Publications

Showing 11 results out of 461 in total.

Yamasaki,K., Drolle,E., Nakagawa,H., Hisamuare,R., Ngo,W., Jones,L. W. Impact of a low molecular weight hyaluronic acid derivative on contact lens wettability Cont Lens Anterior Eye 2021;44(3):101334 [ Show Abstract ]

Purpose
To investigate the interaction of a novel low molecular weight hyaluronic acid derivative containing hydrophobic groups with soft contact lenses and its effect on lens hydrophilicity compared with a conventional form of hyaluronic acid.

Methods
This investigation studied the uptake of fluorescently-labelled hyaluronic acid and a low molecular weight hyaluronic acid derivative to four types of contact lenses using fluorescent microscopy and confocal laser scanning microscopy. Further, the four lens types were used to compare efficacy in improving hydrophilicity, as well as maintenance of contact angle measurements, in commercially available multipurpose solutions that contained either hyaluronic acid, the low molecular weight hyaluronic acid derivative, or an alternative wetting agent.

Results
The low molecular weight hyaluronic acid derivative was found to sorb more readily to silicone hydrogel lenses and exhibit a greater accumulation over time than conventional hyaluronic acid. Multipurpose solutions containing the low molecular weight hyaluronic acid derivative showed an increase in lens hydrophilicity through decreases in contact angle measurements when compared with those obtained from lenses treated with multipurpose solutions containing conventional hyaluronic acid or alternative wetting agents. This increase in lens hydrophilicity associated with the low molecular weight hyaluronic acid derivative was also maintained over multiple cycles in phosphate buffered saline, while alternative solutions with conventional hyaluronic acid did not.

Conclusion
Overall, lens treatment using a low molecular weight hyaluronic acid derivative-based solution lead to improved in vitro lens hydrophilicity.

Yamasaki,K., Mizuno,Y., Kitamura,Y., McCanna,D. J., Ngo,W., Jones,L. W. The efficacy of povidone-iodine, hydrogen peroxide and a chemical multipurpose contact lens care system against Pseudomonas aeruginosa on various lens case surfaces Cont Lens Anterior Eye 2021;44(1):18-23 [ Show Abstract ]

Purpose
To determine the antimicrobial efficacy of a povidone-iodine system (PVP-I; cleadew, OPHTECS Corporation, Kobe, Japan), a peroxide system (AOSEPT Plus with HydraGlyde, Alcon, Fort Worth, TX), and a chemical multipurpose system (renu fresh, Bausch & Lomb, Rochester, NY) on contact lens case surfaces that are both in contact and not in contact with the solutions during lens disinfection.

Methods
The surfaces of the inner walls, underside of the lid, and lens holder (if applicable) of the cases were inoculated with P. aeruginosa ATCC 27853. The cases were disinfected with the solutions as per their manufacturer instructions. After disinfection, the inoculated surfaces were swabbed and the amount of surviving P. aeruginosa was determined. Following this experiment, separate cases were inoculated and disinfected as before. This time the cases were agitated after recommended disinfection time and the amount of P. aeruginosa in the disinfecting solution was quantified immediately, and again after resting for 7 days. Experiments were conducted in triplicate (n = 3).

Results
Units are expressed in log CFU. All three solutions significantly reduced P. aeruginosa on direct-contact surfaces (all p < 0.039). On non-contact surfaces, the reduction of P. aeruginosa in the PVP-I system (pre-disinfection: 6.8 ± 0.5, post-disinfection: 1.0 ± 0.0; p < 0.001) was significant, but not for the hydrogen peroxide system (pre-disinfection: 6.3 ± 0.6, post: 5.5 ± 0.5; p = 0.194) and the chemical multipurpose system (pre-disinfection: 6.6 ± 0.1, post-disinfection: 5.6 ± 0.8; p = 0.336). After 7 days post-disinfection, no P. aeruginosa regrowth was observed in the PVP-I system (Day 1: 1.0 ± 0.0, Day 7: 1.0 ± 0.0; p = 1) and the chemical multipurpose system (Day 1: 4.2 ± 0.2, Day 7: 1.8 ± 0.9; p = 0.012), however regrowth was observed in the hydrogen peroxide system (Day 1: 3.4 ± 0.6, Day 7: 6.1 ± 0.4; p = 0.003).

