Optometry and Vision Sciences - Research Publications

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    Optical coherence tomography: seeing the unseen
    Bui, B ; Downie, LE ; Lindsay, RG (TAYLOR & FRANCIS LTD, 2019-05-01)
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    Citizen Science Models in Health Research: an Australian Commentary.
    Borda, A ; Gray, K ; Downie, L (University of Illinois Libraries, 2019)
    This qualitative review explores how established citizen science models can inform and support meaningful engagement of public in health research in Australia. In particular, with the growth in participatory health research approaches and increasing consumer participation in contributing to this research through digital technologies, there are gaps in our understanding of best practice in health and biomedical citizen science research to address these paradigm shifts. Notable gaps are how we might more clearly define the parameters of such research and which citizen science models might best support digitally-enabled participation falling within these. Further work in this area is expected to lead to how established citizen science methods may help improve the quality of and the translation of public engagement in health research.
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    Tear film inflammatory cytokine upregulation in contact lens discomfort
    Gad, A ; Vingrys, AJ ; Wong, CY ; Jackson, DC ; Downie, LE (ELSEVIER, 2019-01)
    PURPOSE: To investigate the ocular inflammatory response, using clinical and immunological techniques, in people experiencing contact lens (CL) discomfort. METHODS: This study involved 38 adults who were full-time, silicone-hydrogel CL wearers. Participants were categorized into groups based upon a validated CL dry-eye questionnaire (CLDEQ-8) (n = 17 'asymptomatic', CLDEQ-8 score <9; n = 21 'symptomatic', CLDEQ-8 score ≥13). Examinations were performed at two visits (one with, and one without, CL wear), separated by one-week. Testing included: tear osmolarity, ocular redness, tear stability, ocular surface staining, meibography, tear production and tear collection. Tear osmolarity was taken from the inferior-lateral and superior-lateral menisci. The 'Inferior-Superior Osmotic Difference', I-SOD, was the absolute osmolarity difference between these menisci. Concentrations of seven cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-gamma, TNF-alpha) were assayed from basal tears using multiplex cytometric bead array. RESULTS: At baseline, there was no significant difference in key clinical signs between asymptomatic and symptomatic CL wearers (p > 0.05). The I-SOD was greater in symptomatic than asymptomatic CL wearers (23.1 ± 2.6 versus 11.3 ± 1.4 mOsmol/L, p = 0.001). People experiencing CL discomfort had higher tear IL-17A (122.6 ± 23.7 versus 44.0 ± 10.0 pg/mL, p = 0.02) and reduced tear stability (6.3 ± 1.1 versus 10.4 ± 1.6 s, p = 0.03) after several hours of CL wear. Tear IL-17A levels correlated with both the I-SOD (r = 0.43, p = 0.01) and CLDEQ-8 score (r = 0.40, p = 0.01). CONCLUSIONS: CL discomfort occurs in individuals having no clinical dry eye signs, and is associated with higher tear levels of the pro-inflammatory cytokine IL-17A. These findings support an association between the discomfort response and low-grade, ocular surface inflammation.
