Publications by authors named "Michael Kalloniatis"

158 Publications

Effects of stereopsis on vection, presence and cybersickness in head-mounted display (HMD) virtual reality.

Sci Rep 2021 Jun 11;11(1):12373. Epub 2021 Jun 11.

School of Optometry and Vision Science, University of New South Wales (UNSW Sydney), Kensington, Australia.

Stereopsis provides critical information for the spatial visual perception of object form and motion. We used virtual reality as a tool to understand the role of global stereopsis in the visual perception of self-motion and spatial presence using virtual environments experienced through head-mounted displays (HMDs). Participants viewed radially expanding optic flow simulating different speeds of self-motion in depth, which generated the illusion of self-motion in depth (i.e., linear vection). Displays were viewed with the head either stationary (passive radial flow) or laterally swaying to the beat of a metronome (active conditions). Multisensory conflict was imposed in active conditions by presenting displays that either: (i) compensated for head movement (active compensation condition), or (ii) presented pure radial flow with no compensation during head movement (active no compensation condition). In Experiment 1, impairing stereopsis by anisometropic suppression in healthy participants generated declines in reported vection strength, spatial presence and severity of cybersickness. In Experiment 2, vection and presence ratings were compared between participants with and without clinically-defined global stereopsis. Participants without global stereopsis generated impaired vection and presence similarly to those found in Experiment 1 by subjects with induced stereopsis impairment. We find that reducing global stereopsis can have benefits of reducing cybersickness, but has adverse effects on aspects of self-motion perception in HMD VR.
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http://dx.doi.org/10.1038/s41598-021-89751-xDOI Listing
June 2021

Classifying Retinal Degeneration in Histological Sections Using Deep Learning.

Transl Vis Sci Technol 2021 Jun;10(7)

Graduate School of Biomedical Engineering, University of New South Wales, Kensington, NSW, Australia.

Purpose: Artificial intelligence (AI) techniques are increasingly being used to classify retinal diseases. In this study we investigated the ability of a convolutional neural network (CNN) in categorizing histological images into different classes of retinal degeneration.

Methods: Images were obtained from a chemically induced feline model of monocular retinal dystrophy and split into training and testing sets. The training set was graded for the level of retinal degeneration and used to train various CNN architectures. The testing set was evaluated through the best architecture and graded by six observers. Comparisons between model and observer classifications, and interobserver variability were measured. Finally, the effects of using less training images or images containing half the presentable context were investigated.

Results: The best model gave weighted-F1 scores in the range 85% to 90%. Cohen kappa scores reached up to 0.86, indicating high agreement between the model and observers. Interobserver variability was consistent with the model-observer variability in the model's ability to match predictions with the observers. Image context restriction resulted in model performance reduction by up to 6% and at least one training set size resulted in a model performance reduction of 10% compared to the original size.

Conclusions: Detecting the presence and severity of up to three classes of retinal degeneration in histological data can be reliably achieved with a deep learning classifier.

Translational Relevance: This work lays the foundations for future AI models which could aid in the evaluation of more intricate changes occurring in retinal degeneration, particularly in other types of clinically derived image data.
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http://dx.doi.org/10.1167/tvst.10.7.9DOI Listing
June 2021

Viability of performing multiple 24-2 visual field examinations at the same clinical visit: the Frontloading Fields Study (FFS).

Am J Ophthalmol 2021 May 2. Epub 2021 May 2.

Centre for Eye Health, University of New South Wales, Kensington, NSW; School of Optometry and Vision Science, University of New South Wales, Kensington, NSW.

Purpose: To assess the viability in terms of time taken for testing and repeatability of frontloading (performing multiple perimetric examinations) in a single clinic visit.

Design: Reliability enhancement analysis.

Participants: 329 healthy, glaucoma suspect, and glaucoma subjects within a glaucoma clinic undergoing perimetric testing using SITA-Faster twice for each eye within the same session. We analysed global indices, pointwise sensitivity and probability scores, test duration and reliability metrics.

Results: 9.1% of right and 6.7% of left eye results were unreliable for both tests, with 58.4% and 67.5% of right and left eyes achieving reliable results on both. 83.8% of all subjects spent less than 20 minutes performing all tests. Differences in global indices, pointwise sensitivity and probability scores showed no systematic nor clinically significant difference between test one and two for each eye. There was also no systematic difference in the number of test locations identified as defective at the p < 0.05 level between tests. Test results that were unreliable tended to show more instances of a failed "cluster" criterion that were not repeatable.

Conclusions: Frontloading using SITA-Faster was viable for obtaining sets of reliable, repeatable perimetric data in terms of conventional outputs, overcoming practical issues regarding low test reliability using singleton results and confirmation of visual field defects. Despite the need to remain cognisant of the reliability of SITA-Faster, frontloading using this algorithm may be a practical method for meeting recommendations for multiple perimetric data required to make confident inferences about glaucoma state and progression.
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http://dx.doi.org/10.1016/j.ajo.2021.04.019DOI Listing
May 2021

Topical Review: Assessment of Binocular Sensory Processes in Low Vision.

Optom Vis Sci 2021 04;98(4):310-325

Guide Dogs New South Wales/Australian Capital Territory, Sydney, New South Wales, Australia.

Significance: This article summarizes the evidence for a higher prevalence of binocular vision dysfunctions in individuals with vision impairment. Assessment for and identification of binocular vision dysfunctions can detect individuals 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 individuals' 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.
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http://dx.doi.org/10.1097/OPX.0000000000001672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8051935PMC
April 2021

Radial Peripapillary Capillary Plexus Sparing and Underlying Retinal Vascular Impairment in Intermediate Age-Related Macular Degeneration.

Invest Ophthalmol Vis Sci 2021 Apr;62(4)

Centre for Eye Health, University of New South Wales, Sydney, Australia.

Purpose: To examine location-specific retinal vascular changes in intermediate age-related macular degeneration (iAMD) using age-matched, high-density en face optical coherence tomography angiography (OCTA) cluster analysis.

Methods: En face OCTA images of the 6 × 6 mm macular area were retrospectively acquired from 60 iAMD eyes and 60 age-matched normal eyes and then subdivided into 126 × 126 (47.62 × 47.62 µm) grids within the superficial and deep vascular complex. Grid-wise vessel perfusion (VP) were compared between iAMD and normal eyes from the corresponding 10-yearly age cohort, forming difference plots. Difference plots were further separated by normative topographical map spatial clusters (C1-6), derived from normaldatabase eyes (n = 236, 20-81 years old).