Conclusion
The PVP-I system was more effective against P. aeruginosa on non-contact surfaces than the hydrogen peroxide system or the chemical multipurpose system and is capable of inhibiting regrowth of P. aeruginosa for at least 7 days post-disinfection.

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.

Yang,M., Ngo,W., Srinivasan,S., Heynen,M. L., Dantam,J., Subbaraman,L. N., Jones,L., Senchyna,M. Optimization of goblet cell density quantification methods Experimental Eye Research 2021;207(June):108607 [ Show Abstract ]

The purpose of this study was to develop a standardized, accurate and efficient method for estimating conjunctival goblet cell density (GCD) via optimizing sample storage conditions and quantification methods. Conjunctival impression cytology (CIC) membranes were collected from both eyes of 32 participants and were randomized to two storage durations (2-3 weeks, 6-7 weeks) and two storage container types (microcentrifuge tube, flat histology cassette). The CIC membranes were stained and subdivided into 25 areas (5 mm × 5 mm) for imaging and the GCs were counted under 200X magnification using three different methods: (1) full CIC membrane GC count of the 25 images with cell-counting software ("full"; reference method), (2) partial membrane GC count of 9 images with cell-counting software ("partial"), and (3) manual counting of the 25 images ("manual"). In all cases, GCD was determined by dividing the GC count by the counting area. The average time required for quantification was recorded to gauge efficiency. Results showed no significant difference in GC count between the two storage durations (p = 0.745) or storage container types (p = 0.552). The median (interquartile range (IQR)) time required to quantify a CIC membrane for the full, partial, and manual methods of GC counting, was 14.8(17.6), 4.6(5.2) and 5.0 (5.0) minutes, respectively. The agreement of GCD values between the full and manual methods (bias: 0.4, 95% LOA: [-4.6, 5.5]) was stronger than that comparing the full and partial methods (bias: 0.5, 95% LOA: [-18, 17]). All together, through systematic examination of key procedural variables, an optimized method for GCD quantification within 7 weeks of sample collection was outlined. Adaption of procedures described in this paper to facilitate accurate and efficient GCD quantification may serve as a valuable step in clinical trials investigating DED pathophysiology and/or novel DED treatment strategies.

Yee,A., Chan,V., Heynen,M., Phan,C. M., Jones,L. Uptake and release of a multipurpose solution biocide (MAP-D) from hydrogel and silicone hydrogel contact lenses using a radiolabel methodology Eye & Contact Lens 2021;47(5):249-255 [ Show Abstract ]

Purpose:
The purpose of this study was to evaluate the uptake and release of radiolabelled myristamidopropyl dimethylamine (MAP-D) on reusable daily wear contact lenses (CLs) over 7 days.

Methods:
Three silicone hydrogel (SH) CL materials (lotrafilcon B, balafilcon A, senofilcon A) and two conventional hydrogel (CH) materials (etafilcon A, omafilcon A) were tested. A short-term (experiment 1, N=4) and a longer-term (experiment 2, N=3) study was conducted. In experiment 1, the CLs were incubated in 2 mL of phosphate buffered solution (PBS) containing 14C MAP-D (5 μg/mL) for 8 hrs. The release of 14C MAP-D was measured at t=0.25, 0.5, 1, 2, 4, 8, and 24 hr in PBS. In experiment 2, the CLs were incubated in the 14C MAP-D solution for 8 hrs followed by a 16-hr release in PBS. This cycle was repeated daily for 7 days. At the end of both experiments, lenses were extracted to determine the total uptake of MAP-D. The radioactivity was measured using a beta scintillation counter.

Results:
In experiment 1, all three SH lenses sorbed similar amounts of MAP-D (P=0.99), all of which were higher than the two CH materials (P<0.01). However, the CH materials released a greater amount of MAP-D than the SH materials (P<0.01). In experiment 2, the uptake of MAP-D in SH materials increased over 7 days, whereas the amount of MAP-D remained constant in the CH materials (P=0.99). Similar to experiment 1, the CH lenses released more MAP-D than SH lenses after 7 days (P<0.01).

