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Philibert M, Milea D. Basics, benefits, and pitfalls of pupillometers assessing visual function. Eye (Lond) 2024; 38:2415-2421. [PMID: 38802485 PMCID: PMC11306737 DOI: 10.1038/s41433-024-03151-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 04/22/2024] [Accepted: 05/17/2024] [Indexed: 05/29/2024] Open
Abstract
Numerous commercially and non-commercially available pupillometers are nowadays able to assess various biological functions in humans, by evaluating pupils' dynamics in response to specific stimuli. However, the use of pupillometers for ophthalmic afferent evaluations (i.e., photoreceptoral responses) in real-world settings is relatively limited. Recent scientific and technological advances, coupled with artificial intelligence methods have improved the performance of such devices to objectively detect, quantify, and classify functional disturbances of the retina and the optic nerve. This review aims to summarize the scientific principles, indications, outcomes, and current limitations of pupillometry used for evaluation of afferent pathways in ophthalmic clinical settings.
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Affiliation(s)
| | - Dan Milea
- Rothschild Foundation Hospital, Paris, France.
- Copenhagen University Hospital, Copenhagen, Denmark.
- Singapore National Eye Centre, Singapore, Singapore.
- Angers University Hospital, Angers, France.
- Duke-NUS Medical School, Singapore, Singapore.
- Singapore Eye Research Institute, Singapore, Singapore.
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Rai BB, Sabeti F, van Kleef JP, Carle CF, Rohan EMF, Essex RW, Barry RC, Maddess T. Comparing 2-dimensional macular pigment optical density with objective and subjective perimetry and visual acuity in age-related macular degeneration. Graefes Arch Clin Exp Ophthalmol 2024; 262:2449-2459. [PMID: 38483610 PMCID: PMC11271426 DOI: 10.1007/s00417-024-06437-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/01/2024] [Accepted: 03/07/2024] [Indexed: 07/20/2024] Open
Abstract
PURPOSE To compare diagnostic power for different severities of age-related macular degeneration (AMD) of two-dimensional macular pigment optical densities (2D-MPOD) and spatially matched objective perimetry, with standard perimetry and best-corrected visual acuity (BCVA). METHODS The ObjectiveField Analyser (OFA) provided objective perimetry, and a Heidelberg Spectralis optical coherence tomography (OCT) measured 2D-MPOD in AMD patients, both completed twice over 0.99 ± 0.16 years. From each 2D-MPOD image, we extracted 20 regions/macula, matched to the 20 OFA stimuli/macula. For each region, we calculated 7 measures from the 2D-MPOD pixel values and correlated those with OFA sensitivities and delays. We quantified 2D-MPOD changes, the ability of 2D-MPOD and OFA to discriminate AMD stages, and the discriminatory power of Matrix perimetry and BCVA using percentage area under receiver operator characteristic plots (%AUROC). RESULTS In 58 eyes of 29 subjects (71.6 ± 6.3 years, 22 females), we found significant correlations between 2D-MPOD and OFA sensitivities for Age-Related Eye Disease Studies (AREDS)-3 and AREDS-4 severities. Delays showed significant correlations with AREDS-2. For AREDS-4, correlations extended across all eccentricities. Regression associated with the Bland-Altman plots showed significant changes in 2D-MPOD over the study period, especially variability measures. MPOD per-region medians discriminated AREDS-1 from AREDS-3 eyes at a %AUROC of 80.0 ± 6.3%, outperforming OFA, Matrix perimetry, and BCVA. CONCLUSIONS MPOD changes correlated with central functional changes and significant correlations extended peripherally in later-stage AMD. Good diagnostic power for earlier-stage AMD and significant change over the study suggest that 2D-MPOD and OFA may provide effective biomarkers.
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Affiliation(s)
- Bhim B Rai
- John Curtin School of Medical Research, Australian National University, Building 131, Garran Road, Canberra, ACT, 2601, Australia.
| | - Faran Sabeti
- John Curtin School of Medical Research, Australian National University, Building 131, Garran Road, Canberra, ACT, 2601, Australia
- Faculty of Health, School of Optometry, University of Canberra, Canberra, ACT, Australia
| | - Joshua P van Kleef
- John Curtin School of Medical Research, Australian National University, Building 131, Garran Road, Canberra, ACT, 2601, Australia
| | - Corinne F Carle
- John Curtin School of Medical Research, Australian National University, Building 131, Garran Road, Canberra, ACT, 2601, Australia
| | - Emilie M F Rohan
- John Curtin School of Medical Research, Australian National University, Building 131, Garran Road, Canberra, ACT, 2601, Australia
| | - Rohan W Essex
- Department of Ophthalmology, Canberra Hospital, Canberra, ACT, Australia
| | | | - Ted Maddess
- John Curtin School of Medical Research, Australian National University, Building 131, Garran Road, Canberra, ACT, 2601, Australia
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Rai BB, Sabeti F, Carle CF, Maddess T. Visual Field Tests: A Narrative Review of Different Perimetric Methods. J Clin Med 2024; 13:2458. [PMID: 38730989 PMCID: PMC11084906 DOI: 10.3390/jcm13092458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/11/2024] [Accepted: 04/16/2024] [Indexed: 05/13/2024] Open
Abstract
Visual field (VF) testing dates back to fifth century B.C. It plays a pivotal role in the diagnosis, management, and prognosis of retinal and neurological diseases. This review summarizes each of the different VF tests and perimetric methods, including the advantages and disadvantages and adherence to the desired standard diagnostic criteria. The review targets beginners and eye care professionals and includes history and evolution, qualitative and quantitative tests, and subjective and objective perimetric methods. VF testing methods have evolved in terms of technique, precision, user-friendliness, and accuracy. Consequently, some earlier perimetric techniques, often still effective, are not used or have been forgotten. Newer technologies may not always be advantageous because of higher costs, and they may not achieve the desired sensitivity and specificity. VF testing is most often used in glaucoma and neurological diseases, but new objective methods that also measure response latencies are emerging for the management of retinal diseases. Given the varied perimetric methods available, clinicians are advised to select appropriate methods to suit their needs and target disease and to decide on applying simple vs. complex tests or between using subjective and objective methods. Newer, rapid, non-contact, objective methods may provide improved patient satisfaction and allow for the testing of children and the infirm.
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Affiliation(s)
- Bhim Bahadur Rai
- John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia; (F.S.); (C.F.C.); (T.M.)
| | - Faran Sabeti
- John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia; (F.S.); (C.F.C.); (T.M.)
- Faculty of Health, School of Optometry, University of Canberra, Canberra, ACT 2601, Australia
| | - Corinne Frances Carle
- John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia; (F.S.); (C.F.C.); (T.M.)
| | - Ted Maddess
- John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia; (F.S.); (C.F.C.); (T.M.)
