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Rosin B, Banin E, Sahel JA. Current Status of Clinical Trials Design and Outcomes in Retinal Gene Therapy. Cold Spring Harb Perspect Med 2024; 14:a041301. [PMID: 37696658 PMCID: PMC11216172 DOI: 10.1101/cshperspect.a041301] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
With the rapid expansion of methods encompassed by the term gene therapy, new trials exploring the safety and efficacy of these methods are initiated more frequently. As a result, important questions arise pertaining the design of these trials and patient participation. One of the most important aspects of any clinical trial is the ability to measure the trial's outcome in a manner that will reflect the effect of the treatment and allow its quantification, whether the trial is aimed at preservation or restoration of retinal cells (photoreceptors and others), vision, or both. Here we will review the existing methods for quantification of trial outcomes, stressing the importance of assessing the participant's visual function and not just visual acuity. We will also describe the key considerations in trial design. Finally, as patient safety remains the primary concern in any trial participation, we will outline the key principles in that regard.
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Affiliation(s)
- Boris Rosin
- The UPMC Vision Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
| | - Eyal Banin
- Division of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Jose-Alain Sahel
- The UPMC Vision Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
- Division of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
- Institut Hospitalo-Universitaire FOReSIGHT, Paris 75012, France
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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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Predicting Visual Field Progression by Optical Coherence Tomography Angiography and Pattern Electroretinography in Glaucoma. J Glaucoma 2022; 31:881-890. [PMID: 35882039 DOI: 10.1097/ijg.0000000000002088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/12/2022] [Indexed: 02/04/2023]
Abstract
PRCIS Reduced P50-N95 amplitude on pattern electroretinography (PERG) and the presence of microvasculature dropout (MvD) on optical coherence tomography angiography (OCT-A) at baseline were significant factors associated with visual field (VF) progression in predominantly normal tension glaucoma (NTG) patients. OBJECTIVE We investigated the baseline demographics and ocular characteristics that predict future progression in glaucoma patients, including PERG and OCT-A parameters. METHODS One Hundred forty eyes with open angle glaucoma that were prospectively enrolled and followed up for at least 3 years, and underwent at least 5 serial VF tests were included. Baseline PERG was performed, and N35, P50, and N95 latencies and amplitudes were obtained. Superficial vessel density at the macula and complete loss of microvasculature within the deep retinal layer of the parapapillary region (MvD) were evaluated from baseline OCT-A images. Eyes with a glaucomatous VF defect in either both hemifields within 24 points of a central 10 degrees of fixation, and with no VF abnormality in the nasal periphery outside 10 degrees of fixation, were considered to have isolated central scotoma. During follow-up, detected disc hemorrhage (DH) was recorded. Parameters associated with VF progression were determined using linear regression analysis of the mean deviation (MD) values, in combination with an event-based analysis using the Glaucoma Progression Analysis (GPA) software from the Humphrey Field Analyzer. "Likely progression" using GPA was considered to have glaucoma progression. RESULTS Of the 140 eyes, 107 (76.4%) were NTG and 57 (40.7%) exhibited glaucoma progression as defined by Humphrey VF GPA. The MD slopes were -0.43±1.11 dB/y in the progressors and 0.59±1.27 dB/y in the nonprogressors ( P <0.001). Glaucoma patients with progression showed frequent MvD on OCT-A, isolated central scotoma, frequent DH, and reduced baseline P50-N95 amplitude compared with patients without progression. Age at diagnosis ( P =0.038) and baseline P50-N95 amplitude ( P =0.019) showed significant associations with the MD slope. The presence of MvD on OCT-A ( P <0.001) and baseline P50-N95 amplitude ( P =0.037) were significantly associated with VF progression on GPA. CONCLUSIONS The presence of MvD and retinal ganglion cell dysfunction by PERG at baseline, DH or central scotoma were significant factors associated with VF progression in predominantly NTG patients. These patients should be monitored more closely.
