ORCID Profile
0000-0003-4591-3658
Current Organisation
Australian National University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Sensory Systems | Neurosciences | Diagnostic Applications | Intelligent Robotics | Neurocognitive Patterns and Neural Networks | Biomedical Instrumentation | Cognitive Science | Sensory Systems | Interdisciplinary Engineering Not Elsewhere Classified | Interdisciplinary Engineering |
ANZSRC Socio-Economic Objective (SEO)
Medical instrumentation | Air Force | Hearing, vision, speech and their disorders | Scientific Instruments | Health related to ageing | Expanding Knowledge in Psychology and Cognitive Sciences | Health not elsewhere classified | Biological sciences | Scientific instrumentation
Related Links
Publications
Objective Perimetry in Sporting-Related Mild Traumatic Brain Injury
Publisher: Elsevier BV
Date: 07-2019
Retinotopic effects of visual attention revealed by dichoptic multifocal pupillography
Publisher: Springer Science and Business Media LLC
Date: 14-02-2018
DOI: 10.1038/S41598-018-21196-1
Abstract: Multifocal pupillographic objective perimetry (mfPOP) has recently been shown to be able to measure cortical function. Here we assessed 44 regions of the central 60 degrees of the visual fields of each eye concurrently in 7 minutes/test. We examined how foveally- and peripherally-directed attention changed response sensitivity and delay across the 44 visual field locations/eye. Four experiments were completed comparing white, yellow and blue stimulus arrays. Experiments 1 to 4 tested 16, 23, 9 and 6 subjects, 49/54 being unique. Experiment 1, Experiments 2 and 3, and Experiment 4 used three variants of the mfPOP method that provided increasingly improved signal quality. Experiments 1 to 3 examined centrally directed attention, and Experiment 4 compared effects of attention directed to different peripheral targets. Attention reduced the sensitivity of the peripheral locations in Experiment 1, but only for the white stimuli not yellow . Experiment 2 confirmed that result. Experiment 3 showed that blue stimuli behaved like white. Peripheral attention showed increased sensitivity around the attentional targets. The results are discussed in terms of the cortical inputs to the pupillary system. The results agree with those from multifocal and other fMRI and VEP studies. mfPOP may be a useful adjunct to those methods.
Re: inter-optometrist variability of IOP measurement for modern tonometers and their agreement with Goldmann Applanation Tonometry
Publisher: Informa UK Limited
Date: 08-08-2021
Rapid, non-contact multifocal visual assessment in multiple sclerosis
Publisher: Springer Science and Business Media LLC
Date: 13-09-2023
DOI: 10.1007/S10072-022-06387-Z
Abstract: Previous work on temporally sparse multifocal methods suggests that the results are correlated with disability and progression in people with multiple sclerosis (PwMS). Here, we assess the diagnostic power of three cortically mediated sparse multifocal pupillographic objective perimetry (mfPOP) methods that quantified response-delay and light-sensitivity at up to 44 regions of both visual fields concurrently. One high-spatial-resolution mfPOP method, P129, and two rapid medium-resolution methods, W12 and W20, were tested on 44 PwMS and controls. W12 and W20 took 82 s to test both visual fields concurrently, providing response delay and sensitivity at each field location, while P129 took 7 min. Diagnostic power was assessed using areas under the receiver operating characteristic (AUROC) curves and effect-size (Hedges’ g ). Linear models examined significance. Concurrent testing of both eyes permitted assessment of between-eye asymmetries. Per-region response delays and asymmetries achieved AUROCs of 86.6% ± 4.72% (mean ± SE) in relapsing–remitting MS, and 96.5% ± 2.30% in progressive MS. Performance increased with increasing disability scores, with even moderate EDSS 2 to 4.5 PwMS producing AUROCs of 82.1 to 89.8%, Hedge’s g values up to 2.06, and p = 4.0e − 13. All tests performed well regardless of any history of optic neuritis. W12 and W20 performed as well or better than P129. Overall, the 82-s tests (W12 and W20) performed better than P129. The results suggest that mfPOP assesses a correlate of disease severity rather than a history of inflammation, and that it may be useful in the clinical management of PwMS.