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Carle CF, Chain AYH, Kolic M, Maddess T. The structure-function relationship between multifocal pupil perimetry and retinal nerve fibre layer in glaucoma. BMC Ophthalmol 2024; 24:159. [PMID: 38600474 PMCID: PMC11008001 DOI: 10.1186/s12886-024-03402-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 03/18/2024] [Indexed: 04/12/2024] Open
Abstract
BACKGROUND Multifocal pupillographic objective perimetry (mfPOP) is a novel method for assessing functional change in diseases like glaucoma. Previous research has suggested that, in contrast to the pretectally-mediated melanopsin response of intrinsically photosensitive retinal ganglion cells, mfPOP responses to transient onset stimuli involve the extrastriate cortex, and thus the main visual pathway. We therefore investigate the correlation between peripapillary retinal nerve fibre layer (pRNFL) thickness and glaucomatous visual field changes detected using mfPOP. Parallel analyses are undertaken using white on white standard automated perimetry (SAP) for comparison. METHODS Twenty-five glaucoma patients and 24 normal subjects were tested using SAP, 3 mfPOP variants, and optical coherence tomography (OCT). Arcuate clusters of the SAP and mfPOP deviations were weighted according to their contribution to published arcuate divisions of the retinal nerve fibre layer. Structure-function correlation coefficients (r) were computed between pRNFL clock-hour sector thickness measurements, and the local visual field sensitivities from both SAP and mfPOP. RESULTS The strongest correlation was observed in the superior-superotemporal disc sector in patients with worst eye SAP MD < -12 dB: r = 0.93 for the mfPOP LumBal test (p < 0.001). Correlations across all disc-sectors were strongest in these same patients in both SAP and mfPOP: SAP r = 0.54, mfPOP LumBal r = 0.55 (p < 0.001). In patients with SAP MD ≥ -6 dB in both eyes, SAP correlations across all sectors were higher than mfPOP; mfPOP correlations however, were higher than SAP in more advanced disease, and in normal subjects. CONCLUSIONS For both methods the largest correlations with pRNFL thickness corresponded to the inferior nasal field of more severely damaged eyes. Head-to-head comparison of mfPOP and SAP showed similar structure-function relationships. This agrees with our recent reports that mfPOP primarily stimulates the cortical drive to the pupils.
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Affiliation(s)
- Corinne F Carle
- Neuroscience, The John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra ACT, 2601, Australia.
| | - Allan Y H Chain
- Neuroscience, The John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra ACT, 2601, Australia
| | - Maria Kolic
- CERA Retinal Gene Therapy Unit, University of Melbourne, Melbourne Vic, Australia
| | - Ted Maddess
- Neuroscience, The John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra ACT, 2601, Australia
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Crux K, Huchzermeyer C, Kremers J, Horn FK. Objective detection of visual field defects with multifrequency VEPs. Doc Ophthalmol 2024; 148:15-24. [PMID: 37749441 PMCID: PMC10879258 DOI: 10.1007/s10633-023-09949-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 08/25/2023] [Indexed: 09/27/2023]
Abstract
PURPOSE To correlate multifrequency pattern reversal VEPs in quadrants (QmfrVEPs) with perimetric field losses for objective detection of visual field losses. METHODS QmfrVEP measurements were performed using four LED-based checkerboard stimulators to stimulate the four quadrants of the visual field. QmfrVEPs were measured monocularly in 5 normal subjects and in 5 glaucoma patients who showed losses in conventional Octopus perimetry. The pattern reversal frequency varied slightly between the stimulators: (11.92, 12.00, 12.08 and 12.16 reversals/sec). The responses to the different stimuli were identified by discrete Fourier analysis. VEPs were recorded using different electrode configurations, and the recording with the highest signal-to-noise ratio (SNR) was used for further analysis. RESULTS QmfrVEP responses from the different quadrants can be reliably measured and separated using the 0.08 reversals/sec interstimulus reversal frequency differences. The signal-to-noise ratio in the four quadrants was significantly correlated with the equivalent visual field losses obtained with perimetry (Spearman rank correlation: P < 0.001). In the five glaucoma patients, the SNR was reduced in 15 out of the 16 quadrants with a perimetric defect, in comparison to the results in quadrants of healthy subjects. This confirms the sensitivity of the procedure. CONCLUSION QmfrVEP responses can be measured reliably. This pilot study suggests that high SNR values exclude visual field defects and that focal defects can be identified in glaucoma patients. TRIAL REGISTRATION www. CLINICALTRIALS gov . NCT00494923.
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Affiliation(s)
- Katja Crux
- Department of Ophthalmology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Cord Huchzermeyer
- Department of Ophthalmology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Folkert K Horn
- Department of Ophthalmology, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
- Department of Ophthalmology, University Eye Hospital, Friedrich-Alexander University Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany.
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Liu Y, Mahony BW, Wang X, Daye PM, Wang W, Cavanagh P, Pouget P, Andolina IM. Assessing perceptual chromatic equiluminance using a reflexive pupillary response. Sci Rep 2024; 14:2420. [PMID: 38286801 PMCID: PMC10825167 DOI: 10.1038/s41598-024-51982-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/11/2024] [Indexed: 01/31/2024] Open
Abstract
Equiluminant stimuli help assess the integrity of colour perception and the relationship of colour to other visual features. As a result of individual variation, it is necessary to calibrate experimental visual stimuli to suit each individual's unique equiluminant ratio. Most traditional methods rely on training observers to report their subjective equiluminance point. Such paradigms cannot easily be implemented on pre-verbal or non-verbal observers. Here, we present a novel Pupil Frequency-Tagging Method (PFTM) for detecting a participant's unique equiluminance point without verbal instruction and with minimal training. PFTM analyses reflexive pupil oscillations induced by slow (< 2 Hz) temporal alternations between coloured stimuli. Two equiluminant stimuli will induce a similar pupil dilation response regardless of colour; therefore, an observer's equiluminant point can be identified as the luminance ratio between two colours for which the oscillatory amplitude of the pupil at the tagged frequency is minimal. We compared pupillometry-based equiluminance ratios to those obtained with two established techniques in humans: minimum flicker and minimum motion. In addition, we estimated the equiluminance point in non-human primates, demonstrating that this new technique can be successfully employed in non-verbal subjects.