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Araya-Arriagada J, Garay S, Rojas C, Duran-Aniotz C, Palacios AG, Chacón M, Medina LE. Multiscale entropy analysis of retinal signals reveals reduced complexity in a mouse model of Alzheimer's disease. Sci Rep 2022; 12:8900. [PMID: 35614075 PMCID: PMC9132967 DOI: 10.1038/s41598-022-12208-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/06/2022] [Indexed: 11/26/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most significant health challenges of our time, affecting a growing number of the elderly population. In recent years, the retina has received increased attention as a candidate for AD biomarkers since it appears to manifest the pathological signatures of the disease. Therefore, its electrical activity may hint at AD-related physiological changes. However, it is unclear how AD affects retinal electrophysiology and what tools are more appropriate to detect these possible changes. In this study, we used entropy tools to estimate the complexity of the dynamics of healthy and diseased retinas at different ages. We recorded microelectroretinogram responses to visual stimuli of different nature from retinas of young and adult, wild-type and 5xFAD-an animal model of AD-mice. To estimate the complexity of signals, we used the multiscale entropy approach, which calculates the entropy at several time scales using a coarse graining procedure. We found that young retinas had more complex responses to different visual stimuli. Further, the responses of young, wild-type retinas to natural-like stimuli exhibited significantly higher complexity than young, 5xFAD retinas. Our findings support a theory of complexity-loss with aging and disease and can have significant implications for early AD diagnosis.
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Affiliation(s)
- Joaquín Araya-Arriagada
- Escuela de Tecnología Médica, Facultad de Salud, Universidad Santo Tomás, Santiago, Chile
- Centro de Investigación e Innovación en Gerontología Aplicada (CIGAP), Facultad de Salud, Universidad Santo Tomás, Antofagasta, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Sebastián Garay
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile
| | - Cristóbal Rojas
- Instituto de Ingeniería Matemática y Computacional, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia Duran-Aniotz
- Latin American Institute for Brain Health (BrainLat), Universidad Adolfo Ibanez, Santiago, Chile
- Center for Social and Cognitive Neuroscience (CSCN), Universidad Adolfo Ibanez, Santiago, Chile
| | - Adrián G Palacios
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Instituto de Sistemas Complejos de Valparaíso, Valparaíso, Chile
| | - Max Chacón
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile
| | - Leonel E Medina
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile.
- Millennium Nucleus for Applied Control and Inverse Problems, Santiago, Chile.
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Macular Blood Flow and Pattern Electroretinogram in Normal Tension Glaucoma. J Clin Med 2022; 11:jcm11071790. [PMID: 35407398 PMCID: PMC8999873 DOI: 10.3390/jcm11071790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 03/17/2022] [Accepted: 03/22/2022] [Indexed: 02/04/2023] Open
Abstract
Purpose: To investigate whether macular vessel density (VD) was associated with the pattern electroretinogram (PERG) in normal tension glaucoma (NTG). Design: Cross-sectional study. Methods: Seventy-six eyes from patients with NTG were included in this study. Macular VD was calculated from the superficial retinal layer, including the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL), using the built-in software provided with the optical coherence tomography angiography (OCTA) device. Functional parameters were obtained from standard automated perimetry (SAP) and PERG, using a commercial ERG stimulator. Moreover, structural parameters, such as peripapillary RNFL and macular ganglion cell/inner plexiform layer (GCIPL) thickness, were measured using OCT. Results: Patients with higher VD had higher N95 amplitude (p = 0.048). Macular VD was significantly correlated with N95 amplitude, irrespective of disease severity (r = 0.352, p = 0.002 for the total subjects and r = 0.276, p = 0.043 for mild glaucoma). According to regression analyses, N95 amplitude and macular VD were bidirectional significant factors (p = 0.035 and 0.019, respectively). For patients with mild to moderate glaucoma, N95 amplitude and macular VD were also significantly associated bidirectionally, according to regression analyses (p = 0.032 and 0.040, respectively). Conclusions: Macular VD was significantly associated with N95 amplitude from PERG. The correlation was prominent in early glaucoma, in contrast to the other structural or functional parameters. When considering that PERG represents the objective function of the retinal ganglion cell (RGC), macular VD was associated with RGC dysfunction before the functional change became apparent on SAP.