Results: Overall difference plots showed decreased VP in the superficial (-12.19%) and deep vascular complex (-6.44%) of iAMD compared to normal eyes (P < 0.0001 both comparisons). Cluster-based difference plots highlighted nonuniform changes in the superficial vascular complex, with sparing of VP at the nasal macula (corresponding to the radial peripapillary capillary plexus) versus decreased VP toward the temporal macula and foveal avascular zone (FAZ) (C1-6 all comparisons P < 0.0001, except C1 vs. C2P > 0.99 and C4 vs. C5P = 0.11). The deep vascular complex displayed diffusely decreased VP, greater at the FAZ (P < 0.0001).

Conclusions: High-density en face OCTA cluster analysis suggests relative sparing of the radial peripapillary capillary plexus and impairment of underlying retinal vasculature, supporting potential anterograde transsynaptic degeneration in iAMD. These location-specific data may better guide future diagnostic and management protocol of iAMD.
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http://dx.doi.org/10.1167/iovs.62.4.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024775PMC
April 2021

Comparison of 10-2 and 24-2C Test Grids for Identifying Central Visual Field Defects in Glaucoma and Suspect Patients.

Ophthalmology 2021 Mar 17. Epub 2021 Mar 17.

Centre for Eye Health, University of New South Wales, Kensington, New South Wales; School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales.

Purpose: To compare the ability of 24-2C and 10-2 test grids in measuring visual field global indices, identifying central visual field defects, and facilitating macular structure-function analysis with OCT scans in glaucoma and glaucoma suspect patients.

Design: Prospective, cross-sectional study.

Participants: One eye from 131 glaucoma and 57 glaucoma suspect patients recruited from a referral-only, university-based glaucoma clinic.

Methods: Each subject underwent perimetric testing using 24-2C SITA-Faster and 10-2 SITA-Fast in random order, and Cirrus OCT macular imaging (Ganglion Cell Analysis) for structure-function correlations.

Main Outcome Measures: Visual field global indices (mean deviation, pattern standard deviation, binarized "cluster" pass/fail, and central mean sensitivity), number and proportion of visual field defects, and structure-function concordance with the Cirrus OCT deviation map following visual field location displacement for correspondence with underlying retinal ganglion cell position.

Results: Global indices (mean deviation, pattern standard deviation, and central mean sensitivity) were similar between both grids. The 10-2 detected more defects compared with the 24-2C (P < 0.0001 for all patients, P = 0.006 for glaucoma patients). This was preserved when analyzing the proportion of defects in the central visual field for all patients (P = 0.02) but was not significantly different for glaucoma patients (P = 0.051). The 10-2 identified more central "clusters" of 2+ contiguous points of deficit (P < 0.0001). Structure-function comparisons performed at locations where visual field and OCT test locations were colocalized revealed greater concordance of structural and functional deficits using the 10-2 (P < 0.0001). The 10-2 took a median of 201 seconds, and the 24-2C took a median of 154 seconds, corresponding to the different thresholding algorithms.

Conclusions: The 24-2C and 10-2 test grids return similar global indices of visual field performance and proportionally similar amounts of central visual field loss. The additional points in the 10-2 grid return more "clusters" of defects and a greater rate of structure-function concordance compared with the 24-2C test grid. Thus, the 24-2C can identify the presence of a clustered central visual field defect using similar probability criteria, whereas the 10-2 may be more useful in comprehensively characterizing the defect and predicting central visual function.
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http://dx.doi.org/10.1016/j.ophtha.2021.03.014DOI Listing
March 2021

Headaches related to latanoprost in open-angle glaucoma.

Clin Exp Optom 2021 Mar 2:1-9. Epub 2021 Mar 2.

Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.

: The existing notion that topical latanoprost can lead to symptoms of headaches by reporting three cases of headache symptoms that developed following instillation of latanoprost prescribed as first-line therapy for newly diagnosed primary open-angle glaucoma (POAG) is explored in this case series.: Prostaglandin analogues (PGAs) are often used as first-line treatment in the treatment of POAG. An uncommon and infrequently reported side effect of PGAs is headaches.: A retrospective review of patient records was conducted on patients seen at the Centre for Eye Health between April 2016 and August 2017. Clinical findings, including outcomes following interventions such a punctal occlusion, as well as the proposed pharmacological mechanism underlying this phenomenon are presented and discussed.: Case 1 is a 62-year-old Caucasian male diagnosed with POAG and prescribed latanoprost in both eyes. At the follow-up visit, he reported waking up in with a dull throbbing headache following instillation of the eye drops the night before. Case 2 is a 58-year-old Asian male with POAG prescribed latanoprost to both eyes. Within a week, he developed symptoms of recurrent progressively worsening headaches post-instillation which persisted into the morning. Case 3 is a 75-year-old Caucasian male with POAG prescribed latanoprost for both eyes. He developed latanoprost sensitivity as well as headache symptoms associated with the eye drops which resolved followed its cessation. All patients reported initial symptoms of headaches associated with latanoprost use however the headaches were not persistent with intermittent punctal occlusion (cases 1 and 2) or intra-class drug rechallenge (case 3).: Although there may be a yet-undiscovered link between a headache response and latanoprost, these cases call to question the pharmacological relationship between latanoprost and headache symptoms. A systemic approach to critically examine the pathophysiological link between pharmacological therapy and potential adverse effects is proposed.
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http://dx.doi.org/10.1080/08164622.2021.1878846DOI Listing
March 2021

Clinical outcomes of the Centre for Eye Health: an intra-professional optometry-led collaborative eye care clinic in Australia.

Clin Exp Optom 2021 Feb 25:1-10. Epub 2021 Feb 25.

Centre for Eye Health, Sydney, Australia.