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Affiliation(s)
- Ye Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | | | - Xiaochun Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Pierre M Daye
- Sorbonne Université, Inserm, CNRS, ICM, Paris, France
| | - Wei Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Patrick Cavanagh
- Glendon College and Centre for Vision Research, York University, Toronto, Canada
| | - Pierre Pouget
- Sorbonne Université, Inserm, CNRS, ICM, Paris, France.
| | - Ian Max Andolina
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
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Sabeti F, van Kleef JP, Iyer RM, Carle CF, Nolan CJ, Chia RH, Maddess T. Discriminating early-stage diabetic retinopathy with subjective and objective perimetry. Front Endocrinol (Lausanne) 2024; 14:1333826. [PMID: 38264290 PMCID: PMC10804944 DOI: 10.3389/fendo.2023.1333826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 12/13/2023] [Indexed: 01/25/2024] Open
Abstract
Introduction To prevent progression of early-stage diabetic retinopathy, we need functional tests that can distinguish multiple levels of neural damage before classical vasculopathy. To that end, we compared multifocal pupillographic objective perimetry (mfPOP), and two types of subjective automated perimetry (SAP), in persons with type 2 diabetes (PwT2D) with either no retinopathy (noDR) or mild to-moderate non-proliferative retinopathy (mmDR). Methods Both eyes were assessed by two mfPOP test methods that present stimuli within either the central ±15° (OFA15) or ±30° (OFA30), each producing per-region sensitivities and response delays. The SAP tests were 24-2 Short Wavelength Automated Perimetry and 24-2 Matrix perimetry. Results Five of eight mfPOP global indices were significantly different between noDR and mmDR eyes, but none of the equivalent measures differed for SAP. Per-region mfPOP identified significant hypersensitivity and longer delays in the peripheral visual field, verifying earlier findings. Diagnostic power for discrimination of noDR vs. mmDR, and normal controls vs. PwT2D, was much higher for mfPOP than SAP. The mfPOP per-region delays provided the best discrimination. The presence of localized rather than global changes in delay ruled out iris neuropathy as a major factor. Discussion mfPOP response delays may provide new surrogate endpoints for studies of interventions for early-stage diabetic eye damage.
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Affiliation(s)
- Faran Sabeti
- Eccles Institute for Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
- Discipline of Optometry, Faculty of Health, University of Canberra, Canberra, ACT, Australia
| | - Joshua P. van Kleef
- Eccles Institute for Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Rakesh M. Iyer
- Department of Endocrinology, The Canberra Hospital, Garran, ACT, Australia
| | - Corinne F. Carle
- Eccles Institute for Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
| | - Christopher J. Nolan
- Department of Endocrinology, The Canberra Hospital, Garran, ACT, Australia
- School of Medicine and Psychology, The Australian National University, Canberra, ACT, Australia
| | - Rong Hui Chia
- School of Medicine, University of Western Australia, Crawley, WA, Australia
| | - Ted Maddess
- Eccles Institute for Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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Rai BB, van Kleef JP, Sabeti F, Vlieger R, Suominen H, Maddess T. Early diabetic eye damage: Comparing detection methods using diagnostic power. Surv Ophthalmol 2024; 69:24-33. [PMID: 37797701 DOI: 10.1016/j.survophthal.2023.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 08/22/2023] [Accepted: 09/06/2023] [Indexed: 10/07/2023]
Abstract
It is now clear that retinal neuropathy precedes classical microvascular retinopathy in diabetes. Therefore, tests that underpin useful new endpoints must provide high diagnostic power well before the onset of moderate diabetic retinopathy. Hence, we compare detection methods of early diabetic eye damage. We reviewed data from a range of functional and structural studies of early diabetic eye disease and computed standardized effect size as a measure of diagnostic power, allowing the studies to be compared quantitatively. We then derived minimum performance criteria for tests to provide useful clinical endpoints. This included the criteria that tests should be rapid and easy so that children with type 1 diabetes can be followed into adulthood with the same tests. We also defined attributes that lend test data to further improve performance using Machine/Deep Learning. Data from a new form of objective perimetry suggested that the criteria are achievable.
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Affiliation(s)
- Bhim B Rai
- John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia; ANU Eccles Institute of Neuroscience, Australian National University, Canberra, ACT, Australia.
| | - Joshua P van Kleef
- John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia; ANU Eccles Institute of Neuroscience, Australian National University, Canberra, ACT, Australia
| | - Faran Sabeti
- John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia; School of Optometry, Faculty of Health, 2 University of Canberra, Canberra, ACT, Australia
| | - Robin Vlieger
- ANU School of Computing, Australian National University, Canberra, ACT, Australia
| | - Hanna Suominen
- ANU Eccles Institute of Neuroscience, Australian National University, Canberra, ACT, Australia; ANU School of Computing, Australian National University, Canberra, ACT, Australia; University of Turku, Turku, Finland
| | - Ted Maddess
- John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia; ANU Eccles Institute of Neuroscience, Australian National University, Canberra, ACT, Australia
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Sabeti F, Rai BB, van Kleef JP, Rohan EMF, Carle CF, Barry RC, Essex RW, Nolan CJ, Maddess T. Objective perimetry identifies regional functional progression and recovery in mild Diabetic Macular Oedema. PLoS One 2023; 18:e0287319. [PMID: 37319294 PMCID: PMC10270604 DOI: 10.1371/journal.pone.0287319] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 06/02/2023] [Indexed: 06/17/2023] Open
Abstract
PURPOSE Retinal function beyond foveal vision is not routinely examined in the clinical screening and management of diabetic retinopathy although growing evidence suggests it may precede structural changes. In this study we compare optical coherence tomography (OCT) based macular structure with function measured objectively with the ObjectiveFIELD Analyzer (OFA), and with Matrix perimetry. We did that longitudinally in Type 2 diabetes (T2D) patients with mild Diabetic Macular Oedema (DMO) with good vision and a similar number of T2D patients without DMO, to evaluate changes in retinal function more peripherally over the natural course of retinopathy. METHODS Both eyes of 16 T2D patients (65.0 ± 10.1, 10 females), 10 with baseline DMO, were followed for up longitudinally for 27 months providing 94 data sets. Vasculopathy was assessed by fundus photography. Retinopathy was graded using to Early Treatment of Diabetic Retinopathy Study (ETDRS) guidelines. Posterior-pole OCT quantified a 64-region/eye thickness grid. Retinal function was measured with 10-2 Matrix perimetry, and the FDA-cleared OFA. Two multifocal pupillographic objective perimetry (mfPOP) variants presented 44 stimuli/eye within either the central 30° or 60° of the visual field, providing sensitivities and delays for each test-region. OCT, Matrix and 30° OFA data were mapped to a common 44 region/eye grid allowing change over time to be compared at the same retinal regions. RESULTS In eyes that presented with DMO at baseline, mean retinal thickness reduced from 237 ± 25 μm to 234.2 ± 26.7 μm, while the initially non-DMO eyes significantly increased their mean thickness from 250.7 ± 24.4 μm to 255.7 ± 20.6 μm (both p<0.05). Eyes that reduced in retinal thickness over time recovered to more normal OFA sensitivities and delays (all p<0.021). Matrix perimetry quantified fewer regions that changed significantly over the 27 months, mostly presenting in the central 8 degrees. CONCLUSIONS Changes in retinal function measured by OFA possibly offer greater power to monitor DMO over time than Matrix perimetry data.
