CL material worn. Storage cases maintained with CLEAR CARE (mean Log colony forming units (CFU)/ well ± SD, 2.0 ± 1.0) revealed significantly (p < 0.001) greater levels of contamination, compared to those maintained with Biotrue (1.3 ± 0.8) and RevitaLens OcuTec (1.2 ± 0.8). Predominantly, storage cases were contaminated with Gram-positive bacteria (= 80%). There were significant differences (p = 0.013) for the levels of Gram-negative bacteria recovered from the storage cases maintained with different CL care solutions. Storage cases maintained withOPTI-FREE PureMoist (0.526 ± 0.629) showed significantly higher biofilm formation (p = 0.028) compared to those maintained with Biotrue (0.263 ± 0.197). Conclusions. Levels of contamination ranged from 0 to 6.4 Log CFU/storage case well, which varied significantly (p < 0.001) between different CL care solutions, and storage case contamination was not modulated by CL materials. © Copyright 2016 American Academy of Optometry.

Berntsen,D. A., Hickson-Curran,S. B., Jones,L. W., Mathew,J. H., Maldonado-Codina,C., Morgan,P. B., Schulze,M. M., Nichols,J. J., Cox,S. M., Bickle,K. M., Powell,D. R., Cox,J., Miller,W. L., Wallace-Tucker,A., Charrier,S., Chen,Y. -J, Cardenas,L., Huerta,S., Dionne,K., Plowright,A. J., Howarth,G. F., Chatterjee,N., Mirza,A., Smith,S., Dumbleton,K., Moezzi,A. M., Luensmann,D., Ngo,W., Paquette,L., Srinivasan,S., Varikooty,J., Johnson,J., Simpson,M., Voss,L., Ryan,L., Careless,N., Smith,A., Subbar Subjective comfort and physiology with modern contact lens care products. Optometry and Vision Science 2016;93,8:809-819. [ Show Abstract ]

Purpose. To compare subjective comfort and ocular physiology with three multipurpose solutions (MPSs) to that of a peroxide-based system with three different soft contact lens materials. Methods. Habitual soft contact lens wearers (n = 236) were enrolled at three sites and completed a washout period with no contact lens solution for =4 days. Subjects were randomly assigned to one of three lens types: etafilcon A, galyfilcon A, or senofilcon A. A new lens of the assigned type was worn for 10 to 14 days each while using one of four care solutions, in random order (A - polyaminopropyl biguanide + polyquaternium, B - POLYQUAD + Aldox, C - alexidine + polyquaternium-1, and D - hydrogen peroxide) with a washout period (=4 days) between each solution. After each care solution, biomicroscopy was performed and subjective comfort was assessed using the Contact Lens User Experience (CLUE) questionnaire and other instruments including comfortable wear time (CWT). Linear mixed models were used for analysis. Comfort and biomicroscopy signs with each MPS were compared to that of the peroxide solution. Results. Subjective CLUE Comfort score across all lens types with each MPS was not significantly different than with the peroxide solution (p = 0.98). There were no differences in CWT between each MPS and the peroxide solution for any lens type (range of differences: -0.8 to 0.8 h; all p = 0.13). Six MPS/material combinations had no clinically meaningful change in corneal staining versus peroxide (<0.5 units); three combinations could increase staining by up to 0.57 units. Staining was

Schulze,M. -M, Srinivasan,S., Hickson-Curran,S. B., Berntsen,D. A., Howarth,G. F., Toubouti,Y., Morgan,P., Nichols,J. J., Jones,L. W., Mathew,J. H., Cox,S. M., Bickle,K. M., Powell,D. R., Cox,J., Miller,W. L., Wallace-Tucker,A., Charrier,S., Chen,Y. -J, Cardenas,L., Huerta,S., Dionne,K., Maldonado-Codina,C., Plowright,A. J., Chatterjee,N., Mirza,A., Smith,S., Dumbleton,K., Moezzi,A. M., Luensmann,D., Ngo,W., Paquette,L., Varikooty,J., Johnson,J., Simpson,M., Voss,L., Ryan,L., Careless,N., Smith, Lid wiper epitheliopathy in soft contact lens wearers. Optometry and Vision Science 2016;93,8:943-954. [ Show Abstract ]

Purpose. To evaluate lid wiper epitheliopathy (LWE) in soft contact lens (SCL) wearers on initial presentation and after using various SCL and solution combinations. Methods. LWE was assessed in 253 habitual SCL wearers who attended a screening visit at one of three study sites. LWE was assessed using lissamine green and sodium fluorescein dyes (Korb scale); a final LWE grade was calculated as the averaged LWE grade of the two dyes. Eligible habitual wearers continued into the four study periods, during which they wore one of three SCL types (etafilcon A, galyfilcon A, or senofilcon A) while using each of four care solutions for 10 to 14 days in randomized order. Statistical analyses were performed using linear mixed models, testing for differences in LWE for subject characteristics and between three multipurpose (MPS) test solutions (BioTrue, OPTI-FREE PureMoist, RevitaLens OcuTec) compared to a hydrogen peroxide (Clear Care) control solution. Results. LWE was present in 85% of habitual SCL wearers. LWE was not different for age (p = 0.28), sex (p = 0.99), race (p = 0.34), and comfort (p = 0.38) and not correlated with refractive error (r = 0.07). LWE was lower in habitual senofilcon A wearers (least-squares (LS) mean ± SE = 0.82 ± 0.19) compared to wearers of lotrafilcon B (1.34 ± 0.20; p < 0.02), comfilcon A (1.41 ± 0.21; p < 0.01), and other (1.18 ± 0.16; p < 0.03). Two hundred three participants completed all four study solutions with their assigned lens type; LWE was not different between the MPSs compared to the peroxide control solution across lens materials, except for less LWE for BioTrue (0.88 ± 0.17) versus Clear Care for participants wearing galyfilcon A (1.11 ± 0.18; p < 0.01). Conclusions. On initial presentation, LWE was present in 85% of habitual wearers and found to be independent of age, sex, race, comfort, and refractive error but dependent on habitual SCL type. There were no clinically meaningful differences in LWE between the MPSs and hydrogen peroxide solution for the three lens types studied. © Copyright 2016 American Academy of Optometry.

