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Contactless measurements of retinal activity using optically pumped magnetometers. Neuroimage 2021; 243:118528. [PMID: 34464740 DOI: 10.1016/j.neuroimage.2021.118528] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/20/2021] [Accepted: 08/27/2021] [Indexed: 11/23/2022] Open
Abstract
Optically pumped magnetometers (OPMs) have been adopted for the measurement of brain activity. Without the need to be cooled to cryogenic temperatures, an array of these sensors can be placed more flexibly, which allows for the recording of neuronal structures other than neocortex. Here we use eight OPM sensors to record human retinal activity following flash stimulation. We compare this magnetoretinographic (MRG) activity to the simultaneously recorded electroretinogram of the eight participants. The MRG shows the familiar flash-evoked potentials (a-wave and b-wave) and shares a highly significant amount of information with the electroretinogram (both in a simultaneous and separate measurement). We conclude that OPM sensors have the potential to become a contactless alternative to fiber electrodes for the measurement of retinal activity. Such a contactless solution can benefit both clinical and neuroscientific settings.
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Kim K, Kim HJ, Zhang H, Park W, Meyer D, Kim MK, Kim B, Park H, Xu B, Kollbaum P, Boudouris BW, Lee CH. All-printed stretchable corneal sensor on soft contact lenses for noninvasive and painless ocular electrodiagnosis. Nat Commun 2021; 12:1544. [PMID: 33750806 PMCID: PMC7943761 DOI: 10.1038/s41467-021-21916-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 12/17/2020] [Indexed: 02/03/2023] Open
Abstract
Electroretinogram examinations serve as routine clinical procedures in ophthalmology for the diagnosis and management of many ocular diseases. However, the rigid form factor of current corneal sensors produces a mismatch with the soft, curvilinear, and exceptionally sensitive human cornea, which typically requires the use of topical anesthesia and a speculum for pain management and safety. Here we report a design of an all-printed stretchable corneal sensor built on commercially-available disposable soft contact lenses that can intimately and non-invasively interface with the corneal surface of human eyes. The corneal sensor is integrated with soft contact lenses via an electrochemical anchoring mechanism in a seamless manner that ensures its mechanical and chemical reliability. Thus, the resulting device enables the high-fidelity recording of full-field electroretinogram signals in human eyes without the need of topical anesthesia or a speculum. The device, superior to clinical standards in terms of signal quality and comfortability, is expected to address unmet clinical needs in the field of ocular electrodiagnosis.
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Affiliation(s)
- Kyunghun Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Ho Joong Kim
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
| | - Haozhe Zhang
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA
| | - Woohyun Park
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Dawn Meyer
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Min Ku Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Bongjoong Kim
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Heun Park
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Baoxing Xu
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, USA.
| | - Pete Kollbaum
- School of Optometry, Indiana University, Bloomington, IN, USA.
| | - Bryan W Boudouris
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA.
- Department of Chemistry, Purdue University, West Lafayette, IN, USA.
| | - Chi Hwan Lee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA.
- School of Materials Engineering, Purdue University, West Lafayette, IN, USA.
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Cabral T, Lima de Carvalho JR, Kim J, Oh JK, Levi SR, Park KS, Duong JK, Park J, Boudreault K, Belfort R, Tsang SH. Comparative Analysis of Functional and Structural Decline in Retinitis Pigmentosas. Int J Mol Sci 2020; 21:ijms21082730. [PMID: 32326409 PMCID: PMC7215932 DOI: 10.3390/ijms21082730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/07/2020] [Accepted: 04/10/2020] [Indexed: 11/25/2022] Open
Abstract
Retinitis pigmentosa (RP) is a category of inherited retinal dystrophies that is best prognosticated using electroretinography (ERG). In this retrospective cohort study of 25 patients with RP, we evaluated the correlation between 30 Hz flicker ERG and structural parameters in the retina. Internationally standardized 30 Hz flicker ERG recordings, short-wavelength autofluorescence (SW-AF), and spectral domain–optical coherence tomography (SD-OCT) were acquired at two visits at least one year apart. Vertical and horizontal hyperautofluorescent ring diameter measurements with SW-AF, as well as ellipsoid zone (EZ) line width measurements with SD-OCT, were used as structural parameters of disease progression. The 30 Hz flicker ERG amplitude decreased by 2.2 ± 0.8 µV/year (p = 0.011), while implicit times remained unchanged. For SD-OCT, the EZ line decreased by 204.1 ± 34.7 µm/year (p < 0.001). Horizontal and vertical hyperautofluorescent ring diameters decreased by 161.9 ± 25.6 µm/year and 146.9 ± 34.6 µm/year, respectively (p = 0.001), with SW-AF. A correlation was found between the progression rates of the 30 Hz flicker amplitude recorded with Burian–Allen electrodes and both the horizontal ring diameter (p = 0.020) and EZ line (p = 0.044). SW-AF and SD-OCT, two readily available imaging techniques, may be used to prognosticate disease progression because of the reliability of their measurements and correlation with functional outcome.