Conclusion:
The SH materials absorbed greater amounts of MAP-D compared to CH materials. However, the CH materials released the greatest amount of MAP-D. Radioactive labelling of MAP-D offers a highly sensitive method of assessing the uptake and release profiles of biocides to CL materials.

Yee,A., Walsh,K., Schulze,M., Jones,L The impact of patient behaviour and care system compliance on reusable soft contact lens complications Contact Lens Anterior Eye 2021;Online ahead of print [ Show Abstract ]

Reusable soft daily wear contact lenses (CLs) remain popular and were fit to just over half of all wearers in the most recent international CL prescribing survey. Unlike daily disposable CLs, reusables require cleaning and disinfecting after every use, along with storage in a CL case. These additional requirements add a number of steps to the daily wear and care routine, increasing the opportunities for CL wearers to exhibit non-compliant behaviour. The impact of non-compliance ranges from poor lens comfort through to potentially sight- threatening infective keratitis. The coronavirus pandemic has refocused the profession on the importance of hand hygiene in particular, and the need for promoting safe CL wear in general. This review summarises typical non-compliant behaviour related to reusable CLs, and examines strategies and opportunities to better support wearers. Patient education has a central role in encouraging compliant behaviour, although patient recall of information is low, and personal belief systems may result in continuation of non-compliant behaviour despite awareness of the risks. CL care solutions are required for the daily disinfection of lenses, however misuse of multipurpose solutions (MPS) and hydrogen peroxide (H2O2)-based care systems can challenge their ability to be fully efficacious. Standard efficacy testing is reviewed, with consideration of how well current protocols model real-world use of CL solutions. Although some recommendations are in place for the inclusion of additional variables such as lens cases, CL materials, organic soil and efficacy against Acanthamoeba, opportunity still exists to reevaluate global standards to ensure consistency of testing in all markets. Finally, potential future innovations are discussed which may further support increased safety in reusable lens wear through novel antimicrobial additions to both CL materials and cases

Yeu,E., Silverstein,S., Guillon,M., Schulze,M., Galaretta,D., Srinivasan,S., Manoj,V. Efficacy and Safety of Phospholipid Nanoemulsion-Based Ocular Lubricant for the Management of Various Subtypes of Dry Eye Disease: A Phase IV, Multicenter Trial Clinical Ophthalmology 2020;14:2561-2570 [ Show Abstract ]

Purpose: To evaluate the clinical efficacy and safety of propylene glycol/hydroxypropylguar (PG-HPG)-based nanoemulsion (Systane ® Complete) lubricant eye drops in participants with dry eye disease (DED).

Participants and Methods: In this phase IV, open-label, single-arm, interventional, multicenter study, adult participants with DED – subtyped into aqueous deficient, evaporative, and mixed dry eye – were instructed to instill one drop of PG-HPG in each eye twice a day for 28 days. Endpoints included change from baseline in tear film break-up time (TFBUT) (primary) and ocular discomfort visual analog scale (VAS) score at Day 14 and TFBUT at Day 28 (secondary). Safety was assessed throughout the study. Data were analyzed for overall patient cohort and by DED subtypes. Results: A total of 134 participants received treatment (mean age: 56.6 years; female: 75.4%). At Day 14, the mean (standard deviation [SD]) TFBUT increased from 2.6 (1.00) seconds at baseline to 4.2 (2.92) seconds (mean change: 1.5 [2.80] seconds); median change was 0.8 seconds (95% CI: 0.52, 1.19) for the overall cohort; the change was maintained at Day 28 (mean change: 1.4 (2.80) seconds, median change: 0.8 seconds (95% CI: 0.49, 1.17). Subgroup analysis showed a mean change (SD) from baseline in TFBUT of 1.1 (2.41) seconds for aqueous deficient, 2.4 (3.17) seconds for evaporative, and 1.2 (2.63) seconds for mixed dry eye at Day 14, respectively. The ocular discomfort VAS score improved (decreased) from baseline at Day 14 (mean [SD] change: −17.3 [24.80]) for the overall cohort, −22.0 [21.73] for aqueous deficient, −17.6 [24.17] for evaporative and −13.1 [27.49] for mixed dry eye subgroups). Adverse events (AEs) were reported in 9 (6.7%) participants. No serious AEs were reported during the study.

