Please use the archived list on the right to look at past peer-reviewed articles.
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
Caffery,B., Dogru,M., Jones,L. W., Lin,M. C., Nichols,J. J., Papas,E., Pucker,A., Pult,H., Willcox,M. D. P. Contact lens comfort. Optometry and Vision Science 2016;93,8:790-792.
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 (Â±SD) of 30.3 Â± 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. Â© Copyright 2016 American Academy of Optometry.
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 Â± SD, 2.0 Â± 1.0) revealed significantly (p < 0.001) greater levels of contamination, compared to those maintained with Biotrue (1.3 Â± 0.8) and RevitaLens OcuTec (1.2 Â± 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 Â± 0.629) showed significantly higher biofilm formation (p = 0.028) compared to those maintained with Biotrue (0.263 Â± 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. Â© Copyright 2016 American Academy of Optometry.
Hall,B., Heynen,M., Jones,L. W., Forrest,J. A. Analysis of Using I125 Radiolabeling for Quantifying Protein on Contact Lenses. Current eye research 2016;41,4:456-465. [ Show Abstract ]
Purpose: To investigate the accuracy of I125 radiolabeling to quantitatively determine the deposition of protein onto various commercially available contact lens (CL) materials. Methods: Commercially available silicone hydrogel and conventional hydrogel CL materials were examined for times ranging from 10 s to 1 week. Adsorption of free I125 was measured directly for the CL. The use of dialyzing labeled proteins and/or using NaI to compete with free I125 uptake was investigated as ways to minimize effects due to free I125. Results: At all time points and with all lens materials, there was 0.3 Âµg/lens or greater of apparent mass attributable to free I125 uptake. Dialyzing labeled proteins significantly reduced free I125 uptake for all materials investigated. The benefit of using dialyzed protein was most prominent at shorter times, as free I125 is continuously generated over time. Using NaI can reduce free I125 uptake for some lens materials, but this is shown to directly affect protein deposition on some materials. Conclusions: Periodic replenishment of incubation solutions with freshly dialyzed labeled protein to limit free I125 generation is recommended, but the incorporation of NaI onto the buffer solution is not. Irrespective of the exact procedure to limit free I125 uptake, extra steps must be performed to quantify the amount of I125 adsorbed onto contact lens materials, to determine thresholds of confidence with respect to the actual protein deposition that occurs.
Jones,L. W., Byrne,M., Ciolino,J. B., Legerton,J., Markoulli,M., Papas,E., Subbaraman,L. Revolutionary future uses of contact lenses. Optometry and Vision Science 2016;93,4:325-327.
Liu,L. Y., Seo,J., McCanna,D. J., Subbaraman,L. N., Jones,L. W. Assessment of biofilm formation of E. meningoseptica, D. acidovorans, and S. maltophilia in lens cases and their growth on recovery media. Contact Lens and Anterior Eye 2016;39,2:117-123. [ Show Abstract ]
Purpose: Bacterial biofilm formation in contact lens cases is a risk factor in the development of both microbial and infiltrative keratitis. This investigation evaluated three emerging pathogens: Stenotrophomonas maltophilia, Elizabethkingia meningoseptica, and Delftia acidovorans for biofilm formation and metabolic activity in lens cases. Also, growth of these bacteria on different media was assessed to optimize recovery conditions. Methods: The three bacteria were incubated in lens cases with different concentrations of tryptic soy broth. Biofilm formation was evaluated by measuring metabolic activity using MTT and enumerating the number of viable bacteria. To determine the optimal recovery media, dilutions of these microorganisms were plated on six different media. The number of colony forming units (CFU) was recorded after 48, 72, and 96 h of incubation at 32 Â°C and 37 Â°C for S. maltophilia, and at 37 Â°C for E. meningoseptica and D. acidovorans. Results: All three microorganisms established biofilms in the lens cases, with significant numbers of CFU recovered. Biofilms of S. maltophilia and E. meningoseptica were metabolically active. Significant reduction in metabolic activity and number of viable S. maltophilia occurred when the incubation temperature was raised from 32 Â°C to 37 Â°C (p < 0.05). The metabolic activity of the biofilms increased with greater organic load present. The highest percent recovery for all three organisms was given by Columbia blood agar, followed by chocolate. Conclusion: Based on the results, the presence of the three emerging pathogens present in lens cases and from corneal isolates can be accurately determined if proper growth media and incubation temperatures are utilized.
