ORCID Profile
0000-0002-4696-9226
Current Organisation
UNSW Sydney
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Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 16-09-2022
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2021
DOI: 10.1097/OPX.0000000000001672
Abstract: This article summarizes the evidence for a higher prevalence of binocular vision dysfunctions in in iduals with vision impairment. Assessment for and identification of binocular vision dysfunctions can detect in iduals experiencing difficulties in activities including reading, object placement tasks, and mobility. Comprehensive vision assessment in low vision populations is necessary to identify the extent of remaining vision and to enable directed rehabilitation efforts. In patients with vision impairment, little attention is typically paid to assessments of binocular vision, including ocular vergence, stereopsis, and binocular summation characteristics. In addition, binocular measurements of threshold automated visual fields are not routinely performed in clinical practice, leading to an incomplete understanding of in iduals' binocular visual field and may affect rehabilitation outcomes. First, this review summarizes the prevalence of dysfunctions in ocular vergence, stereopsis, and binocular summation characteristics across a variety of ocular pathologies causing vision impairment. Second, this review examines the links between clinical measurements of binocular visual functions and outcome measures including quality of life and performance in functional tasks. There is an increased prevalence of dysfunctions in ocular alignment, stereopsis, and binocular summation across low vision cohorts compared with those with normal vision. The identification of binocular vision dysfunctions during routine low vision assessments is especially important in patients experiencing difficulties in activities of daily living, including but not limited to reading, object placement tasks, and mobility. However, further research is required to determine whether addressing the identified deficits in binocular vision in low vision rehabilitative efforts directly impacts patient outcomes.
Publisher: BMJ
Date: 09-0010
DOI: 10.1136/BMJOPEN-2020-047246
Abstract: Many chronic eye conditions are managed within public hospital ophthalmology clinics resulting in encumbered wait lists. Integrated care schemes can increase system capacity. In order to direct implementation of a public hospital-based integrated eye care model, this study aims to evaluate the quality of referrals for new patients through information content, assess triage decisions of newly referred patients and evaluate the consistency of referral content for new patients referred multiple times. A retrospective and prospective review of all referral forms for new patients referred to a public hospital ophthalmology clinic between January 2016 and September 2017, and September 2017 and August 2018, respectively. A referral-only public hospital ophthalmology clinic in metropolitan Sydney, Australia. 418 new patients on existing non-urgent wait lists waiting to be allocated an initial appointment, and 528 patients who were newly referred. The primary outcome was the information content of referrals for new patients. The secondary outcomes were triage outcomes for new incoming referrals, and the number of new patients with multiple referrals. Of the wait-listed referrals, 0.2% were complete in referral content compared with 9.8% of new incoming referrals (p .001). Of new incoming referrals, 56.7% were triaged to a non-urgent clinic. Multiple referrals were received for 49 patients, with no change in the amount of referral content. Most referrals were incomplete in content, leading to triage based on limited clinical information. Some new patients were referred multiple times with their second referral containing a similar amount of content as their first. Lengthy wait lists could be prevented by improving administrative processes and communication between the referral centre and referrers. The future implementation of an integrated eye care model at the study setting could sustainably cut wait lists for patients with chronic eye conditions.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 18-10-2021
Publisher: Springer Science and Business Media LLC
Date: 12-01-2021
DOI: 10.1038/S41598-020-79424-6
Abstract: Current descriptions of retinal thickness across normal age cohorts are mostly limited to global analyses, thus overlooking spatial variation across the retina and limiting spatial analyses of retinal and optic nerve disease. This retrospective cross-sectional study uses location-specific cluster analysis of 8 × 8 macular average grid-wise thicknesses to quantify topographical patterns and rates of normal, age-related changes in all in idual retinal layers of 253 eyes of 253 participants across various age cohorts (n = 23–69 eyes per decade). Most retinal layers had concentric spatial cluster patterns except the retinal nerve fibre layer (RNFL) which displayed a nasal, asymmetric radial pattern. Age-related thickness decline mostly occurred after the late 4th decade, described by quadratic regression models. The ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), and outer nuclear layer + Henle’s fibre layer (ONL +HFL ) were significantly associated with age ( p 0.0001 to 0.05), demonstrating similar rates of thickness decline (mean pooled slope = − 0.07 µm/year), while the IS/OS had lesser mean pooled thickness slopes for all clusters (− 0.04 µm/year). The RNFL, OPL, and RPE exhibited no significant age-related thickness change, and the RNFL were significantly associated with sex. Analysis using spatial clusters compared to the ETDRS sectors revealed more extensive spatial definition and less variability in the former method. These spatially defined, clustered normative data and age-correction functions provide an accessible method of retinal thickness analysis with more spatial detail and less variability than the ETDRS sectors, potentially aiding the diagnosis and monitoring of retinal and optic nerve disease.