Cox,S. M., Berntsen,D. A., Chatterjee,N., Hickson-Curran,S. B., Jones,L. W., Moezzi,A. M., Morgan,P. B., Nichols,J. J., Mathew,J. H., Bickle,K. M., Powell,D. R., Cox,J., Miller,W. L., Wallace-Tucker,A., Charrier,S., Chen,Y. -J, Cardenas,L., Huerta,S., Dionne,K., Maldonado-Codina,C., Plowright,A. J., Howarth,G. F., Mirza,A., Smith,S., Dumbleton,K., Schulze,M., Luensmann,D., Ngo,W., Paquette,L., Srinivasan,S., Varikooty,J., Johnson,J., Simpson,M., Voss,L., Ryan,L., Careless,N., Smith,A., Subbarama Eyelid margin and meibomian gland characteristics and symptoms in lens wearers. Optometry and Vision Science 2016;93,8:901-908. [ Show Abstract ]

Purpose. To describe the lid margin characteristics of contact lens wearers and relate them to comfort during lens wear. Methods. Three study sites enrolled habitual contact lens wearers. Subjects completed the Comfort domain of the Contact Lens User Experience (CLUE) questionnaire, and each eye was graded for the presence of mucocutaneous junction (MCJ) displacement, lid margin irregularity, and lid margin vascularity. Examiners counted the number of meibomian gland (MG) orifices in the central centimeter of the lower eyelid and the number of those that showed pouting/plugging and vascular invasion. MG expressibility was graded according to the Shimazaki schema. Subjects were grouped based on presence/ absence of each characteristic, total number of orifices (=5 vs. 0). Descriptive statistics are reported. A linear model was used to assess the fixed effect of each characteristic on combined CLUE score and each CLUE statement, if the effect on combined CLUE score showed p < 0.10. Results. The study included 203 subjects (67.5% female) with mean age (±SD) of 30.3 ± 9.6 years. The most commonly observed characteristics were orifice pouting/plugging, compromised MG expressibility, and lid margin vascularity (35.0, 30.3, and 20.4%, respectively). MCJ displacement and MG expressibility had an effect on the combined CLUE score such that individual CLUE statements were analyzed (p = 0.01 and p = 0.06, respectively). MCJ displacement had an effect on comfort upon insertion (p = 0.01), comfort after 5 minutes (p = 0.03), end-of-day comfort (p = 0.01), and ability to maintain ocular moisture (p = 0.030). MG expressibility had a significant effect on general comfort (p = 0.01), comfort throughout the day (p = 0.02), and the ability to maintain ocular moisture (p = 0.02). Conclusions. MCJ displacement and MG expressibility have an effect on contact lens comfort. © Copyright 2016 American Academy of Optometry.

Omali,N. B., Heynen,M., Subbaraman,L. N., Papinski,D., Lakkis,C., Smith,S. L., Morgan,P. B., Berntsen,D. A., Nichols,J. J., Jones,L. W., Mathew,J. H., Cox,S. M., Bickle,K. M., Powell,D. R., Cox,J., Miller,W. L., Wallace-Tucker,A., Charrier,S., Chen,Y. -J, Cardenas,L., Huerta,S., Dionne,K., Maldonado-Codina,C., Plowright,A. J., Howarth,G. F., Chatterjee,N., Mirza,A., Dumbleton,K., Schulze,M., Moezzi,A. M., Luensmann,D., Ngo,W., Paquette,L., Srinivasan,S., Varikooty,J., Johnson,J., Simpson,M., Vos Impact of lens care solutions on protein deposition on soft contact lenses. Optometry and Vision Science 2016;93,8:963-972. [ Show Abstract ]

Purpose. To evaluate the effect of four contemporary lens care solutions on total protein, total lysozyme, and active lysozyme extracted from three contact lens materials. Methods. Adapted contact lens wearers were recruited at three sites, and all subjects were randomly assigned to daily wear of either etafilcon A, galyfilcon A, or senofilcon A for 2 weeks. Four lens care solutions (Biotrue, OPTI-FREE PureMoist, RevitaLens OcuTec, and ClearCare) were used by each subject in random order with a new pair of lenses after a washout period between solutions of at least 4 days. After 2 weeks of daily wear, contact lenses were collected for analysis. Proteins were extracted from a subset of contact lenses (n = 568) and total protein, total lysozyme, and lysozyme activity were quantified using a modified Bradford assay, an enzyme-linked immunosorbent assay, and a micrococcal assay, respectively. Results. Higher levels of total protein were extracted from etafilcon A when used with Biotrue compared to other solutions (p = 0.0001). There were higher levels of total lysozyme extracted from galyfilcon A lenses when used with PureMoist than with Biotrue or Clear Care (p < 0.006). Higher total lysozyme was extracted from senofilcon A when used with RevitaLens OcuTec compared to Biotrue (p = 0.002). Lower lysozyme activity was recovered from senofilcon A lenses with RevitaLens OcuTec when compared to all other care solutions (all p < 0.004). When Biotrue, PureMoist, or RevitaLens OcuTec were used, higher total lysozyme was extracted from galyfilcon A compared to senofilcon A(p < 0.01). When RevitaLens OcuTec was used, higher levels of active lysozyme were extracted from galyfilcon A compared to senofilcon A (p = 0.02). Conclusions. The ability of lens care solutions to remove protein from lenses varies depending upon the care solution composition and also the polymeric make-up of the contact lens material. © Copyright 2016 American Academy of Optometry.