Retinal laser services in Bhutan: a 3-year national survey
Publisher: Springer Science and Business Media LLC
Date: 08-10-2020
DOI: 10.1186/S12886-020-01675-8
Abstract: We conducted this study to report on the indications and types of retinal laser therapy (RLT) performed in Bhutan, knowing which is critical for proper planning and successful delivery of the services. We reviewed the laser registers maintained in the laser rooms and vitreoretinal (VR) operating theatres (including paediatric cases managed under anaesthesia) over three years at the national and the two regional referral hospitals (RRHs). Intraoperative laser treatments (endolaser) were excluded. Patient demography, indications and types of RLT were recorded and quantified. Comparisons of the expected and observed frequencies used Chi-squared tests. A total of 685 patients, including 8 cases of bilateral retinopathy of prematurity (ROP) received RLT. The majority of patients (411 cases, 60.0%, p 0.0001) were males. The mean age was 54.1 ± 14.1 years, median 56 years. The most common indications for RLT were diabetic retinopathy (DR) and diabetic macular oedema (DMO) (542 cases, 66.0%), followed by retinal vein occlusion (RVO) (91 cases, 13.3%). Pan-retinal photocoagulation was the most common type of RLT performed (337 cases, 49.2%), followed by modified grid laser (207 cases, 30.2%), sectoral laser (41 cases, 6.0%), and prophylactic laser photocoagulation (33 cases, 4.8%). The majority of patients were within working-age. Common indications for RLT were preventable such as DR, DMO and RVO, indicating need to control systemic diseases such as diabetes, hypertension, and dyslipidaemia. Currently, regular RLT is provided only at the national referral hospital in Thimphu, and periodically in the eastern and central RRHs when the retinal specialist visits. There is need to extend the retinal services to the eastern and central RRHs to improve accessibility and patient coverage in these regions challenged with difficult terrain and poor public transport system.
Insights for mfVEPs from perimetry using large spatial frequency-doubling and near frequency-doubling stimuli in glaucoma
Publisher: Springer Science and Business Media LLC
Date: 08-02-2020
Prevalence and severity of diabetic retinopathy at first presentation to vitreoretinal services in Bhutan: a 3-year national study
Publisher: Springer Science and Business Media LLC
Date: 18-04-2023
Novel morphometric analysis of higher order structure of human radial peri-papillary capillaries: relevance to retinal perfusion efficiency and age
Publisher: Springer Science and Business Media LLC
Date: 17-09-2019
DOI: 10.1038/S41598-019-49443-Z
Abstract: We apply novel analyses to images of superficial capillaries that are located near and around the optic disc of the human retina: the radial peri-papillary capillaries (RPCs). Due to their unique perfusion of the nerve fibre layer the RPCs are particularly significant for optic-neuropathies. The inputs to the analysis were z-stacks from 3D confocal fluorescence microscopy from 62 human retinas aged 9 to 84 years. Our aim was to find morphometric correlates of age. The retinas had no ophthalmic history. The analysis was undertaken in two stages: (1) converting the z-stacks to 3D tubular networks of vessels, and (2) characterizing the tubular networks using features derived from the Minkowski functionals (MFs). The MFs measure: the capillary volume, surface area, mean breadth, and Euler number. The mean breadth is related to tortuosity, wall shear stress and resistance to flow, and the Euler number is related to the density of loops (collaterals). Features derived from the surface area, mean breadth and Euler number were most related to age (all p ≤ 0.006). The results indicate the importance of pressure-equalizing loops and tortuosity as quantitative measures related to perfusion efficiency. The novel morphometric analysis could quantify disease-related accelerated aging and vessel malformation.
Improving face identity perception in age-related macular degeneration via caricaturing
Publisher: Springer Science and Business Media LLC
Date: 12-10-2018
DOI: 10.1038/S41598-018-33543-3
Abstract: Patients with age-related macular degeneration (AMD) have difficulty recognising people’s faces. We tested whether this could be improved using caricaturing: an image enhancement procedure derived from cortical coding in a perceptual ‘face-space’. Caricaturing exaggerates the distinctive ways in which an in idual’s face shape differs from the average. We tested 19 AMD-affected eyes (from 12 patients ages 66–93 years) monocularly, selected to cover the full range of vision loss. Patients rated how different in identity people’s faces appeared when compared in pairs (e.g., two young men, both Caucasian), at four caricature strengths (0, 20, 40, 60% exaggeration). This task gives data reliable enough to analyse statistically at the in idual-eye level. All 9 eyes with mild vision loss (acuity ≥ 6/18) showed significant improvement in identity discrimination (higher dissimilarity ratings) with caricaturing. The size of improvement matched that in normal-vision young adults. The caricature benefit became less stable as visual acuity further decreased, but caricaturing was still effective in half the eyes with moderate and severe vision loss (significant improvement in 5 of 10 eyes at acuities from 6/24 to poorer than /360). We conclude caricaturing has the potential to help many AMD patients recognise faces.