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    The effect of blue-light blocking spectacle lenses on visual performance, macular health and the sleep-wake cycle: asystematic review of the literature
    Lawrenson, JG ; Hull, CC ; Downie, LE (WILEY, 2017-11)
    PURPOSE: Blue-blocking (BB) spectacle lenses, which attenuate short-wavelength light, are being marketed to alleviate eyestrain and discomfort when using digital devices, improve sleep quality and potentially confer protection from retinal phototoxicity. The aim of this review was to investigate the relative benefits and potential harms of these lenses. METHODS: We included randomised controlled trials (RCTs), recruiting adults from the general population, which investigated the effect of BB spectacle lenses on visual performance, symptoms of eyestrain or eye fatigue, changes to macular integrity and subjective sleep quality. We searched MEDLINE, EMBASE, the Cochrane Library and clinical trial registers, until 30 April 2017. Risk of bias was assessed using the Cochrane tool. RESULTS: Three studies (with 136 participants) met our inclusion criteria; these had limitations in study design and/or implementation. One study compared the effect of BB lenses with clear lenses on contrast sensitivity (CS) and colour vision (CV) using a pseudo-RCT crossover design; there was no observed difference between lens types (log CS; Mean Difference (MD) = -0.01 [-0.03, 0.01], CV total error score on 100-hue; MD = 1.30 [-7.84, 10.44]). Another study measured critical fusion frequency (CFF), as a proxy for eye fatigue, on wearers of low and high BB lenses, pre- and post- a two-hour computer task. There was no observed difference between low BB and standard lens groups, but there was a less negative change in CFF between the high and low BB groups (MD = 1.81 [0.57, 3.05]). Both studies compared eyestrain symptoms with Likert scales. There was no evidence of inter-group differences for either low BB (MD = 0.00 [-0.22, 0.22]) or high BB lenses (MD = -0.05 [-0.31, 0.21]), nor evidence of a difference in the proportion of participants showing an improvement in symptoms of eyestrain or eye fatigue. One study reported a small improvement in sleep quality in people with self-reported insomnia after wearing high compared to low-BB lenses (MD = 0.80 [0.17, 1.43]) using a 10-point Likert scale. A study involving normal participants found no observed difference in sleep quality. We found no studies investigating effects on macular structure or function. CONCLUSIONS: We find a lack of high quality evidence to support using BB spectacle lenses for the general population to improve visual performance or sleep quality, alleviate eye fatigue or conserve macular health.
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    Omega-3 supplementation is neuroprotective to corneal nerves in dry eye disease: a pilot study
    Chinnery, HR ; Golborne, CN ; Downie, LE (WILEY, 2017-07)
    PURPOSE: To investigate whether oral, long-chain omega-3 (ω-3) essential fatty acid (EFA) supplementation, for 3 months, induces changes to the central corneal sub-basal nerve plexus in dry eye disease and whether nerve alterations correlate with clinical findings. METHODS: This prospective, comparative study involved the final 12 participants enrolled in a randomised, double-masked, placebo-controlled clinical trial of 60 participants with moderate dry eye disease. Participants received either placebo (olive oil 1500 mg/day; n = 4) or ω-3 EFA supplements (~1000 mg/day eicosapentaenoic acid + ~500 mg/day docosahexaenoic acid; n = 8) for 90 days. The main outcome measure was the mean change in central corneal sub-basal plexus nerve parameters between days one and 90, quantified using in vivo confocal microscopy. Secondary outcomes included mean change in tear osmolarity, corneal dendritic cell density and basal epithelial cell density. RESULTS: Compared with baseline, the reduction in OSDI score and tear osmolarity at day 90 were greater in the ω-3 EFA group than the placebo group (OSDI: ω-3 EFA, mean ± SEM: -15.6 ± 2.8 vs placebo: -2.8 ± 4.1 units, t5 = 2.6, p = 0.04; tearosmolarity: ω-3 EFA: -22.63 ± 5.7 vs placebo: -8 ± 2.7 mOsmol/L, t9 = 2.3, p = 0.04). At day 90, corneal total nerve branch density (CTBD: 91.1 ± 8.6 vs 45.1 ± 13.4 branches/mm2 , F1,10 = 14, p = 0.004) and corneal nerve branch density on the main fibre (CNBD: 63.4 ± 6.5 vs 27.9 ± 11.5 branches/mm2 , F1,10 = 6, p = 0.03) were higher in the ω-3 EFA group compared with placebo. Relative to day 1, CNBD (branches/mm2 ) increased at day 90 in the ω-3 EFA group (+20.0 ± 9.2, t8 = 3.2 p = 0.01) compared with placebo (-10.8 ± 3.2). Similar changes were evident for corneal nerve fibre length (CNFL, mm/mm2 ), which increased from baseline at day 90 in the omega-3 EFA group (+2.9 ± 1.6, t8 = 3.4 p = 0.01) compared with placebo (-2.7 ± 0.5). There was a negative correlation between CTBD and tear osmolarity (r10 = -0.70, p = 0.01). No significant changes were observed for basal epithelial cell or corneal dendritic cell density. CONCLUSION: These pilot study findings suggest that ω-3 EFA supplementation imparts neuroprotective effects in the corneal sub-basal plexus that correlate with the extent of tear osmolarity normalisation.
