Publications by authors named "Katrina L Schmid"

91 Publications

IMI Accommodation and Binocular Vision in Myopia Development and Progression.

Invest Ophthalmol Vis Sci 2021 Apr;62(5)

School of Optometry, Aston University, Birmingham, United Kingdom.

The role of accommodation in myopia development and progression has been debated for decades. More recently, the understanding of the mechanisms involved in accommodation and the consequent alterations in ocular parameters has expanded. This International Myopia Institute white paper reviews the variations in ocular parameters that occur with accommodation and the mechanisms involved in accommodation and myopia development and progression. Convergence is synergistically linked with accommodation and the impact of this on myopia has also been critiqued. Specific topics reviewed included accommodation and myopia, role of spatial frequency, and contrast of the task of objects in the near environment, color cues to accommodation, lag of accommodation, accommodative-convergence ratio, and near phoria status. Aspects of retinal blur from the lag of accommodation, the impact of spatial frequency at near and a short working distance may all be implicated in myopia development and progression. The response of the ciliary body and its links with changes in the choroid remain to be explored. Further research is critical to understanding the factors underlying accommodative and binocular mechanisms for myopia development and its progression and to guide recommendations for targeted interventions to slow myopia progression.
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http://dx.doi.org/10.1167/iovs.62.5.4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8083074PMC
April 2021

Combination Effect of Outdoor Activity and Screen Exposure on Risk of Preschool Myopia: Findings From Longhua Child Cohort Study.

Front Public Health 2021 5;9:607911. Epub 2021 Mar 5.

Department of Medical Statistics and Epidemiology, Guangzhou Key Laboratory of Environmental Pollution and Health Assessment, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, China.

Evidence regarding screen use and outdoor activity during very early childhood (i. e., from aged 1 to 3 years) and their potential combined links to the later preschool myopia is limited. This information is needed to release effective public health messages and propose intervention strategies against preschool myopia. We collected information regarding very early childhood screen use, outdoor activity and the kindergartens vision screenings of 26,611 preschoolers from Longhua Child Cohort Study by questionnaires. Logistic regression models were used to examine the associations between reported outdoor activity, screen use from 1 to 3 years of age, and preschool myopia. Throughout very early childhood, from 1 to 3 years, the proportion of children exposed to screens increased (from 35.8 to 68.4%, < 0.001), whereas the proportion of children who went outdoors ≥7 times/week (67.4-62.1%, < 0.001) and who went outdoors for ≥60 min/time (53.3-38.0%, < 0.001) declined. Exposure to fixed screen devices [adjusted odds ratio (AOR) = 2.66, 95% confidence interval (CI) = 2.09-3.44], mobile screen devices (AOR = 2.76, 95% CI = 2.15-3.58), and limited outdoor activity (AOR = 1.87, 95% CI = 1.42-2.51) during early childhood were associated with preschool myopia. Among children whose parents were myopic, the interactions between outdoor activity and fixed or mobile screen use on later preschool myopia were significant; the ORs and 95% CI were 3.34 (1.19-9.98) and 3.04 (1.06-9.21), respectively. Our findings suggest the possibility that the impact of screen exposure during early childhood on preschool myopia could be diminished by outdoor activity for children whose parents have myopia.
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http://dx.doi.org/10.3389/fpubh.2021.607911DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7973103PMC
May 2021

Ophthalmic Physiol Opt 2021 05 20;41(3):632. Epub 2021 Mar 20.

State University of New York, New York, USA.

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http://dx.doi.org/10.1111/opo.12803DOI Listing
May 2021

A snapshot of optometry teaching in Australia and New Zealand in response to COVID-19.

Clin Exp Optom 2021 Aug 1;104(6):723-727. Epub 2021 Mar 1.

Discipline of Optometry, Faculty of Health, The University of Canberra, Canberra, Australia.

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http://dx.doi.org/10.1080/08164622.2021.1878859DOI Listing
August 2021

Association between greater residential greenness and decreased risk of preschool myopia and astigmatism.

Environ Res 2021 05 6;196:110976. Epub 2021 Mar 6.

Department of Epidemiology, Guangzhou Key Laboratory of Environmental Pollution and Health Assessment, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, 510080, Guangzhou, China; Department of Information Management, Xinhua College of Sun Yat-sen University, 510080, Guangzhou, China. Electronic address:

Objective: Rapid urbanization has led to reduced greenness in many areas, this has been linked to adverse health outcomes. The aim was to determine the association between residential greenness experienced during very early childhood with preschool myopia and astigmatism and to explore the potential mediating role of screen time on any associations.

Method: Information regarding socio-demographic characteristics, home address, screen time during early childhood, and refraction data from vision screenings of 53,575 preschoolers from Longhua Child Cohort Study were collected via questionnaires. Residential greenness was calculated as the average of satellite-derived Normalized Difference Vegetation Index in buffers of 100, 250, and 500 m around each child's home address. Logistic and linear regression models were used to examine the relationships between residential greenness, screen time, and preschool myopia and astigmatism.

Result: The mean (SD) age of the 53,575 preschoolers was 5.0 (0.7) years, and 24,849 (46.4%) were girls. A total of 1236 (2.3%) preschoolers had myopia and 5347 (10.0%) had astigmatism. In the adjusted model, a higher neighborhood greenness level within 100 m buffers around the home address was associated with decreased risk of myopia (adjusted odds ratios (AOR): 0.62, 95% confidence interval (CI): 0.38-0.99), and higher neighborhood greenness levels within 100, 250, and 500 m decreased the risk of astigmatism, and their AORs (95% CIs) were 0.55 (0.43-0.70) for 100 m, 0.59 (0.41-0.83) for 250 m, 0.61 (0.42-0.90) for 500 m, respectively. Greater screen time during early childhood increased the risk of myopia (AOR = 1.33) and astigmatism (AOR = 1.23). Reduction in screen time fully mediated the benefits of greater residential greenness on preschool myopia, but partially mediated that on preschool astigmatism (p < 0.05).

Conclusion: Higher residential greenness reduces the risk of preschool myopia and astigmatism; the benefits of residential greenness were mediated through reduced daily screen time.
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http://dx.doi.org/10.1016/j.envres.2021.110976DOI Listing
May 2021

COVID-19: ensuring safe clinical teaching at university optometry schools.

Ophthalmic Physiol Opt 2021 01 10;41(1):144-156. Epub 2020 Dec 10.

State University of New York (SUNY), College of Optometry, New York, USA.