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Affiliation(s)
- Thiago Cabral
- Department of Ophthalmology, Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University, New York, NY 10032, USA; (T.C.); (J.R.L.d.C.J.); (J.K.O.); (S.R.L.); (K.S.P.); (K.B.)
- Department of Specialized Medicine, CCS and Vision Center Unit, Ophthalmology, EBSERH/HUCAM, CCS-UFES—Federal University of Espírito Santo (UFES), Vitória, ES 29047-105, Brazil
- Department of Ophthalmology, Federal University of São Paulo (UNIFESP), São Paulo, SP 04039-032, Brazil
| | - Jose Ronaldo Lima de Carvalho
- Department of Ophthalmology, Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University, New York, NY 10032, USA; (T.C.); (J.R.L.d.C.J.); (J.K.O.); (S.R.L.); (K.S.P.); (K.B.)
- Department of Ophthalmology, Federal University of São Paulo (UNIFESP), São Paulo, SP 04039-032, Brazil
- Department of Ophthalmology, Empresa Brasileira de Serviços Hospitalares (EBSERH)–Hospital das Clínicas de Pernambuco (HCPE), Federal University of Pernambuco (UFPE), Recife, PE 50740-465, Brazil
| | - Joonpyo Kim
- Department of Statistics, Seoul National University, Seoul 08826, Korea;
| | - Jin Kyun Oh
- Department of Ophthalmology, Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University, New York, NY 10032, USA; (T.C.); (J.R.L.d.C.J.); (J.K.O.); (S.R.L.); (K.S.P.); (K.B.)
- College of Medicine, State University of New York at Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Sarah R. Levi
- Department of Ophthalmology, Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University, New York, NY 10032, USA; (T.C.); (J.R.L.d.C.J.); (J.K.O.); (S.R.L.); (K.S.P.); (K.B.)
| | - Karen Sophia Park
- Department of Ophthalmology, Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University, New York, NY 10032, USA; (T.C.); (J.R.L.d.C.J.); (J.K.O.); (S.R.L.); (K.S.P.); (K.B.)
| | - Jimmy K. Duong
- Department of Biostatistics, Columbia University, New York, NY 10032, USA;
| | - Junhyung Park
- Department of Statistics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA;
| | - Katherine Boudreault
- Department of Ophthalmology, Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University, New York, NY 10032, USA; (T.C.); (J.R.L.d.C.J.); (J.K.O.); (S.R.L.); (K.S.P.); (K.B.)
| | - Rubens Belfort
- Department of Ophthalmology, Federal University of São Paulo (UNIFESP), São Paulo, SP 04039-032, Brazil
| | - Stephen H. Tsang
- Department of Ophthalmology, Jonas Children’s Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University, New York, NY 10032, USA; (T.C.); (J.R.L.d.C.J.); (J.K.O.); (S.R.L.); (K.S.P.); (K.B.)