: This novel clinical model is the first of its kind in Australia and was designed to help reduce unnecessary referrals into overburdened public systems by utilising pre-existing community-based resources.: The Centre for Eye Health (CFEH) is an intra-professional optometry-led care clinic offering an alternative pathway to traditional ophthalmology-based pathways (public hospital clinics or private practices) for 'at-risk' patients requiring ocular imaging, diagnostic and management services. This study evaluates the CFEH integrated eye-care model in the identification of chronic eye diseases within the community.: A retrospective random clinical audit of over 750 medical records of patients referred to the CFEH between July 2016 and June 2019 was conducted. Demographics of patients, referral type, final diagnosis and recommended management plans were extracted from this subset. Clinic key performance indicators (referral turnaround time, and net cost per patient appointment) were also extracted.: Of the 755 referrals associated with the audited records, 77.4% resulted in the identification of patients with or at-risk of developing eye diseases with 73.5% of this cohort requiring ongoing monitoring at CFEH or referral to ophthalmology. Although the CFEH model is not designed to diagnose or manage acute conditions, 1.5% of patients in this pathway required same day ophthalmological or medical intervention. The cost per patient was equivalent to hospital eye departments costs.: This integrated care pathway has the potential to reduce unnecessary referrals from optometrists to hospital ophthalmological service by offering a safe and effective alternate pathway. The majority of patients seen within this pathway were able to be monitored within optometry-led services. This is a unique clinical model utilising inter-professional referrals within optometry which has the potential to reduce preventable blindness within the community through the early detection of eye diseases.
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http://dx.doi.org/10.1080/08164622.2021.1878821DOI Listing
February 2021

The performance and confidence of clinicians in training in the analysis of ophthalmic images within a work-integrated teaching model.

Ophthalmic Physiol Opt 2021 Mar 8. Epub 2021 Mar 8.

Centre for Eye Health, University of New South Wales, Kensington, New South Wales, Australia.

Purpose: A fundamental clinical skill is the recognition of artefacts within the outputs of advanced imaging modalities. However, current teaching programmes of healthcare practitioners are becoming increasingly challenged to provide practical exposure within an already crowded curriculum. This study evaluates the impact of a novel work-integrated teaching model on the confidence and competence of clinicians in the use of optical coherence tomography (OCT) and the recognition of its artefacts. The outcomes were then used to develop a model to predict performance and guide teaching strategies.

Methods: We prospectively evaluated a 6-week clinical placement for final year optometry students within a diagnostic eye clinic in 2018-2020. Participants completed a quiz on the identification of common OCT artefacts and rated their confidence levels on key areas of OCT application using a five-point Likert scale. Both were completed before (pre-rotation) and after (post-rotation) the placement. The cohort was divided into two groups; the first group was used to assess the impact of the placement and derive the prediction model for post-placement performance, which was then validated against the second group.

Results: A significant improvement in detecting OCT imaging artefacts was seen upon completion of the placement, which was greater in participants with lower entry level performance. Across all OCT artefact subtypes, there was an improvement in detecting segmentation error, delineation error and media opacities. A model predicting post-placement student performance was developed using entry level knowledge base as the key dependent variable. Self-rated confidence improved across all domains of OCT application but was not found to be a direct predictor of actual performance.

Conclusions: These results highlight the benefit of a work-integrated learning programme on both academic performance and confidence whilst identifying entry level knowledge base as the key variable predicting improvement. Tailored teaching incorporating entering knowledge is the best predictor of improvement during clinical placements. Integrating clinicians into a work-integrated setting with tailored teaching and comprehensive practical exposure can be an effective method for training future or current healthcare professionals.
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http://dx.doi.org/10.1111/opo.12795DOI Listing
March 2021

Vision Impairment Provides New Insight Into Self-Motion Perception.

Invest Ophthalmol Vis Sci 2021 Feb;62(2)

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

Purpose: Leading causes of irreversible blindness such as age-related macular degeneration (AMD) and glaucoma can, respectively, lead to central or peripheral vision loss. The ability of sufferers to process visual motion information can be impacted even during early stages of eye disease. We used head-mounted display virtual reality as a tool to better understand how vision changes caused by eye diseases directly affect the processing of visual information critical for self-motion perception.

Methods: Participants with intermediate AMD or early manifest glaucoma with near-normal visual acuities and visual fields were recruited for this study. We examined their experiences of self-motion in depth (linear vection), spatial presence, and cybersickness when viewing radially expanding patterns of optic flow simulating different speeds of self-motion in depth. Viewing was performed with the head stationary (passive condition) or while making lateral-sway head movements (active conditions).

Results: Participants with AMD (i.e., central visual field loss) were found to have greater vection strength and spatial presence, compared to participants with normal visual fields. However, participants with glaucoma (i.e., peripheral visual field loss) were found to have lower vection strength and spatial presence, compared to participants with normal visual fields. Both AMD and glaucoma groups reported reduced severity in cybersickness compared to healthy normals.

Conclusions: These findings strongly support the view that perceived self-motion is differentially influenced by peripheral versus central vision loss, and that patients with different visual field defects are oppositely biased when processing visual cues to self-motion perception.
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http://dx.doi.org/10.1167/iovs.62.2.4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7862735PMC
February 2021

A combined convolutional and recurrent neural network for enhanced glaucoma detection.

Sci Rep 2021 Jan 21;11(1):1945. Epub 2021 Jan 21.

Vision Science Group, Graduate School of Health, University of Technology Sydney, Sydney, Australia.

Glaucoma, a leading cause of blindness, is a multifaceted disease with several patho-physiological features manifesting in single fundus images (e.g., optic nerve cupping) as well as fundus videos (e.g., vascular pulsatility index). Current convolutional neural networks (CNNs) developed to detect glaucoma are all based on spatial features embedded in an image. We developed a combined CNN and recurrent neural network (RNN) that not only extracts the spatial features in a fundus image but also the temporal features embedded in a fundus video (i.e., sequential images). A total of 1810 fundus images and 295 fundus videos were used to train a CNN and a combined CNN and Long Short-Term Memory RNN. The combined CNN/RNN model reached an average F-measure of 96.2% in separating glaucoma from healthy eyes. In contrast, the base CNN model reached an average F-measure of only 79.2%. This proof-of-concept study demonstrates that extracting spatial and temporal features from fundus videos using a combined CNN and RNN, can markedly enhance the accuracy of glaucoma detection.
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http://dx.doi.org/10.1038/s41598-021-81554-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820237PMC
January 2021

Modelling normal age-related changes in individual retinal layers using location-specific OCT analysis.

Sci Rep 2021 Jan 12;11(1):558. Epub 2021 Jan 12.

Centre for Eye Health, University of New South Wales, Sydney, 2052, Australia.

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 individual 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) 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.
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http://dx.doi.org/10.1038/s41598-020-79424-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7804110PMC
January 2021

Authors' reply.

Ophthalmic Physiol Opt 2021 Jan 25;41(1):203-204. Epub 2020 Nov 25.

Centre for Eye Health, University of New South Wales, Kensington, Australia.