The COVID-19 pandemic has been spreading across the globe for several months. The nature of the virus (SARS-CoV-2) with easy person-to-person transmissions and the severe clinical course observed in some people necessitated unprecedented modifications of everyday social interactions. These included the temporary suspension of considerable elements of clinical teaching at optometry schools worldwide. This article describes the challenges optometry schools were facing in early to mid 2020. The paper highlights the experiences of six universities in five countries on four continents. Strategies to minimise the risk of virus transmission, to ensure safe clinical optometric teaching and how to overcome the challenges presented by COVID-19 are described. An outlook on opportunities to further improve optometric education is provided.
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http://dx.doi.org/10.1111/opo.12764DOI Listing
January 2021

Comparison of blur and magnification effects on stereopsis: overall and meridional, monocularly- and binocularly-induced.

Ophthalmic Physiol Opt 2020 09 10;40(5):660-668. Epub 2020 Aug 10.

McGill Vision Research Unit, Department of Ophthalmology, McGill University, Montreal, Canada.

Purpose: To determine whether monocularly- and binocularly-induced spherical and meridional blur and aniseikonia had similar effects on stereopsis thresholds.

Methods: Twelve participants with normal binocular vision viewed McGill modified random dot stereograms to determine stereoacuities in a four-alternative forced-choice procedure. Astigmatism was induced by placing trial lenses in front of the eyes. Twenty-three conditions were used, consisting of zero (no lens), +1 D and +2 D spheres and cylinders at axes 180, 45 and 90 in front of the right eye, and the following binocular combinations of both lens powers: R × 180/L × 180, R × 45/L × 45, R × 90/L × 90, R sphere/L sphere, R × 180/L × 90, R × 45/L × 135, R × 90/L × 180. Aniseikonia was induced by placing magnifying lenses in front of the eyes. Twenty-three conditions were used, consisting of zero, 6% and 12% overall magnification and both magnifications at axes 180, 45 and 90 in front of the right eye only, and the following binocular combinations using 3% and 6% lenses: R × 90/L × 90, R × 45/L × 45, R × 180/L × 180, R overall/L overall, R × 90/L × 180, R × 45/L × 135, and R × 180/L × 90.

Results: Stereopsis losses for binocular blur effects with parallel axes (non-anisometropic) were the same as for monocular blur effects of the same axes, and these were strongly dependent on axis (spherical blur and ×90 had the greatest effects). Binocular blur effects with orthogonal axes had greater effects than with parallel axes, with the axis combination of the former having no effect (e.g. R × 90/L × 180 was similar to R × 45/L × 135). For induced aniseikonia, splitting the magnifications between the eyes improved stereopsis slightly, and the effects were not dependent on axis.

Conclusion: Binocular blur affects stereopsis similarly to monocular meridional blur if axes in the two eyes are parallel, whereas the effect is greater if the axes are orthogonal. In meridional aniseikonia, splitting magnification between the right and left lenses produces a small improvement in stereopsis that is independent of axis direction and right/left combination.
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http://dx.doi.org/10.1111/opo.12724DOI Listing
September 2020

Suppression Rather Than Visual Acuity Loss Limits Stereoacuity in Amblyopia.

Invest Ophthalmol Vis Sci 2020 06;61(6):50

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Purpose: To investigate the influence of interocular suppression and visual acuity loss on stereoacuity in observers with and without abnormal vision development from strabismus or amblyopia. To determine whether stereoacuity improves in amblyopic observers when suppression is neutralized.

Methods: Experiment 1: Visual acuity (VA), depth of suppression (contrast ratio [CR]), and stereoacuity (digital random-dot) were tested in adult amblyopic observers (n = 21; age 27 ± 11 years). Experiment 2: VA, stereoacuity, and CR were measured at baseline and through a series of monocular contrast attenuation and Bangerter filter conditions that degrade visual input in participants with normal binocular vision (n = 19; age 31 ± 13 years). Multiple regression models were used to determine relative contribution of VA and CR to stereoacuity in both groups. Experiment 3: stereoacuity was retested in a subsample of amblyopic observers (n = 7) after contrast reduction of the stimulus presented to dominant eye to neutralize suppression.

Results: In amblyopic observers, stereoacuity significantly correlated with CR (P < 0.001), but not with interocular VA difference (P = 0.863). In participants with normal vision development, stereoacuity, VA, and CR declined with introduction of monocular Bangerter filter (P < 0.001), and stereoacuity reduced with monocular attenuation of stimulus contrast (P < 0.001). Reduction in stereoacuity correlated with both VA decrement and degraded CR. Stereoacuity significantly improved in amblyopic observers when the contrast to the dominant eye was adjusted based on the contrast ratio.

Conclusions: Suppression rather than visual acuity loss limits stereoacuity in observers with abnormal vision development. Stereopsis can be improved when interocular sensory dominance is neutralized.
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http://dx.doi.org/10.1167/iovs.61.6.50DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7419721PMC
June 2020

Fluoroquinolones are a potent form of chemotherapy.

Authors:
Katrina L Schmid

Clin Exp Optom 2021 Apr 15;104(3):412-416. Epub 2021 Mar 15.

School of Optometry and Vision Science, Faculty of Health, Queensland University of Technology, Brisbane, Australia.

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http://dx.doi.org/10.1111/cxo.13102DOI Listing
April 2021

Development of Feasible Methods to Image the Eyelid Margin Using In Vivo Confocal Microscopy.

Cornea 2020 Oct;39(10):1325-1333

Institute of Health and Biomedical Innovation, School of Optometry and Vision Science, Faculty of Health, Queensland University of Technology, Kelvin Grove, Australia.

Purpose: To develop a feasible method to image eyelid margin structures using in vivo confocal microscopy (IVCM) for use in clinical research. Second, to assess the association between IVCM and meibography images.

Methods: IVCM was performed on the central upper eyelid margin of 13 healthy participants (31 ± 5 years). Overall morphology montages (1600 × 1600 μm) were created of 3 participants. Single frames (400 × 400 μm) of 10 participants were imaged to determine the feasibility of measuring eyelid features. Meibography was performed with EASYTEARview+ in the same 10 participants. ImageJ software was used to quantify image structures.

Results: In the montages, structures of rete ridges, meibomian gland openings, and the lid wiper region were observed. The maximum possible montage size, using multiple single frames, was approximately 5200 × 1500 × 150 μm in the X, Y, and Z directions, respectively. The mean number, density, area, perimeter, and shortest and longest diameters of rete ridges of the 9 nonoverlapped frames were 12 ± 2/frame, 73 ± 5/mm, 2504 ± 403 μm, 250 ± 33 μm, 40 ± 6 μm, and 84 ± 13 μm, respectively. Sampling analysis determined at least 5 nonoverlapped frames were necessary to accurately represent the parameters of the ridges. The mean areas of 3 meibomian openings were 785 ± 784 μm, 1036 ± 963 μm, 950 ± 1071 μm, 848 ± 954 μm, 737 ± 831 μm, 735 ± 743 μm, and from 30 μm to 130 μm at 20-μm depth intervals, respectively. No significant association between IVCM and meibography parameters (P = 0.53) was found.