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Panorgias A, Aigbe S, Jeong E, Otero C, Bex PJ, Vera-Diaz FA. Retinal Responses to Simulated Optical Blur Using a Novel Dead Leaves ERG Stimulus. Invest Ophthalmol Vis Sci 2021; 62:1. [PMID: 34338749 PMCID: PMC8340654 DOI: 10.1167/iovs.62.10.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose The purpose of this study was to evaluate retinal responses to different types and magnitudes of simulated optical blur presented at specific retinal eccentricities using naturalistic images. Methods Electroretinograms (ERGs) were recorded from 27 adults using 30-degree dead leaves naturalistic images, digitally blurred with one of three types of optical blur (defocus, astigmatism, and spherical aberrations), and one of three magnitudes (0.1, 0.3, or 0.5 µm) of blur. Digitally computed blur was applied to the entire image, or on an area outside the central 6 degrees or 12 degrees of retinal eccentricity. Results ERGs were significantly affected by blur type, magnitude, and retinal eccentricity. ERGs were differentially affected by defocus and spherical aberrations; however, astigmatism had no effect on the ERGs. When blur was applied only beyond the central 12 degrees eccentricity, the ERGs were unaffected. However, when blur was applied outside the central 6 degrees, the ERG responses were significantly reduced and were no different from the ERGs recorded with entirely blurred images. Conclusions Blur type, magnitude, and location all affect the retinal responses. Our data indicate that the retinal area between 6 and 12 degrees eccentricity has the largest effect on the retinal responses to blur. In addition, certain optical blur types appear to have a more detrimental effect on the ERGs than others. These results cannot be solely explained by changes to image contrast and spatial frequency content, suggesting that retinal neurons might be sensitive to spatial cues in order to differentiate between different blur types.
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Affiliation(s)
| | - Stephanie Aigbe
- New England College of Optometry, Boston, Massachusetts, United States
| | - Emily Jeong
- New England College of Optometry, Boston, Massachusetts, United States
| | - Carles Otero
- EMEA Scientific Communications - Alcon, Barcelona, Cataluña, Spain
| | - Peter J Bex
- New England College of Optometry, Boston, Massachusetts, United States.,Psychology Department, College of Science, Northeastern University, Boston, Massachusetts, United States
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Karaca U, Dagli O, Ozge G, Mumcuoglu T, Bayer A. Comparison of structural and functional tests in primary open angle glaucoma. Indian J Ophthalmol 2021; 68:805-811. [PMID: 32317450 PMCID: PMC7350476 DOI: 10.4103/ijo.ijo_921_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Purpose: To comparatively analyze the structural and functional tests used in the diagnosis and follow-up of glaucoma. Methods: Eighty eyes of 40 patients with primary open angle glaucoma (POAG) and 46 eyes of 23 healthy individuals were included in the study. Transient pattern electroretinography (PERG), steady-state PERG (ssPERG), computerized visual field (VF) screening, and examination of retinal nerve fiber layer (RNFL) and macular thickness on optical coherence tomography (OCT) were undertaken. The results were compared between the groups. Results: 80 eyes belonging to 40 patients with a diagnosis of POAG (23 female, 17 male) (18 mild 22 moderate POAG) with a mean of 57.37 (±8.6) years, and 46 eyes of 23 healthy individuals (14 female, 9 male) with a mean age of 55.30 (±8.09) years were included in the study. PERG P50 and N95 and ssPERG latency revealed a significant delay in the POAG group. When the wave amplitudes were examined, they were found to be significantly lower in both PERG and sSPERG tests for the POAG group, but the results were more pronounced in ssPERG. The latency values of PERG and ssPERG tests were not significantly correlated with any of the parameters of the remaining tests. However, the amplitude values of these tests had a positive correlation with the mean deviation value and negative correlation with the pattern standard deviation value of VF. All associated parameters were significant for the amplitude value of the ssPERG test. Conclusion: For the proper management of glaucoma, rather than approaching damage simply as the loss of retinal ganglion cells or the neuroretinal rim, it is necessary to focus on the ongoing anatomical and functional relationship and evaluate structural and functional tests together. In addition, ssPERG test, which is not widely adopted in routine practice, provides valuable information and is significantly correlated with OCT parameters.