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Affiliation(s)
- Faran Sabeti
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
- Faculty of Health, School of Optometry, University of Canberra, Bruce, Canberra, Australia
| | - Bhim B. Rai
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Josh P. van Kleef
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Emilie M. F. Rohan
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Corinne F. Carle
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Richard C. Barry
- The Canberra Hospital, ACT Health, Garran, Canberra, ACT, Australia
- Blink Eye Clinic, Canberra, ACT, Australia
| | - Rohan W. Essex
- The Canberra Hospital, ACT Health, Garran, Canberra, ACT, Australia
- ANU Medical School, Australian National University, Canberra, ACT, Australia
| | - Christopher J. Nolan
- The Canberra Hospital, ACT Health, Garran, Canberra, ACT, Australia
- ANU Medical School, Australian National University, Canberra, ACT, Australia
| | - Ted Maddess
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
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Rapid, non-contact multifocal visual assessment in multiple sclerosis. Neurol Sci 2023; 44:273-279. [PMID: 36098887 PMCID: PMC9816274 DOI: 10.1007/s10072-022-06387-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/31/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE 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. METHODS 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. RESULTS 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. CONCLUSION 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.
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Maddess T, Carle CF, Rohan EM, Baird-Gunning J, van Kleef JP, Lueck CJ. Objective perimetry and progression of multiple sclerosis. eNeurologicalSci 2022; 29:100430. [PMID: 36254171 PMCID: PMC9568864 DOI: 10.1016/j.ensci.2022.100430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/07/2022] [Accepted: 10/07/2022] [Indexed: 11/29/2022] Open
Abstract
Introduction We re-examined the per-region response amplitudes and delays obtained from multifocal pupillographic objective perimetry (mfPOP) after 10 years in 44 persons living with multiple sclerosis (PwMS), both to examine which parts of the visual field had progressed in terms of response properties and to examine if the baseline data could predict the overall progression of disease. Methods Expanded Disability Status Scale (EDSS) scores were assessed in 2009 and 2019. Both eyes of each participant were concurrently tested at 44 locations/eye on both occasions. Several measures of clinical progression were examined, using logistic regression to determine the odds of progression. Results At the second examination the 44 PwMS (31 females) were aged 61.0 ± 12.2 y. Mean EDSS had not changed significantly (3.69 ± 1.23 in 2009, 3.81 ± 2.00 in 2019). mfPOP delay increased progressively from inferior to superior regions of the visual fields while amplitudes demonstrated a temporal to nasal gradient. The mean of the 3 most delayed visual field regions was correlated with progression of MS by 2019 (p = 0.023). Logistic regression indicated a significant association between delay and odds of progression (p = 0.045): an individual with 3 regions at least 1 SD (40 ms) slower than the mean in 2009 had 2.05× (±SE: 1.43× to 2.95×) the odds of progression by 2019. A 1 SD shorter delay was associated with 2.05× lower odds of progression. Amplitude changes were not predictive of progression. Significance mfPOP may provide a rapid, convenient method of monitoring and predicting MS progression.
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Affiliation(s)
- Ted Maddess
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia
| | - Corinne F. Carle
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia
| | - Emilie M.F. Rohan
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia
| | | | - Josh P. van Kleef
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia
| | - Christian J. Lueck
- Department of Neurology, the Canberra Hospital, Canberra, ACT, Australia
- Australian National University Medical School, Acton, ACT, Australia
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12
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Portengen BL, Porro GL, Imhof SM, Naber M. Comparison of unifocal, flicker, and multifocal pupil perimetry methods in healthy adults. J Vis 2022; 22:7. [PMID: 35998063 PMCID: PMC9424968 DOI: 10.1167/jov.22.9.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
To this day, the most popular method of choice for testing visual field defects (VFDs) is subjective standard automated perimetry. However, a need has arisen for an objective, and less time-consuming method. Pupil perimetry (PP), which uses pupil responses to onsets of bright stimuli as indications of visual sensitivity, fulfills these requirements. It is currently unclear which PP method most accurately detects VFDs. Hence, the purpose of this study is to compare three PP methods for measuring pupil responsiveness. Unifocal (UPP), flicker (FPP), and multifocal PP (MPP) were compared by monocularly testing the inner 60 degrees of vision at 44 wedge-shaped locations. The visual field (VF) sensitivity of 18 healthy adult participants (mean age and SD 23.7 ± 3.0 years) was assessed, each under three different artificially simulated scotomas for approximately 4.5 minutes each (i.e. stimulus was not or only partially present) conditions: quadrantanopia, a 20-, and 10-degree diameter scotoma. Stimuli that were fully present on the screen evoked strongest, partially present stimuli evoked weaker, and absent stimuli evoked the weakest pupil responses in all methods. However, the pupil responses in FPP showed stronger discriminative power for present versus absent trials (median d-prime = 6.26 ± 2.49, area under the curve [AUC] = 1.0 ± 0) and MPP performed better for fully present versus partially present trials (median d-prime = 1.19 ± 0.62, AUC = 0.80 ± 0.11). We conducted the first in-depth comparison of three PP methods. Gaze-contingent FPP had best discriminative power for large (absolute) scotomas, whereas MPP performed slightly better with small (relative) scotomas.
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Affiliation(s)
- Brendan L Portengen
- Ophthalmology Department, University Medical Center Utrecht, The Netherlands.,Experimental Psychology, Helmholtz Institute, Utrecht University, The Netherlands.,
| | - Giorgio L Porro
- Ophthalmology Department, University Medical Center Utrecht, The Netherlands.,
| | - Saskia M Imhof
- Ophthalmology Department, University Medical Center Utrecht, The Netherlands.,
| | - Marnix Naber
- Experimental Psychology, Helmholtz Institute, Utrecht University, The Netherlands.,
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Rapid Objective Testing of Visual Function Matched to the ETDRS Grid and Its Diagnostic Power in Age-Related Macular Degeneration. OPHTHALMOLOGY SCIENCE 2022; 2:100143. [PMID: 36249701 PMCID: PMC9559873 DOI: 10.1016/j.xops.2022.100143] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/17/2022] [Accepted: 03/14/2022] [Indexed: 11/21/2022]
Abstract
Purpose To study the power of an 80-second multifocal pupillographic objective perimetry (mfPOP) test tailored to the ETDRS grid to diagnose age-related macular degeneration (AMD) by Age-Related Eye Disease Study (AREDS) severity grade. Design Evaluation of a diagnostic technology. Methods We compared diagnostic power of acuity, ETDRS grid retinal thickness data, new 80-second M18 mfPOP test, and two wider-field 6-minute mfPOP tests (Macular-P131, Widefield-P129). The M18 stimuli match the size and shape of bifurcated ETDRS grid regions, allowing easy structure–function comparisons. M18, P129, and P131 stimuli test both eyes concurrently. We recruited 34 patients with early-stage AMD with a mean ± standard deviation (SD) age of 72.6 ± 7.06 years. The M18 and P129 plus P131 stimuli had 26 and 51 control participants, respectively with mean ± SD ages of 73.1 ± 8.17 years and 72.1 ± 5.83 years, respectively. Multifocal pupillographic objective perimetry testing used the Food and Drug Administration-cleared Objective FIELD Analyzer (OFA; Konan Medical USA). Main Outcome Measures Percentage area under the receiver operator characteristic curve (AUC) and Hedge’s g effect size. Results Acuity and OCT ETDRS grid thickness and volume produced reasonable diagnostic power (percentage AUC) for AREDS grade 4 eyes at 83.9 ± 9.98% and 90.2 ± 6.32% (mean ± standard error), respectively, but not for eyes with less severe disease. By contrast, M18 stimuli produced percentage AUCs from 72.8 ± 6.65% (AREDS grade 2) to 92.9 ± 3.93% (AREDS grade 4), and 82.9 ± 3.71% for all eyes. Hedge’s g effect sizes ranged from 0.84 to 2.32 (large to huge). Percentage AUC for P131 stimuli performed similarly and for P129 performed somewhat less well. Conclusions The rapid and objective M18 test provided diagnostic power comparable with that of wider-field 6-minute mfPOP tests. Unlike acuity or OCT ETDRS grid data, OFA tests produced reasonable diagnostic power in AREDS grade 1 to 3 eyes.