Conclusions: Imaging rete ridges with IVCM should include at least 5 nonoverlapping single frames in the upper eyelid margin. At least 3 openings imaged between 30 and 130 μm at 20-μm depth intervals are recommended to determine the opening area.
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http://dx.doi.org/10.1097/ICO.0000000000002347DOI Listing
October 2020

Screen Exposure during Early Life and the Increased Risk of Astigmatism among Preschool Children: Findings from Longhua Child Cohort Study.

Int J Environ Res Public Health 2020 03 26;17(7). Epub 2020 Mar 26.

Department of Medical Statistics and Epidemiology, Guangzhou Key Laboratory of Environmental Pollution and Health Assessment, Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.

Screen media usage has become increasingly prevalent in daily life with children being exposed to screens at an early age. This is a growing public health concern with evidence linking screen exposure to detrimental health outcomes, whereas relationship between screen exposure and the presence of astigmatism among preschoolers remains unknown, thus we aimed to resolve this issue. During the 2017 survey of the Longhua Child Cohort Study, data of 29,595 preschoolers were collected via a caregiver-reported questionnaire regarding socio-demographics, screen exposure and refraction. Cox regression models were adopted to generate adjusted prevalence ratios (APR) and 95% confidence intervals (CI) to estimate the association between early screen exposure and astigmatism. 28,029 preschoolers were included in the final analysis. After adjustment for potential confounders, screen exposure during early life was significantly associated with the increased risk of astigmatism (APR and 95% CI: 2.25, 1.76-2.88), and the greatest risk was observed in the period from birth to 1-year (APR and 95% CI: 3.10, 2.41-3.98). The risk of astigmatism increased with both the total years of exposure and the average daily duration of screen exposure. Our findings suggested that preschoolers who were exposed to screens during early life might have an increased risk of astigmatism.
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http://dx.doi.org/10.3390/ijerph17072216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7177845PMC
March 2020

Central corneal basal cell density and nerve parameters in ocular surface disease and limbal stem cell deficiency: a review and meta-analysis.

Br J Ophthalmol 2020 12 5;104(12):1633-1639. Epub 2020 Mar 5.

School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.

Objective: To conduct a review and meta-analysis for investigating the relative reduction of central corneal basal cell density (BCD) and nerve parameters in ocular surface disease (OSD) and limbal stem cell deficiency (LSCD).

Methods: A systematic literature search using the terms ((1) "ocular surface disease" or "ocular surface disorder"; (2) "in vivo confocal microscopy"; (3) "limbal stem cell deficiency"; (4) "basal cell density" or "corneal basal cell density" or "central corneal basal cell density"; (5) "corneal nerves" or "corneal nerve parameters" or "central corneal nerve parameters") was performed. The results are presented as weighted mean difference (WMD) with corresponding 95% CI.

Results: 16 studies that reported the central corneal BCD and 21 studies that reported the central corneal nerve parameters in OSD (including LSCD) were included. A significant reduction in central corneal BCD was observed in patients with various OSDs (WMD=-9.50, 95% CI -14.04 to -4.97, p<0.01) as well as in patients with LSCD (WMD=-22.14, 95% CI -37.91 to -6.37, p<0.01) compared with healthy controls, however, no significant difference in BCD was observed between the two groups (WMD=-11.61, 95% CI -15.96 to -7.26, p=0.13). There was no conclusive difference in various central corneal nerve parameters between OSDs and LSCD.

Conclusion: Central corneal BCD and nerve parameters are reduced in LSCD, there is a similar reduction in other OSDs.
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http://dx.doi.org/10.1136/bjophthalmol-2019-315231DOI Listing
December 2020

Effects of simulated anisometropia and aniseikonia on stereopsis.

Ophthalmic Physiol Opt 2020 05 3;40(3):323-332. Epub 2020 Mar 3.

School of Optometry & Vision Sciences and Institute of Health & Biomedical Innovation, Queensland University of Technology, Queensland, Australia.

Purpose: Stereopsis depends on horizontally disparate retinal images but otherwise concordance between eyes. Here we investigate the effect of spherical and meridional simulated anisometropia and aniseikonia on stereopsis thresholds. The aims were to determine effects of meridian, magnitude and the relative effects of the two conditions.

Methods: Ten participants with normal binocular vision viewed McGill modified random dot stereograms through synchronised shutter glasses. Stereoacuities were determined using a four-alternative forced-choice procedure. To induce anisometropia, trial lenses of varying power and axes were placed in front of right eyes. Seventeen combinations were used: zero (no lens) and both positive and negative, 1 and 2 D powers, at 45, 90 and 180 axes; spherical lenses were also tested. To induce aniseikonia 17 magnification power and axis combinations were used. This included zero (no lens), and 3%, 6%, 9% and 12% at axes 45, 90 and 180; overall magnifications were also tested.

Results: For induced anisometropia, stereopsis loss increased as cylindrical axis rotated from 180° to 90°, at which the loss was similar to that for spherical blur. For example, for 2 D meridional anisometropia threshold increased from 1.53 log sec arc (i.e. 34 sec arc) for x 180 to 1.89 log sec arc (78 sec arc) for x 90. Anisometropia induced with either positive or negative lenses had similar detrimental effects on stereopsis. Unlike anisometropia, the stereopsis loss with induced meridional aniseikonia was not affected by axis and was about 64% of that for overall aniseikonia of the same amount. Approximately, each 1 D of induced anisometropia had the same effect on threshold as did each 6% of induced aniseikonia.

Conclusion: The axes of meridional anisometropia but not aniseikonia affected stereopsis. This suggests differences in the way that monocular blur (anisometropia) and interocular shape differences (aniseikonia) are processed during the production of stereopsis.
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http://dx.doi.org/10.1111/opo.12680DOI Listing
May 2020

Associations Between Screen Exposure in Early Life and Myopia amongst Chinese Preschoolers.

Int J Environ Res Public Health 2020 02 7;17(3). Epub 2020 Feb 7.

Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.