Conclusion: Our study findings demonstrated that PG-HPG-based nanoemulsion lubricant eye drops were effective and well tolerated in participants with DED and all of its subtypes. Keywords: aqueous deficient dry eye, dry eye disease, evaporative dry eye, propylene glycol/hydroxypropyl guar-nanoemulsion ocular lubricant, mixed dry eye

Youn,H. -Y, McCanna,D. J., Sivak,J. G., Jones,L. W. In vitro ultraviolet-induced damage in human corneal, lens, and retinal pigment epithelial cells Molecular Vision 2011;17237-246

Young,G., Chalmers,R., Napier,L., Kern,J., Hunt,C., Dumbleton,K. Soft contact lens-related dryness with and without clinical signs Optometry and Vision Science 2012;89(8):1125-1132 [ Show Abstract ]

PURPOSE.: To report demographics, wearing patterns, and symptoms from soft contact lens (SCL) wearers with significant SCL-related dryness symptoms with and without significant ocular signs of dryness. METHODS.: In a multicenter, prospective observational clinical trial, symptomatic SCL wearers reported significant SCL-related dryness via self-administered questionnaire of frequency and intensity of dryness after a dry eye (DE) examination. DE etiology was assigned post hoc by an expert panel, and those with and without significant DE-related signs were analyzed by univariate logistic regression. Possible DE etiologies were aqueous tear deficiency, SCL-induced tear instability, meibomian gland dysfunction, or "other." Wearers without signs that qualified for any DE etiology were designated as No DE Signs (NDES). RESULTS.: Of the 226 SCL symptomatic wearers examined, 23% were without signs, 30% had aqueous tear deficiency, 25% had SCL-induced tear instability, 14% had meibomian gland dysfunction, and 8% had "other" diagnoses. The NDES wearers had significantly longer pre-lens break-up time (9.8 vs. 6.6 s, p < 0.0001), better lens wetting (3.4 vs. 2.4 0 to 4 scale, p < 0.0001), lower levels of film deposits on lenses (0.45 vs. 0.92, 0 to 4 scale, p < 0.0001), and of most slit lamp signs. The NDES wearers were significantly more likely to be male (36% vs.19%, p ≤ 0.013), were less likely to have deteriorating comfort during the day (81% vs. 97%, p ≤ 0.001), reported longer average hours of comfortable wear (11 ± 3 vs. 9 ± 4 h, p ≤ 0.014), had older contact lenses (18 ± 14 vs. 13 ± 12 days, p ≤ 0.029), and greater intensity of photophobia early and late in the day (p ≤ 0.043 and 0.021). CONCLUSIONS.: Symptoms of dryness in SCL wearers stem from a variety of underlying causes. However, nearly one-quarter of these symptomatic SCL wearers appear to be free of signs of dryness. The effective management of CL-related dryness requires a comprehensive range of clinical assessments and the use of a diverse range of management strategies. Copyright © 2012 American Academy of Optometry.

Young,G., Keir,N., Hunt,C., Woods,C. A. Clinical evaluation of long-term users of two contact lens care preservative systems Eye and Contact Lens 2009;35(2):50-58 [ Show Abstract ]