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Ali EN, Lueck CJ, Carle CF, Martin KL, Borbelj A, Maddess T. Response characteristics of objective perimetry in persons living with epilepsy. J Neurol Sci 2022; 436:120237. [DOI: 10.1016/j.jns.2022.120237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/06/2022] [Accepted: 03/22/2022] [Indexed: 10/18/2022]
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Multifocal pupillographic objective perimetry for assessment of early diabetic retinopathy and generalised diabetes-related tissue injury in persons with type 1 diabetes. BMC Ophthalmol 2022; 22:166. [PMID: 35418088 PMCID: PMC9008936 DOI: 10.1186/s12886-022-02382-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/28/2022] [Indexed: 12/01/2022] Open
Abstract
Background To examine the potential utility of five multifocal pupillographic objective perimetry (mfPOP) protocols, in the assessment of early diabetic retinopathy (DR) and generalised diabetes-related tissue injury in subjects with type 1 diabetes (T1D). Methods Twenty-five T1D subjects (age 41.8 ± 12.1 (SD) years, 13 male) with either no DR (n = 13) or non-proliferative DR (n = 12), and 23 age and gender-matched control subjects (age 39.7 ± 12.9 years, 9 male) were examined by mfPOP using five different stimulus methods differing in visual field eccentricity (central 30° and 60°), and colour (blue, yellow or green test-stimuli presented on, respectively, a blue, yellow or red background), each assessing 44 test-locations per eye. In the T1D subjects, we assessed 16 metabolic status and diabetes complications variables. These were summarised as three principal component analysis (PCA) factors. DR severity was assessed using Early Treatment of Diabetic Retinopathy Study (ETDRS) scores. Area under the curve (AUC) from receiver operator characteristic analyses quantified the diagnostic power of mfPOP response sensitivity and delay deviations for differentiating: (i) T1D subjects from control subjects, (ii) T1D subjects according to three levels of the identified PCA-factors from control subjects, and (iii) TID subjects with from those without non-proliferative DR. Results The two largest PCA-factors describing the T1D subjects were associated with metabolic variables (e.g. body mass index, HbA1c), and tissue-injury variables (e.g. serum creatinine, vibration perception). Linear models showed that mfPOP per-region response delays were more strongly associated than sensitivities with the metabolic PCA-factor and ETDRS scores. Combined mfPOP amplitude and delay measures produced AUCs of 90.4 ± 8.9% (mean ± SE) for discriminating T1D subjects with DR from control subjects, and T1D subjects with DR from those without of 85.9 ± 8.8%. The yellow and green stimuli performed better than blue on most measures. Conclusions/interpretation In T1D subjects, mfPOP testing was able to identify localised visual field functional abnormalities (retinal/neural reflex) in the absence or presence of mild DR. mfPOP responses were also associated with T1D metabolic status, but less so with early stages of non-ophthalmic diabetes complications.
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Carle CF, James AC, Sabeti F, Kolic M, Essex RW, Shean C, Jeans R, Saikal A, Licinio A, Maddess T. Clustered Volleys Stimulus Presentation for Multifocal Objective Perimetry. Transl Vis Sci Technol 2022; 11:5. [PMID: 35113130 PMCID: PMC8819283 DOI: 10.1167/tvst.11.2.5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Multifocal pupillographic objective perimetry (mfPOP) is being developed as an alternative to subjective threshold perimetry for the management of visual and neurological disorders. Here, we evaluate, in normal subjects, differences in signal quality between the original mfPOP method of spatially sparse Continuous stimulus presentation and the new Clustered Volleys (CVs) method. We hypothesized that the CVs method would lead to increased signal-to-noise ratios (SNRs) over the original method due to the stabilization of gain within the pupillary system. Methods Data were collected from six separate studies where otherwise-identical pairs of mfPOP tests using either the original Continuous stimulus presentation method or the new CVs method were undertaken; 440 6-minute tests from 96 normal subjects of varying ages were included. Per-region SNRs were compared between the two methods. Results Mean SNRs for the CVs mfPOP variants were between 35% and 57% larger than the original Continuous mfPOP variants (P < 0.001 in five of six studies). Similarly, the goodness-of-fit measure (r2) demonstrated large and significant fold increases of between 2.3× and 3.4× over the original method (all P < 0.001). Significant improvements in SNRs were present in all of the 88 test regions (44/eye), ranging between 8.4% and 93.7%; mean SNRs were significantly larger in 98% of test subjects. Conclusions The CVs mfPOP stimulus presentation method produced substantial increases in signal quality over the original method. This is likely due to the stabilization of pupillary gain during stimulus presentation. Translational Relevance These improvements increase diagnostic accuracy and have enabled shorter, 80-second mfPOP tests to be developed.
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Affiliation(s)
- Corinne F Carle
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Andrew C James
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Faran Sabeti
- John Curtin School of Medical Research, Australian National University, Canberra, Australia.,Optometry and Vision Science, University of Canberra, Canberra, Australia
| | - Maria Kolic
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Rohan W Essex
- John Curtin School of Medical Research, Australian National University, Canberra, Australia.,Canberra Hospital, Canberra, Australia
| | - Chris Shean
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Rhiannon Jeans
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Aiasha Saikal
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Alice Licinio
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Ted Maddess
- John Curtin School of Medical Research, Australian National University, Canberra, Australia
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17
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Rai BB, Essex RW, Sabeti F, Maddess T, Rohan EMF, van Kleef JP, Carle CF. An Objective Perimetry Study of Central Versus Peripheral Sensitivities and Delays in Age-Related Macular Degeneration. Transl Vis Sci Technol 2021; 10:24. [PMID: 34932115 PMCID: PMC8711003 DOI: 10.1167/tvst.10.14.24] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/18/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to compare central versus peripheral retinal sensitivities and delays in neovascular age-related macular degeneration (nAMD) using US Food and Drug Administration (FDA)-cleared multifocal pupillographic objective perimetry (mfPOP). Methods We recruited 18 patients with nAMD and commenced Pro re nata intravitreal anti- vascular endothelial growth factor (VEGF) injection. We compared macular (±15 degrees) and wide-field (±30 degrees) mfPOP variants. We examined temporal correlations between treated and untreated fellow eyes. We fitted linear models to selected treatment patterns, and compared the ability of central versus peripheral responses to predict the need for treatment. Results Central sensitivity decreased by -2.23 ± 0.051 dB/month (P < 0.0002) in treated eyes, and -0.17 ± 0.07 dB/month (P = 0.033) in untreated eyes. Treated eyes showed quicker central responses by 13.08 ± 3.77 ms than untreated eyes (P = 0.001). Based on peripheral responses, we identified two eye-types. Among positive-eyes peripheral sensitivity increased by 9.88 ± 4.41 dB (P = 0.042) before treatment; delays increased by 3.49 ± 1.75 ms/month (P = 0.049). For negative-eyes peripheral delays were shorter a month before treatment by 9.38 ± 3.59 ms (P = 0.013). Correlations between treatment and peripheral sensitivities or delays peaked at 1 to 2 months post-treatment. Peripheral data significantly determined treatment frequency and final acuity (all P < 0.044). Conclusions Peripheral macular function of treated and untreated eyes divided eyes into positive and negative groups. Those peripheral responses determined outcomes; changes preceding active disease by 1 to 3 months. Overall, mfPOP may provide potential biomarkers to assist nAMD management. Translational Relevance Objective perimetry may identify the requirement for treatment in nAMD that accords with the decision of a skilled clinician based on optical coherence tomography (OCT) and clinical findings.