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http://dx.doi.org/10.1111/opo.12760DOI Listing
January 2021

Custom extraction of macular ganglion cell-inner plexiform layer thickness more precisely co-localizes structural measurements with visual fields test grids.

Sci Rep 2020 10 28;10(1):18527. Epub 2020 Oct 28.

Centre for Eye Health, University of New South Wales, Sydney, NSW, 2052, Australia.

We aimed to evaluate methods of extracting optical coherence tomography (OCT)-derived macular ganglion cell-inner plexiform layer (GCIPL) thickness measurements over retinal locations corresponding to standard visual field (VF) test grids. A custom algorithm was developed to automatically extract GCIPL thickness measurements from locations corresponding to Humphrey Field Analyser 10-2 and 30-2 test grids over Goldmann II, III and V stimulus sizes from a healthy cohort of 478 participants. Differences between GCIPL thickness measurements based on VF test grids (VF-based paradigms) and the 8 × 8 grid, as per instrument review software, were analyzed, as were impacts of fovea to optic disc tilt and areas over which GCIPL thickness measurements were extracted. Significant differences between the VF-based paradigms and the 8 × 8 grid were observed at up to 55% of locations across the macula, with the greatest deviations at the fovea (median 25.5 μm, 95% CI 25.24-25.72 μm, P < .0001). While significant correlations with fovea to optic disc tilt were noted at up to 33% of locations distributed 6°-8° from the foveal center, there were no marked differences in GCIPL thickness measurements between VF-based paradigms using different stimulus sizes. As such, standard high-density OCT measurement paradigms do not adequately reflect GCIPL measurements at retinal locations tested with standard VF patterns, with the central macular region contributing most to the observed differences and with further correction required for fovea to optic disc tilt. Spatial direction of GCIPL thickness measurements will improve future comparisons of structure and function, thereby improving methods designed to detect pathology affecting the inner retina.
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http://dx.doi.org/10.1038/s41598-020-75599-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7595126PMC
October 2020

Visualizing the Consistency of Clinical Characteristics that Distinguish Healthy Persons, Glaucoma Suspect Patients, and Manifest Glaucoma Patients.

Ophthalmol Glaucoma 2020 Jul - Aug;3(4):274-287. Epub 2020 Apr 26.

Centre for Eye Health, University of New South Wales, Kensington, Australia; School of Optometry and Vision Science, University of New South Wales, Kensington, Australia.

Purpose: To use factor analysis to visualize and assess the reproducibility and consistency of clinical quantitative parameters that can optimally distinguish among healthy, glaucoma suspect, and manifest glaucoma patients at a cross-sectional level and thus to describe the transition of quantitative change among the diagnostic categories.

Design: Retrospective cross-sectional study.

Participants: The medical records of healthy, glaucoma suspect, and manifest glaucoma patients (diagnosed by expert clinicians) seen at the Centre for Eye Health in 2015 (n = 148, n = 664, and n = 129, respectively) and 2018 (n = 242, n = 464, and n = 126, respectively) were reviewed. One eye was selected for the study.

Methods: Quantitative clinical measures (intraocular pressure [IOP], central corneal thickness [CCT], visual field [VF], and OCT) were extracted and binary logistic (backward stepwise) regression was performed to identify factors that dictated separation between diagnostic pairs. These were used systematically as inputs for factor analysis to determine a final model that could potentially predict a clinical diagnosis.

Main Outcome Measures: Intraocular pressure, CCT, VF (mean deviation and pattern standard deviation) indices, and OCT optic nerve head parameters and thickness values (retinal nerve fiber layer [RNFL] and ganglion cell-inner plexiform layer).

Results: Few clinical parameters were identified commonly as significant across all diagnostic pairings for 2015 (3 of 23: IOP, pattern standard deviation, and 7-o'clock RNFL thickness) and 2018 (1 of 23: vertical cup-to-disc ratio). Few parameters overlapped when comparing 2015 and 2018 results, highlighting inconsistencies in the models between years. Factor analysis showed good separation between healthy persons and glaucoma patients. Using biplots to visualize the data in 2-dimensional clusters, glaucoma suspect patients demonstrated substantial overlap with healthy and glaucoma cohorts. The contributions of each parameter to diagnostic separation changed between groups and years.

Conclusions: Despite advances in quantitative ocular imaging and perimetry, the transition among healthy, glaucoma suspect, and manifest glaucoma patients remains confounded by a lack of consistent, reproducible combinations of quantitative clinical criteria. These results highlight the nebulousness (at patient-, instrument-, and clinician-related levels) of glaucoma diagnosis that remains contingent on individual clinical expertise and assessment.
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http://dx.doi.org/10.1016/j.ogla.2020.04.009DOI Listing
April 2020

Clinical utility of irx3 in keratoconus.

Clin Exp Optom 2021 Jan;104(1):107-114

School of Optometry and Vision Science, The University of New South Wales , Sydney, Australia.

Clinical Relevance: Diagnosis and monitoring of keratoconus is increasingly being conducted with the aid of imaging equipment such as corneal aberrometry. There is a need to also know the confidence with which ocular aberration measurements can be made.

Background: To assess the repeatability of lower- and higher-order aberration measurements in patients with keratoconus using the irx3 wavefront aberrometer (Imagine Eyes, Orsay, France) and evaluate correlations with corneal curvature.

Methods: The irx3 wavefront aberrometer was used to measure bilateral lower- and higher-order ocular aberrations on 33 participants with keratoconus. Three measurements were taken from each eye to determine the repeatability of lower-order aberrations (quantified as sphere and cylinder in dioptres) and higher-order aberration co-efficients (up to eighth order in micrometres), coma, trefoil and total higher-order aberration root mean square (in micrometres). Corneal curvature was measured using the Pentacam HR system (OCULUS, Wetzlar, Germany).

Results: Repeat measurements for lower-order aberrations resulted in larger co-efficients of repeatability than higher-order aberrations. Similarly, larger co-efficients of repeatability between repeated measures across all Zernike co-efficients were observed in eyes with severe keratoconus (that is, corneal curvature > 52-D) compared to eyes with flatter corneas. The difference between repeated measures tended to be significant for the lower-order aberrations regardless of corneal curvature. The highest correlations with corneal curvature for right and left eyes respectively, were identified for total higher-order aberration root mean square (r = 0.92, p < 0.001 and r = 0.91, p < 0.001), followed closely by coma (r = -0.93, p < 0.001 and r = -0.86, p < 0.001) and the Z (3, -1) co-efficient (r = -0.92, p < 0.001 and r = -0.86, p < 0.001 for right and left eyes, respectively).

