Showing 25 results out of 100 in total.

Jones D. Myopia – How to control the Epidemic British Columbia Doctors of Optometry, Virtual Presentation, September 17, 2021

Jones D. Multifunction Instruments Global Myopia Symposium, Virtual Conference, September 19, 2021

Jones D. Instrument Fundamentals - Workshop Global Myopia Symposium, Virtual Conference, September 19, 2021

Jones D. Myopia Management in Clinical Practice: Module 1: Why is myopia management essential in clinical practice Canadian Association of Optometrists – Online CE modules for Canadian ODs, March, 2021

Jones D. Myopia Management. Online module for Canadian Certified Optometric Assistants Canadian Association of Optometrists, Virtual presentation, April , 2021

Jones D. Biometry in Myopia Management IACLE Global Webinar, September 22, 2021

Jones D, Thakrar V. Myopia Management in Clinical Practice: Module 3: How to implement myopia management in to clinical practice Canadian Association of Optometrists – Online CE modules for Canadian ODs, March, 2021

Jones DA, Luensmann D, Alton K, Werner L. The prevalence of refractive error in children in a Canadian rural, First Nation Community
American Academy of Optometry, Boston, 2021 [ PDF ]

Jones L. CLEAR: Future applications of contact lenses BCLA Virtual Clinical Conference & Exhibition, June 13, 2021

Jones L. Contact lens comfort: Materials and methodologies to reduce drop outs Optician Contact Lens Week webinar, February 10, 2021

Jones L. CLEAR report summary: Contact Lens Wettability, Cleaning, Disinfection and Interactions with Tears 2021

Jones L. Dry eye & contact lenses: COVID-19 did not help! Online Optom Learning Series, Webinar (India), March 6, 2021

Jones L. Material and solution impacts on contact lens discomfort and dropout OVN (Netherlands Association of Optometrists) webinar, March 15, 2021

Jones L, Stahl U, Guthrie S, Yang M, Moezzi A, Thom M. Contact Lens Compendium: Contact Lenses and Solutions Available in Canada. Vol 47 2021.

Jones L, Stahl U, Guthrie S, Yang M, Moezzi A, Thom M. Contact Lens Compendium: Contact Lenses & Solutions Available in America. Vol 2 2021.

Khanal,S., Ngo,W., Nichols,K. K., Wilson,L., Barnes,S., Nichols,J. J. Human meibum and tear film derived (O-acyl)-omega-hydroxy fatty acids in meibomian gland dysfunction Ocular Surface 2021;21(July):118-128 [ Show Abstract ]

Purpose: The molecular basis of the tear film and lipid layer alterations in meibomian gland dysfunction (MGD) is unknown. This study aimed to identify and compare (O-acyl)-omega-hydroxy fatty acids (OAHFAs) derived from human meibum and tears in MGD. Methods: Of 195 eligible subjects (18–84 years, 62.6% female), 183 and 174 provided samples for tears and meibum, respectively. Subjects were classified into four groups: Normal, Asymptomatic MGD, MGD, and Mixed. Samples from the right eye of each subject were infused into the SCIEX 5600 TripleTOF mass spectrometer in negative ion mode. Lipid intensities identified with Analyst1.7 TF and SCIEX LipidView1.3 were normalized by an internal standard and total ion current, then statistically compared in MetaboAnalyst 4.0. Results: In meibum and tears, 76 and 78 unique OAHFAs were identified, respectively. The five most frequent and abundant OAHFAs were 18:2/16:2, 18:1/32:1, 18:1/30:1, 18:2/32:1, and 18:1/34:1. Two OAHFAs, 18:2/20:2 and 18:2/20:1, were identified only in tears. Initial univariate analysis revealed three differently regulated OAHFAs in meibum and eight in tears. Partial Least Square Discriminant Analysis showed 18:1/32:1, 18:2/16:2, 18:1/34:1 and 18:0/32:1 in tears, and 18:2/16:2, 18:1/32:1 and 18:2/32:2 in meibum, had variable importance in projection scores >1.5 and contributed the most to the separation of groups. In both meibum and tears, all OAHFAS except 18:2/16:2 were reduced in MGD compared to the normal group. Conclusion: MGD is accompanied by differential expression of specific OAHFAs in meibum and tears. These results suggest OAHFAs play a role in the altered biochemical profile of the tear film lipid layer in humans with MGD.