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    A comparison of the self-reported dry eye practices of New Zealand optometrists and ophthalmologists
    Xue, AL ; Downie, LE ; Ormonde, SE ; Craig, JP (WILEY, 2017-03)
    PURPOSE: The aim of this cross-sectional survey was to evaluate the self-reported clinical practices of New Zealand optometrists and ophthalmologists with respect to the diagnosis and management of dry eye disease. It also sought to compare these behaviours with the current research evidence base. METHODS: An anonymous survey was distributed electronically to New Zealand eye care clinicians (optometrists n = 614, ophthalmologists n = 113) to determine practitioner interest in dry eye disease, practice experience, practice modality, preferred diagnostic and management strategies, and information used to guide patient care. RESULTS: Respondents from both professions (response rates, optometrists: 26%, ophthalmologists: 26%) demonstrated similarly strong knowledge of tear film assessment. Ninety percent of respondents ranked patient symptoms and meibomian gland evaluation as the most valuable and common diagnostic approaches. Conversely, standardised grading scales and validated dry eye questionnaires were infrequently adopted. Both professions tailored dry eye management according to severity, indicating eyelid hygiene and non-preserved lubricants as mainstay therapies. Ophthalmologists prescribed systemic tetracyclines significantly more often than optometrists for moderate (48% vs 11%) and severe (72% vs 32%) dry eye (p < 0.05). Continuing education conferences were acknowledged as the primary information source used to guide dry eye management practices by both professions. CONCLUSIONS: Consistent with evidence-based guidelines, New Zealand eye care professionals combine subjective and objective techniques to diagnose and stratify dry eye management according to disease severity. There is potential to improve dissemination of research evidence into clinical practice, with continuing education via professional conferences the favoured mode of delivery.
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    What do patients think about the role of optometrists in providing advice about smoking and nutrition?
    Downie, LE ; Douglass, A ; Guest, D ; Keller, PR (WILEY, 2017-03)
    PURPOSE: Tobacco smoking and nutrition are key lifestyle factors with long-term effects on eye health. However, little is known about patients' perceptions and experiences in these areas in relation to the care received from optometrists. The main aim was to survey patients' perceptions and prior experience regarding the role of optometrists in enquiring and providing advice about tobacco smoking and nutrition. METHODS: An anonymous, paper-based survey was distributed to a convenience sample of 225 adults attending the University of Melbourne eye care clinic. Respondents provided demographic and other information (age, sex, length of time since last eye examination, country of most recent eye examination, smoking status and intake of nutritional supplements) and indicated their level of agreement (using a five-step Likert scale) with a series of statements relating to the care provided by optometrists in the areas of health, smoking and nutrition. The statements were designed to assess the perceived scope of practice of optometrists and the extent to which patients expect, and feel comfortable, discussing these issues with their optometrist. RESULTS: 220 completed surveys were returned. Most respondents (>80%) agreed that they visit their optometrist to quantify their refractive error and to examine their eye health. About two-thirds of respondents indicated that they expect their optometrist to ask about their general health, with almost half expecting their optometrist to communicate with their general medical practitioner. Approximately one-third of respondents indicated having been routinely questioned about their smoking status, diet and nutritional supplement intake by their optometrist. This was despite about half expecting their optometrist to question them about these factors and almost three out of four respondents indicating that they felt comfortable talking with their optometrist about these lifestyle behaviours. CONCLUSIONS: This study provides novel insight into patients' perceptions and experience with optometric practice in the areas of tobacco smoking and nutrition. The majority of respondents expected their optometrist to examine their eye health, ask them about their smoking and diet habits, and indicated feeling comfortable discussing these topics with their primary eye care provider. These findings suggest that brief advice interventions relating to tobacco use and diet are likely to be acceptable to deliver in optometry practice.
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    Comparing self-reported optometric dry eye clinical practices in Australia and the United Kingdom: is there scope for practice improvement?