Moezzi,A. M., Varikooty,J., Schulze,M., Ngo,W., Lorenz,K. O., Boree,D., Jones,L. W. Corneal Swelling with Cosmetic etafilcon A Lenses versus No Lens Wear. Optometry and Vision Science 2016;93,6:619-628. [ Show Abstract ]
Purpose: To determine if the use of pigments or adding polyvinyl pyrrolidone during the fabrication of 1-DAY ACUVUE DEFINE (AD) brand contact lenses impacts open-eye corneal swelling compared with no lens wear (NLW). Methods: A partial double-masked, randomized, bilateral crossover study was conducted in 24 Asian subjects using AD, 1-DAY ACUVUE DEFINE with Lacreon (ADL), NLW, and a control lens with no tint (1-DAY ACUVUE MOIST [AM]). Central corneal thickness was measured before insertion and immediately after removal after 8 Â± 1 h of open-eye wear using an optical pachymeter in one eye. Corneal thickness along a 10-mm cord was measured in the contralateral eye using the Visante optical coherence tomographer (OCT). Corneal swelling was tested for noninferiority using a 5% margin. The endothelial bleb response was measured at baseline and 20 min after lens insertion using specular microscopy. Subjective grading of corneal staining and limbal/bulbar hyperemia were also monitored. Results: After 8 Â± 1 h of open-eye wear, central corneal swelling across the study lenses with either optical pachymeter or OCT methods was negligible. Peripheral corneal swelling least-square mean differences with OCT were -0.03% (95% confidence interval [95% CI], -0.65 to 0.58%) and -0.26% (95% CI, -0.87 to 0.36%) between AD and ADL and the control lens (AM), respectively, and 1.67% (95% CI, 1.06 to 2.29%) and 1.45% (95% CI, 0.84 to 2.06%) between AD and ADL and NLW, respectively. No endothelial blebs were observed. No clinically significant differences were distinguished between the lenses and NLW for corneal staining and limbal/bulbar hyperemia. Conclusions: After 8 Â± 1 h of open-eye wear, central and peripheral corneal swelling along the horizontal meridian with AD, ADL, AM, and NLW were equivalent. These results confirm that the addition of polyvinyl pyrrolidone or pigments to etafilcon A to obtain a limbal ring design have no impact on corneal swelling or limbal/bulbar hyperemia during normal open-eye wear.
Muntz,A., van Doorn,K., Subbaraman,L. N., Jones,L. W. Impression cytology of the lid wiper area. Journal of Visualized Experiments 2016;2016,114:. [ Show Abstract ]
Few reports on the cellular anatomy of the lid wiper (LW) area of the inner eyelid exist and only one report makes use of cytological methods. The optimization of a method of collecting, staining and imaging cells from the LW region using impression cytology (IC) is described in this study. Cells are collected from the inner surface of the upper eyelid of human subjects using hydrophilic polytetrafluoroethylene (PTFE) membranes, and stained with cytological dyes to reveal the presence of goblet cells, mucins, cell nuclei and various degrees of pre- and parakeratinization. Immunocytochemical dyes show cell esterase activity and compromised cell membranes by the use of a confocal scanning laser microscope. Up to 100 microscopic digital images are captured for each sample and stitched into a high-resolution, large scale image of the entire IC span. We demonstrate a higher sensitivity of IC than reported before, appropriate for identifying cellular morphologies and metabolic activity in the LW area. To our knowledge, this is the first time this selection of fluorescent dyes was used to image LW IC membranes. This protocol will be effective in future studies to reveal undocumented details of the LW area, such as assessing cellular particularities of contact lens wearers or patients with dry eye or lid wiper epitheliopathy. Â© 2016 Journal of Visualized Experiments.