This study aimed to explore the association between screen exposure in early life and preschool myopia. During the baseline survey of the Longhua Child Cohort Study (LCCS), data of 29,595 preschoolers were collected via a caregiver-reported questionnaire regarding children's socio-demographic characteristics, visual status, screen exposure and relevant parental information. Data of 26,433 preschoolers with normal eyesight or myopia were included in the analysis and cox regression modelling was employed to assess the associations. Results suggested the hypothesis that screen exposure in early life could be significantly and positively associated with preschool myopia, and in agreement with this hypothesis was the association being strengthened with the increasing daily exposure duration and total years of exposure; in the stratification analysis based on the presence of parental myopia, these associations still existed, and the strength of associations was stronger in preschoolers with myopic parents than those without. Moreover, a statistically significant association was only observed between initial screen exposure that occurred during 0-1-years old and myopia for preschoolers without myopic parents, while the significant associations were observed between initial screen exposure that occurred during 0-1, 1-2, 2-3, and after 3 years old and myopia for preschoolers who had myopic parents, with the strongest association found in the group of children initially exposed to electronic screens during 0-1 year old. Thus our findings indicated the hypothesis that screen exposure in early life might be associated with the occurrence of preschool myopia, and that the postnatal first year might be the sensitive period for the association. However, it is premature to conclude that early screen time leads to myopia with current data. Further longitudinal studies performed with cycloplegia are necessary to verify the hypothesis and shed light on the more urgent question whether early screen exposure contributes to the later myopia epidemic of school-aged children.
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http://dx.doi.org/10.3390/ijerph17031056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7037286PMC
February 2020

Associations between the menstrual cycle, lifestyle factors and clinical assessment of the ocular surface: a prospective observational study.

BMC Womens Health 2020 02 7;20(1):23. Epub 2020 Feb 7.

Institute of Health and Biomedical Innovation, School of Optometry and Vision Science, Queensland University of Technology, Room Q-504, Level 5, Kelvin Grove, Queensland, 4059, Australia.

Background: Little is known about the ocular surface changes over the menstrual cycle in young women and the interactions with lifestyle factors. Therefore, the purpose of this study was to explore the associations between modifiable lifestyle factors and menstrual cycle phases on the ocular signs and symptoms of dry eye in young healthy women.

Methods: This was a prospective 1-month observational study. Thirty young healthy women with regular, 24 to 32-day menstrual cycles were recruited. Participants attended three visits at day 7, 14, and 21 (± 1) of their menstrual cycle. At baseline, general health questionnaire was conducted. At each visit, symptomology was quantified using Ocular Surface Disease Index (OSDI) and overall ocular comfort (OOC, visual analogue scale). Ocular signs were assessed using Efron scales, tear break-up time (TBUT) and phenol red thread (PRT). Pearson's correlation was used to determine associations between variables at each visit.

Results: A total of 26 participants (mean age = 22.3 ± 3.7 years) with an average menstrual cycle of 28.3 ± 1.3 days completed the 3 visits. The interaction between signs/symptoms and lifestyle factors changed over the cycle. At the follicular phase (day 7), lifestyle factors such diet and levels of stress were correlated with PRT and OSDI, (r = - 0.4, p = 0.022; r = 0.4, p = 0.045 respectively). At the ovulation phase (day 14), the general health score was correlated with OOC scores (r = 0.4, p = 0.047). At day 14, exercise frequency correlated with PRT (r = - 0.4, p = 0.028) and caffeine intake was positively correlate with both; TBUT (r = 0.5, p = 0.020) and PRT (r = 0.5, p = 0.014). At the luteal phase (day 21), we found no correlations between lifestyle factors and dry eye signs or symptoms.

Conclusions: The associations between lifestyle factors and objective and subjective ocular surface assessment appeared to be more pronounced during the ovulation phase of the menstrual cycle compared to the follicular and luteal phases. Misalignment of these factors with the ocular health during the luteal phase could be attributed to central sensitization and changes in levels of luteinising hormone. Natural hormonal changes during menstrual cycle should be considered for diagnosis and treatment of dry eye in young healthy women.
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http://dx.doi.org/10.1186/s12905-020-0894-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7006113PMC
February 2020

Stability of peripheral refraction changes in orthokeratology for myopia.

Cont Lens Anterior Eye 2020 02 30;43(1):44-53. Epub 2019 Nov 30.

School of Optometry and Vision Science, and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove QLD 4059 Australia.

Purpose: Orthokeratology (OK) is known to alter relative peripheral refraction (RPR) with this presumed to be its key myopia control mechanism. A prospective, longitudinal study was performed to examine stability of OK-induced RPR changes in myopic children and young adults.

Methods: RPR of twelve children (C)(8-16 years) and eight adults (A)(18-29 years) with spherical equivalent refraction of -0.75 to -5.00D were measured unaided and while wearing single vision soft contact lenses (SCL). Measurements were repeated after 1, 6 and 12 months of OK wear. RPR was measured using an open-field Shin Nippon SRW-5000 autorefractor at 10, 20 and 30 degrees nasally (N) and temporally (T), converted into power vectors M, J0 and J45. On-axis refractions and axial lengths (IOL Master) were also measured.

Results: Compared to the unaided state, 1-month of OK wear shifted the RPR in the myopic direction at 30 T (C: p = 0.023; A:, p = 0.002) and 30 N (C&A, p = 0.003) and was stable thereafter, with similar changes compared to SCL wear. J0 showed a myopic shift in comparison to both unaided and SCL correction in children but not adults, and J45 did not change in either group. The on-axis OK correction was predictive of the RPR shift in both children and adults at 30 T (C: r=-0.58, p = 0.029; A: r=-0.92, p < 0.001) and 30 N (C: r=-0.60, p = 0.024; A: r=-0.74, p = 0.013) with symmetry of RPR shifts (C: r = 0.67, p = 0.008; A: r = 0.85, p = 0.004). No relationships between changes in RPR and axial length were found after twelve months of OK wear; level of myopia was stable in both groups.

Conclusion: Relative to both unaided and single vision SCL correction, OK shifted the RPR in the myopic direction; the RPR was stable from 1 to 12 months. The RPR shift in OK wear varied with the degree of myopia but was not correlated with myopia progression.
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http://dx.doi.org/10.1016/j.clae.2019.11.008DOI Listing
February 2020

Associations between Environmental Tobacco Smoke Exposure in Early Life and Astigmatism among Chinese Preschool Children.

Int J Environ Res Public Health 2019 10 3;16(19). Epub 2019 Oct 3.

Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.