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Affiliation(s)
- Umut Karaca
- Isparta Suleyman Demirel University Faculty of Medicine Department of Ophthalmology Isparta, Turkey
| | - Ozan Dagli
- Katip Celebi University Department of Ophthalmology Izmir, Turkey
| | - Gokhan Ozge
- University of Medical Sciences, Gulhane Education and Research Hospital, Department of Ophthalmology, Ankara, Turkey
| | - Tarkan Mumcuoglu
- TOBB ETU University Faculty of Medicine Department of Ophthalmology Ankara, Ankara, Turkey
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Joo JH, Moon SW. Usefulness of the Components of Full-Field Electroretinography to Predict Postoperative Visual Outcomes in Patients With Epiretinal Membranes. Transl Vis Sci Technol 2021; 10:6. [PMID: 33505773 PMCID: PMC7794275 DOI: 10.1167/tvst.10.1.6] [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: 08/19/2020] [Accepted: 11/09/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose To confirm the predictors of postoperative visual outcomes by performing full-field electroretinography (ffERG) before surgery in patients with epiretinal membranes (ERMs). Methods Sixty-one eyes of patients with ERMs who underwent pars plana vitrectomy with membrane peeling were prospectively reviewed. Correlations between preoperative data (ffERG and optical coherence tomography) and postoperative best-corrected visual acuity (BCVA) were investigated. Receiver operating characteristic (ROC) curve analysis was performed to obtain cutoff values of the ffERG parameters predicting good visual outcome (final BCVA ≥ 20/30). Results Postoperative BCVA was significantly correlated with the implicit time and amplitude of the b-wave in light-adapted (LA) 3.0 electroretinography (ERG), with the amplitude difference between N1 and P1 in the LA 30-Hz flicker ERG, and with the sum of the amplitudes of OS1, OS2, and OS3 in dark-adapted (DA) oscillatory potential (OP) ERG (P < 0.01). The area under the ROC curve to predict good visual outcome was statistically significant for the four parameters (0.787, 0.815, 0.757, and 0.792, respectively). Conclusions The postoperative BCVA in patients with ERM was significantly correlated with the implicit time and amplitude of the b-wave in the LA 3.0 ERG, the amplitude difference between N1 and P1 in the LA 30-Hz flicker ERG, and the sum of the amplitudes of OS1, OS2, and OS3 in DA OP ERG of ffERG. It is thought that ffERG before surgery may help predict visual outcomes after surgery. Translational Relevance It was confirmed that the degree of retinal function in the ERM can predict BCVA after treatment.
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Affiliation(s)
- Jin-Ho Joo
- Department of Ophthalmology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
| | - Sang Woong Moon
- Department of Ophthalmology, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
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Kılınç Hekimsoy H, Sekeroglu MA. The effect of ocular dominance on macular function: A pattern electroretinogram study. Eur J Ophthalmol 2020; 31:3177-3181. [PMID: 33353418 DOI: 10.1177/1120672120983169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To investigate the effect of ocular dominance on pattern electroretinogram (PERG) recordings in the participants who have no ophthalmic diseases. METHODS One hundred and twelve eyes of 56 participants (mean age 32.96 ± 10.82 years) were included in this prospective, cross-sectional study. After detailed ophthalmological examination and determination of the ocular dominance with hole-in-a-card test, the PERG was performed to determine implicit time and amplitudes of P50 and N95. RESULTS There were no significant interocular differences in visual acuity, refractive error, or intraocular pressure (p > 0.05 for all). Thirty-six (64.3%) of the participants had ocular dominance in the right eye. The dominant eyes had significantly higher P50 amplitude than in the fellow nondominant eyes (6.90 µV in dominant vs 5.87 µV in nondominant; p = 0.015; 95% confidence interval). There was no significant difference in N95 amplitude, N95/P50 ratio, and implicit times of P50 and N95 between the dominant and nondominant eyes of the participants (p = 0.090, p = 0.124 p = 0.817, p = 0.668; respectively). CONCLUSION The analysis revealed a significantly increased P50 amplitude of the PERG, which is known to be highly associated with macular function, in dominant eyes of the patients when compared to fellow nondominant eyes.
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Affiliation(s)
- Hilal Kılınç Hekimsoy
- Ophthalmology Clinic, Ulucanlar Eye Training and Research Hospital, University of Health Sciences, Ankara, Turkey
| | - Mehmet Ali Sekeroglu
- Ophthalmology Clinic, Ulucanlar Eye Training and Research Hospital, University of Health Sciences, Ankara, Turkey
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Hassankarimi H, Noori SMR, Jafarzadehpour E, Yazdani S, Radinmehr F. Analysis of pattern electroretinogram signals of early primary open-angle glaucoma in discrete wavelet transform coefficients domain. Int Ophthalmol 2019; 39:2373-2383. [PMID: 30725244 DOI: 10.1007/s10792-019-01077-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 01/25/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE To evaluate discrete wavelet transform coefficients and identify descriptors of pattern electroretinogram (PERG) waveforms in order to determine PERG characteristics for optimizing the diagnosis of early primary open-angle glaucoma (POAG). METHODS Pattern electroretinogram was performed in 30 normal eyes and 30 eyes with primary open-angle glaucoma according to the ISCEV protocol. The check size was 0.8° and 16°, and the color was black/white in both groups. The results were analyzed in time domain (TD) and discrete wavelet transform (DWT) using the MATLAB software. The mean value, standard deviation, and relative energy of level 6 and 7 detail coefficients (d6, d7) and level 7 approximation coefficients (a7) of Daubechies 4 (db4), Daubechies 8 (db8), Symlet 5 (sym5), Symlet 7 (sym7), and Coiflet 5 (coif5) wavelets were calculated. In all the mentioned wavelets, DWT descriptors were extracted. Signals were reconstructed by inverse DWT. All data obtained by TD and DWT analyses were compared between the two groups. RESULTS In both check sizes, a significant attenuation of N95 amplitude was seen in the patient group. The relative energy of a7 of db8 increased significantly in the POAG group in the 0.8° check size. In larger check stimuli, the relative energy of d7 of coif5 decreased significantly and the standard deviation of d7 of sym7 increased markedly in glaucomatous patients (P < 0.05). In small stimuli, N95 descriptor (7N) of db8 had the highest value and showed a significant increase as compared to the POAG group. In the 16° check size, there was no significant difference. A strong correlation was seen between reconstructed signals and originals (r = 0.99). CONCLUSION The DWT can quantify PERG responses more accurately. In agreement with TD and wavelet coefficients domain results, 7N of db8 decomposition can be used as a good indicator for early detection of POAG.