Kondela,T., Dushanov,E., Vorobyeva,M., Mamatkulov,K., Drolle,E., Soloviov,D., Hrubovcak,P., Kholmurodov,K., Arzumanyan,G., Leonenko,Z., Kucerka,N Investigating the competitive effects of cholesterol and melatonin in model lipid membranes Biochimica et Biophysica Acta - Biomembranes 2021;1863(9):183651 [ Show Abstract ]

We have studied the impact of cholesterol and/or melatonin on the static and dynamical properties of bilayers made of DPPC or DOPC utilizing neutron scattering techniques, Raman spectroscopy and molecular dynamics simulations. While differing in the amplitude of the effect due to cholesterol or melatonin when comparing their interactions with the two lipids, their addition ensued recognizable changes to both types of bilayers. As expected, based on the two-component systems of lipid/cholesterol or lipid/melatonin studied previously, we show the impact of cholesterol and melatonin being opposite and competitive in the case of three-component systems of lipid/cholesterol/melatonin. The effect of cholesterol appears to prevail over that of melatonin in the case of structural properties of DPPC-based bilayers, which can be explained by its interactions targeting primarily the saturated lipid chains. The dynamics of hydrocarbon chains represented by the ratio of trans/gauche conformers reveals the competitive effect of cholesterol and melatonin being somewhat more balanced. The additive yet opposing effects of cholesterol and melatonin have been observed also in the case of structural properties of DOPC-based bilayers. We report that cholesterol induced an increase in bilayer thickness, while melatonin induced a decrease in bilayer thickness in the three-component systems of DOPC/cholesterol/melatonin. Commensurately, by evaluating the projected area of DOPC, we demonstrate a lipid area decrease with an increasing concentration of cholesterol, and a lipid area increase with an increasing concentration of melatonin. The demonstrated condensing effect of cholesterol and the fluidizing effect of melatonin appear in an additive manner upon their mutual presence.

Luensmann,D., Schaeffer,J. L., Rumney,N. J., Stanberry,A., Fonn,D. Magnitude of astigmatism – A comparison between eyes Contact Lens Anterior Eye 2021;Online ahead of print [ Show Abstract ]

Astigmatism is a highly prevalent refractive error and while studies typically focus to describe the axis symmetry between eyes, little is known about the refractive symmetry. Therefore, this study determined the astigmatic power symmetry between eyes in a large clinic population.

A clinical chart review was conducted at three optometric practices in the United States, the United Kingdom and Canada and subjective refraction data from 88,891 patients 14–70 years of age who presented with at least −0.25DC refractive astigmatism in at least one eye were included in the analysis. Data were obtained at these practices between January 2014 and March 2017. The overall distribution (%) and magnitude (DC) of astigmatism was determined and refractive differences between eyes were identified.

The mean age of the patients was 42.1 ± 15.9 years and included 51,685 (58%) female and 37,206 (42%) male patients. In this data pool of 177,782 eyes, 10.9% required zero astigmatic correction, while 56.2% had astigmatism of −0.25 to −0.75DC. In total 23.9% of patients presented with astigmatism of at least −0.75DC in only one eye, while the other eye had 0 to −0.50DC. Overall, the difference in astigmatism between eyes was less than −0.75DC for 82.1% of astigmatic patients. For patients who presented with astigmatism of −1.00DC in the right eye, 80.8% of them had an astigmatic prescription of −1.00 ± 0.50DC in the left eye. For an astigmatic prescription of −4.00DC in the right eye, only 40.6% of patients exhibited astigmatism of −4.00DC ± 0.50DC in the left eye.

The majority of patients exhibited a difference in astigmatism between eyes of less than −0.75DC, however the refractive cylinder power symmetry was significantly lower in patients with higher refractive astigmatism.

Luensmann D, Schulze M, Woods J, Lazon de la Jara P, Vega J, Orsborn G. Fitting success with stenfilcon A daily disposable multifocal lenses
BCLA Virtual Clinical Conference & Exhibition, 2021 [ Show Abstract ][ PDF ]

Purpose: Multifocal contact lens (MFCL) fitting sometimes raises concerns about the number of fitting attempts required to determine the optimal lens prescription. This study compared the fit process and success rates of stenfilcon A (stenA) MFCL with delefilcon A (delA) MFCL when fitted to existing MFCL wearers in a randomized order.