This study aimed to investigate the association between environmental exposure to tobacco smoke (ETS) during early life and astigmatism in Chinese preschool children. In this cross-sectional study, information concerning prenatal and postnatal ETS exposure at three stages of early life (during pregnancy, from birth to one year and from one to three years), visual problems of children and parents (including a confirmed diagnosis of astigmatism), socio-demographics and perinatal characteristics were obtained from 27,890 parent-reported questionnaires. Logistic regression analyses were undertaken to yield adjusted odds ratios (OR) for assessing their associations. After adjusting for the potential confounders, children were more likely to exhibit astigmatism when they were exposed to ETS during pregnancy + from one to three years [OR (95% CI) = 1.37 (1.02, 1.84)], or from birth to one year + from one to three years [OR (95% CI) = 1.36 (1.11, 1.66)], or during pregnancy + from birth to one year + from one to three years old [OR (95% CI) = 1.29 (1.16, 1.45)], compared to children without ETS exposure at any stage of early life. In Chinese preschool children, prenatal and postnatal astigmatism was associated with ETS exposure; the greater the ETS dose, the greater the astigmatism risk.
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http://dx.doi.org/10.3390/ijerph16193725DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6801470PMC
October 2019

Multifocal spectacles in childhood myopia: Are treatment effects maintained? A systematic review and meta-analysis.

Surv Ophthalmol 2020 Mar - Apr;65(2):239-249. Epub 2019 Oct 14.

School of Optometry and Vision Sciences and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, QLD, Australia.

We evaluate the impact of duration on the treatment effect of multifocal spectacle lenses used to inhibit myopia progression in children. A systematic literature search identified randomized controlled trials where multifocal lenses were prescribed as the intervention, with single-vision lenses as the control. Nine randomized control trials involving 1,701 children aged 8-13 years were included in the meta-analysis. Treatment effects, that is, differences in spherical equivalent refraction between intervention and nonintervention groups, were analyzed over both 6- and 12-month intervals. As treatment duration increased, effectiveness reduced. In 6-month intervals, treatment effects were 0.07 D (95 % CI 0.02, 0.13), 0.03 D (95% CI -0.02, 0.08), and 0.02 D (95% CI -0.05, 0.11) for baseline to 6, 6-12, and 12-18 months, respectively. For 12-month intervals, treatment effects were 0.21 D (95% CI 0.12, 0.29), 0.11 D (95% CI 0.03, 0.19), and 0.12 D (95% CI -0.01, 0.25) for baseline to 12, 12-24, and 24-36 months, respectively. Even during the second 6 months of wear, the ability of multifocal spectacle lenses to inhibit myopia progression was reduced. It is not appropriate to extrapolate the treatment effect observed in the first 6 months or 12 months to estimate the likely future benefit of treatment.
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http://dx.doi.org/10.1016/j.survophthal.2019.10.001DOI Listing
March 2021

Effects of eye rotation and contact lens decentration on horizontal peripheral refraction.

Ophthalmic Physiol Opt 2019 09 3;39(5):370-377. Epub 2019 Sep 3.

Institute of Health & Biomedical Innovation and School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Australia.

Purpose: Peripheral refraction is important in design of myopia control therapies. The aim was to investigate the influence of contact lens decentration associated with eye rotation on peripheral refraction in the horizontal visual field.

Methods: Participants were 10 emmetropes and 10 myopes in good general and ocular health. Right eyes underwent cycloplegic peripheral refraction, using a Grand-Seiko WAM-5500 Autorefractor, in 5° steps to ±35° eccentricities along the horizontal visual field. Targets were fixated using eye rotation only or head rotation only. Refractions were measured without correction and with three types of contact lenses: single vision, a multifocal centre-distance aspheric with +2.50 D add and NaturalVue aspheric. Photographs of eyes during lens wear were taken for each eye rotation. Effects of visual field angle, lens type and test method (head or eye rotation) on vector components of relative peripheral refraction were evaluated using repeated measures anovas. Test method for each visual field angle/lens combination were compared via paired t-tests.

Results: Horizontal decentration ranges across the visual field were 1.2 ± 0.6 mm for single vision and 1.2 ± 0.4 mm for multifocal lenses but smaller at 0.7 ± 0.4 mm for NaturalVue lenses. There were only two significant effects of test method across the visual field angle/lens type combinations (single vision: for emmetropes horizontal/vertical astigmatism component at 35° nasal with mean difference -0.38 D and for myopes spherical equivalent refraction at 20° temporal with mean difference +0.24 D).

Conclusion: Upon eye rotation the contact lenses decentred on the eye, but not enough to affect peripheral refraction. For the types assessed and for the horizontal visual field out to ±35° when measurements were performed with the Grand-Seiko WAM-5500 autorefractor, it is valid to use eye rotations to investigate peripheral refraction.
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http://dx.doi.org/10.1111/opo.12641DOI Listing
September 2019

Involving patients in the development of interpersonal skills of optometry students.

Clin Exp Optom 2020 05 15;103(3):361-367. Epub 2019 Jul 15.

School of Optometry and Vision Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.

Background: Providing patients an opportunity to give feedback to optometry students on their communication and interpersonal skills allows for a unique learning opportunity. The aim of the current project was to determine if the Doctors' Interpersonal Skills Questionnaire (DISQ) was suitable for use with optometry students in a large teaching clinic and if it provided useful feedback to the students for learning purposes.

Methods: The DISQ is a 12-item questionnaire that utilises a five-point Likert scale; a higher score indicates better performance. The DISQ was modified for an optometry context and developed into an online questionnaire. Patients were invited to complete the survey following their consultation with a final year student. Patients provided feedback on the interpersonal skills of the student optometrist who conducted the consultation under supervision. Students were provided with both individual and collated feedback obtained for the entire student group; strategies for improving communication were discussed. This activity did not form part of the grades of the students.

Results: Patients were very satisfied with the interpersonal skills of final year optometry students. Highest scores were given for questions relating to the warmth of greeting, respect shown and time given. Lowest scores were for questions relating to explanations, reassurance and confidence. There was a significant improvement in the communication and interpersonal skills of students following the provision of patient feedback and strategies for improving these skills, and an additional period of clinical experience.

Conclusion: Patients can provide feedback on the interpersonal skills of optometry students using the DISQ. This feedback results in further skill development for students and makes patients feel valued within the teaching clinic environment. This activity assisted in ensuring that graduating optometrists have the interpersonal skills required to communicate clearly and effectively with patients, a requirement for practising with a patient-centred focus.
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http://dx.doi.org/10.1111/cxo.12939DOI Listing
May 2020

The Effect of Vertically Yoked Prisms on Binocular Vision and Accommodation.