- Department of Pathology & Cell Biology, Stem Cell Initiative (CSCI), Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
- Correspondence: ; Tel.: +1-(212)-342-1189; Fax: +1-(212)-305-4987
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Pasmanter N, Petersen-Jones SM. A review of electroretinography waveforms and models and their application in the dog. Vet Ophthalmol 2020; 23:418-435. [PMID: 32196872 DOI: 10.1111/vop.12759] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 02/04/2023]
Abstract
Electroretinography (ERG) is a commonly used technique to study retinal function in both clinical and research ophthalmology. ERG responses can be divided into component waveforms, analysis of which can provide insight into the health and function of different types and populations of retinal cells. In dogs, ERG has been used in the characterization of normal retinal function, as well as the diagnosis of retinal diseases and measuring effects of treatment. While many components of the recorded waveform are similar across species, dogs have several notable features that should be differentiated from the responses in humans and other animals. Additionally, modifications of standard protocols, such as changing flash frequency and stimulus color, and mathematical models of ERG waveforms have been used in studies of human retinal function but have been infrequently applied to visual electrophysiology in dogs. This review provides an overview of the origins and applications of ERG in addition to potential avenues for further characterization of responses in the dog.
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Affiliation(s)
- Nathaniel Pasmanter
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
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Brouwer AH, de Wit GC, de Boer JH, van Genderen MM. Effects of DTL electrode position on the amplitude and implicit time of the electroretinogram. Doc Ophthalmol 2019; 140:201-209. [PMID: 31686287 PMCID: PMC7205847 DOI: 10.1007/s10633-019-09733-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/24/2019] [Indexed: 11/24/2022]
Abstract
PURPOSE This study sought to investigate whether there is an optimal position of the Dawson, Trick, and Litzkow (DTL) electrodes when measuring the full-field electroretinogram (ERG) for monitoring purposes. METHODS In 200 uveitis patients, an extended light-adapted (LA) ERG protocol was measured twice, incorporating the International Society for Clinical Electrophysiology of Vision standards. First, a LA ERG was measured with the DTL in the lower lid position (LLP) and thereafter in the fornix position. Differences in amplitudes and implicit times of a-waves, b-waves, and the 30 Hz peak were investigated. Intraclass correlation coefficients (ICCs) as well as coefficients of variation (CoV) were calculated, to assess both reliability and relative variability between the two DTL positions. RESULTS Implicit times showed no statistically significant differences between the two DTL positions. As expected, amplitudes at the different stimulus strengths were 1.12-1.19 higher in the LLP, but there were no significant differences in the CoV between the two DTL positions. The ICC was high for the b-wave and 30 Hz flicker response (0.842-0.979), but lower for the a-wave, especially for amplitudes (0.584-0.716). CONCLUSIONS For monitoring purposes in patients, we conclude that based on relative variability, no position is preferable above the other. However, because in most diseases amplitudes are decreased, the LLP may be chosen because it yields higher amplitudes. Whatever the choice, it is important to ensure that the DTL position remains stable during an ERG recording.
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Affiliation(s)
- Anna H Brouwer
- Bartiméus Diagnostic Centre for Complex Visual Disorders, Zeist, The Netherlands. .,Department of Ophthalmology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.
| | - Gerard C de Wit
- Bartiméus Diagnostic Centre for Complex Visual Disorders, Zeist, The Netherlands
| | - Joke H de Boer
- Department of Ophthalmology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Maria M van Genderen
- Bartiméus Diagnostic Centre for Complex Visual Disorders, Zeist, The Netherlands.,Department of Ophthalmology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
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Ross M, Honig H, Ezra-Elia R, Banin E, Obolensky A, Averbukh E, Rosov A, Gootwine E, Ofri R. Consecutive unilateral recording of the two eyes affects dark-adapted ERG responses, when compared to simultaneous bilateral recording. Doc Ophthalmol 2018; 137:183-192. [DOI: 10.1007/s10633-018-9661-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023]
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Woo J, Jung S, Gauvin M, Lachapelle P. The DTL ERG electrode comes in different shapes and sizes: Are they all good? Doc Ophthalmol 2017; 135:155-164. [PMID: 28741115 DOI: 10.1007/s10633-017-9600-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/03/2017] [Indexed: 11/29/2022]
Abstract
PURPOSE Although the DTL fiber electrode has been in use in the ERG field for more than four decades, its composition was never clearly defined. We compared five different types of conductive (DTL type) yarn (differing in terms of mass, number of filaments, and crimping degree) in order to determine whether we could identify one that would be better suited for the recording of ERGs. METHODS Photopic flash ERGs were recorded from five subjects using the following DTL electrodes: 27/7, 22/1, 11/1, 11/1*2, and 22/1*2. Data analysis included amplitude and peak time measurements of the a- and b-waves in the time domain (TD) as well as measurements of specific frequency descriptors of the ERG waveform in the time-frequency domain using the discrete wavelet transform (DWT) approach. The degree of comfortableness was also assessed in 12 subjects with two surveys (Likert 5-point and the ranking scale). RESULTS Comparisons of TD and DWT parameters did not permit to identify the best DTL electrode, all yielding comparable measures. There was a slight trend for the largest electrode (22/1*2) to yield the largest response, but this was at the expense of comfort, the 22/1*2 electrode being rated as the least comfortable. CONCLUSIONS Given the minimal impact the different electrodes had on the amplitude of the signal, we believe that comfort should dictate our choice. It would appear from our results that use of a multifilament electrode is the best choice since one can get an electrode whose size is optimized for the recording of large responses while minimizing the foreign-body sensation due to the small size of each of the filaments that compose this multifilament electrode.