Ng,A., Evans,K., North,R. V., Jones,L., Purslow,C. Impact of Eye Cosmetics on the Eye, Adnexa, and Ocular Surface. Eye and Contact Lens 2016;42,4:211-220. [ Show Abstract ]
Despite the fact that cosmetic products undergo rigorous testing to ensure they are safe for human use, some users report mild discomfort following their application. The cutaneous changes, such as allergic dermatitis, are well reported, but the ocular changes associated with eye cosmetic use are less so. Some pigmented cosmetic products may accumulate within the lacrimal system and conjunctivae over many years of use, but immediate reports of eye discomfort after application are most common. Changes to the tear film and its stability may occur shortly after application, and contact lens wearers can also be affected by lens spoliation from cosmetic products. Additionally, creams used in the prevention of skin aging are often applied around the eyes, and retinoids present in these formulations can have negative effects on meibomian gland function and may be a contributing factor to dry eye disease. The aim of this review is to summarize current knowledge regarding the impact of cosmetic products on the eye, ocular surface, and tear film. Â© 2015 Contact Lens Association of Ophthalmologists.
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. Â© Copyright 2016 American Academy of Optometry.
Phan,C. -M, Bajgrowicz,M., Gao,H., Subbaraman,L. N., Jones,L. W. Release of fluconazole from contact lenses using a novel in vitro eye model. Optometry and Vision Science 2016;93,4:387-394. [ Show Abstract ]
Purpose. Rapid drug release followed by a plateau phase is a common observation with drug delivery from contact lenses (CLs) when evaluated in a vial. The aim of this study was to compare the release of fluconazole from seven commercially available daily disposable CLs using a conventional vial-based method with a novel in vitro eye model. Methods. An eye model was created using two 3-dimensional printed molds, which were filled with polydimethylsiloxane to obtain an inexpensive model that would mimic the eyeball and eyelid. The model was integrated with a microfluidic syringe pump, and the flow-through was collected in a 12-well microliter plate. Four commercial daily disposable conventional hydrogels (nelfilcon A, omafilcon A, etafilcon A, ocufilcon B) and three silicone hydrogels (somofilcon A, narafilcon A, delefilcon A) were evaluated. These CLs were incubated with fluconazole for 24 h. The drug release was measured in a vial containing 4.8 mL of phosphate-buffered saline and in the polydimethylsiloxane eye model with a 4.8-mL tear flow across 24 h. Results. Overall, conventional hydrogel CLs had a higher uptake and release of fluconazole than silicone hydrogel CLs (p < 0.05). A higher drug release was observed in the vial condition compared with the eye model (p < 0.001). In the vial system, the drugs were rapidly released from the CL within the first 2 h, followed by a plateau phase. In contrast, drug release in the eye model under low tear volume was sustained and did not reach a plateau across 24 h (p < 0.05). Conclusions. Rapid drug release results from using a vial as the release system. Under low tear volume at physiological tear flow, commercial CLs can maintain a sustained drug release profile for up to 24 h. However, eyes with fungal keratitis may have increased tearing, which would significantly accelerate drug release. Â© 2015 American Academy of Optometry.
Phan,C. -M, Subbaraman,L., Jones,L. W. The use of contact lenses as biosensors. Optometry and Vision Science 2016;93,4:419-425. [ Show Abstract ]
The tear film is a complex multilayer film consisting of various proteins, enzymes, and lipids and can express a number of biomarkers in cases of disease. The development of a contact lens sensor presents a noninvasive alternative for the detection and management of various diseases. Recent work has resulted in the commercialization of a device to monitor intraocular pressure for up to 24 h, and there are extensive efforts underway to develop a contact lens sensor capable of continuous glucose tear film monitoring to manage diabetes. This clinical perspective will highlight the major developments within this field and list some of the major challenges that still need to be addressed. Â© 2015 American Academy of Optometry.