Optom Vis Sci 2019 06;96(6):414-423

Carl Zeiss Vision Australia Holdings Limited, ZEISS Group, Tonsley, South Australia, Australia

Significance: Vertically yoked prisms have been used in treatment of binocular vision dysfunction despite minimal supporting evidence. In people with normal binocular vision, the impact on phorias has been assessed but not the impact on accommodation, accommodation vergence interactions, or the horopter. We found that vertically yoked prisms have minor effects during short-term wear in young adults.

Purpose: The purpose of this study was to determine effects of vertically yoked prisms on accommodative response and several binocular vision tasks.

Methods: There were 45 participants aged 18 to 24 years. The 23 myopes wore distance-corrected soft contact lenses. In a random arrangement, each person wore spectacles containing planopower lenses with either 8 Δ base-up, 4 Δ base-up, zero, 4 Δ base-down, and 8 Δ base-down prisms. Before spectacle wear, baseline measurements of near heterophoria, accommodation response, negative and positive relative accommodations, fusional vergence, and Nonius-horopter spatial perception were taken. Measurements were repeated after a 40-minute wear, spectacles were removed, and tests were performed 20 minutes later. On a 22-participant subset, on a separate occasion, measurements of heterophoria, accommodation response, and relative accommodation were made immediately after spectacles were fitted.

Results: Most changes relative to baseline were not significant. Where effects occurred, these were nearly all associated with prism presence rather than adaptation. There were significant effects on accommodation response, but these seem to be refraction effects produced by pantoscopic tilt-induced power changes rather than perceptual effects altering accommodation. There were statistically significant effects on negative relative accommodation (P < .01), with zero prism giving more negative relative accommodation than 8 Δ base-down prisms. Tendencies were noted for prisms to move horopter limits toward the observer. Effects were small and likely not of clinical relevance.

Conclusions: Vertically yoked prisms have minor effects on accommodation and binocular vision, at least during short-term wear in young adults with normal binocular vision.
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http://dx.doi.org/10.1097/OPX.0000000000001388DOI Listing
June 2019

Zone of Clear Single Binocular Vision in Myopic Orthokeratology.

Eye Contact Lens 2020 Mar;46(2):82-90

School of Optometry and Vision Science (K.G., P.L.H., K.L.S.), Faculty of Health, Institute of Health and Biomedical Innovation, Queensland University of Technology, Queensland, Australia; and School of Optometry and Vision Science (P.G.), Faculty of Science, University of New South Wales, New South Wales, Australia.

Purpose: To examine the zone of clear single binocular vision (ZCSBV) in myopic children and young adults after 12 months of orthokeratology (OK) wear, in comparison with single-vision soft contact lens (SCL) wear.

Methods: Twelve children (8-16 years) and 8 adults (18-29 years) were assessed with a series of near-point binocular vision tests when myopia was corrected using single-vision SCLs and again after 1 and 12 months of OK wear, and axial length was measured. The ZCSBV was constructed for baseline SCL wear and after 12 months of OK wear.

Results: After 1 month of OK wear, increased accommodative responses were noted in children (C) and adults (A) as increased binocular amplitude (C:P=0.03, A:P=0.04) and reduced accommodative lag (C:P=0.01, A:P=0.01). Divergence reserves improved after 1 month in both groups (P<0.04), and a near exophoric shift was evident at 12 months (C:P=0.01, A:P=0.04). All changes at 1 month maintained stability at 12 months. An increase in accommodation and vergence responses without reduction in range resulted in an expansion of the ZCSBV in both age groups. Axial length did not significantly change in either children (P=0.25) or adults (P=0.72).

Conclusion: In both pediatric and young adult myopes, the ZCSBV expands toward a more divergent, increased accommodation response in OK compared with SCL wear. This occurs without a corresponding loss of convergence or accommodation deactivation, indicating improved depth of focus. These findings are relevant to visual acceptance and possible mechanisms of OK's efficacy for myopia control.
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http://dx.doi.org/10.1097/ICL.0000000000000614DOI Listing
March 2020

IMI - Industry Guidelines and Ethical Considerations for Myopia Control Report.

Invest Ophthalmol Vis Sci 2019 02;60(3):M161-M183

Brien Holden Vision Institute, and School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.

Purpose: To discuss guidelines and ethical considerations associated with the development and prescription of treatments intended for myopia control (MC).

Methods: Critical review of published papers and guidance documents was undertaken, with a view to carefully considering the ethical standards associated with the investigation, development, registration, marketing, prescription, and use of MC treatments.

Results: The roles and responsibilities of regulatory bodies, manufacturers, academics, eye care practitioners, and patients in the use of MC treatments are explored. Particular attention is given to the ethical considerations for deciding whether to implement a MC strategy and how to implement this within a clinical trial or practice setting. Finally, the responsibilities in marketing, support, and education required to transfer required knowledge and skills to eye care practitioners and academics are discussed.

Conclusions: Undertaking MC treatment in minors creates an ethical challenge for a wide variety of stakeholders. Regulatory bodies, manufacturers, academics, and clinicians all share an ethical responsibility to ensure that the products used for MC are safe and efficacious and that patients understand the benefits and potential risks of such products. This International Myopia Institute report highlights these ethical challenges and provides stakeholders with recommendations and guidelines in the development, financial support, prescribing, and advertising of such treatments.
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http://dx.doi.org/10.1167/iovs.18-25963DOI Listing
February 2019

Experimental Study of Refraction Effects of Nominally Plano Ophthalmic Prisms and Magnifying Lenses.

Optom Vis Sci 2019 02;96(2):111-116

School of Optometry and Vision Sciences and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Kelvin Grove, Queensland, Australia

Significance: Nominally plano ophthalmic prisms give autorefraction results similar to those predicted on the basis of how effective powers change with pantoscopic tilt, and magnifying lenses give autorefraction results similar to those predicted on the basis of vergence changes. Without appreciation of the optics involved, these effects might wrongly be considered artifacts.

Purpose: The purpose of this study was to investigate the interactions of autorefractors with lenses and prisms.

Methods: There were 15 adult participants across three experiments, with a range of ages and refractions. In experiments 1 and 2, participants wore frames containing base-up and base-down nominally plano prisms. In experiment 3, participants wore a lens that produced either 6.3% magnification or 5.9% minification, depending on which surface faced the eye. Autorefracting instruments with different operating principles were used: Shin-Nippon SRW5000 autorefractor, Grand Seiko 5100K autorefractor, Hoya AR-530 autorefractor, a Complete Ophthalmic Analysis System-High Definition wavefront sensor, and Tomey FC-800 autorefractor. A theory on the likely effects of magnifying lenses was presented.