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Affiliation(s)
- Homa Hassankarimi
- Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Seyed Mohammad Reza Noori
- Departments of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ebrahim Jafarzadehpour
- Department of Optometry, School of Rehabilitation Science, Iran University of Medical Sciences, Tehran, Iran. .,Department of Optometry, Faculty of Rehabilitation, Iran University of Medical Sciences, Shahnazary St., Mohseni Sq., Mirdamad Blvd., Tehran, Iran.
| | - Shahin Yazdani
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Radinmehr
- Department of Optometry, School of Rehabilitation Science, Iran University of Medical Sciences, Tehran, Iran
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Fry LE, Fahy E, Chrysostomou V, Hui F, Tang J, van Wijngaarden P, Petrou S, Crowston JG. The coma in glaucoma: Retinal ganglion cell dysfunction and recovery. Prog Retin Eye Res 2018; 65:77-92. [DOI: 10.1016/j.preteyeres.2018.04.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/18/2018] [Accepted: 04/03/2018] [Indexed: 01/07/2023]
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Porciatti V, Ventura LM. The PERG as a Tool for Early Detection and Monitoring of Glaucoma. CURRENT OPHTHALMOLOGY REPORTS 2017. [DOI: 10.1007/s40135-017-0128-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Ostrin LA, Choh V, Wildsoet CF. The pattern ERG in chicks - Stimulus dependence and optic nerve section. Vision Res 2016; 128:45-52. [PMID: 27668989 DOI: 10.1016/j.visres.2016.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/21/2016] [Accepted: 09/22/2016] [Indexed: 10/20/2022]
Abstract
The chick is widely used in studies of eye growth regulation and myopia. The aim of this study was to explore the utility of pattern (p)ERG as a tool to assess retinal function in such studies. Effects of optical defocus and diffusing blur, manipulations used to alter eye growth experimentally, were evaluated. PERGs were recorded from White-Leghorn chickens, using a checkerboard pattern, including 8 spatial frequencies (0.05-2.2c/d SF), 13 contrast levels (1-100%), and 8 temporal reversal frequencies (0.5-20Hz). The acute effects of defocus and diffusing blur were examined. Flash- and pERGs were also recorded from chicks that underwent monocular optic nerve section (ONS), to explore the contribution of retinal ganglion cells (RGCs). Measurements were made up to 6weeks post-ONS, complemented with SD-OCT imaging. In normal chicks, the response to 1Hz, 100% contrast stimuli showed positive- and negative-going waveforms at 43ms (P1) and 75ms (N95), respectively, with 0.06-0.1c/d SF eliciting the largest P1 amplitudes of 21.9±2.5μV. Contrast levels above 5% yielded measurable P1 responses. Responses were transient and monophasic for 0.5-5Hzreversal rates, with higher temporal frequencies yielding steady state responses. Defocus and diffusing blur decreased pERG amplitude across all SFs. pERG responses remained normal after ONS, despite the loss of RGCs. In conclusion, chicks show robust pERG responses, which are attenuated by defocus and diffusing blur. The pERG response is not affected by ONS, suggesting that RGCs do not contribute to the chick pERG.