2015

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 50° 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. © 2015 Contact Lens Association of Opthalmologists, Inc.

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. © 2015 Contact Lens Association of Opthalmologists, Inc.

2013

Weeks,A., Boone,A., Luensmann,D., Jones,L., Sheardown,H. The effects of hyaluronic acid incorporated as a wetting agent on lysozyme denaturation in model contact lens materials. Journal of Biomaterials Applications 2013;28,3:323-333. [ Show Abstract ]

Conventional and silicone hydrogels as models for contact lenses were prepared to determine the effect of the presence of hyaluronic acid on lysozyme sorption and denaturation. Hyaluronic acid was loaded into poly(2-hydroxyethyl methacrylate) and poly(2-hydroxyethyl methacrylate)/TRIS - methacryloxypropyltris (trimethylsiloxy silane) hydrogels, which served as models for conventional and silicone hydrogel contact lens materials. The hyaluronic acid was cross-linked using 1-ethyl-3-(3-dimethylaminopropyl)- carbodiimide in the presence of dendrimers. Active lysozyme was quantified using a Micrococcus lysodeikticus assay while total lysozyme was determined using 125-I radiolabeled protein. To examine the location of hyaluronic acid in the gels, 6-aminofluorescein labeled hyaluronic acid was incorporated into the gels using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide chemistry and the gels were examined using confocal laser scanning microscopy. Hyaluronic acid incorporation significantly reduced lysozyme sorption in poly(2-hydroxyethyl methacrylate) (p < 0.00001) and poly(2-hydroxyethyl methacrylate)/TRIS - methacryloxypropyltris (trimethylsiloxy silane) (p < 0.001) hydrogels, with the modified materials sorbing only 20% and 16% that of the control, respectively. More importantly, hyaluronic acid also decreased lysozyme denaturation in poly(2-hydroxyethyl methacrylate) (p < 0.005) and poly(2-hydroxyethyl methacrylate)/TRIS - methacryloxypropyltris (trimethylsiloxy silane) (p < 0.02) hydrogels. The confocal laser scanning microscopy results showed that the hyaluronic acid distribution was dependent on both the material type and the molecular weight of hyaluronic acid. This study demonstrates that hyaluronic acid incorporated as a wetting agent has the potential to reduce lysozyme sorption and denaturation in contact lens applications. The distribution of hyaluronic acid within hydrogels appears to affect denaturation, with more surface mobile, lower molecular weight hyaluronic acid being more effective in preventing denaturation. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Ng,A., Heynen,M., Luensmann,D., Subbaraman,L. N., Jones,L. Impact of tear film components on the conformational state of lysozyme deposited on contact lenses. Journal of Biomedical Materials Research - Part B Applied Biomaterials 2013;101,7:1172-1181. [ Show Abstract ]

Purpose To investigate the impact of lactoferrin and lipids on the kinetic denaturation of lysozyme deposited on silicone and conventional hydrogel lenses, using a complex artificial tear solution (ATS). Methods Two silicone hydrogel lenses (AIR OPTIX AQUA; lotrafilcon B and ACUVUE OASYS; senofilcon A) and two conventional hydrogel lenses (ACUVUE 2; etafilcon A and PROCLEAR; omafilcon A) were incubated in four solutions: an ATS, ATS without lactoferrin, ATS without lipids, and ATS without lactoferrin and lipids. At various time points over a 28-day period, the percentage of active lysozyme per lens was determined using a fluorescence activity assay and an ELISA. Results After 28 days, the percentage of active lysozyme extracted from etafilcon A lenses in all solutions was significantly higher than all other lens materials (p 0.05). The inclusion of lipids in the ATS significantly increased the lysozyme denaturation on both silicone hydrogel materials (p 0.05). The inclusion of lipids in the ATS significantly increased the lysozyme denaturation on both silicone hydrogel materials (p 0.05). Conclusions Lactoferrin and lipids have an impact on the denaturation of lysozyme deposited onto silicone hydrogel contact lenses, while conventional hydrogel lenses were unaffected. Future in vitro studies should consider the impact of tear film components when investigating protein deposition and denaturation on contact lenses. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 1172-1181, 2013. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

Ng,A., Heynen,M., Luensmann,D., Subbaraman,L. N., Jones,L. Optimization of a fluorescence-based lysozyme activity assay for contact lens studies. Current eye research 2013;38,2:252-259. [ Show Abstract ]

