Jacksonville, FL, United States
Jacksonville, FL, United States

Time filter

Source Type

Young G.,Visioncare Research Ltd. | Schnider C.,Vistakon | Hunt C.,Visioncare Research Ltd. | Efron S.,University of Manchester
Optometry and Vision Science | Year: 2010

PURPOSE.: To determine which ocular topography variables affect soft contact lens fit. METHODS.: Fifty subjects each wore three pairs of soft lenses in random succession (Vistakon Acuvue 2, Vistakon Acuvue Advance, Ciba Vision Night & Day), and various aspects of lens fit were evaluated. The steeper base curves of each type were worn in one eye and the flatter base curves in the other eye. Corneal topography data were collected using a Medmont E300 corneal topographer (Camberwell, Australia). Corneal curvature, shape factor (SF), and corneal height were measured over a 10 mm chord and also over the maximum measurable diameter. These were measured in the horizontal, vertical, steepest, and flattest meridians. RESULTS.: With each lens type, the steeper base curve provided the best fit on the greatest proportion of eyes and the significant differences in various aspects of fit were noted between base curves. For each lens type, there was no significant difference in mean K-reading between those eyes best fit with the steeper base curve and those eyes best fit with the flatter base curve. Two of the lenses showed a positive correlation between centration and horizontal corneal height (maximum), whereas one lens showed a negative correlation between centration and horizontal SF (SF = e). Several lenses showed a positive correlation between post-blink movement and horizontal or vertical corneal SF. CONCLUSIONS.: The measurement of corneal topography using current Placido disc instrumentation allows a better prediction of soft lens fit than by keratometry, but it is not reliable enough to enable accurate selection of the best fitting base curve. Some correlations are evident between corneal measurements; however, trial fitting remains the method of choice for selection of soft lens base curve. Copyright © 2010 American Academy of Optometry.


Fife D.,Janssen Pharmaceutical | Zhu V.,Janssen Pharmaceutical | Voss E.,Janssen Pharmaceutical | Levy-Clarke G.,Vistakon | Ryan P.,Janssen Pharmaceutical
Drug Safety | Year: 2014

Background: A recent Canadian case-control study reported a 4.5-fold increased risk of retinal detachment (RD) during oral fluoroquinolone use. Of the fluoroquinolone-exposed cases, 83 % were exposed to ciprofloxacin. We sought to replicate this finding, and assess whether it applied to all fluoroquinolones. Methods: In two large US healthcare databases, we performed three case-control analyses: one replicating the recent study; one addressing additional potential confounders; and one that increased sample size by dropping the Canadian study's requirement for a prior ophthalmologist visit. We also performed a self-controlled case-series (SCCS) analysis in which each subject served as his or her own comparator. Results: In the replication case-control analyses, the adjusted odds ratios (ORs) for any exposure to fluoroquinolones or ciprofloxacin were approximately 1.2 in both databases, and were statistically significant, and the ORs for current exposure were modestly above 1 in one database, modestly below 1 in the other, and not statistically significant. In the other case-control analyses, the ORs were close to 1. In a post hoc age-stratified case-control analysis, we observed an association of RD with fluoroquinolone exposure among older subjects in one of the two databases. All estimates from the SCCS analyses were below 1.2 and none was statistically significant. Conclusion: The present study does not confirm the recent Canadian study's finding of a strong relationship between RD and current exposure to fluoroquinolones. Instead, it found a modest association between RD and current or any exposure to fluoroquinolones in the case-control analyses, and no association in the SCCS analyses. © 2014 The Author(s).