Phan,C. -M, Walther,H., Gao,H., Rossy,J., Subbaraman,L. N., Jones,L. Development of an in Vitro ocular platform to test contact lenses. Journal of Visualized Experiments 2016;2016,110:e53907. [ Show Abstract ]
Currently, in vitro evaluations of contact lenses (CLs) for drug delivery are typically performed in large volume vials,1-6 which fail to mimic physiological tear volumes.7 The traditional model also lacks the natural tear flow component and the blinking reflex, both of which are defining factors of the ocular environment. The development of a novel model is described in this study, which consists of a unique 2-piece design, eyeball and eyelid piece, capable of mimicking physiological tear volume. The models are created from 3-D printed molds (Polytetrafluoroethylene or Teflon molds), which can be used to generate eye models from various polymers, such as polydimethylsiloxane (PDMS) and agar. Further modifications to the eye pieces, such as the integration of an explanted human or animal cornea or human corneal construct, will permit for more complex in vitro ocular studies. A commercial microfluidic syringe pump is integrated with the platform to emulate physiological tear secretion. Air exposure and mechanical wear are achieved using two mechanical actuators, of which one moves the eyelid piece laterally, and the other moves the eyeballeyepiece circularly. The model has been used to evaluate CLs for drug delivery and deposition of tear components on CLs.
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 Â± SE = 0.82 Â± 0.19) compared to wearers of lotrafilcon B (1.34 Â± 0.20; p < 0.02), comfilcon A (1.41 Â± 0.21; p < 0.01), and other (1.18 Â± 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 Â± 0.17) versus Clear Care for participants wearing galyfilcon A (1.11 Â± 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. Â© Copyright 2016 American Academy of Optometry.
Stahl,U., Keir,N. J., Landers,A., Jones,L. W. Effect of short recovery periods on ocular comfort during daily lens wear. Optometry and Vision Science 2016;93,8:861-871. [ Show Abstract ]
Purpose. To assess the impact of lens-free intervals of varying lengths on end-of-day comfort with soft contact lenses. Methods. Twenty-five symptomatic lens wearers participated in this randomized, cross-over study involving nine individual 12-hour days: one spectacle (no lens) and eight lens wear days. On each lens wear day, lenses were worn bilaterally in 2-hour intervals, separated by lens-free (recovery) periods of 0, 30, 60, or 80 minutes (repeated throughout the day). For each 2-hour lens wear interval, new lenses were worn. Ocular comfort was rated on a 0 to 100 visual analogue scale (0 = extremely uncomfortable); tear film and ocular parameters were assessed at the beginning and end of each study day. This study involved two different types of silicone hydrogel lenses, and the order of lens type and length of recovery period was randomized. Participants were unaware of the true study purpose and that a new lens pair was used for each lens wear interval. Results. End-of-day comfort on lens wear days was significantly worse than on the spectacle day (p 0.05). Although lens wear affected noninvasive tear film break-up time and conjunctival staining, there were no effects of recovery period length on noninvasive tear film break-up time (p > 0.05), tear meniscus height (p > 0.05), corneal staining (p > 0.05), conjunctival staining (p > 0.05), bulbar conjunctival redness (p > 0.05), or limbal redness (p > 0.05). There was no consistent effect of recovery period length on lid margin staining. Conclusions. Lens-free recovery periods during a 12-hour lens wear day did not positively impact end-of-day comfort in this study. Cumulative lens wear times ranged from 8 to 12 hours, and the results suggest that once the length of lens wear exceeds the usual comfortable wear time, there is no benefit of short recovery periods. Â© Copyright 2016 American Academy of Optometry.