PURPOSE: To clinically evaluate long-term users of two different contact lens care preservative systems and to investigate whether prolonged use is associated with an increase in the prevalence of dry eye. METHODS: Eighty-nine wearers of group IV hydrogel or silicone hydrogel lenses participated in this one-visit, investigator-masked study. Subjects were required to have consistently used a polyhexamethylene biguanide (PHMB) or polyquaternium-1 (PQT) based solution for 2 years. Consistent use was defined as 80% for the past 2 years and 100% for the past year. Clinical assessments included: average and comfortable wear time; overall and end-of-day comfort; signs of dryness, discomfort, burning or stinging, grittiness or scratchiness and visual changes; non-invasive and fluorescein break-up-time; pre-ocular tear film lipids, tear meniscus height, Schirmer and fluorescein clearance tests; limbal and bulbar hyperemia; palpebral roughness; corneal and conjunctival staining; lens front surface wetting; and lens film deposits. RESULTS: Significantly more grittiness or scratchiness was reported by subjects using a PHMB-containing system (67% vs. 44%; P = 0.02). Palpebral roughness and hyperemia were significantly greater in the PHMB group wearing group IV lenses (P = 0.01 and P = 0.05, respectively). Corneal staining was significantly higher in the PHMB users in all four peripheral sectors (P < 0.01). Nasal and temporal conjunctival staining was also significantly higher for users of PHMB-containing systems (P < 0.05). Front surface lens wettability was significantly better for group IV PQT users compared to PHMB users (P = 0.008), with 84% vs. 72%, respectively, with lenses graded by the investigator as having "good" or "excellent" wettability. Significantly higher levels of lens front surface film deposits were noted with PHMB users (P = 0.007), with 58% of group IV lenses treated with PHMB compared with 38% of group IV lenses treated with PQT showing some lens front surface film deposition. No significant differences between the two preservative system groups were noted for the range of dry eye evaluations nor the remaining clinical assessments. CONCLUSIONS: Differences in both ocular and lens characteristic were observed between long-term users of two preservative systems used in many contact lens multi-purpose solutions. The findings from this study did not support the hypothesis that prolonged use of PHMB-containing solutions leads to dry eye. Additional studies including a larger sample size and perhaps longer use of the systems could help to further elucidate differences in clinical performance between systems.

Young,G., Veys,J., Pritchard,N., Coleman,S. A multi-centre study of lapsed contact lens wearers Ophthalmic and Physiological Optics 2002;22(6):516-527 [ Show Abstract ]

Purpose: Discontinuation from contact lens wear has been identified as a contributing factor in the lack of growth of contact lens use in Europe. The purpose of this study was to determine the proportion of lapsed contact lens wearers that can be refitted successfully with contact lenses and to evaluate the reasons for discontinuation from contact lens wear. Methods: This was a multi-site clinical study involving 15 UK investigators and 236 lapsed contact lens wearers who had previously tried contact lenses and discontinued. The reasons for discontinuation were assessed by subjects, who were then refitted with contact lenses. Investigators subsequently evaluated factors associated with their initial discontinuation. Short-term success was defined as the successful completion of 1 month of contact lens wear with absence of complications that would prevent further wear. Subjects were interviewed by telephone 6 months after being refitted to determine whether they were still wearing contact lenses. Those who were not wearing lenses were questioned about the reasons for discontinuation and their likelihood of resuming lens wear. Results: A majority of subjects (51%) cited discomfort as the principal reason for having previously given up contact lens wear. Problems with vision were the second most common reason (13%), either with reading (6%) or general vision (7%). The most common type of discomfort was dryness (40%). In almost all cases (97%), the investigator's assessment of the reasons for discontinuation agreed with the subject's own assessment but investigators also cited product-related and practitioner-related factors as contributing to previous failure. The short-term success rate for refitting lapsed wearers was found to be 77% (CI: 70-82%). The highest short-term success rates were for 2-weekly/monthly soft spherical lenses (91%) and daily disposable lenses (89%). Lower success rates were found for soft toric (69%) and soft bifocal (53%) lenses. At the 6-month stage, 73% of those who continued in lenses after the 1-month visit were still wearing contact lenses and a further 18% indicated that they were either 'very likely' or 'likely' to resume lens wear. Conclusions: A high proportion of lapsed contact lens wearers can be successfully refitted with contact lenses. The prime reason for previous discontinuation from contact lenses is discomfort and, in particular, dryness-related discomfort. In many cases, previous contact lens failure is product or practitioner-related rather than because of patient-specific problems. Once refitted with contact lenses, lapsed wearers cite vision problems rather than discomfort as the most common reason for discontinuing. This finding suggests that recent advances in contact lens material, design, replacement frequencies and care systems have improved the prospects for avoiding lens-related discomfort and for continuing contact lens wear. © 2002 The College of Optometrists.