Conclusions: Lower-order aberrations tended to be less repeatable, indicating that instrument variability must be considered when monitoring progression. Total higher-order aberration root mean square and third-order aberrations, in particular the vertical coma Z (3, -1) co-efficient, demonstrated a stronger correlation with corneal curvature than the lower-order aberrations.
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http://dx.doi.org/10.1111/cxo.13133DOI Listing
January 2021

Validation of a novel functional test for assessing metamorphopsia using epiretinal membranes as a model.

Sci Rep 2020 09 10;10(1):14938. Epub 2020 Sep 10.

Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.

Current tests for assessing metamorphopsia do not account for confounders such as perceptual filling-in and spatial redundancy, which affect its sensitivity and repeatability. This proof-of-concept study aimed to assess the performance of a novel laboratory-based psychophysical test (Line Sag Test, LST) which addresses these issues for quantification of metamorphopsia in idiopathic epiretinal membranes. The LST quantifies perpendicular metamorphopsia at three eccentricities (3°, 6°, and 9°) along eight meridians (45° steps). Metamorphopsia was assessed using the LST and Amsler grid and the hit rates of both tests for detecting metamorphopsia were compared. Normal metamorphopsia scores using the LST did not differ significantly from 0 and fell within one step-size (p = 0.500). The LST detected significantly more cases of metamorphopsia than the Amsler grid (14/21 versus 3/21) (p = 0.003). Similarly, significantly more cases of visual distortions in asymptomatic iERMs were detected using the LST than the Amsler grid (11/18 versus 0/18) (p = 0.008). The LST has a higher hit rate compared to the Amsler grid (67% versus 14%). This work demonstrates a psychophysically-robust functional test addressing perceptual confounders is more sensitive for quantifying and localising metamorphopsia in macular disease, particularly in asymptomatic disease.
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http://dx.doi.org/10.1038/s41598-020-71627-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7484749PMC
September 2020

Glaucoma Community Care: Does Ongoing Shared Care Work?

Int J Integr Care 2020 Aug 7;20(3). Epub 2020 Aug 7.

Centre for Eye Health, Sydney, NSW, AU.

Purpose: We assessed a novel, public, vertical integrated care model for glaucoma management in the community.

Methods: This study was a retrospective, longitudinal study of 266 patients diagnosed or suspected of glaucoma. Patients were stratified to either ongoing ophthalmology-led (n = 81) or optometry-led shared care (n = 185). Demographics and clinical characteristics, including the re-referral rate and timeliness of follow up were analysed.

Results: Just under half (565/1224, 46%) of all follow up consultations over the total study period of 45 months were seen in optometry-led care, with a re-referral rate to ophthalmology of 21%. Treated patients showed a median intraocular pressure reduction of 20% and a median time delay of just two days between the actual and recommended review period.

Conclusions: Shared care provides an effective option for managing the ongoing care burden in chronic stable glaucoma cases at low risk of vision loss.
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http://dx.doi.org/10.5334/ijic.5470DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7427692PMC
August 2020

Management of open-angle glaucoma by primary eye-care practitioners: toward a personalised medicine approach.

Clin Exp Optom 2021 Apr 29;104(3):367-384. Epub 2021 Mar 29.

Ophthalmology Department, Prince of Wales Hospital, Sydney, Australia.

Glaucoma is the leading cause of irreversible blindness worldwide. As a chronic disease, glaucoma presents a significant burden to the individual, health-care provider and the health-care system. Currently, strategies for treating glaucoma are focused on lowering intraocular pressure, which is aimed at slowing or arresting disease progression over time. This is the only current accepted therapeutic strategy for glaucoma, and can be achieved using topical drugs, laser trabeculoplasty, filtration surgery or cyclodestructive techniques. The lowering of intraocular pressure has been well-supported by numerous large-scale seminal clinical trials in primary open-angle glaucoma, in both its early and advanced stages. Although such guidance remains current, in the last 10-years, there has been a significant evolution in preferred first-line therapies in the treatment of open-angle glaucoma with a resultant shift in practice patterns, particularly early in the course of the disease. These changes reflect both from the perspective of the doctor - in titrating the most effective and least risky treatment modality - and the perspective of the patient, in consenting to a treatment that preserves vision and results in minimal negative impact on quality of life. In this review, the most recent evidence regarding treatment modalities for early primary open-angle glaucoma is presented and an updated framework for management guidance is proposed.
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http://dx.doi.org/10.1111/cxo.13114DOI Listing
April 2021

Assessment of angle closure spectrum disease as a continuum of change using gonioscopy and anterior segment optical coherence tomography.

Ophthalmic Physiol Opt 2020 09 14;40(5):617-631. Epub 2020 Aug 14.

Centre for Eye Health, University of New South Wales, Kensington, New South Wales, Australia.

Purpose: Studies examining the anterior chamber angle and angle closure disease often compare quantitative angle information obtained using anterior segment optical coherence tomography (ASOCT) with one of several ordinal scales derived using gonioscopy. We test the assumption that the ordinal gonioscopic angle grades have equal step sizes and can be analysed using metric statistics.

Methods: The medical records of 214 consecutive patients who were referred for assessment of the anterior chamber angle were prospectively examined using gonioscopy and ASOCT (Spectralis Optical Coherence Tomography, OCT, www.heidelbergengineering.com). Anterior chamber angle parameters (angle opening distance, AOD, and trabecular-iris space area, TISA at 500 and 750 microns) were extracted from ASOCT images using a semi-automated segmentation algorithm written on MATLAB (www.mathworks.com). We first matched the quantitative values for each gonioscopic grade (0-4, from no structures visible to ciliary body visible) and described the frequency distributions to determine separability. We then applied a grade-agnostic clustering algorithm to determine the concordance between algorithm-clustered groups (using solely quantitative data) and those obtained using gonioscopy.

Results: The frequency distributions of the quantitative ASOCT parameters for each angle grade were mostly non-parametric and displayed unique distribution characteristics, with a floor effect seen for grade 0 and the lack of a ceiling effect seen for grades 3 and 4. Although we found significant differences in quantitative values across the five angle grades using the frequency distributions, some pairwise comparisons were indistinguishable (such as grades 0 and 1, and grades 3 and 4) due to the overlaps in distributions. On average, differences in quantitative values were consistent between gonioscopic grade steps, but there remained substantial variability that confounds prediction of change between ordinal steps. The clustering algorithm showed approximately 10% of cases with the same group assignment as that of the gonioscopic grade, improving slightly to 30% when the top 5% of quantitative data were excluded from analysis.