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Affiliation(s)
- Lisa A Ostrin
- University of Houston College of Optometry, 4901 Calhoun, Houston, TX 77004, USA.
| | - Vivian Choh
- University of Waterloo, 200 University West, Waterloo, ON N2L 3G1, Canada.
| | - Christine F Wildsoet
- University of California Berkeley, School of Optometry, 588 Minor Hall, Berkeley, CA 94720, USA.
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Liu HQ, Wei JK, Li B, Wang MS, Wu RQ, Rizak JD, Zhong L, Wang L, Xu FQ, Shen YY, Hu XT, Zhang YP. Divergence of dim-light vision among bats (order: Chiroptera) as estimated by molecular and electrophysiological methods. Sci Rep 2015; 5:11531. [PMID: 26100095 PMCID: PMC5155579 DOI: 10.1038/srep11531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 05/13/2015] [Indexed: 02/05/2023] Open
Abstract
Dim-light vision is present in all bats, but is divergent among species. Old-World fruit bats (Pteropodidae) have fully developed eyes; the eyes of insectivorous bats are generally degraded, and these bats rely on well-developed echolocation. An exception is the Emballonuridae, which are capable of laryngeal echolocation but prefer to use vision for navigation and have normal eyes. In this study, integrated methods, comprising manganese-enhanced magnetic resonance imaging (MEMRI), f-VEP and RNA-seq, were utilized to verify the divergence. The results of MEMRI showed that Pteropodidae bats have a much larger superior colliculus (SC)/ inferior colliculus (IC) volume ratio (3:1) than insectivorous bats (1:7). Furthermore, the absolute visual thresholds (log cd/m(2)•s) of Pteropodidae (-6.30 and -6.37) and Emballonuridae (-3.71) bats were lower than those of other insectivorous bats (-1.90). Finally, genes related to the visual pathway showed signs of positive selection, convergent evolution, upregulation and similar gene expression patterns in Pteropodidae and Emballonuridae bats. Different results imply that Pteropodidae and Emballonuridae bats have more developed vision than the insectivorous bats and suggest that further research on bat behavior is warranted.
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Affiliation(s)
- He-Qun Liu
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming, 650204, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Jing-Kuan Wei
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming, 650204, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Bo Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, and Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Ming-Shan Wang
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming, 650204, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Rui-Qi Wu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, and Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Joshua D. Rizak
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Li Zhong
- Laboratory for Conservation and Utilization of Bio-resource, Yunnan University, Kunming, 650091, China
| | - Lu Wang
- Laboratory for Conservation and Utilization of Bio-resource, Yunnan University, Kunming, 650091, China
| | - Fu-Qiang Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, and Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Yong-Yi Shen
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Joint Influenza Research Centre (SUMC/HKU), Shantou University Medical College, Shantou, 515041, China
| | - Xin-Tian Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
| | - Ya-Ping Zhang
- State Key Laboratory of Genetic Resources and Evolution, Yunnan Laboratory of Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China
- Laboratory for Conservation and Utilization of Bio-resource, Yunnan University, Kunming, 650091, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming, 650204, China
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15
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Vision function abnormalities in Alzheimer disease. Surv Ophthalmol 2014; 59:414-33. [DOI: 10.1016/j.survophthal.2013.10.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 09/28/2013] [Accepted: 10/01/2013] [Indexed: 12/16/2022]
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16
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SERIAL IMAGING AND STRUCTURE-FUNCTION CORRELATES OF HIGH-DENSITY RINGS OF FUNDUS AUTOFLUORESCENCE IN RETINITIS PIGMENTOSA. Retina 2011; 31:1670-9. [DOI: 10.1097/iae.0b013e318206d155] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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17
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Intrinsic optical signal imaging of retinal activation. Jpn J Ophthalmol 2009; 53:327-33. [PMID: 19763749 DOI: 10.1007/s10384-009-0685-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Accepted: 02/25/2009] [Indexed: 10/20/2022]
Abstract
Fast intrinsic optical signals (IOSs) correlated with stimulus-activated retinal responses are reviewed. Fast IOSs have a time course comparable to the stimulus-evoked electrophysiological kinetics of the retina, and thus promise a new methodology for high-resolution evaluation of the physiological health of the retina. However, practical application of fast IOSs for retinal study and diagnosis is challenging because of their low sensitivity and limited specificity. Using isolated amphibian retinas, a series of experiments to optimize and characterize fast IOSs has been conducted. Fast, high-resolution nearinfrared light imaging disclosed both positive (increasing) and negative (decreasing) optical responses in adjacent retinal areas, which satisfied spatial resolution essential to the differentiation of IOSs from opposite polarities. At the subcellular (approximately microm) level, fast IOSs often exceeded 5% DeltaI/I, where I is the dynamic optical change, and I is the background light intensity. Experiments with isolated frog retinas suggest that negative IOSs stem primarily from the photoreceptor layer, while positive IOSs come from inner retinal layers.