    Downie, LE ; Rumney, N ; Gad, A ; Keller, PR ; Purslow, C ; Vingrys, AJ (WILEY-BLACKWELL, 2016-03)
    PURPOSE: The aim of this study was to compare the self-reported clinical practice behaviours of optometrists in Australia and the United Kingdom (UK) with respect to the diagnosis and management of dry eye disease (DED). We also sought to examine whether the reported practices of clinicians in each region were consistent with current evidence-based recommendations for DED. METHODS: An online survey was distributed to optometrists (Australia, n = 654; UK, n = 1006). Respondents provided information about practice modality, years of optometric experience, preferred diagnostic and management strategies (stratified by DED severity) and the information/evidence base used to guide patient care. RESULTS: A total of 317 completed surveys were received (response rates, Australia: 21%, UK: 17%). Optometrists in both regions demonstrated similarly strong knowledge of tear film assessment and adopted both subjective and objective techniques to diagnose DED. Patient symptoms were considered the most important, valuable and commonly performed assessment by both Australian and UK respondents. UK practitioners valued and utilised conjunctival signs and tear meniscus height assessments more than Australian optometrists (p < 0.05), who placed relatively greater emphasis on sodium fluorescein tear break-up time to diagnose DED (p < 0.05). Clinicians in both locations tailored DED therapy to severity. While practitioners in both regions predominantly managed mild DED with eyelid hygiene and tear supplementation, Australian optometrists indicated prescribing topical corticosteroid therapy significantly more often than UK practitioners for moderate (14% vs 6%) and severe (52% vs 8%) disease (p < 0.05). The major source of information used to guide practitioners' dry eye management practices was continuing education conferences. CONCLUSIONS: This study highlights a range of parallels and divergences in dry eye clinical practice between Australian and UK optometrists. Our data identify both areas of strength in the adoption of evidence-based practice, as well as some potential to improve international translation of dry eye research evidence into practice.
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    Insights into Australian optometrists' knowledge and attitude towards prescribing blue light-blocking ophthalmic devices
    Singh, S ; Anderson, AJ ; Downie, LE (WILEY, 2019-05)
    PURPOSE: The aim of this cross-sectional study was to survey Australian optometrists regarding their attitudes towards, and knowledge of, blue light-blocking lenses designed to attenuate blue light transmission to the eye. METHODS: A 29-item survey was distributed at a major national optometry education conference and through professional networks. Respondents provided information regarding their demographics and practice modalities, knowledge about the potential effects of blue light, and attitudes towards prescribing blue light-blocking ophthalmic devices. Ordinal logistic regression analysis was performed to assess the factors that predicted optometrists' prescribing of blue light-blocking lenses. RESULTS: Of 372 respondents, 75.3% indicated prescribing blue light-blocking spectacle lenses in their clinical practice. Forty-four per cent of optometrists considered daily environmental exposure to blue light as a potential cause of retinal damage, and approximately half of respondents thought blue light emitted from computer screens was an important factor in causing computer vision syndrome. About half of optometrists considered placebo effects to potentially play a role, at least sometimes, in patients' experiences with blue light-blocking lenses. Most optometrists estimated that they first prescribed a blue light-blocking lens in 2016. The most common reason optometrists prescribed these devices was for patients who were computer or electronic device users (87.9%). The two main sources of information used to guide practitioners' management approaches were conference presentations and manufacturer product information. Practitioners were significantly more likely to prescribe blue light-blocking lenses if they considered blue light to cause either retinal damage (odds ratio, OR 2.28, 95%CI 1.34-3.88, p = 0.002) or computer vision syndrome (OR 2.52, 95%CI 1.41-4.50, p = 0.002) compared with practitioners who did not consider such factors to be relevant. CONCLUSION: Prescribing trends by Australian optometrists in relation to blue light-blocking lenses reflect the inconclusive nature of several aspects of the evidence in this field. Blue light-blocking lens prescribing has increased since 2010, despite practitioners acknowledging the lack of high-quality evidence to support their use and also commonly believing that placebo effects may have a role in patient responses to these lenses. Information from this study will help inform the development of resources to guide evidence-based prescribing of blue light-blocking lens products.
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