Conclusions: Our results do not necessarily support the assumption that the ordinal scales used in gonioscopy can be interpreted using an interval scale. We highlight the need for better methods of describing the course and risk of angle closure spectrum disease to identify disease progression and conversion, where gonioscopy remains the gold standard.
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http://dx.doi.org/10.1111/opo.12721DOI Listing
September 2020

A Strategy for Seeding Point Error Assessment for Retesting (SPEAR) in Perimetry Applied to Normal Subjects, Glaucoma Suspects, and Patients With Glaucoma.

Am J Ophthalmol 2021 01 8;221:115-130. Epub 2020 Aug 8.

Centre for Eye Health and the School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales, Australia.

Purpose: We sought to determine the impact of seeding point errors (SPEs) as a source of low test reliability in perimetry and to develop a strategy to mitigate this error early in the test.

Design: Cross-sectional study.

Methods: Visual field test results from 1 eye of 364 patients (77 normal eyes, 178 glaucoma suspect eyes, and 109 glaucoma eyes) were used to develop models for identifying SPE. Two test cohorts (326 undertaking Swedish interactive thresholding algorithm [SITA]-Faster and 327 glaucoma eyes undertaking SITA-Standard) were used to prospectively evaluate the models for identifying SPEs. Global visual field metrics were compared among reliable and unreliable results. Regression models were used to identify factors distinguishing SPEs from non-SPEs. Models were evaluated using receiver operating characteristic (ROC) curves.

Results: In the test cohorts, SITA-Faster produced a higher rate of unreliable visual field results (30%-49.7%) compared with SITA-Standard (10.8%-16.6%). SPEs contributed to most of the unreliable results in SITA-Faster (57.5%-64.9%) compared with gaze tracker deviations accounting for most of the unreliable results in SITA-Standard (40%-77.8%). In SITA-Faster, results with SPEs had worse global indices and more clusters of sensitivity reduction than reliable results. Our best model (using 9 test locations) can identify SPEs with an area under the ROC curve of 0.89.

Conclusion: SPEs contribute to a large proportion of unreliable visual field test results, particularly when using SITA-Faster. We propose a useful model for identifying SPEs early in the test that can then guide retesting using both SITA algorithms. We provide a simplified framework for the perimetrist to improve the overall fidelity of the test result.
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http://dx.doi.org/10.1016/j.ajo.2020.07.047DOI Listing
January 2021

Cluster analysis reveals patterns of age-related change in anterior chamber depth for gender and ethnicity: clinical implications.

Ophthalmic Physiol Opt 2020 09 9;40(5):632-649. Epub 2020 Jul 9.

Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.

Purpose: To identify patterns of age-, gender- and refractive- related changes in Scheimpflug-based anterior chamber depth across the central 8 mm of chamber width, to derive normative models, potentially useful for angle closure disease diagnosis.

Methods: This was a retrospective, cross-sectional study. Scheimpflug photography was used to obtain anterior chamber depth measurements at 57 points across the central 8 mm of the chamber width from one eye of each healthy subject (male Caucasians (n = 189), female Caucasians (n = 186), male Asians (n = 165) and female Asians (n = 181)). Sliding window and nonlinear regression analysis was used to identify the age-related changes in chamber depth. Hierarchical cluster analysis was used to identify test locations with statistically identical age-related shifts, which were used to perform age-correction for all subjects, resulting in normative distributions of chamber depth across the chamber width. The model was examined with and without the contribution of spherical equivalent refractive error.

Results: Distinct clusters, demonstrating statistically indistinguishable age-related changes of chamber depth over time, were identified. These age-related changes followed a nonlinear regression (fifth or sixth order polynomial). Females tended to have a greater rate of chamber depth shallowing. Incorporating refractive error into the model produced minimal changes to the fit relative to the ground truth. Comparisons with cut-offs for angle closure from the literature showed that ageing alone was insufficient for identifying angle closure disease.

Conclusions: Age-, ethnicity- and gender-related differences need to be acknowledged in order to utilise anterior chamber depth data for angle closure disease diagnosis correctly. Ageing alone does not adequately account for the angle closure disease process.
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http://dx.doi.org/10.1111/opo.12714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7540376PMC
September 2020

Ability of 24-2C and 24-2 Grids to Identify Central Visual Field Defects and Structure-Function Concordance in Glaucoma and Suspects.

Am J Ophthalmol 2020 11 2;219:317-331. Epub 2020 Jul 2.

Centre for Eye Health, University of New South Wales, Kensington, New South Wales, Australia; School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales, Australia.

Purpose: The purpose of this study was to compare the ability of the 24-2 test grid with that of the 24-2C test grid to measure visual field global indices, identify central visual field defects, and facilitate macular structure-function analysis with optical coherence tomography (OCT) scans in glaucoma suspects and glaucoma patients.

Design: Prospective, cross-sectional study.

Methods: One eye from each of 100 glaucoma suspects and glaucoma patients (60 undergoing SITA-Faster [Zeiss Meditec] testing on 24-2 and 24-2C; 40 undergoing SITA-Standard [Zeiss Meditec] testing on 24-2 and SITA-Faster on 24-2C) were included in the study. Global visual field indices, test duration, and pattern deviation results were extracted. The deviation map from the Cirrus OCT (Carl Zeiss Meditec) Ganglion Cell Analysis (GCA) was extracted, and structure-function relationships were compared after correction of the visual field test stimulus location that stimulated the corresponding retinal ganglion cell.

Results: Global index results of the 24-2 grid were similar to those of the 24-2C grid, and both identified a comparable number of clusters of visual field defects. Centrally, the 24-2C grid identified more clusters of defects than the 24-2 grid, but this was not statistically significant. Although the 24-2C test locations resulted in more instances of structure-function concordance than the 24-2 locations, half the locations in the 24-2C grid fell close to or outside the GCA grid when corrected for ganglion cell displacement.

Conclusions: The 24-2C returned global visual field indices similar to the 24-2 grid but tended to identify more clusters of central functional defects. Central structure-function concordance was better achieved using the 24-2C grid, but half of the visual field test locations did not coincide with the commonly used macular thickness scan.
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http://dx.doi.org/10.1016/j.ajo.2020.06.024DOI Listing
November 2020

Normal aging changes in the choroidal angioarchitecture of the macula.