Results: For ophthalmic prisms, refractions showed results similar to those predicted on the basis of how effective prism powers change with pantoscopic tilt. As tilt increased, base-up prism gave more positive mean refractions and more negative horizontal/vertical astigmatism and vice versa for base-down prisms. In the presence of 10° tilt, 8Δ base-up prisms and 8Δ base-down prisms had different effects by a mean of 0.36 diopters. Magnifying lenses affected refractions similar to those predicted on the basis of vergence changes, with 6% magnification and minification producing mean changes of -11 and +8%, respectively, in absolute mean refraction. There was no strong evidence that different instruments had different effects.

Conclusions: The results have implications for studies in which prisms and lenses are placed in the front eyes, such as accommodation studies using thick lenses close to the eyes to stimulate accommodation rather than by changing object distance.
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http://dx.doi.org/10.1097/OPX.0000000000001334DOI Listing
February 2019

Treatment of contact lens related dry eye with antibacterial honey.

Cont Lens Anterior Eye 2017 Dec 9;40(6):389-393. Epub 2017 Oct 9.

School of Optometry and Vision Science and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Qld, 4059, Australia. Electronic address:

Aim: Contact lens induced dry eye affects approximately 50% of contact lens wearers. The aim was to assess the effects of Manuka (Leptospermum sp.) honey eye drops (Optimel, Melcare, Australia) on dry eye in contact lens wearers. The safety of the honey eye drops in contact lens wear and contact lens wearers' compliance were also evaluated.

Design: Prospective, randomised, cross over study, examiner masked, pilot treatment trial.

Methods: Twenty-four participants aged 20 to 55 years with contact lens related dry eye were recruited and randomised to two treatment groups; 20 completed the study. One group used Optimel eye drops twice a day for two weeks followed by conventional lubricant (Systane Ultra, Alcon) therapy for two weeks; the other group completed the treatments in the reverse order. Before and after each treatment dry eye symptomology, ocular surface inflammation, and tear quantity and quality were assessed. Participants completed a daily log detailing their usage of treatments and any issues.

Results: Dry eye symptoms improved significantly after Optimel treatment. Patients with more severe symptoms at baseline showed a greater improvement in symptoms. No significant differences were observed in the objective signs of dry eye; presumably because of the short treatment duration. Seventy-five% of contact lens wearers reported good adherence to Optimel treatment and 95% reported no issues using this product.

Conclusions: Optimel Eye Drops reduce the symptoms of dry eye in contact lens wearers and are safe to use. A longer treatment period to assess the effect on clinical signs of dry eye is required.
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http://dx.doi.org/10.1016/j.clae.2017.10.001DOI Listing
December 2017

Impact of oral vitamin D supplementation on the ocular surface in people with dry eye and/or low serum vitamin D.

Cont Lens Anterior Eye 2018 02 12;41(1):69-76. Epub 2017 Sep 12.

School of Optometry and Vision Science, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia; Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia; Queensland Eye Institute, Brisbane, Queensland, Australia. Electronic address:

Purpose: To determine the possible association between serum vitamin D levels and dry eye symptoms, and the impact of an oral vitamin D supplement.

Methods: Three linked studies were performed. (i) 29 older adult participants, (ii) 29 dry eyed participants, and (iii) 2-month vitamin D supplementation for 32 dry eyed/low serum vitamin D levelled participants. All participants were assessed by the Ocular Surface Diseases Index (OSDI) to determine dry eye symptoms, and the phenol red thread test (PRT) and/or Schirmer's tear test, tear meniscus height, non-invasive tear break up time, grading ocular surface redness and fluorescein staining of the cornea to detect the tear quality and ocular surface conditions. Blood samples were collected for serum vitamin D analysis and interleukin-6 (IL-6) levels.

Results: Among older adult participants, vitamin D levels were negatively correlated with dry eye symptoms, the severity of dry eye, and associated with tired eye symptom. Vitamin D levels of people with dry eye diagnosis were not correlated with OSDI scores and IL-6 levels; while IL-6 levels showed correlation with tear production. In supplement study, vitamin D levels increased by 29mol/l, while dry eye symptoms and grading of corneal staining appeared significant reductions. No significant changes in IL-6 levels.

Conclusions: Low vitamin D levels (<50nmol/l) were associated with dry eye symptoms in older individuals but not those diagnosed with dry eye. Vitamin D supplement increased the vitamin D levels, and improved dry eye symptoms, the tear quality and ocular surface conditions.
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http://dx.doi.org/10.1016/j.clae.2017.09.007DOI Listing
February 2018

Three-dimensional MRI study of the relationship between eye dimensions, retinal shape and myopia.

Biomed Opt Express 2017 May 5;8(5):2386-2395. Epub 2017 Apr 5.

Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, 4059 Australia.

We investigated changes in eye dimensions and retinal shape with degree of myopia, gender and race. There were 58 young adult emmetropes and myopes (range -1.25D to -8.25D), with 30 East-Asians (21 female/9 male), 23 Caucasians (16/7) and 5 South-Asians (1/4). Three-dimensional magnetic resonance imaging was undertaken with a 3.0 Tesla whole-body clinical MRI system using a 4.0 cm receive-only surface coil positioned over the eye. Automated methods determined eye length, width and height, and curve fitting procedures determined asymmetric and symmetric ellipsoid shapes to 75%, 55% and 35% of the retina. With myopia increase, eye dimensions increased in all directions such that increase in length was considerably greater than increases in width and height. Emmetropic retinas were oblate (steepening away from the vertex) but oblateness decreased with the increase in myopia, so that retinas were approximately spherical at 7 to 8D myopia. Asymmetry of eyes about the best fit visual axis was generally small, with small differences between the vertex radii of curvature and between asphericities in the axial and sagittal planes. Females had smaller eyes than males, with overall dimensions being about 0.5mm less for the former. Race appeared not to have a systematic effect.
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http://dx.doi.org/10.1364/BOE.8.002386DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5480487PMC
May 2017

Intense pulsed light treatment and meibomian gland expression for moderate to advanced meibomian gland dysfunction.

Clin Exp Optom 2018 Jan 6;101(1):23-33. Epub 2017 Jun 6.

School of Optometry and Vision Science, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia.

Background: The aim was to evaluate the efficacy of periocular intense pulsed light therapy combined with meibomian gland expression for chronic dry eye due to moderate to advanced meibomian gland dysfunction.