Purpose: To optimize a fluorescence-based lysozyme activity assay to investigate the conformational state of lysozyme in solution and to determine the impact of extraction and evaporation procedures and the possible interference of contact lens materials on lysozyme activity. Methods: The fluorescence-based lysozyme activity assay, Enzchek (Molecular Probes Inc, Eugene, OR) which utilizes fluorescently quenched Micrococcus lysodeikticus, was compared to the gold standard, classical lysozyme turbidity assay, using four differently concentrated lysozyme samples (20, 10, 5.0 and 2.0 ng/µL). Furthermore, six differently concentrated lysozyme samples (2.0, 1.0, 0.5, 0.25, 0.125 and 0.01 µg/µL) were quantified using the fluorescence-based assay in the presence of extraction solvents consisting of 0.2% and 0.02% trifluroacetic acid/acetonitrile and following evaporation procedures. Results: A standard curve was generated by the fluorescence-based assay ranging from 2 to 150 ng. The total active lysozyme quantified in the four lysozyme samples was not significantly different between the two assays (p > 0.05) and the concordance correlation coefficient was determined to be 0.995. However an average discrepancy between the two assays was found to be 0.474 ng, with the turbidity assay typically reporting higher active lysozyme measurements. The sensitivity of the fluorescence-based assay was higher than the classical turbidity assay when quantifying 20 ng or less active lysozyme. Following the extraction and evaporation procedures and the addition of lens extracts, the total active lysozyme recovered was 95% or greater. Conclusions: In comparison to the classical turbidity assay, the fluorescence-based assay is a very sensitive method, making it a favorable technique, particularly when studying contact lens materials that deposit relatively low levels of lysozyme. © Informa Healthcare USA, Inc.

2012

Jadi,S., Heynen,M., Luensmann,D., Jones,L. Composition of incubation solution impacts in vitro protein uptake to silicone hydrogel contact lenses. Molecular Vision 2012;18337-347. [ Show Abstract ]

Purpose: To determine the impact of incubation solution composition on protein deposition to silicone hydrogel (SH) contact lenses using a simplistic and a complex model of the tear film. Methods: Three SH materials - senofilcon A (SA), lotrafilcon B (LB), and balafilcon A (BA) - were incubated in two different solutions; Solution A was a simplistic augmented buffered saline solution containing a single protein, whereas Solution B was a complex artificial tear solution (ATS), containing the augmented buffered saline solution in addition to proteins, lipids, and mucins (pH=7.4). The proteins of interest (lysozyme, lactoferrin, albumin) were radiolabeled with Iodine-125 (2% protein of interest) and the accumulation of the conjugated protein to the lens materials was determined after 1, 7, 14, and 28 days of incubation. Protein deposition was measured using a gamma counter and the raw data were translated into absolute amounts (μg/lens) via extrapolation from standards. Results: After 28 days, lysozyme uptake was significantly lower on BA lenses when incubated in Solution A (33.7 μg) compared to Solution B (56.2 μg), p0.05. LB lenses also deposited similar amounts of lysozyme for both solutions (Solution A: 5.0 μg, Solution B: 4.7 μg, p>0.05). After 28 days, BA lenses accumulated approximately twice the amount of lactoferrin than the other lens materials, with 30.3 μg depositing when exposed to Solution A and 22.0 μg with Solution B. The difference between the two solutions was statistically significant (p0.05. LB lenses also deposited similar amounts of lysozyme for both solutions (Solution A: 5.0 μg, Solution B: 4.7 μg, p>0.05). After 28 days, BA lenses accumulated approximately twice the amount of lactoferrin than the other lens materials, with 30.3 μg depositing when exposed to Solution A and 22.0 μg with Solution B. The difference between the two solutions was statistically significant (p0.05). After 28 days, albumin deposition onto BA lenses was significantly greater when lenses were incubated in Solution B (1.7 μg) compared to Solution A (0.9 μg), p0.05). LB lenses incubated in Solution A deposited more albumin compared to Solution B (0.9 μg versus 0.6 μg), p=0.003. Discussion: Protein deposition onto SH materials varied when contact lenses were incubated in either a complex ATS compared to a single protein solution. More lysozyme accumulated onto BA lenses incubated in a complex analog of the human tear film, whereas lactoferrin deposited onto SA lenses independent of incubation solution composition. To better mimic the ex vivo environment, future studies should use more appropriate analogs of the tear film. © 2012 Molecular Vision.

Luensmann,D., Jones,L. Protein deposition on contact lenses: The past, the present, and the future. Contact Lens and Anterior Eye 2012;35,2:53-64. [ Show Abstract ]

Proteins are a key component in body fluids and adhere to most biomaterials within seconds of their exposure. The tear film consists of more than >400 different proteins, ranging in size from 10 to 2360 kDa, with a net charge of pH 1-11. Protein deposition rates on poly-2-hydroxyethyl methacrylate (pHEMA) and silicone hydrogel soft contact lenses have been determined using a number of ex vivo and in vitro experiments. Ionic, high water pHEMA-based lenses attract the highest amount of tear film protein (1300 μg/lens), due to an electrostatic attraction between the material and positively charged lysozyme. All other types of pHEMA-based lenses deposit typically less than 100 μg/lens. Silicone hydrogel lenses attract less protein than pHEMA-based materials, with <10 μg/lens for non-ionic and up to 34 μg/lens for ionic materials. Despite the low protein rates on silicone hydrogel lenses, the percentage of denatured protein is typically higher than that seen on pHEMA-based lenses. Newer approaches incorporating phosphorylcholine, polyethers or hyaluronic acid into potential contact lens materials result in reduced protein deposition rates compared to current lens materials. © 2012 British Contact Lens Association.