Sci Rep 2020 07 2;10(1):10810. Epub 2020 Jul 2.

National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore.

The choroidal vascularity index (CVI) has been shown to be sensitive in detecting changes in choroidal angioarchitecture in a range of ocular diseases. However, changes in CVI in association with normal physiological aging and spatial distribution remains to be determined. This is significant as a range of ocular conditions with choroidal degeneration are associated with aging. In this study, we assessed CVI for 106 healthy eyes from 106 individuals (range 21-78 years old, ~ 20 individuals/decade) at 15 eccentricities across the macula (0, 230 µm, 460 µm, 690 µm, 1,150 µm, 1,380 µm and 2,760 µm from the fovea in the superior and inferior direction). Total choroidal area, luminal area and stromal area were all significantly decreased with age (p < 0.001 for all parameters). CVI was also significantly decreased with age (p < 0.01) and eccentricity. Fitting of quadratic regression curves to CVI as a function of age yielded a good fit for all eccentricities (r = 0.55-0.80) and suggested a decrease in CVI from the ages of 33-43 years at a rate of 0.7-2.7% per decade. CVI was lower in the inferior versus superior retina at matching eccentricities and a significant difference in age-related decline of CVI with eccentricity only occurred in inferior locations. These findings suggest choroidal angioarchitecture declines from the 4th decade of life with potential eccentricity differences in the inferior and superior retina. Considering the number of age-related diseases with choroidal dysfunction, these results provide foundational knowledge to understand choroidal involvement in these diseases.
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http://dx.doi.org/10.1038/s41598-020-67829-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7331638PMC
July 2020

Evaluation of a hospital-based integrated model of eye care for diabetic retinopathy assessment: a multimethod study.

BMJ Open 2020 04 30;10(4):e034699. Epub 2020 Apr 30.

Australian Institute of Health Innovation, Macquarie University, Sydney, New South Wales, Australia.

Objectives: Diabetic eye disease is a leading cause of blindness but can be mitigated by regular eye assessment. A framework of issues, developed from the literature of barriers to eye assessment, was used to structure an examination of perceptions of a new model of care for diabetic retinopathy from the perspective of staff using the model, and health professionals referring patients to the new service.

Design: Multimethod: interviews and focus groups, and a separate survey.

Setting: A new clinic based on an integrated model of care was established at a hospital in outer metropolitan Sydney, Australia in 2017. Funded jointly by Centre for Eye Health (CFEH) and the hospital, the clinic was equipped and staffed by optometrists who work alongside the ophthalmologists in the existing hospital eye clinic.

Participants: Five (of seven) hospital staff working in the clinic (ophthalmologists and administrative officers) or referring to it from other departments (endocrinologists); nine optometrists from CFEH who developed or worked in the clinic; 10 community-based optometrists as potential referrers.

Results: The new clinic was considered to have addressed known barriers to eye assessment, including access, assistance for patients unable/unwilling to organise eye checks and efficient management of human resources. The clinic optimised known drivers of this model of care: providing clear scope of practice and protocols for shared care between optometrists and ophthalmologists, good communication between referrers and eye professionals and a collegial approach promoting interprofessional trust. Remaining areas of concern were few referrals from general practitioners, fewer referrals from hospital endocrinologists than expected and issues with stretched administrative capacity. There were also perceived mismatches between the priorities of hospital management and aims of the clinic.

Conclusions: The new model was considered to have addressed many of the barriers to assessment. While there remain issues with the model, there were also unexpected benefits.
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http://dx.doi.org/10.1136/bmjopen-2019-034699DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7213850PMC
April 2020

Macula Ganglion Cell Thickness Changes Display Location-Specific Variation Patterns in Intermediate Age-Related Macular Degeneration.

Invest Ophthalmol Vis Sci 2020 03;61(3)

.

Purpose: The purpose of this study was to examine changes in the ganglion cell layer (GCL) of individuals with intermediate age-related macular degeneration (AMD) using grid-wise analysis for macular optical coherence tomography (OCT) volume scans. We also aim to validate the use of age-correction functions for GCL thickness in diseased eyes.

Methods: OCT macular cube scans covering 30° × 25° were acquired using Spectralis spectral-domain OCT for 87 eyes with intermediate AMD, 77 age-matched normal eyes, and 254 non-age-matched normal eyes. The thickness of the ganglion cell layer (GCL) was defined after segmentation at 60 locations across an 8 × 8 grid centered on the fovea, where each grid location covered 0.74 mm2 (approximately 3° × 3°) within the macula. Each GCL location of normal eyes (n = 77) were assigned to a specific iso-ganglion cell density cluster in the macula, based on patterns of age-related GCL thickness loss. Analyses were then performed comparing AMD GCL grid-wise data against corresponding spatial clusters, and significant AMD GCL thickness changes were denoted as values outside the 95% distribution limits.

Results: Analysis of GCL thickness changes revealed significant differences between spatial clusters, with thinning toward the fovea, and thickening toward the peripheral macula. The direction of GCL thickness changes in AMD were associated more so with thickening than thinning in all analyses. Results were corroborated by the application of GCL thickness age-correction functions.

Conclusions: GCL thickness changed significantly and nonuniformly within the macula of intermediate AMD eyes. Further characterization of these changes is critical to improve diagnoses and monitoring of GCL-altering pathologies.
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http://dx.doi.org/10.1167/iovs.61.3.2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7401429PMC
March 2020

A holistic model of low vision care for improving vision-related quality of life.

Clin Exp Optom 2020 11 3;103(6):733-741. Epub 2020 Mar 3.

Centre for Eye Health, The University of New South Wales, Sydney, Australia.

Vision impairment can have a significant impact on the wellbeing and quality of life of an individual. Vision rehabilitation has the potential to improve these areas; however, four in five patients with vision impairment are not being referred to the appropriate services. Barriers to on-referral include, but are not limited to: (1) misunderstandings by both practitioners and patients alike regarding which individuals with vision impairment might benefit or qualify for low vision services; (2) lack of awareness of available services; (3) unfamiliarity with practice guidelines; (4) miscommunication between practitioners and patients; (5) required patient travel or limitations in access; and (6) the perceived costs of goods and services. Further, current referral patterns do not represent a holistic patient-centric approach. Vision-related quality of life questionnaires are tools which can assist health professionals in providing optimal individualised care. This review explores current evidence regarding low vision service delivery within Australia and globally, the impact of vision impairment on activities of daily living, the instruments used for the assessment of vision-related quality of life (VRQOL), competing priorities of individual needs in low vision services and rehabilitation, and provides recommendations for a more patient-centred model of care.
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http://dx.doi.org/10.1111/cxo.13054DOI Listing
November 2020

Determining Significant Elevation of Intraocular Pressure Using Self-tonometry.