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Affiliation(s)
- Jungeun Woo
- Departments of Ophthalmology and Neurology and Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montreal, QC, Canada
| | - Suna Jung
- Departments of Ophthalmology and Neurology and Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montreal, QC, Canada
| | - Mathieu Gauvin
- Departments of Ophthalmology and Neurology and Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montreal, QC, Canada
| | - Pierre Lachapelle
- Departments of Ophthalmology and Neurology and Neurosurgery, Research Institute of the McGill University Health Centre/Montreal Children's Hospital, Montreal, QC, Canada. .,Department of Ophthalmology, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Glen Site, Block E, Room EM03238 (Program Mail Drop Point EM03211), Montreal, QC, H4A 3J1, Canada.
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Variability of the multifocal electroretinogram based on the type and position of the electrode. Doc Ophthalmol 2016; 133:99-108. [PMID: 27665467 DOI: 10.1007/s10633-016-9560-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 08/24/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE To evaluate and compare the wave amplitude of multifocal electroretinogram (mfERG) measurements and discomfort from Dawson-Trick-Litzkow (DTL) electrode located on the cornea (cDTL) and on the conjunctival fornix (fDTL) and ERG-jet contact lens electrode (CL). METHODS Thirty-six patients and 18 healthy volunteers were evaluated with three different methods (cDTL, fDTL and CL). Wave amplitude, number of artifacts, number of electrode dislocations and level of discomfort obtained with each electrode were compared. These variables were also compared between patients and healthy volunteers (control group). Comparisons between wave amplitudes were made using intraclass correlation coefficient (ICC). RESULTS Responses by the three tested electrode were better correlated (ICC) in patient (0.616-0.756) than in control groups (0.342-0.679). CL provided the highest wave amplitude in both groups (p < 0.005), but it was associated with higher discomfort (p < 0.001) and the highest rate of dislocations (72 and 100 % in control and patients, respectively). Looking at the differences obtained by each electrode between both groups, CL seems to be able to differentiate patient from control in the ring 1 of the mfERG. By contrast, fDTL gave the lowest wave amplitude in both groups, but it had the advantage to, apparently, discriminate between patients and control group in rings 1 and 2. cDTL produced more artifacts than the other electrodes in both groups (p < 0.001). CONCLUSIONS Although wave amplitude measurements with different electrodes were correlated, they cannot be directly compared, so it is mandatory to create an appropriate normative database with each electrode. Despite providing the lowest amplitudes, fDTL seems to offer the best features to perform mfERG regarding discomfort, number of artifacts and diagnostic capability.