Luensmann,D., Moezzi,A., Peterson,R. C., Woods,C., Fonn,D. Corneal staining and cell shedding during the development of solution-induced corneal staining. Optometry and Vision Science 2012;89,6:868-874. [ Show Abstract ]

Purpose. This non-dispensing cross-over study was conducted to determine if lenses presoaked in Opti-Free RepleniSH (OFR) or ReNu MultiPlus (RMP) cause solution-induced corneal staining (SICS) and subsequent cell sloughing before the typical 2 h in vivo examination point. Methods. Study lenses (PureVision) were worn bilaterally by 13 participants for periods of 15, 30, 60, and 120 min using two different contralateral care regimen pairings. The lens worn on the test eye was soaked overnight in either OFR or RMP and the control eye in Clear Care (CC). After lens removal, corneal staining was rated on a scale of 0 (negligible) to 100 (severe) for four peripheral quadrants and the central region, and the differential global staining score was calculated by subtracting baseline staining scores. Following the staining assessment, corneal cells were collected from the ocular surface using a non-contact irrigation system to determine ocular cell shedding rates. Results. Differential global staining score with OFR was greater than CC with the differences being statistically significant at 30 and 60 min (p 0.05). Conclusions. SICS occurred earlier but to a significantly lower degree when PureVision lenses were presoaked in OFR compared with RMP, while lenses presoaked in CC did not cause SICS. Ocular surface cell shedding after lens removal was not impacted by lens wear durations of ≤2 h. © 2012 American Academy of Optometry.

Ng,A., Heynen,M., Luensmann,D., Jones,L. Impact of tear film components on lysozyme deposition to contact lenses. Optometry and Vision Science 2012. [ Show Abstract ]

PURPOSE: To investigate the impact of lactoferrin and lipids on the kinetic deposition of lysozyme on silicone and conventional hydrogel lenses, using a complex artificial tear solution (ATS). METHODS: Two silicone hydrogel lenses (AIR OPTIX AQUA; lotrafilcon B and ACUVUE OASYS; senofilcon A) and two conventional hydrogel lenses (ACUVUE 2; etafilcon A and PROCLEAR; omafilcon A) were investigated. Lenses were incubated in four different solutions: a complex ATS consisting of various salts, lipids, proteins, and mucins, an ATS without lactoferrin (ATS w/o Lac), an ATS without lipids (ATS w/o Lip), and an ATS without lactoferrin and lipids (ATS w/o Lac & Lip), each containing 2% radiolabeled (125I) lysozyme (1.9 mg/ml). After each time point (4, 12 h and 1, 2, 3, 5, 7, 14, 21, 28 days), the amount of lysozyme per lens was quantified. RESULTS: After 28 days, lotrafilcon B lenses incubated in ATS deposited significantly less lysozyme (9.7 ± 1.4 μg) than when incubated in solutions not containing lactoferrin and lipids (more than 11.8 μg) (p < 0.001). Lysozyme uptake to senofilcon A lenses was higher in ATS w/o Lip (5.3 ± 0.1 μg) compared with other solutions (less than 3.9 μg) (p < 0.001). Etafilcon A lenses deposited the most lysozyme in all four solutions compared with the rest of the lens types (p < 0.001). For etafilcon A lenses, less lysozyme was deposited when incubated in ATS w/o Lip (588.6 ± 0.4 μg) compared with the other solutions (more than 642.6 μg) (p < 0.001). Omafilcon A lenses in ATS w/o Lac accumulated significantly less lysozyme (12.8 ± 1.0 μg) compared with the other solutions (more than 14.2 μg) (p < 0.001). CONCLUSIONS: An ATS containing lactoferrin and lipids impacts lysozyme deposition on both silicone and conventional hydrogel contact lenses. When performing in vitro experiments to study protein deposition on contact lenses, more complex models should be used to better mimic the human tear film.

2011

Weeks,A., Luensmann,D.,Boone,A, Jones,L., Sheardown,H. Hyaluronic acid as an internal wetting agent in model DMAA/TRIS contact lenses. 2011001-10. [ Show Abstract ]

Model silicone hydrogel contact lenses, comprised of N,N-dimethylacrylamide and methacryloxypropyltris (trimethylsiloxy) silane, were fabricated and hyaluronic acid (HA) was incorporated as an internal wetting agent using a dendrimer-based method. HA and dendrimers were loaded into the silicone hydrogels and cross-linked using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide chemistry. The presence and location of HA in the hydrogels was confirmed using X-ray photoelectron spectroscopy and confocal laser scanning microscopy, respectively. The effects of the presence of HA on the silicone hydrogels on hydrophilicity, swelling behavior, transparency, and lysozyme sorption and denaturation were evaluated. The results showed that HA increased the hydrophilicity and the equilibrium water content of the hydrogels without affecting transparency. HA also significantly decreased the amount of lysozyme sorption (p < 0.002). HA had no effect on lysozyme denaturation in hydrogels containing 0% and 1.7% methacrylic acid (MAA) (by weight) but when the amount of MAA was increased to 5%, the level of lysozyme denaturation was significantly lower compared to control materials. These results suggest that HA has great potential to be used as a wetting agent in silicone hydrogel contact lenses to improve wettability and to decrease lysozyme sorption and denaturation.