Optom Vis Sci 2020 02;97(2):86-93

Centre for Eye Health and School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales, Australia.

Significance: Icare HOME rebound tonometry is increasingly adopted into clinical practice for IOP phasing of glaucoma patients and suspects. Because of measurement differences with applanation tonometry and diurnal fluctuations, interpretation of the IOP measured with Icare HOME phasing can be challenging.

Purpose: The purpose of this study was to use a large patient cohort to develop a practical, analytical tool for interpreting Icare HOME measurements with respect to applanation pressure.

Methods: IOP measurements using the Icare HOME and an applanation tonometer were taken prospectively in 498 consecutive patients. Bland-Altman, frequency distribution, and linear regression analysis were applied to determine measurement differences. A novel criterion, Threshold Icare HOME IOP, was developed to assist identification of elevation above target applanation pressure, considering the expected diurnal variation and measurement variability.

Results: Icare HOME tended to underestimate applanation tonometry (mean bias, -1.7 mmHg; 95% limits of agreement, -7.0 to +3.6). Overall, differences were within ±3 mmHg in 71.5% and ±5 mmHg in 92% of patients. Based on the novel criterion developed, Icare HOME measurements that exceed target applanation pressure by 6 mmHg or greater are generally outside the 95% limit of expected observations.

Conclusions: The Threshold Icare HOME IOP is a novel and practical criterion that can assist clinicians in their interpretation of Icare HOME phasing measurements with respect to target applanation pressures. Elevation above the expected thresholds may prompt closer monitoring or even modifications to glaucoma management.
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http://dx.doi.org/10.1097/OPX.0000000000001478DOI Listing
February 2020

Impact of referral refinement on management of glaucoma suspects in Australia.

Clin Exp Optom 2020 09 18;103(5):675-683. Epub 2019 Dec 18.

Centre for Eye Health, The University of New South Wales, Sydney, Australia.

Background: In ageing populations, the prevalence of chronic diseases such as glaucoma is projected to increase, placing additional demands on limited health-care resources. In the UK, the demand for secondary care in hospital eye clinics was inflated by high rates of false positive glaucoma referrals. Collaborative care models incorporating referral refinement, whereby glaucoma suspect referrals are triaged by suitably trained optometrists through further testing, can potentially reduce false positive referrals. This study examined the impact of a referral refinement model on the accuracy of glaucoma referrals in Australia.

Methods: Optometrist-initiated glaucoma suspect referrals to the Glaucoma Management Clinic (Sydney, Australia) were prospectively recruited. Glaucoma suspect referrals arising from two pathways were eligible for inclusion, either directly from a community optometrist (standard care) or following comprehensive assessment at the Centre for Eye Health (referral refinement). Main outcome measures were the positive predictive value and false positive rate of referrals. The impact of referral letter content on management outcomes was also investigated.

Results: Of 464 referrals received between March 2015 and June 2018, 252 were for treatment of naïve glaucoma suspects and eligible for inclusion. Following ophthalmological assessment, 45.6 per cent (n = 115/252) were prescribed treatment for open angle glaucoma or ocular hypertension. Positive predictive value of community optometry referrals was 33.8 per cent (n = 25/74) and 50.6 per cent (n = 90/178) following referral refinement. The first visit discharge (false positive) rate was 26 per cent (n = 19/74) for community referrals compared to four per cent (n = 8/178) with referral refinement. Positive predictive value increased with the number of abnormal clinical examination findings associated with referral (χ test, p < 0.0001). The number of abnormal findings reported in referrals was significantly higher with referral refinement compared to without (n = 1.9 versus 1.5, t-test, p < 0.0001).

Conclusion: Referral refinement can improve the diagnostic accuracy of optometry-initiated referrals for glaucoma suspects in Australia, thereby decreasing unnecessary referrals to hospital and other secondary clinics.
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http://dx.doi.org/10.1111/cxo.13030DOI Listing
September 2020

Multimodal imaging characteristics of congenital grouped hyper- and hypo-pigmented fundus lesions.

Clin Exp Optom 2020 09 25;103(5):641-647. Epub 2019 Nov 25.

Centre for Eye Health, Sydney, Australia.

Background: The imaging characteristics of congenital grouped pigmentation of the retinal pigment epithelium (CGP-RPE) and its non-pigmented variant - grouped congenital albinotic retinal pigment epithelial spots (GCARPES) are poorly defined in the literature. Our case series reports their multimodal imaging characteristics across a spectrum of presentations.

Methods: A retrospective review of patient records was conducted on patients seen at the Centre for Eye Health between January and December 2016. The multimodal imaging findings across four cases is described using optical coherence tomography (OCT), infrared imaging, ultra-widefield imaging, fundus photography and fundus autofluorescence (FAF).

Results: Case 1 is a 55-year-old female with a bilateral presentation of CGP-RPE showing typical features. Case 2 is a 28-year-old male with a classical presentation of GCARPES in the left eye. Case 3 is a 33-year-old female with unilateral CGP-RPE and an atypical solitary congenital hypertrophy of the retinal pigment epithelium (CHRPE) in the same eye. Case 4 is a unilateral presentation in an 11-year-old female with unusual characteristics. Ocular imaging characteristics of CGP-RPE lesions varied between patients: OCT showed visible RPE changes in cases 3 and 4 but not case 1. The pattern of FAF and infrared imaging also varied with most lesions displaying a pattern of hypo-autofluorescence, but some central lesions in case 3 exhibited hyper-autofluorescence. All lesions were visible with fundus photography.

Conclusion: FAF can be helpful in alerting clinicians to the presence of lesions that may be difficult to visualise funduscopically and OCT can be helpful in differentiating between CGP-RPE and its variants from more sinister ocular conditions. All in all, these findings highlight the variable manifestation of CGP-RPE and its variants on multimodal imaging; the diagnosis of CGP-RPE and its variants should remain based on its characteristic funduscopic appearance.
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http://dx.doi.org/10.1111/cxo.12984DOI Listing
September 2020