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Lapkovska A, Palmowski-Wolfe AM, Todorova MG. Comparing DTL microfiber and Neuroline skin electrode in the Mini Ganzfeld ERG. BMC Ophthalmol 2016; 16:137. [PMID: 27491453 PMCID: PMC4974799 DOI: 10.1186/s12886-016-0311-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/28/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In infant ERG recordings skin electrodes frequently result in a better compliance. In order to assess the quality of such recordings, we compared the recording characteristics of DTL microfiber and Neuroline surface electrodes using a modified ISCEV protocol in the Mini Ganzfeld ERG. METHODS A prospective cohort study on healthy adult subjects was conducted at the Department of Ophthalmology, University of Basel, Switzerland. Thirty healthy volunteers were tested. The microfiber electrode (DTL Plus Electrode) was placed across the cornea, above the lower eyelid. The Neuroline skin electrode was placed on the surface of the lower lid on the opposite eye. The eye on which each electrode type was placed was randomised. Amplitudes of the rod, standard combined, standard flash cone, light-adapted 3.0 Hz flicker and red cone responses were analysed, as well as their respective implicit times. RESULTS Both electrode recordings showed the same waveform characteristics. Responses with the Neuroline electrode were significantly weaker than those from the DTL electrode. Amplitudes of the rod, standard combined, standard flash cone, light-adapted 3.0 Hz flicker and red cone responses were up to four times larger when recorded with the DTL electrode (p < 0.005, ANOVA). Implicit times of the red cone ERGs were slightly faster for the Neuroline skin electrode recordings (p ≤ 0.039). CONCLUSIONS Comparison of full-field ERG recordings with microfiber DTL and Neuroline skin electrodes showed that DTL electrodes produce larger ERGs. Hence, we provide evidence that both electrode types allow successful full-field ERG recording, although separate normative data for both electrodes are necessary.
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Affiliation(s)
- Anastasia Lapkovska
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, CH-4031, Basel, Switzerland
| | - Anja M Palmowski-Wolfe
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, CH-4031, Basel, Switzerland
| | - Margarita G Todorova
- Department of Ophthalmology, University of Basel, Mittlere Strasse 91, CH-4031, Basel, Switzerland.
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Pereira AL, Montiani-Ferreira F, Santos VR, Salomão SR, Souza C, Berezovsky A. Electroretinography in dogs using a fiber electrode prototype. Braz J Med Biol Res 2013; 46:257-62. [PMID: 23558860 PMCID: PMC3854367 DOI: 10.1590/1414-431x20122769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 12/20/2012] [Indexed: 11/22/2022] Open
Abstract
We compared two electroretinography (ERG) electrodes in dogs using ERG standards
of the International Society for Clinical Electrophysiology of Vision (ISCEV).
Ten healthy Yorkshire terrier dogs (mean age, 2.80 ± 1.42 years; 6 females)
weighing 5.20 ± 1.56 kg were evaluated using an ERG system for veterinary use.
Dark- and light-adapted ERG responses were recorded using an ERG-Jet electrode
and a fiber electrode prototype. The examinations were performed during 2
visits, 3 weeks apart. Both electrodes (ERG-Jet or fiber prototype) were used on
each animal and the first eye to be recorded (OD × OS) was selected randomly.
Three weeks later the examination was repeated on the same animal switching the
type of electrode to be used that day and the first eye to be examined. The
magnitude and waveform quality obtained with the two electrode types were
similar for all ERG responses. ERG amplitudes and implicit times obtained from
dogs using the fiber electrode prototype were comparable to those obtained with
the ERG-Jet electrode for rod, maximal rod-cone summed, cone, and 30-Hz flicker
responses. The fiber electrode prototype is a low-cost device, available as an
alternative instrument for clinical veterinary ERG recording for retinal
function assessment.
