Jump to:

Peer-reviewed articles

2019

Moezzi,A. M., Varikooty,J., Luensmann,D., Schulze,M., Ng,A. Y., Karkkainen,T., Xu, J., Jones,L. The short-term physiological impact of switching reusable silicone hydrogel wearers into a hydrogel daily disposable multifocal Clinical Ophthalmology 2019;13:1193-1202 [ Show Abstract ]

Purpose: To evaluate ocular physiological responses to etafilcon A multifocal (etMF) daily disposable (DD) lenses after 4 weeks of wear, when switching from habitual silicone hydrogel (SiHy) daily wear.
Method: A single-arm, open-label, bilateral dispensing study was conducted in 39 habitual spherical SiHy wearers (14 hyperopes; 25 myopes). Clinical visits occurred with habitual SiHy (control) at baseline and after 4 weeks of etMF DD open-eye lens wear at exit. Objective limbal/bulbar hyperemia using the Oculus K5M (0–4) and subjective grading of lid wiper epitheliopathy (LWE) (0–4) were tested for non-inferiority (NI), using a margin of 1 grade. Corneal thickness along a 10 mm cord was measured using the Visante OCT and tested for NI using a 30 μm margin. Corneal staining area was graded (0–100%).
Results: The least-square mean differences (LSMD) and 95% confidence interval (95% CI) between etMF DD and habitual SiHy in central and peripheral corneal thickness (μm) were 3.64 (−2.0, 9.29) and 3.0 (−7.72, 13.72) in hyperopic, and 3.56 (−0.66, 7.78) and 6.40 (−1.62, 14.42) in myopic subjects. The LSMD (95% CI) for bulbar and limbal hyperemia were −0.08 (−0.19, 0.02) and −0.01 (−0.12, 0.09) in hyperopes, and 0.04 (−0.03, 0.12) and 0.04 (−0.04, 0.11) in myopes. The LSMD (95% CI) for LWE were 0.11 (−0.39, 0.60) and 0.30 (−0.07, 0.67) for hyperopes and myopes, respectively.
Conclusions: No clinically significant differences in a variety of physiological responses were found when habitual reusable SiHy daily wear subjects were refitted into hydrogel etMF, when the subjects were followed for 4 weeks.

2018

Luensmann,D., Schaeffer,J. L., Rumney,N. J., Stanberry,A., Walsh,K., Jones,L. Spectacle prescriptions review to determine prevalence of ametropia and coverage of frequent replacement soft toric contact lenses Contact Lens and Anterior Eye 2018;41(5):412-420 [ Show Abstract ]

Purpose: To determine the prevalence of ametropia and astigmatism in a clinic population and to estimate the coverage of frequent replacement soft toric lenses. Methods: A review of patient files was conducted at three clinical sites. Prescription data collected between January 2014 and March 2017 in a patient cohort 14 to 70 years of age inclusive were analyzed to determine prevalence of ametropia and astigmatism. The percent coverage of frequent replacement soft toric contact lenses has further been estimated using different ranges for sphere, cylinder and axis availability. Results: In total 101,973 patients were included in the analysis of which 69.5% were considered myopic, 26.9% hyperopic and 3.5% emmetropic as determined by the eye with the larger absolute value of the spherical equivalent refraction. Astigmatism in at least one eye was found in 87.2% of the population, with 37.0% of the patients exhibiting astigmatism of at least −1.00DC in at least one eye. With-the-rule astigmatism was most prevalent in the 14 to 20 year-olds (53.0%), while against-the-rule astigmatism was most prevalent in the 41 to 70 year-olds (50.7%). For astigmatic eyes with a cylinder of at least −0.75DC (n = 83,540; 41% of all eyes), the coverage with toric soft lenses varied greatly depending on parameter availability and ranged between 30.7% (sphere: Plano to −3.00D, cylinder: up to −1.75DC, axes: 90 ± 10° and 180 ± 10°) and 96.4% (sphere: + 6.00D to −10.00D, cylinders: up to −2.75DC, 18 axes). Conclusion: Currently available frequent replacement soft toric contact lenses provide coverage for up to 96.4% of potential patients.