Methods: This single-institution, open-label prospective study involved 26 participants who received bilateral treatments using a proprietary intense pulsed light device (E > Eye, E-Swin, Paris, France) combined with therapeutic meibomian gland expression at baseline, Week 2 and Week 6. Clinical evaluations performed at baseline, Week 4, Week 8 and Week 12 were symptom scores (Ocular Surface Disease Index [OSDI], Ocular Comfort Index [OCI], daily lubricant use, tear break-up time and ocular surface staining). Tear secretion, tear osmolarity, InflammaDry tear immunoassay, corneal sensation, meibomian secretion quality and expressibility, bulbar conjunctival, limbal and lid margin redness and eyelid margin bacterial swab for cultures and colony counts were performed at baseline and Week 8 only.

Results: Significant improvements occurred at Week 8 in meibomian gland expressibility (p = 0.002), meibum quality (p = 0.006), tear break-up time (p = 0.002), corneal staining (p = 0.001), lid margin redness (p = 0.001), bulbar redness (p = 0.05) and limbal redness (p = 0.001). Symptom survey outcomes, eyelid margin bacteria colony counts, Schirmer I test, tear osmolarity, corneal sensitivity and daily lubricant use were unchanged. At Week 12, significant improvements in symptoms (OSDI p = 0.025; OCI p = 0.003), tear break-up time (p = 0.001) and corneal staining (p = 0.001) occurred. Improvement in OSDI score was correlated to the improvement in ocular surface staining (R = 0.43, p = 0.03) and associated with baseline meibomian gland expressibility (Kendall tau: the distributions are ordered the same, p = 0.1). There were no adverse effects of treatment.

Conclusions: Serial intense pulsed light therapy combined with meibomian gland expression significantly improved dry eye symptoms and clinical signs, including meibomian gland secretion quality and expressibility and ocular surface inflammation. Treatment effects were cumulative and sustained for at least six weeks after the final treatment.
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http://dx.doi.org/10.1111/cxo.12541DOI Listing
January 2018

Randomised controlled trial of topical antibacterial Manuka (Leptospermum species) honey for evaporative dry eye due to meibomian gland dysfunction.

Clin Exp Optom 2017 Nov 6;100(6):603-615. Epub 2017 Jun 6.

School of Optometry and Vision Science, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia.

Background: The aim was to evaluate the efficacy of standardised Manuka (Leptospermum species) antibacterial honey as adjunctive twice daily treatment to conventional therapy (warm compresses, lid massage and preservative-free lubricant), in participants with evaporative dry eye due to moderate to advanced meibomian gland dysfunction.

Methods: This prospective, open-label study involved 114 participants. After two weeks of conventional therapy participants were randomised to one of three treatment groups: Optimel Antibacterial Manuka Eye Gel (98 per cent Leptospermum species honey) plus conventional therapy (n = 37), Optimel Manuka plus Lubricant Eye Drops (16 per cent Leptospermum species honey) plus conventional therapy (n = 37) and a control (conventional therapy) (n = 40). Clinical evaluations performed at baseline and Week 8 included: symptom scores (Ocular Surface Disease Index, Ocular Comfort Index), daily lubricant use, tear assessments (break-up time, secretion, osmolarity and InflammaDry), corneal sensation, ocular surface staining, meibomian gland secretion quality and expressibility, bulbar conjunctival, limbal and lid marginal redness and eyelid marginal bacterial cultures and colony counts.

Results: Significant improvements (p ≤ 0.05) occurred at Week 8 in symptoms, tear break-up time, staining, tear osmolarity, meibum quality and bulbar, limbal and lid margin redness for all treatments. Improvement in staining was significantly greater with Optimel 16 per cent drops (p = 0.035). Significant improvements (p < 0.05) in meibomian gland expressibility and InflammaDry occurred for both Optimel treatments. Optimel 98 per cent gel was significantly more effective in improving meibum quality (p = 0.005) and gland expressibility (p = 0.042). Total eyelid marginal bacterial colony counts reduced significantly with Optimel 16 per cent drops (p = 0.03) but not the other treatments. Staphylococcus epidermidis counts reduced significantly with Optimel 16 per cent drops (p = 0.041) and Optimel 98 per cent gel (p = 0.027). Both Optimel treatments significantly reduced the need for lubricants, with Optimel 16 per cent drops decreasing lubricant use most (p = 0.001). Temporary redness and stinging were the only adverse effects of Optimel use.

Conclusions: Optimel antibacterial honey treatments are effective as adjunctive therapies for meibomian gland dysfunction.
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http://dx.doi.org/10.1111/cxo.12524DOI Listing
November 2017

Differences in retinal shape between East Asian and Caucasian eyes.

Ophthalmic Physiol Opt 2017 05 29;37(3):275-283. Epub 2017 Mar 29.

Institute of Health & Biomedical Innovation, School of Optometry & Vision Science, Queensland University of Technology, Brisbane, Australia.

Purpose: To investigate whether retinal shape is different between East Asians and Caucasians.

Methods: There were 36 East Asian and 40 Caucasian young adults, with refractions between +0.75D and -5.50D. Peripheral eye lengths were obtained after pupil dilation using the Lenstar partial coherence interferometer. Measurements were obtained along the horizontal and vertical meridians of the visual field out to ±35° and ±30°, respectively, in 5° steps. Retinal co-ordinates were estimated using a validated method from the peripheral eye length measurements and ray-tracing through a modified Le Grand full theoretical eye. Rays were directed normally towards the anterior cornea. Retinal shapes were described in terms of vertex radius of curvature (R ), asphericity (Q) and equivalent radius of curvature (R ) along both horizontal and vertical meridians.

Results: R was smaller in East Asian than in Caucasians (mean difference ± 95% CI -0.7 ± 0.5 mm), along the horizontal meridian than the vertical meridian (-1.2 ± 0.6 mm), and in myopia than in emmetropia (-1.0 ± 0.6 mm). R along the horizontal meridian, but not along the vertical meridian, became smaller as myopia increased. Q did not vary significantly with meridian, refraction group or race. The same pattern of results occurred for R as for R . The percentage differences of heights under the estimated retinal surfaces showed steeper retinas in East Asians than in Caucasians; the differences between East Asian and Caucasian emmetropes were 2.5% and <1% along horizontal and vertical meridians, respectively, and corresponding differences for myopes were 4.6% and 1.8%.

Conclusion: East Asians had steeper retinas than Caucasians. The horizontal meridian had steeper retinas than the vertical meridian. Myopes had steeper retinas than emmetropes. Racial differences in retinal shape in both emmetropes and myopes, combined with the high prevalence of myopia in East Asia, suggest that retinal shape may play a role in myopia development.
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http://dx.doi.org/10.1111/opo.12359DOI Listing
May 2017
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