2010

Luensmann,D., Heynen,M., Liu,L., Sheardown,H., Jones,L. The efficiency of contact lens care regimens on protein removal from hydrogel and silicone hydrogel lenses. Molecular Vision 2010;16,10-11:79-92. [ Show Abstract ]

Purpose: To investigate the efficiency of lysozyme and albumin removal from silicone hydrogel and conventional contact lenses, using a polyhexamethylene biguanide multipurpose solution (MPS) in a soaking or rubbing/soaking application and a hydrogen peroxide system (H2O2). Methods: Etafilcon A, lotrafilcon B and balafilcon A materials were incubated in protein solutions for up to 14 days. Lenses were either placed in radiolabeled protein to quantify the amount deposited or in fluorescent-conjugated protein to identify its location, using confocal laser scanning microscopy (CLSM). Lenses were either rinsed with PBS or soaked overnight in H2O2 or MPS with and without lens rubbing. Results: After 14 days lysozyme was highest on etafilcon A (2,200 μg) >balafilcon A (50 μg) >lotrafilcon B (9.7 μg) and albumin was highest on balafilcon A (1.9 μg) =lotrafilcon B (1.8 μg) >etafilcon A (0.2 μg). Lysozyme removal was greatest for balafilcon A >etafilcon A >lotrafilcon B, with etafilcon A showing the most change in protein distribution. Albumin removal was highest from etafilcon A >balafilcon A >lotrafilcon B. H2O2 exhibited greater lysozyme removal from etafilcon A compared to both MPS procedures (p0.62). Albumin removal was solely material specific, while all care regimens performed to a similar degree (p>0.69). Conclusions: Protein removal efficiency for the regimens evaluated depended on the lens material and protein type. Overall, lens rubbing with MPS before soaking did not reduce the protein content on the lenses compared to nonrubbed lenses (p=0.89). © 2010 Molecular Vision.

Luensmann,D., Jones,L. Impact of fluorescent probes on albumin sorption profiles to ophthalmic biomaterials. Journal of Biomedical Materials Research - Part B Applied Biomaterials 2010;94,2:327-336.

2009

Luensmann,D., Heynen,M., Liu,L., Sheardown,H., Jones,L. Determination of albumin sorption to intraocular lenses by radiolabeling and confocal laser scanning microscopy. Journal of cataract and refractive surgery 2009;35,11:2000-2007. [ Show Abstract ]

Purpose: To determine albumin adsorption profiles and penetration depth of 3 intraocular lens (IOL) materials over time using confocal laser scanning microscopy (CLSM) and radiolabeling. Setting: Centre for Contact Lens Research, School of Optometry, and Department of Biology, University of Waterloo, Waterloo, Ontario, Canada. Methods: Poly(methyl methacrylate) (PMMA), silicone, and foldable hydrophilic acrylic IOLs were incubated in 0.5 mg/mL bovine serum albumin (BSA) for 1, 7, and 14 days. The BSA was conjugated with lucifer yellow VS to allow identification of the protein location by fluorescent imaging with CLSM. Next, the protein uptake was quantified using 2% 125I-labeled BSA. Results: Confocal laser scanning microscopy showed increasing BSA uptake for silicone and PMMA IOLs after 14 days of incubation (P<.05), with an apparent penetration depth of 8.7 μm ± 1.9 (SD) and 9.2 ± 1.4 μm, respectively. For hydrophilic acrylic IOLs, BSA was detected at a depth of 38 ± 7.4 μm after 1 day, followed by an increase to 192.7 ± 16.2 μm after 14 days. Despite the penetration depth into the hydrophilic acrylic IOLs, quantitative results confirmed that PMMA and hydrophilic acrylic deposited significantly less BSA (mean 278.3 ± 41.7 ng and 296.5 ± 33.1 ng, respectively) than silicone IOLs (mean 392.6 ± 37.6 ng) (P<.05). Conclusions: Silicone and PMMA IOL materials showed BSA sorption near the lens surface only, while BSA penetrated deep into the hydrophilic acrylic IOL matrix. Combining the qualitative CLSM method and quantitative radiolabeling technique provided detailed information on protein interactions with implantable biomaterials. © 2009 ASCRS and ESCRS.

Luensmann,D., Zhang,F., Subbaraman,L., Sheardown,H., Jones,L. Localization of lysozyme sorption to conventional and silicone hydrogel contact lenses using confocal microscopy. Current eye research 2009;34,8:683-697. [ Show Abstract ]

PURPOSE: To investigate the distribution profile of hen egg lysozyme (HEL) through poly-2-hydroxyethyl methacrylate (pHEMA)-based lens materials and silicone hydrogel (SH) lens materials using confocal laser scanning microscopy (CLSM). METHODS: Five silicone SH materials (balafilcon A, lotrafilcon A, lotrafilcon B, galyfilcon A, senofilcon A) and four pHEMA-based materials (alphafilcon A, etafilcon A, omafilcon A, vifilcon A) were incubated in 1.9 mg/ml protein solution for 24 hours. The protein solution consisted of HEL, which was conjugated with either fluorescein isothiocyanate (FITC) or lucifer yellow VS dilithium salt (LY). CLSM (Zeiss LSM 510 META) identified the location of the fluorescently labeled protein by using 1 micro m depth scans through the lens. In a second experiment, lenses were incubated with 2% (125) I labeled HEL to determine the amount of deposited protein on each lens. Both techniques were combined to describe the individual HEL profiles. RESULTS: After the incubation in fluorescently labeled HEL, all pHEMA-based materials and the SH material balafilcon A accumulated protein throughout the entire lens material, while, for the SH lenses lotrafilcon A and lotrafilcon B, HEL was primarily detected on the lens surface alone. Differences in protein uptake pattern due solely to the two conjugated dyes were most apparent for the SH materials galyfilcon A and senofilcon A; HEL was detected throughout these lenses when conjugated with LY but accumulated primarily on the surface when conjugated with FITC. CONCLUSION: CLSM in combination with a radiolabel technique can describe both the location and degree of protein deposition on different contact lens materials.