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Affiliation(s)
- A L Pereira
- Clínica Veterinária Arca de Noé, Atibaia, SP, Brasil
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Schatz A, Willmann G, Enderle H, Sliesoraityte I, Messias A, Bartz-Schmidt K, Zrenner E, Gekeler F. A new DTL-electrode holder for recording of electroretinograms in animals. J Neurosci Methods 2011; 195:128-34. [PMID: 21075141 DOI: 10.1016/j.jneumeth.2010.10.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 10/22/2010] [Accepted: 10/26/2010] [Indexed: 10/18/2022]
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Jeong MB, Son WG, Park YW, Kim SE, Park SA, Seo KM. Comparison of two electroretinography systems used in dogs: the HMsERG and the RETIport. J Vet Med Sci 2010; 73:431-8. [PMID: 21099150 DOI: 10.1292/jvms.10-0197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of the study was to compare two different electroretinography (ERG) instruments used on the same animal in a laboratory setting. Retinal function in both eyes of 12 healthy miniature schnauzers was evaluated under general anesthesia. Scotopic and photopic ERGs were recorded by the HMsERG and the RETIport using the Dog Standard Protocol recommended by the European College of Veterinary Ophthalmologists (ECVO). The waveforms of the ERGs obtained by the two ERG units were similar to those described in previous studies. The 90% reference ranges using the multiple of medians (MoM) showed that the changes in ERG parameters obtained by the HMsERG unit were very similar to those of the RETIport for most ERG responses, except for a few. The results demonstrate that the two ERG systems are comparable for evaluating retinal function in dogs. Further, the results also show that it is necessary to establish ERG system-specific limits of normality in each laboratory or clinic in order to obtain a correct diagnosis, for example by using a graphical representation of the 90% reference range.
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Affiliation(s)
- Man Bok Jeong
- Department of Veterinary Surgery and Ophthalmology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul, Korea
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Mortlock KE, Binns AM, Aldebasi YH, North RV. Inter-subject, inter-ocular and inter-session repeatability of the photopic negative response of the electroretinogram recorded using DTL and skin electrodes. Doc Ophthalmol 2010; 121:123-34. [PMID: 20607349 DOI: 10.1007/s10633-010-9239-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 06/21/2010] [Indexed: 10/19/2022]
Abstract
The photopic negative response (PhNR) has attracted interest as a flash ERG component reflecting inner retinal activity, with investigators adopting various approaches to analysing the response. This study has two principal aims: first to determine the most reliable technique for assessing the PhNR amplitude; secondly to compare the repeatability characteristics of the PhNR recorded using DTL and skin active electrodes. Electroretinograms were recorded in 31 subjects, using both electrode types, in response to a Ganzfeld red stimulus (Lee filter "bright red"; 1.76 log phot td.s; 4 Hz) presented over a steady blue background (Schott glass filter BG28; 3.9 log scot td). Sixteen subjects returned to assess repeatability. PhNR amplitude was measured from b-wave peak-to-PhNR trough, pre-stimulus baseline to trough, and from peak and baseline to a fixed time-point; a ratio of b-wave/PhNR amplitude was also calculated. Coefficients of variation (CoV), and inter-ocular and inter-session limits of agreement (LoA) were calculated for all measures. The ratio of b-wave/PhNR amplitude showed the lowest CoV (14.3% DTL; 23.2% skin), inter-ocular LoA (22.2% DTL; 25.0% skin), and inter-session LoA (22.8% DTL; 20.3% skin). The peak-to-trough and peak-to-fixed-time measurements were also consistently reliable. Least reliable measures were those measured from baseline. While skin electrode responses were significantly smaller than DTL responses (P < 0.0001), the variability was only slightly increased. This study suggests that peak-to-trough measurements are the most reliable means of measuring the PhNR and ratio calculation further improves repeatability. Skin electrodes provided a viable alternative to DTL electrodes for recording the PhNR.
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Affiliation(s)
- Katharine E Mortlock
- School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff, CF24 4LU, UK
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Papathanasiou ES, Papacostas SS. Flash electroretinography: normative values with surface skin electrodes and no pupil dilation using a standard stimulation protocol. Doc Ophthalmol 2007; 116:61-73. [PMID: 17610098 DOI: 10.1007/s10633-007-9065-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Accepted: 05/29/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVES To demonstrate the clinical feasibility of using surface electrodes for recording flash electroretinography (ERG), using the stimulation standards of the International Society for the Clinical Electrophysiology of Vision (ISCEV), without pupillary dilation. METHODS Eighteen physiologically normal volunteers were tested. Surface recording electrodes were placed over the middle third of the lower eyelid of each eye, and the reference electrode placed on the temple. The recording filters and method of stimulation for the standard flash cone, 30 Hz flicker, rod, standard combined and oscillatory responses were those recommended by the ISCEV. Four patients with a history of visual dysfunction were also examined. RESULTS The amplitudes of the responses were noted to have a high signal to noise ratio, allowing us to average only a few responses. The waveform configurations were almost identical to those published using other recording methods. Patients with retinitis pigmentosa and early onset retinal dystrophy had abnormal responses, whereas patients with Stargardt's Syndrome and spasm of accommodation had responses within normal limits. CONCLUSIONS This study has established the clinical feasibility of performing flash ERG using surface skin electrodes, with no pupillary dilation and using the stimulation standards of the ISCEV.