Yang,M., Luensmann,D., Fonn,D., Woods,J., Jones,D., Gordon,K., Jones,L. Myopia prevalence in Canadian school children: A pilot study Eye 2018;32(6):1042-1047 [ Show Abstract ]

Purpose: A pilot study to determine the prevalence of myopia, proportion of uncorrected myopia and pertinent environmental factors among children in a suburban region in Canada. Methods: Refraction with cycloplegia and ocular biometry were measured in children of two age groups. Myopia was considered at a spherical equivalent refraction (SER) ≤-0.50 D in at least one eye. Parents completed a questionnaire that captured the child's daily activities. Results: A total of 166 children completed the study (83 aged 6-8 and 83 aged 11-13). Myopia prevalence was 17.5% among the overall group, 6.0% among ages 6-8 and 28.9% among ages 11-13. Mean subjective SER in myopic children was -1.10 D (95% confidence interval (CI), -0.34 to -1.86 D) at ages 6-8 and -2.44 D (95% CI, -1.71 to -3.18 D) at ages 11-13. In this study, 34.5% of the myopic children were uncorrected, which represented 6.0% of the entire group of children. Mean axial length (AL) increased by 1.03 mm from ages 6-8 (mean 22.62 mm; 95% CI, 22.45 to 22.79 mm) to ages 11-13 (mean 23.65 mm; 95% CI, 23.45 to 23.84 mm; p < 0.01). The correlation coefficient between AL and SER was -0.618 (p < 0.01). Binary logistic regression between outdoor time and the prevalence of myopia showed that one additional hour of outdoor time per week lowered the odds of a child having myopia by 14.3% (p = 0.007). Conclusion: Myopia prevalence increased from 6% at ages 6-8 to 29% at ages 11-13. Thirty-five per cent of the myopes in this study were uncorrected. More time outdoors may be beneficial to protect against myopia onset.

2016

Keir,N., Luensmann,D., Woods,C.A., Bergenske,P., Fahmy,M., Fonn,D. Effect of Masking on Subjective Responses to Daily Disposable Contact Lenses Optom Vis Sci 2016;93(8):828-35 [ Show Abstract ]

PURPOSE: To explore the effect of masking on subjective responses when wearing daily disposable (DD) contact lenses.
METHODS: In an adaptation phase, habitual wearers of Manufacturer-A (MFA) (n = 43) and Manufacturer-B (MFB) (n = 53) wore MFA-brand 1 or MFB-brand 1 DDs, respectively, for 30 days, open-label. Subjects were then randomly assigned to one of two experiments. Each experiment included two, 3-day crossover phases. An enhanced version of MFA and MFB lenses (MFA-brand 2 and MFB-brand 2) were worn contralaterally to evaluate potential differences in masking result between manufacturers. Experiment 1: subjects were fully masked to lens and packaging (FM) then unmasked (UM). Experiment 2: subjects were FM then partially masked using an over-label (PM). Comfort ratings (0-100) were recorded for each lens daily and preference between lenses was recorded on day 3 for each crossover phase. The mean difference between 0-100 ratings or preference when FM or PM versus UM for the same lens was considered a measurement of the effect associated with masking. The purpose of the study was withheld from subjects to minimize bias.
RESULTS: The effect associated with masking for habitual wearers of MFA and MFB lenses was less than 1 out of 100 (0 ± 2.5) in both experiments. Fifty-eight subjects (60%) expressed no preference when FM. This decreased to 29 (30%) when UM or PM (proportion test, p < 0.001). Approximately half the subjects had a change in lens preference when they were UM or PM, primarily in favor of their habitual lens manufacturer.
CONCLUSIONS: Masking did not have a measurable impact on 0-100 ratings with the DD lenses used in this study but did have an impact on lens preference. Subjects were more likely to express a preference when they handled the lenses and were exposed to the lens packaging and, in some cases, able to read the lens brand and lens manufacturer.

2015

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.

