Andrew Turpin

Optic nerve tissue displacement during mild intraocular pressure elevation: its relationship to central corneal thickness and corneal hysteresis.

Publisher: Wiley

Date: 19-06-2018

DOI: 10.1111/OPO.12568

Abstract: To determine the extent to which (1) optic nerve tissue is displaced following mild acute elevation of intraocular pressure, and (2) clinically accessible measures at the anterior eye can be used as a surrogate for such displacements. We imaged the optic disc of 21 healthy subjects before and after intraocular pressure (IOP) elevation of ~10 mmHg delivered by ophthalmodynamometry. Steady-state tissue displacement during IOP elevation was assessed axially from OCT data, and laterally from SLO data. Recovery from IOP elevation was assessed by tracking a single vertical B-scan through the cup centre. Anatomical structures were demarcated by three masked clinicians to determine lateral shifts for temporal cup edge and central disc vessels, and axial shifts of disc surface and anterior lamina cribrosa. Spatial maps of deformation were constructed within the demarcated cup and disc to assess within-tissue displacement. Measured displacements were correlated with corneal hysteresis, corneal thickness, and IOP. The temporal cup edge moved more temporally with higher baseline IOP (R Mild acute elevation of IOP produces large and rapidly reversible shifts in optic nerve tissue in young, healthy eyes. The resulting degree, direction and spatial distribution of cup movement are associated with IOP status and corneal thickness, but not corneal hysteresis.

A Comparison between the Compass Fundus Perimeter and the Humphrey Field Analyzer

Publisher: Elsevier BV

Date: 02-2019

DOI: 10.1016/J.OPHTHA.2018.08.010

Abstract: To evaluate relative diagnostic precision and test-retest variability of 2 devices, the Compass (CMP, CenterVue, Padova, Italy) fundus perimeter and the Humphrey Field Analyzer (HFA, Zeiss, Dublin, CA), in detecting glaucomatous optic neuropathy (GON). Multicenter, cross-sectional, case-control study. We sequentially enrolled 499 patients with glaucoma and 444 normal subjects to analyze relative precision. A separate group of 44 patients with glaucoma and 54 normal subjects was analyzed to assess test-retest variability. One eye of recruited subjects was tested with the index tests: HFA (Swedish interactive thresholding algorithm [SITA] standard strategy) and CMP (Zippy Estimation by Sequential Testing [ZEST] strategy), 24-2 grid. The reference test for GON was specialist evaluation of fundus photographs or OCT, independent of the visual field (VF). For both devices, linear regression was used to calculate the sensitivity decrease with age in the normal group to compute pointwise total deviation (TD) values and mean deviation (MD). We derived 5% and 1% pointwise normative limits. The MD and the total number of TD values below 5% (TD 5%) or 1% (TD 1%) limits per field were used as classifiers. We used partial receiver operating characteristic (pROC) curves and partial area under the curve (pAUC) to compare the diagnostic precision of the devices. Pointwise mean absolute deviation and Bland-Altman plots for the mean sensitivity (MS) were computed to assess test-retest variability. Retinal sensitivity was generally lower with CMP, with an average mean difference of 1.85±0.06 decibels (dB) (mean ± standard error, P < 0.001) in healthy subjects and 1.46±0.05 dB (mean ± standard error, P < 0.001) in patients with glaucoma. Both devices showed similar discriminative power. The MD metric had marginally better discrimination with CMP (pAUC difference ± standard error, 0.019±0.009, P = 0.035). The 95% limits of agreement for the MS were reduced by 13% in CMP compared with HFA in participants with glaucoma and by 49% in normal participants. Mean absolute deviation was similar, with no significant differences. Relative diagnostic precision of the 2 devices is equivalent. Test-retest variability of MS for CMP was better than for HFA.

Patients’ Views of Visual Field Testing and Priorities for Research Development and Translation into Practice

Publisher: Elsevier BV

Date: 05-2021

DOI: 10.1016/J.OGLA.2021.10.003

Abstract: Information regarding the views of patients, on visual field testing is limited, and no information exists regarding their preferences for test developments. This study aimed to increase knowledge of patients' experiences of visual field assessment and to explore their opinions and priorities regarding current areas of research and development. Online questionnaire with purposive s ling design. Adults who regularly undergo visual field tests in Australia who report having glaucoma or being at glaucomatous risk. An anonymous survey, implemented using the Qualtrics webtool, with both closed- and-open ended questions designed to explore opinions regarding visual field testing, visit attendance for perimetry, as well as priorities for developments. The survey assessed 3 domains: (1) opinions regarding test duration and visit frequency, (2) subjective experience, and (3) perspectives on future developments. One hundred fifty-two complete survey responses were obtained. The median age of participants was 66 years (interquartile range [IQR], 60-72 years). Most participants (70%) had experience of undergoing more than 11 visual field tests. Participants recalled that they completed visual field tests in median of 6 minutes (IQR, 5-8 minutes) and were willing to accept additional time (median, 5 minutes IQR, 3-6 minutes) to obtain more information. Participants were prepared to increase both the number of visual field tests per eye and the frequency of visual field tests (median, 3 visits per year IQR, 2-4 visits per year) to gain more information about their visual status. Regarding future developments, the most preferred option was "similar test times but an increase in the level of information about my visual field," which ranked significantly higher than all other options, including "shorter test times that maintain the currently available level of information about my visual field." Our study confirms, in a different population and health care system, previous research reporting patient perspectives on visual field assessment. We further revealed that health care consumers show a strong preference for accurate information about their vision and report being prepared to undergo longer visual field tests or more visual field tests to achieve that outcome.