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Affiliation(s)
- Eleftherios S Papathanasiou
- Department of Clinical Neurophysiology, The Cyprus Institute of Neurology & Genetics, 6 International Airport Avenue, P.O. Box 23462, Nicosia 1683, Cyprus.
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Zhang K, Yao G, Gao Y, Hofeldt KJ, Lei B. Frequency spectrum and amplitude analysis of dark- and light-adapted oscillatory potentials in albino mouse, rat and rabbit. Doc Ophthalmol 2007; 115:85-93. [PMID: 17541795 DOI: 10.1007/s10633-007-9061-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 04/26/2007] [Accepted: 04/28/2007] [Indexed: 11/29/2022]
Abstract
We studied frequency spectrum, implicit time and amplitude of oscillatory potentials (OPs) in albino mice, rats, and rabbits. Oscillatory potentials were extracted digitally from dark- and light-adapted electroretinograms (ERGs) recorded with a protocol commonly used in our laboratory. The frequency spectra of OPs were analyzed by using Fast Fourier Transform (FFT). Oscillatory potential amplitudes were calculated via numerically integrating the power spectrum. Oscillatory potential frequency spectra vary among species and are light-intensity dependent. In dark-adapted ERG, mouse and rat OPs have one major component with a frequency peak at approximately 100 Hz. Rabbits show multiple frequency peaks with a low frequency peak around 75 Hz. In all the three species, the implicit time of light-adapted OP is longer than that of the dark-adapted OPs. At a given intensity, mice have the highest OP responses. Our data suggest that the commonly used bandpass of 75 Hz (or even 100 Hz) to 300 Hz for OP extraction is insufficient in these animals. In order to acquire the complete OP responses from the ERG signals, it is necessary to determine the OP frequency spectrum. In this study, the lower end cutoff frequency was set at 40 Hz in mice, 65 Hz in rats and rabbits.
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Affiliation(s)
- Keqing Zhang
- Department of Veterinary and Surgery, University of Missouri-Columbia, Columbia, MO 65211, USA
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Link B, Rühl S, Peters A, Jünemann A, Horn FK. Pattern reversal ERG and VEP--comparison of stimulation by LED, monitor and a Maxwellian-view system. Doc Ophthalmol 2006; 112:1-11. [PMID: 16633720 DOI: 10.1007/s10633-005-5865-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2005] [Indexed: 11/30/2022]
Abstract
PURPOSE Pattern stimulation is widely used to detect inner retinal dysfunction. In this work we describe a pattern stimulation technique with LEDs and compare the results with conventional methods. METHODS PERG and VEP were derived from three normal subjects. Three different techniques were used to generate a checkerboard pattern reversal stimulus: a 70 Hz monitor, a Maxwellian-view system equipped with a Xenon-arc lamp and a mechanical mirror system, and a LED array (Roland Consult) consisting of 100 white LEDs. Two kinds of luminance (125 and 340 cd/m2) and four temporal frequencies (4, 8, 12 and 24 reversals per second) were studied on three healthy subjects. Additionally, a luminance tuning experiment (30, 60, 90, 125 and 340 cd/m2) was performed on one subject. RESULTS Comparison of different stimulation techniques shows reproducible responses of PERG and VEP with all three methods. The LED array leads to slightly smaller amplitudes than both other techniques, which we ascribe to the design of the LED field. No difference of peak times or phases was noticed between different stimulation techniques. A luminance dependency of PERG and VEP is noticeable using stimulation with LED: with decreasing luminance we measured increasing peak times of PERG and VEP and decreasing amplitude of PERG. CONCLUSION We conclude that central retinal stimulation with checkerboard pattern reversal is possible with LED. It gives comparable results to monitor and Maxwellian-view system.