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Affiliation(s)
- Bhim B Rai
- John Curtin School of Medical Research, Australian National University, Australia Capital Territory, Australia
| | - Rohan W Essex
- Academic Unit, ANU Medical School, ANU, Canberra, Australia Capital Territory, Australia
- Department of Ophthalmology, The Canberra Hospital, ACT Health, Canberra, ACT, Australia
| | - Faran Sabeti
- John Curtin School of Medical Research, Australian National University, Australia Capital Territory, Australia
- School of Optometry, University of Canberra, Bruce, Canberra, Australia Capital Territory, Australia
| | - Ted Maddess
- John Curtin School of Medical Research, Australian National University, Australia Capital Territory, Australia
| | - Emilie M F Rohan
- John Curtin School of Medical Research, Australian National University, Australia Capital Territory, Australia
| | - Joshua P van Kleef
- John Curtin School of Medical Research, Australian National University, Australia Capital Territory, Australia
| | - Corinne F Carle
- John Curtin School of Medical Research, Australian National University, Australia Capital Territory, Australia
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18
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Rai BB, Maddess T, Carle CF, Rohan EMF, van Kleef JP, Barry RC, Essex RW, Nolan CJ, Sabeti F. Comparing Objective Perimetry, Matrix Perimetry, and Regional Retinal Thickness in Mild Diabetic Macular Edema. Transl Vis Sci Technol 2021; 10:32. [PMID: 34842920 PMCID: PMC8631055 DOI: 10.1167/tvst.10.13.32] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/31/2021] [Indexed: 12/14/2022] Open
Abstract
Purpose To compare per-region macular sensitivity and delay from objective perimetry with Matrix perimetry and retinal thickness in mild diabetic macular edema (DMO). Methods Thirty-three patients with type 2 diabetes (T2D) aged 59.2 ± 10.5 years participated in a longitudinal study. Macular thickness, sensitivities and delays from the objectiveFIELD Analyzer (OFA), and Matrix perimeter sensitivities were mapped onto a common spatial layout to compute per-region correlations between structure/function measures. A generalized linear mixed-effects logistic regression model determined which variables contributed to clinical diagnosis of DMO. Results For OFA, the mean sensitivity differences compared with normal in patients with T2D were negative and the mean delay differences positive, indicating lowered sensitivities and prolonged delays, both increasing with diabetes duration. Shorter diabetes duration could produce either localized peripheral hypersensitivities or shorter delays. Functional change could occur when retinal thickness was stable. Peripheral macular thickness correlated with central and peripheral OFA sensitivity and delay, all P < 0.0012 in DMO and a median of P = 0.001 without DMO; this was not true for Matrix sensitivities. The logistic model determined that peripheral thickness, OFA sensitivity (P = 0.043), and time in the study (P = 0.001) contribute independently to the odds of DMO versus no DMO. Conclusions Mean sensitivities decreased and mean delays increased with duration of diabetes. Peripheral macular thickness correlated significantly with central and peripheral macular OFA sensitivity and delay. Peripheral macular thickness and functional measures may provide sensitive prognostic data. Translational Relevance Functional loss can precede structural change in DMO, so including such functional assessment for deciding on treatment may be beneficial.
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Affiliation(s)
- Bhim B. Rai
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Ted Maddess
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Corinne F. Carle
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Emilie M. F. Rohan
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Josh P. van Kleef
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Richard C. Barry
- The Canberra Hospital, ACT Health, Garran, Canberra, ACT, Australia
- Blink Eye Clinic, Canberra, ACT, Australia
| | - Rohan W. Essex
- The Canberra Hospital, ACT Health, Garran, Canberra, ACT, Australia
- ANU Medical School, Australian National University, Canberra, ACT, Australia
| | - Christopher J. Nolan
- The Canberra Hospital, ACT Health, Garran, Canberra, ACT, Australia
- ANU Medical School, Australian National University, Canberra, ACT, Australia
| | - Faran Sabeti
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
- University of Canberra, School of Optometry, Faculty of Health, Bruce, Canberra, ACT, Australia
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Seraji M, Mohebbi M, Safari A, Krekelberg B. Multiple sclerosis reduces synchrony of the magnocellular pathway. PLoS One 2021; 16:e0255324. [PMID: 34437558 PMCID: PMC8389379 DOI: 10.1371/journal.pone.0255324] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 07/15/2021] [Indexed: 02/01/2023] Open
Abstract
Multiple Sclerosis (MS) is an autoimmune demyelinating disease that damages the insulation of nerve cell fibers in the brain and spinal cord. In the visual system, this demyelination results in a robust delay of visually evoked potentials (VEPs), even in the absence of overt clinical symptoms such as blurred vision. VEPs, therefore, offer an avenue for early diagnosis, monitoring disease progression, and, potentially, insight into the differential impairment of specific pathways. A primary hypothesis has been that visual stimuli driving the magno-, parvo-, and konio-cellular pathways should lead to differential effects because these pathways differ considerably in terms of myelination. Experimental tests of this hypothesis, however, have led to conflicting results. Some groups reported larger latency effects for chromatic stimuli, while others found equivalent effects across stimulus types. We reasoned that this lack of pathway specificity could, at least in part, be attributed to the relatively coarse measure of pathway impairment afforded by the latency of a VEP. We hypothesized that network synchrony could offer a more sensitive test of pathway impairments. To test this hypothesis, we analyzed the synchrony of occipital electroencephalography (EEG) signals during the presentation of visual stimuli designed to bias activity to one of the three pathways. Specifically, we quantified synchrony in the occipital EEG using two graph-theoretic measures of functional connectivity: the characteristic path length (L; a measure of long-range connectivity) and the clustering coefficient (CC; a measure of short-range connectivity). Our main finding was that L and CC were both smaller in the MS group than in controls. Notably, this change in functional connectivity was limited to the magnocellular pathway. The effect sizes (Hedge's g) were 0.89 (L) and 1.26 (CC) measured with magno stimuli. Together, L and CC define the small-world nature of a network, and our finding can be summarized as a reduction in the small-worldness of the magnocellular network. We speculate that the reduced efficiency of information transfer associated with a reduction in small-worldness could underlie visual deficits in MS. Relating these measures to differential diagnoses and disease progression is an important avenue for future work.