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18
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Srinivasan VJ, Chen Y, Duker JS, Fujimoto JG. In vivo functional imaging of intrinsic scattering changes in the human retina with high-speed ultrahigh resolution OCT. OPTICS EXPRESS 2009; 17:3861-77. [PMID: 19259228 PMCID: PMC2846082 DOI: 10.1364/oe.17.003861] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Non-invasive methods of probing retinal function are of interest for the early detection of retinal disease. While retinal function is traditionally directly measured with the electroretinogram (ERG), recently functional optical imaging of the retina has been demonstrated. In this manuscript, stimulus-induced, intrinsic optical scattering changes in the human retina are measured in vivo with high-speed, ultrahigh resolution optical coherence tomography (OCT) operating at 50,000 axial scans per second and ~3.3 micron axial resolution. A stimulus and measurement protocol that enables measurement of functional OCT retinal signals is described. OCT signal changes in the photoreceptors are demonstrated. Two distinct responses having different temporal and spatial properties are reported. These results are discussed in the context of optical intrinsic signals measured previously in the retina by fundus imaging and scanning laser ophthalmoscopy. Finally, challenges associated with in vivo functional retinal imaging in human subjects are discussed.
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Affiliation(s)
- V. J. Srinivasan
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Y. Chen
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- New England Eye Center, Tufts Medical Center, Boston, Massachusetts 02116
| | - J. S. Duker
- New England Eye Center, Tufts Medical Center, Boston, Massachusetts 02116
| | - J. G. Fujimoto
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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19
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Abstract
PURPOSE OF REVIEW Several studies have shown that the pattern electroretinogram, a direct, objective method of measuring retinal ganglion cell function, is altered early in ocular hypertension and glaucoma. Renewed interest in the pattern electroretinogram for early detection of pre-perimetric glaucoma has been sparked by noninvasive and reproducible methods of recording using skin electrodes. RECENT FINDINGS With the noninvasive pattern electroretinogram, response abnormalities have been detected in up to 50% of glaucoma suspects with normal standard perimetry. In early glaucoma (with either normal or high intraocular pressure), a reduction of intraocular pressure has sometimes yielded improvement in pattern electroretinogram amplitude. A prolonged steady-state stimulus presentation reduces the pattern electroretinogram amplitude and increases optic nerve blood flow in normal subjects, suggesting that sustained activity of retinal ganglion cells is physiologically associated with autoregulatory changes of the neural-vascular system. It is unknown whether this autoregulation is altered in glaucoma. The multifocal pattern electroretinogram does not seem to have an advantage over the pattern electroretinogram in the early detection of glaucoma. The photopic negative response of the diffuse flash electroretinogram has shown changes in glaucoma, but may not be able to detect retinal dysfunction in normal tension glaucoma. SUMMARY The pattern electroretinogram is a noninvasive, direct, objective method that may be useful to clinicians in detecting early retinal ganglion cell dysfunction in glaucoma suspects. The pattern electroretinogram may also optimize treatment strategies based on improvement of retinal ganglion cell function.
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Affiliation(s)
- Lori M Ventura
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, Florida 33136, USA.
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20
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Hidajat RR, McLay JL, Goode DH, Hidayat JR. The value of VEP in the diagnosis and post-operative monitoring of meningioma. Doc Ophthalmol 2006; 113:165-9. [PMID: 17019611 DOI: 10.1007/s10633-006-9025-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Indexed: 10/24/2022]
Abstract
Meningiomas are the most frequently reported primary intracranial neoplasms. At first they usually cause unilateral visual loss but eventually result in a bilateral loss of vision. Depending upon the size and location of the tumour, the ocular signs and symptoms of meningiomas may include visual field abnormalities, optic atrophy, papilledema, diplopia and proptosis. This case report highlights the value of visual evoked potentials (VEP) in a patient with unexplained bilateral optic atrophy and a progressive loss of vision over 2 years. As a result of a delayed response in the VEP recorded from the right eye, a compressive lesion of the optic nerve was suspected. That prompted the referring ophthalmologist to request a MRI scan which led to the diagnosis of meningioma. Following the subtotal removal of the suprasellar meningioma, the remaining vision in the right eye improved and the latency of the VEP returned to the normal range. However, the VEP from the blind eye (left) did not show any measurable response either pre- or postoperatively. Experience with this patient suggests that early recognition of optic nerve compression is vital to an optimal outcome and the VEP technique, which is much more cost-effective than MRI, is clinically useful for detecting such compressive lesions.