Koschier F.,Johnson and Johnson Consumer Products Company | Kostrubsky V.,Vistakon | Toole C.,CeeTox Inc. | Gallo M.A.,UMDNJ
Food and Chemical Toxicology | Year: 2011

The current study investigated the influence of ethanol and ethanol-containing mouthrinses on model chemical permeability in an in vitro oral buccal mucosal construct (EpiOral, ORL-200, MatTek). Innate ethanol transport and metabolism in the tissue construct was also studied. Caffeine flux in buccal tissue was measured after pre-treatment with < 26.9% ethanol or Listerine ® products under conditions modeling a typical mouthwash rinsing. Specifically, a 30s exposure to alcohol products followed by a 10h non-treatment phase and then a second 30s exposure prior to addition of caffeine. At 10min specific intervals, media was collected from the basal part of the tissue insert for HPLC analysis of caffeine. The results demonstrated no increase in caffeine flux due to prior exposure to either ethanol or Listerine ®, and the flux and permeability constants were derived from the linear phase. No cytotoxicity or histopathological effects were observed in these tissues. We also studied the transepithelial transport and metabolism of ethanol in these tissues. Transport of ethanol was concentration-dependent with rate of diffusion proportional to the concentration gradient across the membrane. The potential metabolism of ethanol in the EpiOral construct was addressed by analyzing the remaining level of ethanol after incubation and de novo accumulation of acetaldehyde or acetic acid in culture media. Incubation for 30min incubation resulted in no change in ethanol level up to 2000mM, the highest concentration tested. No acetaldehyde or acetic acid was detected in culture media. In conclusion, ethanol and ethanol-containing mouthrinse treatment modeled after a typical daily mouthrinse pattern had no apparent effect on the permeability of the standard model chemical, caffeine. This exposure also had no effect on the viability of the tissue construct or histopathology, and uptake of ethanol was rapid into the tissue construct. © 2011 Elsevier Ltd.


Hickson-Curran S.,Vistakon | Chalmers R.L.,Clinical Trial Consultant | Riley C.,Vistakon
Contact Lens and Anterior Eye | Year: 2011

To review important aspects of contact lens compliance and to survey contact lens replacement frequency, steps in lens care and hygiene and replacement of the lens storage case via online surveys. Methods: Random US samples (n= 645 and 787) of frequent replacement contact lens wearers answered questions on contact lens wear in online, sponsor-masked surveys. Results: Wearers of lenses prescribed by their practitioner for 2 weekly replacement reported that they replaced lenses as follows: within 2 weeks 45%, within 3 weeks (minor stretching) 68%, within 4 weeks 89%, ≥8 weeks (extreme stretching) 4%, compared to Monthly wearers who reported: within 4 weeks 37%, within 5 weeks (minor stretching) 57%, ≥8 weeks 23% (≥8 weeks extreme stretching, Chi-square p= 0.001). Median frequency for cleaning lens storage case was 2-3 times per week, while 33% reported cleaning monthly or less often. Median lens storage case replacement was every 4-6 months, while 48% reported annual replacement or less often. Most patients cleaned their lens case with hot or cold tap water (72%). Conclusions: These internet surveys revealed significant non-compliance with lens care steps, case hygiene and lens replacement schedule. More than half of the contact lens wearers surveyed were not compliant with their 2-weekly or monthly schedule. Lenses prescribed for longer replacement intervals can lead to more extreme stretching of lens life. To encourage better patient habits, eye care providers should reinforce their recommended frequency of replacement of lenses and storage cases and should reinforce care and hygiene steps at each patient visit. © 2010.


Putt K.S.,Vistakon | Kernick E.R.,Vistakon | Lohse B.K.,Vistakon | Lomboy J.,Vistakon | And 2 more authors.
Journal of Microbiological Methods | Year: 2012

The accurate measurement of ultraviolet (UV) irradiation, especially within a container or vessel is one of the challenges facing the broad implementation of UV sterilization. Currently, biological indicators are the best method to determine whether an applied UV dose has the necessary efficacy to achieve sterilization. To overcome some of the challenges of using a biological indicator, chemical indicators based upon the degradation of food, drug and cosmetic (FD&C) dyes were developed. In this work, the relationship between UV dose and dye degradation was elucidated and used to create standard curves which could be used as a quantitative measurement system. The use of dye degradation as a measurement of UV dose is especially useful when the levels of UV irradiation within a container cannot be measured directly. Additionally, due to the highly colored nature of the FD&C dyes, the visual changes present upon dye irradiation can be used as a qualitative visual indicator of the UV dose. © 2012 Elsevier B.V.