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.

2013

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.

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.

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 2011 1-10 [ 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.

Scientific Presentations

2019

Luensmann D, Woods J, Patel S. Validation of an online lens fitting app for two daily disposable toric lenses BCLA Conference, Manchester, UK, 2019

2018

Luensmann D, van Doorn K, May C, Srinivasan S, Jones L. Physical Dimension and Optical Assessment of Currently Marketed Silicone Hydrogel Contact Lenses After Exposure to Cosmetics American Academy of Optometry, San Antonio, USA, 2018 [ Show Abstract ][ PDF ]

Purpose: Contact lens wearers may inadvertently expose their lenses during the lens insertion and removal process or while wearing their lenses to cosmetic products being used. This study investigated the impact of various cosmetics on the physical dimension and optical properties of three recently marketed silicone hydrogel contact lenses.

Methods: In this in-vitro study, senofilcon C, samfilcon A, and lotrafilcon B+EOBO (polyoxyethylene-polyoxybutylene) were individually coated with cosmetic products followed by a 1-hour soak in phosphate-buffered saline. Cosmetic products included; 3 hand creams (HC1: Glysomed; HC2: Vaseline Healthy Hand & Nail Conditioning; HC3: Intense Relieve), 3 make-up removers (MR1: Lid-Care Towelettes; MR2: Gentle waterproof eye and Lip Makeup Remover; MR3: Oil-Free Makeup Remover), and 3 mascaras (MA1: Great Lash – waterproof; MA2: Wonder’Lash – waterproof, MA3: Voluminous Original). Lens diameter, sagittal depth, and base curve were measured using the Chiltern (Optimec Limited), while lens power and optical quality were assessed using the Contest Plus II (Rotlex) (n=6 for each lens/ cosmetic combination). The impact of cosmetics was tested between lenses and compared to baseline (uncoated control lenses).

Results: For lens diameter, makeup removers (MR2 & MR3) had the largest impact, with an increase of up to 0.27mm (MR2) and 0.36mm (MR3) for senofilcon C and samfilcon A respectively (p<0.01 compared to baseline), while lotrafilcon B+EOBO showed a decrease of only 0.01mm (p<0.01 between lens types). For sagittal depth, mascara MA1 had the greatest impact, followed by makeup removers MR2 & MR3. All lenses had increases in sagittal depth after MA1 exposure (0.16±0.06mm in lotrafilcon B+EOBO, 0.24±0.22 mm and 0.26±0.09mm in samfilcon A and senofilcon C respectively; p<0.01 for all lenses compared to baseline). For base curve, the makeup removers (MR2 & MR3) caused increases for both senofilcon C (up to 0.36mm) and samfilcon A (up to 0.45mm), but lotrafilcon B+EOBO was unaffected. Lens power changes were generally minor (less than 0.25D). However, senofilcon C had a significant increase 1.19±0.65D more minus after MA1 exposure (p<0.001). Image quality was most effected by mascaras, although given that all lens types were adversely affected to similar degrees, none of the lenses performed better or worse after mascara application (p>0.05). Hand creams had no effect on any variable investigated for any lens material.

Conclusion: Overall, mascara MA1 and make-up removers MR2 & MR3 had the largest affect on lens dimensions, and mascara MA1 had the largest affect on optical lens properties. Some dimensional changes were outside of the ISO tolerance, which could affect lens fit. Lotrafilcon B+EOBO lenses were generally least affected by these cosmetic products.

Woods J, Ng AY, Luensmann D, Guthrie S, Jones L. Short-term comfort comparison of two daily disposable contact lenses of different material and modulus Invest Ophthalmol Vis Sci 2018;E-Abstract 1753 [ Show Abstract ][ PDF ]

Purpose: Daily disposable contact lenses (DDs) are now widely available in both silicone hydrogel (SH) and hydrogel (H) materials. The higher oxygen transmissibility of SH materials provides many benefits, but their higher modulus has been linked with reduced lens comfort compared to H lenses. This randomized, double-masked clinical trial assessed the short-term comfort of two DDs of differing modulus, yet similar water content (WC): a SH-DD (somofilcon A; clariti® 1 day; CooperVision; 0.50MPa modulus, 56% WC) and a H-DD (etafilcon A; 1-Day Acuvue® Moist®; Johnson & Johnson; 0.29MPa modulus, 57% WC).