Subjective measurement of the Stiles-Crawford effect with different field sizes

Publisher: Optica Publishing Group

Date: 16-07-2021

DOI: 10.1364/BOE.427834

Abstract: The Stiles-Crawford effect of the first kind (SCE) is the phenomenon in which light entering the eye near the center of the pupil appears brighter than light entering near the edge. Previous investigations have found an increase in the directionality (steepness) of the effect as the testing location moves from the center of the visual field to parafoveal positions, but the effect of central field size has not been considered. The influence of field size on the SCE was investigated using a uniaxial Maxwellian system in which stimulus presentation was controlled by an active-matrix liquid crystal display. SCE directionality increased as field size increased from 0.5° to 4.7° diameter, although this was noted in four mild myopes and not in two emmetropes. The change with field size was supported by a geometric optics absorption model.

Principles of Melbourne Connect

Publisher: Center for Open Science

Date: 09-12-2021

DOI: 10.31219/OSF.IO/WFBYQ

Abstract: Melbourne Connect is a new initiative partnership between The University of Melbourne and industry groups. It is the centrepiece of a new innovation ecosystem connected to the university. In this paper we outlined the motivation and methods used to define a set of underlying principles for the operation of the innovation ecosystem.

Daily vision testing can expose the prodromal phase of migraine.

Publisher: SAGE Publications

Date: 07-11-2017

DOI: 10.1177/0333102417741130

Abstract: Several visual tasks have been proposed as indirect assays of the balance between cortical inhibition and excitation in migraine. This study aimed to determine whether daily measurement of performance on such tasks can reveal perceptual changes in the build up to migraine events. Visual performance was measured daily at home in 16 non-headache controls and 18 in iduals with migraine using a testing protocol on a portable tablet device. Observers performed two tasks: luminance increment detection in spatial luminance noise and centre surround contrast suppression. Luminance thresholds were reduced in migraine compared to control groups ( p 0.05), but thresholds did not alter across the migraine cycle while headache-free, centre-surround contrast suppression was stronger for the migraine group relative to controls ( p 0.05). Surround suppression weakened at around 48 hours prior to a migraine attack and strengthened to approach their headache-free levels by 24 hours post-migraine (main effect of timing, p 0.05). Daily portable testing of vision enabled insight into perceptual performance in the lead up to migraine events, a time point that is typically difficult to capture experimentally. Perceptual surround suppression of contrast fluctuates during the migraine cycle, supporting the utility of this measure as an indirect, non-invasive assay of the balance between cortical inhibition and excitation.

On Crowdsourcing Relevance Magnitudes for Information Retrieval Evaluation

Publisher: Association for Computing Machinery (ACM)

Date: 04-01-2017

DOI: 10.1145/3002172

Abstract: Magnitude estimation is a psychophysical scaling technique for the measurement of sensation, where observers assign numbers to stimuli in response to their perceived intensity. We investigate the use of magnitude estimation for judging the relevance of documents for information retrieval evaluation, carrying out a large-scale user study across 18 TREC topics and collecting over 50,000 magnitude estimation judgments using crowdsourcing. Our analysis shows that magnitude estimation judgments can be reliably collected using crowdsourcing, are competitive in terms of assessor cost, and are, on average, rank-aligned with ordinal judgments made by expert relevance assessors. We explore the application of magnitude estimation for IR evaluation, calibrating two gain-based effectiveness metrics, nDCG and ERR, directly from user-reported perceptions of relevance. A comparison of TREC system effectiveness rankings based on binary, ordinal, and magnitude estimation relevance shows substantial variation in particular, the top systems ranked using magnitude estimation and ordinal judgments differ substantially. Analysis of the magnitude estimation scores shows that this effect is due in part to varying perceptions of relevance: different users have different perceptions of the impact of relative differences in document relevance. These results have direct implications for IR evaluation, suggesting that current assumptions about a single view of relevance being sufficient to represent a population of users are unlikely to hold.

Do Additional Testing Locations Improve the Detection of Macular Perimetric Defects in Glaucoma?