Shen M.,University of Miami | Cui L.,University of Miami | Riley C.,Vistakon | Wang M.R.,University of Miami | Wang J.H.,University of Miami
Investigative Ophthalmology and Visual Science | Year: 2011

Purpose. To characterize the edge fitting of soft contact lenses using ultra-high resolution optical coherence tomography (UHR-OCT) and ultra-long scan depth optical coherence tomography (UL-OCT). Methods. A total of 20 participants (11 men, 9 women; mean age, 32.3 years) were recruited. Four different types of soft contact lenses were randomly fitted to both eyes of each subject on two separate visits. After 30 minutes, the horizontal meridians of the corneal center, midperiphery, and limbus were imaged by UHR-OCT. UL-OCT imaged each lens in vitro and the ocular surface of a physical model eye. Results. Angle-edged lenses had significantly less conjunctival buildup than did round-edged lenses (P = 0.008). Limbal post-lens tear film gaps were present in 42% of the eyes, with the round-edged lenses having the most at 68%. Similarly, post-lens tear film gaps at the corneal mid-periphery were present in 47% of all eyes, with the round-edged lens having the most at 75%. Mismatches between the lens and the ocular surface were simulated based on UL-OCT images of the in vitro lenses and the model eye. The existence of tear film gaps and touching points were predicted in the simulation. Conclusions. The soft contact lens edge fitting was characterized by the conjunctival buildup and tear film gaps. Different types of contact lenses presented different levels of conjunctival buildup as well as different frequencies of tear film gaps. The findings by UHR-OCT were predicted in the simulation by UL-OCT. The application of these new technologies may open new ways of designing lenses and evaluating their fit. © 2011 The Association for Research in Vision and Ophthalmology, Inc.


PubMed | Vistakon
Type: Journal Article | Journal: Contact lens & anterior eye : the journal of the British Contact Lens Association | Year: 2011

To review important aspects of contact lens compliance and to survey contact lens replacement frequency, steps in lens care and hygiene and replacement of the lens storage case via online surveys.Random US samples (n=645 and 787) of frequent replacement contact lens wearers answered questions on contact lens wear in online, sponsor-masked surveys.Wearers of lenses prescribed by their practitioner for 2 weekly replacement reported that they replaced lenses as follows: within 2 weeks 45%, within 3 weeks (minor stretching) 68%, within 4 weeks 89%, 8 weeks (extreme stretching) 4%, compared to Monthly wearers who reported: within 4 weeks 37%, within 5 weeks (minor stretching) 57%, 8 weeks 23% (8 weeks extreme stretching, Chi-square p=0.001). Median frequency for cleaning lens storage case was 2-3 times per week, while 33% reported cleaning monthly or less often. Median lens storage case replacement was every 4-6 months, while 48% reported annual replacement or less often. Most patients cleaned their lens case with hot or cold tap water (72%).These internet surveys revealed significant non-compliance with lens care steps, case hygiene and lens replacement schedule. More than half of the contact lens wearers surveyed were not compliant with their 2-weekly or monthly schedule. Lenses prescribed for longer replacement intervals can lead to more extreme stretching of lens life. To encourage better patient habits, eye care providers should reinforce their recommended frequency of replacement of lenses and storage cases and should reinforce care and hygiene steps at each patient visit.


PubMed | Vistakon
Type: Journal Article | Journal: Journal of microbiological methods | Year: 2012

The accurate measurement of ultraviolet (UV) irradiation, especially within a container or vessel is one of the challenges facing the broad implementation of UV sterilization. Currently, biological indicators are the best method to determine whether an applied UV dose has the necessary efficacy to achieve sterilization. To overcome some of the challenges of using a biological indicator, chemical indicators based upon the degradation of food, drug and cosmetic (FD&C) dyes were developed. In this work, the relationship between UV dose and dye degradation was elucidated and used to create standard curves which could be used as a quantitative measurement system. The use of dye degradation as a measurement of UV dose is especially useful when the levels of UV irradiation within a container cannot be measured directly. Additionally, due to the highly colored nature of the FD&C dyes, the visual changes present upon dye irradiation can be used as a qualitative visual indicator of the UV dose.

Loading Vistakon collaborators
Loading Vistakon collaborators