Method: Successful MFCL wearers with <1.00DC of astigmatism were recruited at five clinical sites in the US. The first trial lenses were determined from current subjective refraction and the respective fitting guides. Prescription changes were reviewed at this first fit visit and also when participants returned for an optimization visit after wearing the lenses for 3-7 days. Multiple lens powers could be trialed at each visit, all were recorded.

Results: Fifty-eight subjects (50F:8M), mean age 54.4±7.3 years [42 to 70 years] were included in the analysis. The spherical-equivalent refraction was OD -1.10±2.7D [-6.50D to +3.75D] with near add +2.00±0.4D [+1.00D to +2.50D]. StenA-MFCL was successfully fit with the first pair of trial lenses in 83% (48) participants, while 10% (6) needed one additional lens and 7% (4) needed an extra two lenses to reach their final power. Regarding count of eyes, 12% (14) needed power optimizations. DelA-MFCL was successfully fit with the first pair of trial lenses in 66% (38) participants, while 17% (10) needed one additional lens, 10% (6) needed two extra lenses and 7% (4) needed three extra lenses to reach their final lens power. Regarding count of eyes, 25% (30) needed power optimizations.

Conclusions: Habitual MFCL wearers were successfully fitted with both MF lens types when following the respective fitting guides. There was a higher success rate with the first lens pair for stenA-MFCL (>8/10 patients) compared to delA-MFCL (<7/10 patients), and no more than one additional fitting lens (per eye) was needed when fitting stenA-MFCL.

Luensmann D, Schulze M, Woods J, Vega J, Orsborn G. Intermediate vision with multifocal contact lenses American Academy of Optometry, Boston, 2021 [ Show Abstract ]

Fitting multifocal contact lenses (MFCL) typically focusses on optimizing distance and near vision, however many presbyopes require good intermediate vision to focus on targets such as desktop screens. This study determined the performance of habitual MFCL (hab-MFCL), stenfilcon A MFCL (stenA-MFCL) and delefilcon A MFCL (delA-MFCL) for intermediate distance vision in existing MFCL wearers.

Five clinical sites in the US recruited habitual MFCL wearers with <1.00DC of astigmatism. Habitual MFCL were power optimized and both study lens types were fit following the respective fitting guides. After two weeks of hab-MFCL wear, study MFCL were worn in a masked/randomized order for the same period of time. Intermediate visual acuity (VA) at 0.75m was determined and subjective responses (fell short of needs; met needs; exceeded needs) were collected along with preference ratings (strongly prefer, slightly prefer, no preference). Subjective responses and logMAR VA were analyzed using Wilcoxon Matched-Pairs testing for differences and binomial testing was conducted on preference ratings.

Fifty-eight subjects (50F:8M), mean age 54.4±7.3 years [42 to 70 years] were included in the analysis. The mean spherical-equivalent refraction was OD -1.10±2.7D [-6.50D to +3.75D]. The average near spectacle Rx add was +2.00±0.4D [+1.00D to +2.50D] and included 18 participants (31%) who required an add of up to +1.75D and 40 (69%) with an add of at least +2.00D. After two weeks of wear, intermediate logMAR VA with stenA-MFCL (0.08±0.10 logMAR) was statistically significantly better compared to hab-MFCL (0.12±0.11 logMAR, p=0.002) and compared to delA-MFCL (0.12±0.12 logMAR, p<0.001). Vision clarity at intermediate distance was rated similarly for hab-MFCL and stenA-MFCL (p=1.00), while both were rated better than delA-MFCL (p=0.01 for both). Preference ratings for intermediate vision clarity showed no significant preferences for stenA-MFCL over hab-MFCL (p=0.36), however both were preferred over delA-MFCL (p=0.03 for both). Vision clarity with digital device use and overall vision clarity were preferred with stenA-MFCL compared to delA-MFCL (p≤0.03 for both), while no preference was found between stenA-MFCL and hab-MFCL for those questions (p>0.05 for both).