Methods: 120 subjects wore the lenses contralaterally, over one day. Targeted recruitment meant that 60 subjects were habitual H-DD wearers (all adapted wearers of 1-Day Acuvue Moist), 60 were non-DD habitual wearers (adapted to various SH and H re-usable lenses). Subjects rated lens comfort on a 0-100 integer scale (100= cannot be felt) at insertion and then hourly until 8hrs. Of particular interest was the comfort at the beginning and end of the 8hr wear period and these data points were tested for equivalence. At the final visit subjects were asked for their lens preference, based on comfort.

Results: Mean subjective comfort was not different between SH-DD and H-DD across the wear period (p>0.05), on insertion (87±14 SH-DD vs 89±14 H-DD; p>0.05) or after 8hrs (82±18 SH-DD vs 83±17 H-DD; p>0.05). Based on equivalency margins of ±5-points, the study lenses showed equivalent comfort at insertion (p=0.03) and at 8hrs (p=0.001). Both lenses exhibited a significant reduction in comfort over the 8hr period (both p<0.001). When subjects’ data was divided according to their habitual lens modality groups (60 H-DD wearers and 60 re-useable wearers), there were also no comfort differences between the study lenses, either across time, or at insertion and 8hrs (all p>0.05). Lens preference was not different between lenses at dispensing or at the final visit (both p>0.05).

Conclusions: Initial and 8hr comfort were not compromised with the SH-DD compared to the H-DD, despite its higher modulus, and there was no difference in the lens preference distribution. The results suggest that lower comfort should not be anticipated when fitting SH-DDs of an appropriate design, thus allowing other material properties such as high oxygen permeability to be considered.

Woods J, Ng AY, Luensmann D, Jones L. Short-term comfort comparison of a low modulus hydrogel vs a higher modulus silicone hydrogel daily disposable lens Contact Lens & Anterior Eye 2018;41, Supp 1:S42

2017

Moezzi A, Varikooty J, Luensmann D, Schulze M, Ng AY, Karkkainen T, Xu J, Jones L. Evaluation of Clinical Success with etafilcon A multifocal daily disposable lenses Optom Vis Sci 2017;94: E-Abstract 175341

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

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

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 ]

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, 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

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

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

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

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

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

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

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. 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, 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

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

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

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 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 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 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

Continuing Education Presentations

2018

Walsh K, Jones L, Luensmann D, Woods J. Rapid Fire: Celebrating 20 Years of Silicone Hydrogels: The Past, Present and Future American Academy of Optometry, San Antonio, USA, 2018 [ Show Abstract ]

Using the analogy of a child growing up, four presenters cover the twenty-year timeline of silicone hydrogels (SiHys). How does the historical performance of this material inform both currently available lenses and future applications? Each part of the talk covers a specific period in the timeline since 1998: from infancy, through to elementary and high school years, balancing properties for comfortable daily wear and gaining increased understanding of interactions with the ocular surface and tear film. At age 20, SiHys have yet to graduate from college, leaving the last talk to share what the future may hold.

Professional Publications

2019

Walsh K, Dantam J, Luensmann D. Contact Lens Wear and Its Disruption of the Tear Film Review of Cornea & Contact Lens 2019;May/June: 38-42.

2017

Luensmann D. Summary: Iatrogenic report – Dry eye disease caused by a medical treatment or procedure ContactLensUpdate.com 2017

2015

Luensmann D, Jones L. Clinical performance of a new silicone hydrogel colored contact lens Optometry Times 2015;June

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

Books

2019

Jones L, Stahl U, Guthrie S, Luensmann D, Yang M, Thom M. Contact Lens Compendium: Contact Lenses and Solutions Available in Canada. Vol 45 2019.