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Affiliation(s)
- Masoud Seraji
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey, United States of America
- Behavioral and Neural Sciences Graduate Program, Rutgers University, Newark, New Jersey, United States of America
| | - Maryam Mohebbi
- School of Electrical Engineering, K.N.Toosi University of Technology, Tehran, Iran
| | - Amirhossein Safari
- School of Electrical Engineering, K.N.Toosi University of Technology, Tehran, Iran
| | - Bart Krekelberg
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey, United States of America
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20
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Bitirgen G, Akpinar Z, Turk HB, Malik RA. Abnormal Dynamic Pupillometry Relates to Neurologic Disability and Retinal Axonal Loss in Patients With Multiple Sclerosis. Transl Vis Sci Technol 2021; 10:30. [PMID: 34004008 PMCID: PMC8083111 DOI: 10.1167/tvst.10.4.30] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To assess alterations in quantitative dynamic pupil responses to light in relation to neurologic disability and retinal axonal loss in patients with multiple sclerosis (MS). Methods Twenty-five patients with relapsing-remitting MS and 25 healthy subjects were included in this cross-sectional study. Pupillary responses were measured with an infrared dynamic pupillometry unit, and peripapillary retinal nerve fiber layer (RNFL) thickness was measured with spectral-domain optical coherence tomography. Neurologic disability was assessed by the Expanded Disability Status Scale (EDSS). Patients with a history of optic neuritis (ON) within 6 months were excluded. Only the right eyes were assessed, except in 11 patients with a history of unilateral ON in whom both eyes were further analyzed to evaluate the effect of previous ON. Results The initial pupil diameter (P = 0.003) and pupil contraction amplitude (P = 0.027) were lower in patients with MS compared with healthy controls. Initial pupil diameter correlated with EDSS score (ρ = −0.458; P = 0.021), and RNFL correlated with contraction latency (ρ = −0.524; P = 0.007). There were no significant differences in any of the pupil parameters between eyes with and without a history of ON, and between the ON and fellow eyes of the 11 patients with previous unilateral ON. Conclusions Dynamic pupillometry reveals significant alterations in pupillary light reflex responses associated with neurologic disability and retinal axonal loss, independent of previous ON. Translational Relevance Dynamic pupillometry is a simple, noninvasive tool that may be useful in detecting autonomic dysfunction in patients with MS.
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Affiliation(s)
- Gulfidan Bitirgen
- Department of Ophthalmology, Necmettin Erbakan University Meram Faculty of Medicine, Konya, Turkey
| | - Zehra Akpinar
- Department of Neurology, Necmettin Erbakan University Meram Faculty of Medicine, Konya, Turkey
| | - Huseyin B Turk
- Department of Ophthalmology, Gaziantep Dr. Ersin Arslan Education and Research Hospital, Gaziantep, Turkey
| | - Rayaz A Malik
- Weill Cornell Medicine-Qatar, Research Division, Qatar Foundation, Doha, Qatar.,Institute of Cardiovascular Sciences, Cardiac Centre, Faculty of Medical and Human Sciences, University of Manchester and NIHR Clinical Research Facility, Manchester, UK
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Ali EN, Carle CF, Lueck CJ, Kolic M, Maddess T. Assessing migraine patients with multifocal pupillographic objective perimetry. BMC Neurol 2021; 21:211. [PMID: 34039302 PMCID: PMC8152334 DOI: 10.1186/s12883-021-02239-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 05/14/2021] [Indexed: 12/22/2022] Open
Abstract
Background 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. Methods 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 amplitude and time-to-peak. Results 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 amplitudes, − 0.64 ± 0.14 dB (mean ± SE), while triptan use increased amplitudes by 0.45 ± 0.10 dB, both at p < 0.001. Conclusions 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.
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Affiliation(s)
- Eman N Ali
- Eccles Institute of Neuroscience, the John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia.,Department of Neuroscience, King Fahad Specialist Hospital, Dammam, Saudi Arabia
| | - Corinne F Carle
- Eccles Institute of Neuroscience, the John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia
| | - Christian J Lueck
- Australian National University Medical School, Acton, ACT, Australia.,Department of Neurology, The Canberra Hospital, Canberra, ACT, Australia
| | - Maria Kolic
- Eccles Institute of Neuroscience, the John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia
| | - Ted Maddess
- Eccles Institute of Neuroscience, the John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia.
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Versek C, Banijamali SMA, Bex P, Lashkari K, Kamarthi S, Sridhar S. Portable Diagnostic System for Age-Related Macular Degeneration Screening Using Visual Evoked Potentials. Eye Brain 2021; 13:111-127. [PMID: 33953628 PMCID: PMC8092944 DOI: 10.2147/eb.s295745] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/04/2021] [Indexed: 11/23/2022] Open
Abstract
Background Delayed Dark-Adapted vision Recovery (DAR) is a biomarker for Age-related Macular Degeneration (AMD), however its measurement is burdensome for patients and examiners. Methods In this study, we developed a portable, wireless and user-friendly system that employs a headset with a smartphone to deliver controlled photo-bleach and monocular pattern reversal stimuli, while using custom electroencephalography (EEG) electrodes and electronics in order to measure Dark-Adapted Visual Evoked Potentials (DAVEP) objectively and separately at the peripheral and central visual field. This is achieved in one comfortable 20-minute session, without requiring subject reporting. DAVEP responses post photo-bleach for up to 15 minutes were measured concurrently from both eyes in 12 AMD-patients, 1 degenerative myopia patient, and 8 controls who had no diagnosed macular vision loss. Results Robust positive polarity DAVEP responses were observed at 200-500 ms from stimulus onset to scotopic stimuli that have been seldom reported and analyzed previously. The amplitude recovery of the DAVEP response was significantly delayed in AMD patients as compared to controls. We developed DAVEP1 scores, a simple metric for DAR, which classified 90% of subject eyes correctly, indicating the presence of AMD in at least one eye of all pre-confirmed subjects with this diagnosis. Conclusion We developed a user-friendly, portable VEP system and DAVEP1 metric, which show a high potential to identify DAR-deficits in AMD-patients. This novel technology could aid in early diagnosis of AMD.