Assessing migraine patients with multifocal pupillographic objective perimetry
Publisher: Springer Science and Business Media LLC
Date: 26-05-2021
DOI: 10.1186/S12883-021-02239-Z
Abstract: To establish the effects of stimulating intrinsically-photosensitive retinal ganglion cells (ipRGCs) on migraine severity, and to determine if migraine produces objectively-measured visual field defects. A randomized, open labelled, crossover study tested migraineurs and normal controls using multifocal pupillographic objective perimetry (mfPOP) with 44 test-regions/eye. A slow blue protocol (BP) stimulated ipRGCs, and a fast yellow protocol (YP) stimulated luminance channels. Migraine diaries assessed migraine severity. Per-region responses were analyzed according to response litude and time-to-peak. Thirty-eight migraineurs (42.0 ± 16.5 years, 23 females) and 24 normal controls (39.2 ± 15.2 years, 14 females) were tested. The proportion of subjects developing a migraine did not differ after either protocol, either during the 1st day (odds ratio 1.0 95% confidence interval 0.2–4.4, p = 0.48) or during the first 3 days after testing (odds ratio 0.8 95% confidence interval 0.3–2.1, p = 0.68). Migraine days/week did not increase following testing with either protocol in comparison to the baseline week (1.4 ± 1.6 pre-testing (mean ± SD), 1.3 ± 1.4 post-BP, and 1.3 ± 1.2 post-YP p = 0.96), neither did other measures of severity. Migraine occurring up to 2 weeks before testing significantly lowered litudes, − 0.64 ± 0.14 dB (mean ± SE), while triptan use increased litudes by 0.45 ± 0.10 dB, both at p 0.001. Stimulating ipRGCs did not affect migraine occurrence or severity. Pupillary response characteristics were influenced by the occurrence of a recent migraine attack and a history of triptan use.
Rural-urban differences in myopia prevalence among myopes presenting to Bhutanese retinal clinical services: a 3-year national study
Publisher: Springer Science and Business Media LLC
Date: 17-08-2020
Early diabetic eye damage: Comparing detection methods using diagnostic power
Publisher: Elsevier BV
Date: 10-2023
Severity of age-related macular degeneration at first presentation in Bhutan: a 3-year national study
Publisher: Springer Science and Business Media LLC
Date: 09-07-2022
DOI: 10.1186/S12886-022-02520-W
Abstract: Medical services are still developing in Bhutan. There is no published national report on age-related macular degeneration (AMD). We therefore aim to determine the demographic characteristics and severity of AMD at first presentation among Bhutanese patients attending their recently inaugurated vitreoretinal (VR) clinics over a 3-year national survey, and to inform national health policy to develop suitable health program to prevent AMD-related blindness and visual impairment. A retrospective cross-sectional consecutive case series study was conducted on all new AMD cases in Bhutan. If a patient presented with asymmetrical AMD, the eye with more severe AMD was considered. If both the eyes had the same severity one eye was chosen randomly. Collection of demographic data and clinical details including diagnostic testing (fundus photography, OCT and fluorescent angiography) and clinical staging were performed. Of 521 new AMD patients aged 71.9 ± 11.3 years, 306/521 (58.7%) were males ( p = 0.005). At their first presentation, 234/521 patients (44.9%) already had late-stage AMD. Importantly, 69/234 patients (29.5%), that is half of total neovascular AMD (nAMD) patients, had disciform scars (DS) which were beyond treatment, and 7/234 patients (3.0%) had geographic atrophy (GA). Seven patients had retinal pigment epithelium tear at presentation. Fourteen of nineteen polypoidal choroidal vasculopathy (PCV) patients were younger than 50 years. Half of nAMD cases presented as DS not amenable to the treatment. Many potentially treatable nAMD patients had already lost central vision and were legally blind. Young people with PCV losing vision early in life with longer morbidity-affected life and socio-economic burden was concerning. GA and DS cases need visual rehabilitation to improve their QoL. Incorporating a screening program for AMD with effective health education, and maintaining a national AMD Registry, would potentially lower AMD-related blindness and visual impairment.