Publisher: Elsevier BV

Date: 12-2021

DOI: 10.1016/J.OPHTHA.2021.06.012

Abstract: To evaluate the ability of additional central testing locations to improve detection of macular visual field (VF) defects in glaucoma. Prospective cross-sectional study. Four hundred forty healthy people and 499 patients with glaucomatous optic neuropathy (GON) were tested with a fundus tracked perimeter (CMP CenterVue) using a 24-2 grid with 12 additional macular locations (24-2+). Glaucomatous optic neuropathy was identified based on expert evaluation of optic nerve head photographs and OCT scans, independently of the VF. We defined macular defects as locations with measurements outside the 5% and 2% normative limits on total deviation (TD) and pattern deviation (PD) maps within the VF central 10°. Classification was based on the total number of affected macular locations (overall detection) or the largest number of affected macular locations connected in a contiguous cluster (cluster detection). Criteria based on the number of locations and cluster size were used to obtain equivalent specificity between the 24-2 grid and the 24-2+ grids, calculated using false detections in the healthy cohort. Partial areas under the receiver operating characteristic curve (pAUCs) were also compared at specificities of 95% or more. Matched specificity comparison of the ability to detect glaucomatous macular defects between the 24-2 and 24-2+ grids. At matched specificity, cluster detection identified more macular defects with the 24-2+ grid compared with the 24-2 grid. For ex le, the mean increase in percentage of detection was 8% (95% confidence interval [CI], 5%-11%) and 10% (95% CI, 7%-13%) for 5% TD and PD maps, respectively, and 5% (95% CI, 2%-7%) and 6% (95% CI, 4%-8%) for the 2% TD and PD maps, respectively. Good agreement was found between the 2 grids. The improvement measured by pAUCs was also significant but generally small. The percentage of eyes with macular defects ranged from about 30% to 50%. Test time for the 24-2+ grid was longer (21% increase) for both cohorts. Between 74% and 98% of defects missed by the 24-2 grid had at least 1 location with sensitivity of < 20 dB. Visual field examinations with additional macular locations can improve the detection of macular defects in GON modestly without loss of specificity when appropriate criteria are selected.

The Proportion of Individuals Likely to Benefit from Customized Optic Nerve Head Structure–Function Mapping

Publisher: Elsevier BV

Date: 04-2017

DOI: 10.1016/J.OPHTHA.2016.12.016

Abstract: Interin idual variance in optic nerve head (ONH) position, axial length, and location of the temporal raphe suggest that customizing mapping between visual field locations and ONH sectors for in iduals may be clinically useful. Herein we quantify the proportion of the population predicted to have structure-function mappings that markedly deviate from "average," and thus would benefit from customized mapping. Database study and case report. Population database of 2836 eyes from the Beijing Eye Study and a single case report of an in idual with primary open-angle glaucoma. Using the morphometric fundus data of the Beijing Eye Study for 2836 eyes and applying a recently developed model based on axial length and ONH position relative to the fovea, we determined for each measurement location in the 24-2 Humphrey (Carl Zeiss Meditec, Dublin, CA) visual field the proportion of eyes for which, in the customized approach as compared with the generalized approach, the mapped ONH sector was shifted into a different sector. We determined the proportion of eyes for which the mapped ONH location was shifted by more than 15°, 30°, or 60°. Mapping correspondence between locations in visual field space to localized sectors on the ONH. The largest interin idual differences in mapping are in the nasal step region, where the same visual field location can map to either the superior or inferior ONH, depending on other anatomic features. For these visual field locations, approximately 12% of eyes showed a mapping opposite to conventional expectations. Anatomically customized mapping shifts the map markedly in approximately 12% of the general population in the nasal step region, where visual field locations can map to the opposite pole of the ONH than conventionally considered. Early glaucomatous damage commonly affects this region hence, in idually matching structure to function may prove clinically useful for the diagnosis and monitoring of progression within in iduals.

University Of Melbourne

Location: Australia

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Curtin University

Location: Australia

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Discovery Projects - Grant ID: DP0558916

Start Date: 02-2005

End Date: 06-2010

Amount: $324,923.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP130104007

Start Date: 2013

End Date: 12-2016

Amount: $315,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0667588

Start Date: 08-2006

End Date: 08-2009

Amount: $210,000.00

Funder: Australian Research Council

ARC Future Fellowships - Grant ID: FT0991326

Start Date: 02-2010

End Date: 12-2014

Amount: $788,800.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0877883

Start Date: 2008

End Date: 12-2010

Amount: $235,944.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP110101743

Start Date: 02-2011

End Date: 12-2014

Amount: $360,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP180101711

Start Date: 05-2018

End Date: 05-2024

Amount: $341,983.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0450820

Start Date: 03-2004

End Date: 12-2007

Amount: $150,658.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP130100055

Start Date: 01-2014

End Date: 06-2018

Amount: $206,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP150100815

Start Date: 02-2016

End Date: 12-2019

Amount: $234,260.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP100100250

Start Date: 08-2010

End Date: 01-2015

Amount: $151,538.00

Funder: Australian Research Council