2008

Luensmann,D., Jones,L. Albumin adsorption to contact lens materials: A review. Contact Lens and Anterior Eye 2008;31,4:179-187. [ Show Abstract ]

During contact lens wear, tear film components such as lipids, mucins and proteins tend to deposit on and within the lens material and may cause discomfort, reduced vision and inflammatory reactions. The tear film protein that has attracted most interest when studying contact lens deposition is the small (14 kDa), positively charged protein lysozyme. Albumin, which is a much larger protein (66 kDa) with an overall net negative charge is also of interest, and shows very different adsorption patterns to lysozyme. The concentration of albumin in the tear film is relatively low compared to the concentration in blood serum, but this value increases markedly under various conditions, including when the eye is closed, during contact lens wear and in various dry eye states. Gaining an understanding of the manner in which albumin deposits on biomaterials is of importance for contact lens wear, as well as for other medical applications where HEMA-based materials are used for implants, artificial blood vessels or drug delivery devices. This review paper summarizes the impact of individual material compositions, water content, hydrophobicity and electrostatic attraction on the adsorption behavior of the protein albumin.

2007

Luensmann,D., Glasier,M. -A, Zhang,F., Bantseev,V., Simpson,T., Jones,L. Confocal microscopy and albumin penetration into contact lenses. Optometry and Vision Science 2007;84,9:839-847. [ Show Abstract ]


Purpose. To develop a novel in vitro method to detect the depth of penetration of the tear film protein albumin into contact lens materials using confocal laser scanning microscopy (CLSM).
Methods. A poly-HEMA-based hydrogel (etafilcon A) and a silicone hydrogel material (lotrafilcon B) were examined. In vitro, bovine serum albumin (BSA) was labeled with 5-(4,6-dichloro-s-triazin-2-ylamino) fluorescein hydrochloride (DTAF). The lenses were incubated in this protein solution (0.5 mg/ml) at 37°C. After 1 and 7 days incubation, the lenses were examined using CLSM (Zeiss 510, config. META 18) and the location of the fluorescently labeled BSA was identified.
Results. BSA adsorption on the surface and penetration into the lens matrix occurred at a higher concentration for etafilcon compared to lotrafilcon (p < 0.001). For both materials, BSA was detected on the surface after 1 day of incubation. Significant levels of BSA were detected within the matrix of etafilcon after as little as 1 day (p < 0.001), but no BSA was detected in the matrix of lotrafilcon at any time (p > 0.05).
Conclusion. CLSM can be successfully used to examine the depth of penetration of fluorescently labeled proteins into various hydrogel polymers. Our results show that etafilcon lenses both adsorb BSA on the surface and absorb BSA within the matrix, whereas lotrafilcon B adsorbs small amounts of BSA on the surface only.

Abstracts

2016

Moezzi A, Varikooty J, Luensmann D, Ng A, Schulze M, Karkkainen T, Xu J, Jones L. Open-eye clinical performance of etafilcon a multifocal daily disposable hydrogel contact lenses compared to habitual silicone hydrogel lens wear. Optom Vis Sci 2016;93: E-abstract 165259. [ PDF ]

Yang M, Luensmann D, Fonn D, Woods J, Gordon K, Jones L, Jones D. Myopia prevalence in canadian school children. Optom Vis Sci 2016;93: E-abstract 165328. [ PDF ]

2015

Schulze M, Luensmann D, Ng AY, Panjwani F, Srinivasan S, Jones L. The relationship between the positioning of multifocal contact lens optics and satisfaction with vision. Optom Vis Sci 2015;92: E-abstract 155256. [ PDF ]

2014

Stahl U, Luensmann D, Lemp J, Moezzi A, Schulze M, Varikooty, Dumbleton K, Jones L. Determination of higher order aberrations with two silicone hydrogel toric lenses. Optom Vis Sci 2014;91: E-abstract 145188. [ PDF ]

Luensmann D, Situ P, Fonn D, Jones L. Evaluation of the Performance of a New Silicone Hydrogel Color Contact Lens. Optom Vis Sci 2014;91: E-abstract 145179. [ PDF ]

Schulze M, Luensmann D, Hickson-Curran S, Toubouti Y, Cox S, Plowright A, Nichols J, Morgan P, Jones L. Analysis of lid wiper epitheliopathy in habitual soft lens wearers. Optom Vis Sci 2014;91: E-abstract 140104.

2013

Flanagan J, Stavropoulos A, Luensmann D, Postnikoff C, Gorbet M. Comparison of the Cellular Response to Overnight Contact Lens Wear on the Sclera and Cornea. Invest Ophthalmol Vis Sci 2013;54:E-abstract 5654.

