Publications by authors named "Andrew Plowright"

6 Publications

  • Page 1 of 1

Using face masks with spectacles versus contact lenses.

Cont Lens Anterior Eye 2021 Oct 1:101516. Epub 2021 Oct 1.

Eurolens Research, Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester M13 9PL, UK.

Purpose: To test the hypothesis that various subjective ocular and task-related parameters associated with wearing a face mask would be better in neophyte contact lens (CL) wear compared to habitual spectacle (Sp) wear.

Methods: Thirty participants were randomised to continue in Sp (n = 15) or wear somofilcon A daily disposable CL (n = 15) ('group'). A surgical face mask (Type II R) was worn for at least one hour per day on four or more days per week. After two weeks, participants completed the Quality of Life Impact of Refractive Correction Questionnaire (QIRC), a two-part face mask usability questionnaire and graded ocular-related symptoms using 0-100 visual analogue scales.

Results: There was no difference between groups for overall QIRC score but some individual question scores reflected better quality of life in the CL: 'outdoor activities', 'keep fit' and 'able to do things' (all p < 0.05). Differences in favour of the CL were seen for the following in the face mask usability questionnaire: 'breathing', 'heat', 'comfort on ears', 'overall comfort', 'walking', 'driving', 'reading', 'computer use', 'exercising' and 'socialising' (all p < 0.05). Significant differences were also seen for the 0-100 VAS symptoms probing vision quality in favour of the CL: glare, distance and near vision, fogging, restricted field of view and peripheral blur.

Conclusion: This work supports anecdotal reports that CL are a better vision correction option than Sp when used in conjunction with a face mask. Participants reported a range of benefits to the CL/face mask combination for vision-related symptoms, breathing and heat-related symptoms and a number of day-to-day activities including walking, driving and exercising. All of the benefits relating to the CL are likely to result in improved adherence to face mask use. Overall, the findings of this work suggest that where possible, CL should be the preferred vision correction option for people using face masks.
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October 2021

The association of comfort and vision in soft toric contact lens wear.

Cont Lens Anterior Eye 2021 Aug 9;44(4):101387. Epub 2020 Dec 9.

Eurolens Research, Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.

Purpose: This work set out to investigate if there was an association between subjective comfort and both subjective and measured vision during the use of contemporary daily disposable soft toric contact lenses.

Methods: Thirty-eight habitual soft contact lens wearers wore each of three daily disposable toric lenses for one week in a prospective, crossover, randomised, single-masked study. The following clinical measures were recorded at dispensing and follow-up visits: biomicroscopy scores, lens fitting (including rotation and rotational stability), high and low contrast visual acuity, subjective vision quality and subjective ocular surface comfort. Subjective scores were collected using 0-10 numerical grading scales. Comfort scores were analysed using a linear regression model with age, sex, visit, phase of crossover ('phase'), lens type, lens rotation, lens rotational stability, visual acuity, cylinder power and subjective vision quality as factors of interest and then refined using backward stepwise regression.

Results: Thirty six participants (31.1 ± 13.5 years) completed the study. Comfort scores were found to be associated with subjective vision quality (F = 127.0 ; p < 0.0001), phase (F = 7.2; p = 0.001) and lens type (F = 4.9; p = 0.009). Greater comfort scores were observed with greater subjective vision quality scores. Visual acuity was not statistically significant in the model.

Conclusion: This work suggests that symptoms of ocular discomfort may be more intense if there is also perceived visual compromise in daily disposable soft toric lenses. There was a stronger positive correlation between comfort and subjective vision quality compared with comfort and measured visual acuity.
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August 2021

Invasive Shrub Mapping in an Urban Environment from Hyperspectral and LiDAR-Derived Attributes.

Front Plant Sci 2016 21;7:1528. Epub 2016 Oct 21.

City of Surrey Surrey, BC, Canada.

Proactive management of invasive species in urban areas is critical to restricting their overall distribution. The objective of this work is to determine whether advanced remote sensing technologies can help to detect invasions effectively and efficiently in complex urban ecosystems such as parks. In Surrey, BC, Canada, Himalayan blackberry () and English ivy () are two invasive shrub species that can negatively affect native ecosystems in cities and managed urban parks. Random forest (RF) models were created to detect these two species using a combination of hyperspectral imagery, and light detection and ranging (LiDAR) data. LiDAR-derived predictor variables included irradiance models, canopy structural characteristics, and orographic variables. RF detection accuracy ranged from 77.8 to 87.8% for Himalayan blackberry and 81.9 to 82.1% for English ivy, with open areas classified more accurately than areas under canopy cover. English ivy was predicted to occur across a greater area than Himalayan blackberry both within parks and across the entire city. Both Himalayan blackberry and English ivy were mostly located in clusters according to a Local Moran's I analysis. The occurrence of both species decreased as the distance from roads increased. This study shows the feasibility of producing highly accurate detection maps of plant invasions in urban environments using a fusion of remotely sensed data, as well as the ability to use these products to guide management decisions.
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October 2016

Where have all the mosquito nets gone? Spatial modelling reveals mosquito net distributions across Tanzania do not target optimal Anopheles mosquito habitats.

Malar J 2015 Aug 19;14:322. Epub 2015 Aug 19.

Department of Biology, University of Ottawa, Gendron 352, 30 Marie Curie, Ottawa, ON, K1N6N5, Canada.

Background: Malaria remains the deadliest vector-borne disease despite long-term, costly control efforts. The United Republic of Tanzania has implemented countrywide anti-malarial interventions over more than a decade, including national insecticide-treated net (ITN) rollouts and subsequent monitoring. While previous analyses have compared spatial variation in malaria endemicity with ITN distributions, no study has yet compared Anopheles habitat suitability to determine proper allocation of ITNs. This study assesses where mosquitoes were most likely to thrive before implementation of large-scale ITN interventions in Tanzania and determine if ITN distributions successfully targeted those areas.