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Affiliation(s)
| | | | - Peter Bex
- Department of Psychology, Northeastern University, Boston, MA, USA
| | - Kameran Lashkari
- Department of Bioengineering, University of Massachusetts Dartmouth, Dartmouth, MA, USA
| | - Sagar Kamarthi
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA
| | - Srinivas Sridhar
- NeuroFieldz Inc, Newton, MA, USA.,Departments of Physics, Bioengineering, and Chemical Engineering, Northeastern University, Boston, MA, USA.,Division of Radiation Oncology, Harvard Medical School, Boston, MA, USA
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Rai BB, Sabeti F, Carle CF, Rohan EMF, Saraç Ö, van Kleef J, Maddess T. Recovery dynamics of multifocal pupillographic objective perimetry from tropicamide dilation. Graefes Arch Clin Exp Ophthalmol 2019; 258:191-200. [PMID: 31720837 DOI: 10.1007/s00417-019-04523-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/14/2019] [Accepted: 10/23/2019] [Indexed: 11/29/2022] Open
Abstract
PURPOSE 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. METHODS 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. RESULTS 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 amplitudes) 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). CONCLUSIONS 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 amplitude measurements with mfPOP should be considered only after 48 h, but time-to-peak can be measured after 8-12 h.
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Affiliation(s)
- Bhim Bahadur Rai
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra, ACT, 2601, Australia.
| | - Faran Sabeti
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra, ACT, 2601, Australia.,School of Optometry, University of Canberra, Bruce, ACT, Australia
| | - Corinne F Carle
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra, ACT, 2601, Australia.,ANU Medical School, ANU, Canberra, ACT, Australia
| | - Emilie M F Rohan
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra, ACT, 2601, Australia
| | - Özge Saraç
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra, ACT, 2601, Australia.,Department of Ophthalmology, Ankara Atatürk Training and Research Hospital, Yildirim Beyazit University, Ankara, Turkey
| | - Joshua van Kleef
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra, ACT, 2601, Australia
| | - Ted Maddess
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Building 131 Garran Road, Canberra, ACT, 2601, Australia
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24
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Disinhibition of intrinsic photosensitive retinal ganglion cells in patients with X-linked congenital stationary night blindness. Graefes Arch Clin Exp Ophthalmol 2019; 257:1207-1215. [PMID: 30982101 DOI: 10.1007/s00417-019-04319-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 02/11/2019] [Accepted: 02/15/2019] [Indexed: 10/27/2022] Open
Abstract
PURPOSE To assess the pupil light response (PLR) to chromatic stimulation in patients with different types of X-linked congenital stationary night blindness (CSNB). METHODS Eight patients with CSNB due to CACNA1F and NYX mutations were exposed to blue and red light stimuli, and PLR was evaluated using infrared video pupillography. Pupil responses were compared between CSNB patients and healthy subjects (n = 34) at baseline, at maximum of constriction, for post-illumination pupil responses (PIPR) and the slope of redilation using Cohen's d. A subgroup comparison was performed descriptively between CACNA1F and NYX associated CSNB patients using the same parameters. RESULTS In CSNB, smaller baseline pupil diameters compared to healthy subjects were measured both before blue and red light stimulation (d = 1.44-1.625). The maximum constriction to blue light stimuli was smaller for the CSNB group compared to healthy subjects (d = 1.251) but not for red light stimuli (d = 0.449). Pupil response latencies were prolonged in CSNB for both light stimuli (d = -1.53 for blue and d = -1.011 for red stimulation). No relevant differences were found between the CSNB group and healthy subjects for PIPR (d = 0.01), but the slope of redilation was smaller for CSNB patients (d = 2.12). Paradoxical pupil constriction at light offset was not seen in our patients. CONCLUSION A reduced redilation and smaller baseline pupil diameters for patients with CSNB indicate a disinhibition of intrinsically photosensitive retinal ganglion cells due to affected post-photoreceptor transduction via bipolar cells and can explain the pupillary behavior in our patient group.
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25
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Sabeti F, Carle CF, Jaros RK, Rohan EMF, Waddington G, Lueck CJ, Hughes D, Maddess T. Objective Perimetry in Sporting-Related Mild Traumatic Brain Injury. Ophthalmology 2019; 126:1053-1055. [PMID: 30711605 DOI: 10.1016/j.ophtha.2019.01.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/08/2019] [Accepted: 01/22/2019] [Indexed: 11/28/2022] Open
Affiliation(s)
- Faran Sabeti
- Department of Optometry, University of Canberra, Canberra, ACT, Australia; The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia.
| | - Corinne F Carle
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia; Australian National University Medical School, Australian National University, Canberra, ACT, Australia
| | - Rachel K Jaros
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Emilie M F Rohan
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Gordon Waddington
- Research Institute for Sport and Exercise, University of Canberra, Canberra, ACT, Australia
| | - Christian J Lueck
- Australian National University Medical School, Australian National University, Canberra, ACT, Australia; Department of Neurology, The Canberra Hospital, Canberra, Australia
| | - David Hughes
- Department of Sports Medicine, Australian Institute of Sport, Canberra, Australia
| | - Ted Maddess
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
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26
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Rosli Y, Carle CF, Ho Y, James AC, Kolic M, Rohan EMF, Maddess T. Retinotopic effects of visual attention revealed by dichoptic multifocal pupillography. Sci Rep 2018; 8:2991. [PMID: 29445236 PMCID: PMC5813021 DOI: 10.1038/s41598-018-21196-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/31/2018] [Indexed: 01/10/2023] Open
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.
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Affiliation(s)
- Yanti Rosli
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
- Biomedical Science Program, Diagnostic & Applied Health Sciences, Faculty of Health Science, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia
| | - Corinne Frances Carle
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Yiling Ho
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Andrew Charles James
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Maria Kolic
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
- Centre for Eye Research Australia, University of Melbourne, East Melbourne, Australia
| | - Emilie Marie Françoise Rohan
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Ted Maddess
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia.
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27
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Mack HG, Fagan X, Symons RA. Functional screening devices for diabetic retinopathy. Clin Exp Ophthalmol 2017; 46:573-575. [PMID: 29205736 DOI: 10.1111/ceo.13124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/20/2017] [Accepted: 12/03/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Heather G Mack
- Melbourne Medical School, University of Melbourne, Melbourne, Victoria, Australia.,Melbourne Health, Melbourne, Victoria, Australia.,Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.,Centre for Eye Research Australia, Melbourne, Victoria, Australia
| | - Xavier Fagan
- Centre for Eye Research Australia, Melbourne, Victoria, Australia.,Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Rc Andrew Symons
- Melbourne Medical School, University of Melbourne, Melbourne, Victoria, Australia.,Melbourne Health, Melbourne, Victoria, Australia
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28
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Maddess T, Daria VR. To BCVA, or not to BCVA, that is the question. Clin Exp Ophthalmol 2017; 45:437-439. [PMID: 28710867 DOI: 10.1111/ceo.12984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ted Maddess
- Diagnostics for Eye Diseases, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Vincent R Daria
- Neurophotonics, John Curtin School of Medical Research, Australian National University, Canberra, Australia
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