Verma,M. S., Tsuji,J. M., Hall,B., Chen,P. Z., Forrest,J., Jones,L., Gu,F. X. Towards point-of-care detection of polymicrobial infections: Rapid colorimetric response using a portable spectrophotometer. Sensing and Bio-Sensing Research 2016;1015-19. [ Show Abstract ]
Infectious diseases spread rapidly because current diagnostic methods are slow, expensive, and require technical expertise. Biosensors have recently been used as devices that can be deployed at the point-of-care for rapid and accurate diagnosis. Here, we show that a â€œchemical noseâ€ biosensor based on gold nanoparticles can be coupled with a portable spectrophotometer to detect monomicrobial and polymicrobial solutions of pathogenic bacteria within 2 min of data collection. The design presented here exploits the rapid kinetics of gold nanoparticle aggregation around bacteria, which leads to a dramatic color change. The â€œchemical noseâ€ produces unique signals based on the surface characteristics of the bacteriaâ€”such as the presence of extracellular polymeric substances, distribution of charged lipids, and localization of proteinsâ€”and hence provides a versatile platform for detection. We present a biosensor design that can easily be translated to the point-of-care because of its rapid response and simple output. Â© 2016 The Authors
Verma,M. S., Wei,S. -C, Rogowski,J. L., Tsuji,J. M., Chen,P. Z., Lin,C. -W, Jones,L., Gu,F. X. Interactions between bacterial surface and nanoparticles govern the performance of "chemical nose" biosensors. Biosensors and Bioelectronics 2016;83115-125. [ Show Abstract ]
Rapid and portable diagnosis of pathogenic bacteria can save lives lost from infectious diseases. Biosensors based on a "chemical nose" approach are attracting interest because they are versatile but the governing interactions between bacteria and the biosensors are poorly understood. Here, we use a "chemical nose" biosensor based on gold nanoparticles to explore the role of extracellular polymeric substances in bacteria-nanoparticle interactions. We employ simulations using Maxwell-Garnett theory to show how the type and extent of aggregation of nanoparticles influence their colorimetric response to bacteria. Using eight different species of Gram-positive and Gram-negative bacteria, we demonstrate that this "chemical nose" can detect and identify bacteria over two orders of magnitude of concentration (89% accuracy). Additionally, the "chemical nose" differentiates between binary and tertiary mixtures of the three most common hospital-isolated pathogens: Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa (100% accuracy). We demonstrate that the complex interactions between nanoparticles and bacterial surface determine the colorimetric response of gold nanoparticles and thus, govern the performance of "chemical nose" biosensors. Â© 2016 Elsevier B.V.
Walther,H., Subbaraman,L., Jones,L. W. In vitro cholesterol deposition on daily disposable contact lens materials. Optometry and Vision Science 2016;93,1:36-41. [ Show Abstract ]
Purpose. The goal of this study was to analyze how various incubation times affect the uptake of cholesterol on silicone hydrogel (SH) and conventional hydrogel (CH) daily disposable (DD) contact lens materials using an in vitro radiochemical detectionmethod. Methods. Three SH (somofilcon A, delefilcon A, and narafilcon A) and four CH (etafilcon A, nesofilcon A, ocufilcon A, and nelfilcon A) contact lenses were incubated in an artificial tear solution that contained major tear film components and a portion of radioactive 14C-cholesterol. Lenses (N = 4) were incubated for four incubation times (2, 6, 12, or 16 h) to assess the effects on cholesterol deposition. Subsequent to the incubation, the lenses were extracted using 2:1 chloroform:methanol, and the extracts were analyzed in a beta counter and (in nanograms per lens) extrapolated from standard curves. Results. In general, cholesterol deposited statistically significantly more on SH lenses than CHs (p e 0.033), with the exception of somofilcon A and nesolfilcon A materials (p = 0.067). Within the SH materials, narafilcon A accumulated the largest quantity of cholesterol (p G 0.05) and somofilcon A the lowest (p G 0.05). The uptake of cholesterol ranged from 22.63 T 2.98 ng/lens to 97.94 T 4.18 ng/lens for all lens materials. The accumulation of cholesterol was shown to be continuous throughout the 16 h of incubation, without reaching a plateau (p G 0.001). Conclusions. For the periods thatDDlens materials are worn, cholesterol deposits significantlymore ontoSHcontact lenses than CHs. This could have implications for wearers who have higher levels of lipid in their tears that are fitted with SH DD materials. Copyright Â© American Academy of Optometry.