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Affiliation(s)
- Barbara Link
- Department of Ophthalmology, Biometry and Epidemiology, University of Erlangen-Nürnberg, Erlangen, Germany.
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Link B, Jünemann A, Horn FK. Pattern reversal ERG with LED-stimulation using cyclic summation technique. Doc Ophthalmol 2006; 112:53-60. [PMID: 16633726 DOI: 10.1007/s10633-005-5868-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2005] [Indexed: 10/24/2022]
Abstract
PURPOSE Multifocal pattern reversal stimulation can be used to detect inner retinal dysfunction. Commonly, the stimulus is generated on a monitor using m-sequence technique. We describe a pattern reversal ERG evoked by LED arrays using cyclic summation (CS). METHODS One eye of eight healthy subjects was examined with an arrangement of 13 LED arrays. Each array consisted of 100 LEDs separated by thin walls. One of the fields was placed centrally, three fields each were placed above, below, left and right of the central field. CS technique at a temporal frequency of 16 reversals per second (RPS) was used for stimulation. Viewing distance was 30 cm, check size was 0.58 cyc/deg. Luminance of the bright fields was 340 cd/m2. RESULTS Fourier analysis was performed. Centrally, the amplitude of the 2nd harmonic wave was highest (0.87 microV). In the first paracentral fields, amplitudes were 0.28 microV (nasally), 0.21 microV (superior, inferior and temporally). In the second paracentral fields, amplitudes were 0.11 microV (nasally), 0.09 microV (superior), 0.13 microV (inferior) and 0.15 microV (temporally). With exception of the temporal field (0.1 microV), in the outermost fields no reproducible ERG response could be recorded. CONCLUSION Peripheral ERG responses to a pattern reversal stimulus can be recorded with LED stimulation using CS technique up to an eccentricity of 30 degrees. Responses are highest centrally and decrease with increasing distance to the centre.
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Affiliation(s)
- Barbara Link
- Department of Ophthalmology, Augenklinik mit Poliklinik, Universität Erlangen-Nürnberg, Schwabachanlage 6, D- 91054, Erlangen, Germany.
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Mentzer AE, Eifler DM, Montiani-Ferreira F, Tuntivanich N, Forcier JQ, Petersen-Jones SM. Influence of Recording Electrode Type and Reference Electrode Position on the Canine Electroretinogram. Doc Ophthalmol 2006; 111:95-106. [PMID: 16514491 DOI: 10.1007/s10633-005-4517-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2005] [Indexed: 11/28/2022]
Abstract
Electroretinography is commonly used to assess the functional integrity of the retina. There are many external variables that can influence the electroretinographic waveforms recorded, and it is important to be aware of these so as not to misinterpret their effects as abnormalities in retinal function. In this study we examined the effect of three different recording electrodes on the ERGs recorded from normal dogs. A bipolar Burian-Allen lens, a monopolar Dawson Trick Litzkow (DTL) fiber electrode, and a monopolar ERG-Jet lens electrode were compared. The effect of altering the distance of the reference electrode from the eye was also examined; using the ERG-Jet lens electrode, the ERG was recorded with the reference electrode placed over the zygomatic arch at 1, 3 and 5 cm caudal to the lateral canthus. The ERGs recorded with the bipolar Burian-Allen lens had significantly lower amplitudes, higher a-wave thresholds and a shallower initial a-wave slope, than those recorded by the two monopolar electrodes. Positioning the reference electrode further from the eye resulted in significantly higher amplitudes. Naka-Rushton fitting and calculation of retinal sensitivity (K) gave significantly different results between the Burian-Allen lens and ERG-Jet lens electrode with the reference electrode 5 cm from the lateral canthus. These results demonstrate that recording electrode type and distance of the reference electrode from the eye significantly affect the ERG tracings of the dog, and may alter the assessment of retinal function that can therefore be derived. Results obtained using these three different types of electrodes cannot be directly compared.
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Affiliation(s)
- Alice E Mentzer
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
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