Gorbet M, Luensmann D, Jones L. The response of tear film neutrophils to occasional overnight lens wear. Invest Ophthalmol Vis Sci 2013;54: E-Abstract 2069.

2012

Gorbet M, Luensmann D, Luck S, Jones L. Response Of Tear Film Neutrophils To Different Stimuli. Invest Ophthalmol Vis Sci 2012;53:ARVO E-Abstract 5271.

Srinivasan S, Luensmann D, Otchere H, Yu M, Yang J, Jones L. The impact of cosmetics on the surface appearance and wettability of silicone hydrogel contact lenses. Optom Vis Sci 2012;89:E-abstract 120317.

Luensmann D, Srinivasan S, Ochtere H, Yu M, Yang G, Jones L. The impact of cosmetics on the physical dimension and optical performance of silicone hydrogel contact lenses. Contact Lens & Anterior Eye 2012;35,S1:e6.

Gorbet M, Cira D, Peterson R, Woods C, Luensmann D. The acute effect of benzalkonium chloride and sodium fluorescein on epithelial cells collected from the human ocular surface. Contact Lens & Anterior Eye 2012;35,S1:e22-e23.

2011

Fisher G, Leung T, Luensmann D, Heynen M, Jones L. 3D TOF-SIMS characterisation of drug-loaded silicone hydrogel contact lenses in the frozen hydrated state. 18th SIMS Conference (Trentino, Italy), 2011.

Luensmann D, Keir N, Richter D, Woods C, Fonn D. In vivo wettability changes over 3 days using daily disposable contact lenses. Optom Vis Sci 2011;88:E-abstract 115384.

Jadi S, Heynen M, Luensmann D, Jones L. Incubation solution composition impacts in vitro protein uptake to silicone hydrogel contact lenses. Optom Vis Sci 2011;88:E-abstract 110546.

Moezzi A, Situ P, Luensmann D, Fonn D, Woods C, McNally J, Jones L. Does comfort with aging silicone hydrogel lenses relate to changes in lens fit and conjunctival staining?. Optom Vis Sci 2011;88:E-abstract 115708.

2010

Srinivasan S, Martell E, Heynen M, Luensmann D, Cira D, Gorbet M, Jones L. Ocular surface sampling techniques. 7th Canadian University Conference in Optometry (Montreal, Canada), 2010.

Srinivasan S, Martell E, Heynen M, Luensmann D, Cira D, Gorbet M, Jones L. Ocular surface sampling techniques. 20:20 National Science and Engineering Council Network meeting (Horseshoe Valley, Ontario, Canada), 2010.

2009

Luensmann D, Heynen M, Jones L. Penetration profile of lysozyme and albumin in silicone hydrogel and pHEMA-based contact lens materials assessed using confocal microscopy. Contact Lens & Anterior Eye 2009;32,5:224.

Weeks A, Luensmann D, Jones L, Sheardown H. Crosslinked HA decrease lysozyme sorption and denaturation in model contact lens materials. 20:20 National Science and Engineering Council (NSERC) Network meeting (Toronto, Canada), 2009.

Luensmann D, Heynen M, Jones L. Determination of albumin sorption to intraocular lenses by radiolabeling and confocal scanning laser microscopy. Ivey Research Institute Day (London, Canada), 2009.

Luensmann D, Heynen M, Liu L, Sheardown H, Jones L. The impact of rub & no-rub care products on protein removal and localization. Optom Vis Sci 2009;86:E-abstract 090517.

2008

Luensmann D, Heynen M, Jones L. Albumin penetration into intraocular lenses imaged by confocal microscopy. Optom Vis Sci 2008;85; E-abstract 80029.

2007

Luensmann D, Heynen M, Jones L. The use of confocal microscopy to investigate albumin penetration into pHEMA-based and silicone hydrogel contact lens materials. Invest Ophthalmol Vis Sci 2007;48: E-abstract 5377.

Luensmann D, Heynen M, Jones L. The use of confocal microscopy to investigate albumin penetration into pHEMA-based and silicone hydrogel contact lens materials. Biomedical Imaging and Computer Vision (BICV) Workshop (University of Waterloo, Canada), 2007.

Luensmann D, Heynen M, Jones L. The use of confocal microscopy to investigate albumin penetration into pHEMA-based and silicone hydrogel contact lenses. 6th Canadian Optometry Conference on Vision Science, Waterloo, Ontario, 2007.

Luensmann D, Heynen M, Jones L. Confocal microscopy and albumin penetration into contact lenses. Optom Vis Sci 2007;84,9:839-847.

2006

Luensmann D, Glasier MA, Zhang F, Jones L. A novel in vitro method to determine the penetration profile of albumin into silicone hydrogel and conventional hydrogel contact lens materials. Optom Vis Sci 2006;83:E-Abstract 060092.

Professional Publications

2014

Luensmann D. A meta-analysis of studies on cosmetically tinted soft contact lenses. ContactLensUpdate.com 2014.

2013

Dumbleton K, Luensmann D. Corneal Infiltrates with Silicone Hydrogel Contact Lens Wear and the Role of Compliance. Optometry Rounds 2013;1,5:.

2011

Luensmann D. Physiological response to protein and cholesterol deposition on silicone hydrogel contact lenses - An article review. ContactLensUpdate.com 2011.

2009

Luensmann D, Jones L. Albuminablagerungen auf kontaklinsen-materialien: Ein uberblick. Die Kontaklinse 2009;518-23.