All MFCL were worn successfully for two weeks, however differences in the intermediate vision clarity were noted between lens types, in favour of stenA-MFCL compared to delA-MFCL. Digital devices are frequently used at work and during leisure time today and form part of the need for optimal intermediate vision. While it may often be overshadowed by distance and near vision assessments, good performance at the intermediate distance can be just as critical to ensure success in MFCL wearers.

Mirzapour,P., McCanna,D. J., Jones,L. In vitro analysis of the interaction of tear film inflammatory markers with contemporary contact lens materials Contact Lens Anterior Eye 2021;44(5):101430 [ Show Abstract ]

Several clinical studies have suggested that reusable silicone hydrogel contact lens materials exhibit a two-times increased rate of corneal infiltrative events compared to reusable hydrogels. One potential factor contributing to this complication relates to the differential uptake of tear film-based pro-inflammatory cytokines. The purpose of this study was to use an in vitro assay to investigate whether four pro-inflammatory cytokines differed in their uptake onto six contemporary contact lens materials.

Conventional hydrogel (etafilcon A, omafilcon A) and silicone hydrogel (balafilcon A, comfilcon A, senofilcon A, somofilcon A) contact lens materials were soaked in solutions containing pro-inflammatory cytokines IL-1β, IL-6, IL-8 and TNF-α. Samples of the soaking solutions were collected over various time points and analyzed using the Meso Scale Discovery system, which served as a measurement of cytokine uptake onto the contact lens materials.

Both conventional hydrogels (etafilcon A, omafilcon A) and two of the four silicone hydrogels tested (balafilcon A, comfilcon A), exhibited some uptake of IL-1β, IL-8 or TNF-α (p < 0.05). Senofilcon A and somofilcon A did not exhibit uptake of any of these cytokines (p > 0.05). There was no uptake of IL-6 onto any of the contact lens materials investigated (p > 0.05).

The contact lens materials tested did not exhibit any uptake of IL-6 and furthermore, did not exhibit more than 10 ± 3 % to 25 ± 12 % uptake of IL-1β, IL-8 or TNF-α. Numerous factors could contribute to the reported increase in corneal infiltrative events with reusable silicone hydrogel materials, however, based on these results, it appears that uptake of these four cytokines are unlikely to contribute to this finding.

Moezzi A. CLEAR report summary: Effect of Contact Lens Materials and Designs on the Anatomy and Physiology of the Eye 2021

Morgan,P. B., Murphy,P. J., Gifford,K. L., Gifford,P., Golebiowski,B., Johnson,L., Makrynioti,D., Moezzi,A. M., Moody, K., Navascues-Cornago,M., Schweizer,H., Swiderska,K., Young,G., Willcox,M. CLEAR - Effect of contact lens materials and designs on the anatomy and physiology of the eye Contact Lens Anterior Eye 2021;44(2):192-219 [ Show Abstract ]

This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia).

However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation.

In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience.

Morgan P, Woods CA, Tranoudis IG, Efron N, Jones L, Grupcheva CN, Jones D, Beeler-Kaupke M, Qi P, Tan KO, Rodriguez Cely LM, Belova S, Ravn O, Santodomingo-Rubido J, Bloise L, Plakitsi A, Végh M, Erdinest N, Montani G, Itoi M, Bendoriene RL, Mulder J, van der Worp E, Ystenaes AE, Romualdez-Oo J, Abesamis-Dichoso C, Gonzalez-Meijome JM, Belousov V, Johansson O, Hsiao J, Nicholes JJ.. International contact lens prescribing in 2020 Contact Lens Spectrum 2021;36, January: 26-32 [ Show Abstract ]

This article is our 20th consecutive annual report of international contact lens prescribing for Contact Lens Spectrum. The premise of the work is simple. As an alternative to asking a cross section of contact lens wearers about the lenses that they use and the basis on which the lenses are worn, we move upstream in the process and directly survey those who are fitting contact lenses in numerous markets around the world. This presents a more “leading edge” indicator of contact lens fitting habits; the lenses fitted today are those sold tomorrow. The aim here is to provide summary information for colleagues in clinical practice, industry, and academia about contact lens prescribing behaviors to inform their patient management, research and development, and educational curricula, respectively.

Muntz A, Walther H.. Das trockene Auge im digitalen Alter: Updates aus der Forschung Sichtkontakte, Virtual Conference, October 9, 2021