Methods: Using Maxent, a species distribution model was constructed relating anopheline mosquito occurrences for 1999-2003 to high resolution environmental observations. A 2011-2012 layer of mosquito net ownership was created using georeferenced data across Tanzania from the Demographic and Health Surveys. The baseline mosquito habitat suitability was compared to subsequent ITN ownership using (1) the average ITN numbers per house and (2) the proportion of households with ≥1 net to test whether national ITN ownership targets have been met and have tracked malaria risk.

Results: Elevation, land cover, and human population distribution outperformed variants of temperature and Normalized Difference Vegetation Index (NDVI) in anopheline distribution models. The spatial distribution of ITN ownership across Tanzania was near-random spatially (Moran's I = 0.07). Householders reported owning 2.488 ITNs on average and 93.41 % of households had ≥1 ITN. Mosquito habitat suitability was statistically unrelated to reported ITN ownership and very weakly to the proportion of households with ≥1 ITN (R(2) = 0.051). Proportional ITN ownership/household varied relative to mosquito habitat suitability (Levene's test F = 3.0037). Quantile regression was used to assess trends in ITN ownership among households with the highest and lowest 10 % of ITN ownership. ITN ownership declined significantly toward areas with the highest vector habitat suitability among households with lowest ITN ownership (t = -3.38). In areas with lowest habitat suitability, ITN ownership was consistently higher.

Conclusions: Insecticide-treated net ownership is critical for malaria control. While Tanzania-wide efforts to distribute ITNs has reduced malaria impacts, gaps and variance in ITN ownership are unexpectedly large in areas where malaria risk is highest. Supplemental ITN distributions targeting prime Anopheles habitats are likely to have disproportionate human health benefits.
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August 2015

Daily disposable contact lenses versus spectacles in teenagers.

Optom Vis Sci 2015 Jan;92(1):44-52

*BSc(Hons), MSc †PhD, MCOptom, FAAO ‡BSc(Hons), MCOptom §MBA, PhD Eurolens Research, The University of Manchester, Manchester, United Kingdom (AJP, CM-C, GFH, PBM); and Alcon Research Ltd, Fort Worth, Texas (JK).

Purpose: To compare clinical and subjective quality-of-life (QoL) data for teenagers wearing daily disposable contact lenses or spectacles.

Methods: This open-label study randomized subjects (aged 13 to 19 years) with no previous contact lens wear experience to nelfilcon A (DAILIES AquaComfort Plus) contact lenses or spectacles for 6 months. A full clinical workup, as well as subjective QoL measures using the Pediatric Refractive Error Profile and Quality of Life Impact of Refractive Correction questionnaires, was conducted at baseline and at week 4 and months 3 and 6, with an additional study visit at week 2 for subjects randomized to wear contact lenses.

Results: A total of 110 teenagers were enrolled in the study; 13 discontinued before study completion, 10 (17.5%) from the contact lens group and 3 (5.7%) from the spectacle group (p = 0.04). Visual acuity was good for both groups at all study visits. Biomicroscopy assessments were similar at baseline for both groups. Significant differences in Pediatric Refractive Error Profile responses were noted between vision correction groups across visits for appearance (p < 0.001), satisfaction (p < 0.001), activities (p < 0.001), peer perception (p = 0.003), and overall score (p < 0.001). For Quality of Life Impact of Refractive Correction, the contact lens group gave more favorable responses than the spectacle group (p = 0.02). After 6 months of wearing contact lenses, teenagers had a more positive attitude toward comfort, vision, and safety with contact lenses. No serious adverse events were reported during the study.

Conclusions: The daily disposable lenses used in this study are suitable for vision correction for teenagers, offering improvements in QoL measures during the first month of wear, including appearance, satisfaction, activities, and peer perceptions, without negatively impacting vision or eye health. Teenagers were able to handle contact lenses with the same amount of confidence as spectacles.
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January 2015

A multi-country assessment of compliance with daily disposable contact lens wear.

Cont Lens Anterior Eye 2013 Dec 8;36(6):304-12. Epub 2013 Jul 8.

Centre for Contact Lens Research, University of Waterloo, Waterloo, Ontario, Canada. Electronic address:

Purpose: To investigate compliance with daily disposable contact lens (DDCL) wear and investigate re-use of lenses according to country and DDCL material worn.

Methods: Optometrists invited eligible DDCL patients from their practices to participate in a survey on DDCL wear in Australia, Norway, the United Kingdom (UK) and the United States (US). Eligible participants completed an online or paper version of the survey.

Results: 805 participants completed the survey (96% online): Australia 13%, Norway 32%, UK 17%, US 38%. The median age was 38 years; 66% were female. Silicone hydrogel (SiHy) DDCLs were worn by 14%. Overall, 9% were non-compliant with DDCL replacement; Australia 18%, US 12%, UK 7% and Norway 4%. There were no differences with respect to sex, years of contact lens wear experience or DDCL material (SiHy versus hydrogels). The primary reason for re-use was "to save money" (60%). Re-use of DDCLs resulted in inferior comfort at insertion and prior to lens removal (p=0.001). 75% reported occasional napping and 28% reported sleeping overnight for at least one night in the preceding month, while wearing their DDCLs.

Conclusion: Non-compliance with replacement of DDCLs occurred in all countries investigated; the rate was highest in Australia and lowest in Norway. Re-use of DDCLs was associated with reduced comfort. DDCL wearers often reported wearing lenses overnight. It is important for optometrists to counsel their patients on the importance of appropriate lens wear and replacement for DDCLs.
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December 2013