Topical chloramphenicol usage in Australia pre‐ and post‐rescheduling as a non‐prescription medication
Publisher: Wiley
Date: 07-2021
DOI: 10.1111/CEO.13963
Recovery Dynamics of Multifocal Pupillographic Objective Perimetry from Tropicamide Dilation
Publisher: Springer Science and Business Media LLC
Date: 13-11-2019
DOI: 10.1007/S00417-019-04523-8
Abstract: To study the pupillary system by combining mydriasis and multifocal pupillographic objective perimetry (mfPOP). In particular, we explored how the dynamics of recovery differ for concurrently measured direct and consensual sensitivity, response delay, and signal-to-noise ratios (SNRs) for binocular mydriasis. We recruited 26 normal participants, all with brown irides. The dichoptic mfPOP stimuli concurrently assessed 44-region/eye and both pupils. Two pre-dilation tests were followed by pairs of repeated tests at 1, 2, 4, 6, 8, 12, 24, and 48 h following dilation of both pupils with 1% tropicamide. Three subjects were retested with only the right pupil dilated. Linear models determined the independent effects of mydriasis upon the per-region and pupil measures over time. Post-dilation, the per-region delays initially decreased by 16.3 ± 6.02 ms (mean ± SE) (p < 0.0001, cf. baseline of 471.1 ± 4.36 ms), then increased to slower than baseline by 17.42 ± 5.57 ms after 4 h (p < 0.002), recovering to baseline at 8 h. By comparison, per-region sensitivities (constriction litudes) were still reduced by - 6.20 ± 0.70 μm at 8 h (p < 0.0001, cf. baseline of 21.1 ± 0.55 μm), recovered at 24 h, but rebounded at 48 h (p = 0.005). The SNRs for sensitivities and delays both recovered by 8-12 h. Across all the data, sensitivities reduced by 2.67 ± 0.25 μm/decade of age, and delay increased by 15.4 ± 1.98 ms/decade (both p < 0.00001). Data from 3 of the 26 subjects who repeated the testing for monocular dilation found that consensual response sensitivities were larger than direct for 8 h (p < 0.018). The per-region sensitivities were affected for longer than SNRs or delays. Strong early SNRs indicated proportionately lower pupil noise for larger pupil diameters. Following mydriasis with tropicamide 1%, the constriction litude measurements with mfPOP should be considered only after 48 h, but time-to-peak can be measured after 8-12 h.
Learning complex texture discrimination
Publisher: Optica Publishing Group
Date: 03-2021
DOI: 10.1364/JOSAA.413065
Abstract: Higher-order spatial correlations contribute strongly to visual structure and salience, and are common in the natural environment. One method for studying this structure has been through the use of highly controlled texture patterns whose obvious structure is defined entirely by third- and higher-order correlations. Here we examine the effects that longer-term training has on discrimination of 17 such texture types. Training took place in 14 sessions over 42 days. Discrimination performance increased at different rates for different textures. The time required to complete a visit reduced by 25.4% ( p = 0.0004 ). Factor analysis was applied to data from the learning and experienced phases of the experiment. This indicated that the gain in speed was accompanied by an increase in the number of mechanisms contributing to discrimination. Learning was not affected by sleep quality but was affected by extreme tiredness ( p <!-- 0.01 ). The improved discrimination and speed were retained for 2.5 months. Overall, the effects were consistent with perceptual learning. The observed learning is likely related to the adaptation of innate mechanisms that underlie our ability to identify nonredundant, visually salient structure in natural images. It may involve cortical V2 and appears to involve increased strength, speed, and breadth of connections within our internal representation of this complex perceptual space.
Related Organisations
Related Funding Activities
Special Research Initiatives - Grant ID: SR0354726
Start Date: 12-2003
End Date: 12-2004
Amount: $10,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP140100763
Start Date: 12-2014
End Date: 06-2018
Amount: $389,000.00
Funder: Australian Research Council
View Funded ActivityTesting For Early Diabetic Retinopathy
Start Date: 2012
End Date: 2014
Funder: National Health and Medical Research Council
View Funded ActivityNovel Functional Testing For Macular Degeneration
Start Date: 2014
End Date: 2016
Funder: National Health and Medical Research Council
View Funded ActivityRapid, Cost-effective, Diagnosis And Monitoring Of Multiple Sclerosis By Novel Multifocal Evoked Potential Methods
Start Date: 2008
End Date: 2008
Funder: National Health and Medical Research Council
View Funded ActivityEffects Of Radiofrequency Electromagnetic Radiation From Long-term Mobile Phone Use On Vision And Hearing
Start Date: 2001
End Date: 2005
Funder: National Health and Medical Research Council
View Funded ActivityBinocular Objective Visual Field Testing Using Pupillography
Start Date: 2006
End Date: 2006
Funder: National Health and Medical Research Council
View Funded ActivityCreating New Methods To Study Structure Vision
Start Date: 2014
End Date: 2018
Funder: Australian Research Council
View Funded ActivityA National T-ray Facility
Start Date: 2005
End Date: 2005
Funder: Australian Research Council
View Funded ActivityNETVISION: AUSTRALIA'S NATIONAL VISION RESEARCH NETWORK
Start Date: 2003
End Date: 2004
Funder: Australian Research Council
View Funded ActivityARC Centres Of Excellence - Grant ID: CE0561903
Start Date: 2006
End Date: 12-2013
Amount: $16,250,000.00
Funder: Australian Research Council
View Funded ActivityARC Centre Of Excellence - Vision Science
Start Date: 2005
End Date: 2013
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE0560716
Start Date: 05-2005
End Date: 12-2006
Amount: $864,610.00
Funder: Australian Research Council
View Funded Activity