Publisher: Wiley
Date: 19-04-2023
DOI: 10.1002/CNE.25483
Abstract: This study sought to identify demographic variations in retinal thickness measurements from optical coherence tomography (OCT), to enable the calculation of cell density parameters across the neural layers of the healthy human macula. From macular OCTs ( n = 247), ganglion cell (GCL), inner nuclear (INL), and inner segment–outer segment (ISOS) layer measurements were extracted using a customized high‐density grid. Variations with age, sex, ethnicity, and refractive error were assessed with multiple linear regression analyses, with age‐related distributions further assessed using hierarchical cluster analysis and regression models. Models were tested on a naïve healthy cohort ( n = 40) with Mann–Whitney tests to determine generalizability. Quantitative cell density data were calculated from histological data from previous human studies. Eccentricity‐dependent variations in OCT retinal thickness closely resemble topographic cell density maps from human histological studies. Age was consistently identified as significantly impacting retinal thickness ( p = .0006, .0007, and .003 for GCL, INL and ISOS), with gender affecting ISOS only ( p .0001). Regression models demonstrated that age‐related changes in the GCL and INL begin in the 30th decade and were linear for the ISOS. Model testing revealed significant differences in INL and ISOS thickness ( p = .0008 and .0001 however, differences fell within the OCT's axial resolution. Qualitative comparisons show close alignment between OCT and histological cell densities when using unique, high‐resolution OCT data, and correction for demographics‐related variability. Overall, this study describes a process to calculate in vivo cell density from OCT for all neural layers of the human retina, providing a framework for basic science and clinical investigations.
Publisher: Informa UK Limited
Date: 27-07-2021
DOI: 10.1080/08164622.2021.1940875
Abstract: There is potential benefit in analysing corneal nerve tortuosity as a marker for assessment and progression of systemic diabetic neuropathy. The aim of this work was to determine whether tortuosity significantly differs in participants with type 1 (T1DM) and type 2 (T2DM) diabetes compared to controls and whether tortuosity differed according to neuropathy status. Corneal nerves of 164 participants were assessed across T1DM, T2DM and control groups. Images of corneal nerves were captured via in vivo corneal confocal microscopy. Diabetic neuropathy status was examined using the Total Neuropathy Score (TNS). Tortuosity was assessed with Cfibre v0.097. Results were compared between groups with a linear mixed model accounting for location of image and controlling for age, producing Tortuosity Factor (TF), an estimate of the marginal means of each group. Tortuosity was significantly reduced in the T1DM group compared to controls (TF = 0.241, 95%CI = 0.225-0.257 vs. TF = 0.272, 95%CI = 0.252-0.292 mean difference = -0.031, p = 0.02) and in the T2DM group compared to controls (TF = 0.261, 95%CI = 0.244-0.278 vs. TF = 0.289, 95%CI = 0.270-0.308 mean difference = -0.029, p = 0.03). Tortuosity did not significantly differ between participants with T1DM and T2DM accounting for age and TNS (TF = 0.240, 95%CI = 0.215-0.265 vs. 0.269, 95%CI = 0.244-0.293, mean difference = -0.029, p = 0.11). Tortuosity was significantly reduced in participants with neuropathy (TNS≥2) compared to participants with no neuropathy (TNS< 2) (TF = 0.248, 95%CI = 0.231-0.265 vs. TF = 0.272, 95%CI = 0.260-0.283 mean difference = -0.024, p = 0.03). Tortuosity is significantly reduced in participants with T1DM and T2DM compared to age matched controls and in participants with neuropathy compared to those without neuropathy.
Publisher: BMJ
Date: 08-2021
DOI: 10.1136/BMJOPEN-2020-044805
Abstract: The Australian Government funded a nationwide diabetic retinopathy screening programme to improve visual outcomes for people with diabetes. This study examined the benefits and barriers of the programme, image interpretation pathways and assessed the characteristics of people who had their fundus photos graded by a telereading service which was available as a part of the programme. Multimethod: survey and retrospective review of referral forms. Twenty-two primary healthcare facilities from urban, regional, rural and remote areas of Australia, and one telereading service operated by a referral-only eye clinic in metropolitan Sydney, Australia. Twenty-seven primary healthcare workers out of 110 contacted completed a survey, and 145 patient referrals were reviewed. Manifest qualitative content analysis showed that primary healthcare workers reported that the benefits of the screening programme included improved patient outcomes and increased awareness and knowledge of diabetic retinopathy. Barriers related to staffing issues and limited referral pathways. Image grading was performed by a variety of primary healthcare workers, with one responder indicating the utilisation of a diabetic retinopathy reading service. Of the people with fundus photos graded by the reading service, 26.2% were reported to have diabetes. Overall, 12.3% of eyes were diagnosed with diabetic retinopathy. Photo quality was rated as excellent in 46.2% of photos. Referral to an optometrist for diabetic retinopathy was recommended in 4.1% of cases, and to an ophthalmologist in 6.9% of cases. This nationwide diabetic retinopathy screening programme was perceived to increase access to diabetic retinopathy screening in regional, rural and remote areas of Australia. The telereading service has diagnosed diabetic retinopathy and other ocular pathologies in images it has received. Key barriers, such as access to ophthalmologists and optometrists, must be overcome to improve visual outcomes.
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Date: 20-09-2019
DOI: 10.1167/TVST.8.5.16
No related grants have been discovered for Vincent Khou.