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Affiliation(s)
- Rudy R Hidajat
- Department of Ophthalmology, Christchurch Hospital, Private Bag 4710, Christchurch, New Zealand.
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21
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Ogden TE. Clinical Electrophysiology. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50021-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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22
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Stiefelmeyer S, Neubauer AS, Berninger T, Arden GB, Rudolph G. The multifocal pattern electroretinogram in glaucoma. Vision Res 2004; 44:103-12. [PMID: 14599576 DOI: 10.1016/j.visres.2003.08.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND The pattern ERG can be used to detect early glaucomatous change, because the response of cells in the inner retina from (typically) 20 degrees -40 degrees of area is reduced before perimetric abnormality is certain. The multifocal pattern electroretinogram (mfPERG) allows analysis of many local regions within this area. The aim of this study was to investigate whether in patients with presumed glaucoma the mfPERG permits diagnosis and discrimination from normals. METHODS Measurements on 25 age-related normal eyes were compared to those on 23 eyes with different stages of glaucoma. A RETIScan system was used to generate a stimulus pattern of 19 hexagons, each consisting of six triangles. The triangles pattern-reversed black to white at 75 Hz. Those 19 hexagons were grouped into three stimulus regions: a central field, a middle, and a peripheral ring. The complete array subtended 48 degrees at the eye. The hexagons alternated between black and white, in a temporal pattern that followed a corrected binary m-sequence (length 512, 10 cycles with 39 s each). The amplitudes and latencies of positive responses at approximately 50 ms (P-50) and negative responses at approximately 95 ms (N-95) were analyzed. RESULTS In patients with glaucoma the P-50 and N-95 components of the mfPERG were significantly reduced for the central area and both outer rings compared to normal volunteers (p<0.001, Mann-Whitney-U). The most distinct reduction was observed for N-95 and the central ring. Changes in latencies were not conclusive. The reduction of the components increased with the stage of glaucoma. A predictive model for detecting early glaucomatous changes was designed based on P-50-N-95 with 88% sensitivity and 76% specificity. CONCLUSION In glaucoma a marked reduction of components, especially centrally is observed in the mfPERG. This hints to an early involvement of central ganglion cells and may be useful for future functional tests.
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Affiliation(s)
- Sandra Stiefelmeyer
- Department of Ophthalmology, Ludwig-Maximilians-Universität, Mathildenstrasse 8, 80336 Muenchen, Germany
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23
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Bui BV, Fortune B, Cull G, Wang L, Cioffi GA. Baseline characteristics of the transient pattern electroretinogram in non-human primates: inter-ocular and inter-session variability. Exp Eye Res 2003; 77:555-66. [PMID: 14550397 DOI: 10.1016/s0014-4835(03)00195-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This study assessed the inter-ocular and inter-session variability of the transient pattern electroretinogram (PERG) in a group of non-human primates. The transient PERG was measured both eyes of 29 non-human primates, and again after three months in 23 eyes of 23 of these animals. Signals were elicited using a contrast (90%, 75 cdm(-2)) reversing (5 reversals sec(-1)) checkerboard pattern (0.56 cpd). PERGs were also measured for stimuli of varied spatial frequency (n=8, 0.07-2.22 cpd), contrast (n=4, 20-100%), mean luminance (n=4, 4.7-75 cdm(-2)) and defocus (n=5, +1, +2, +3 diopters). The inter-eye and inter-session limits-of-agreement (LOA; 95%) were determined for each PERG parameter. Variability was also compared with previous studies using the coefficient-of-variability (COV). Pharmacological blockade of the inner retinal contributions to the PERG measured under these conditions was conducted in one animal using intravitreal injection of tetrodotoxin (approximately 6 microM) and N-methyl-D-aspartic acid (approximately 6 microM). The N95 component of the primate transient PERG showed spatial tuning, with a peak between 0.14 and 0.28cpd. This spatial tuning was not as apparent for the P50 component. A linear relationship between P50 and N95 amplitude was found with contrast and mean luminance. Both components were attenuated with the introduction of +2 diopters or more of defocus. The inter-session COV for the P50 and N95 components were 23.8 and 19.2%, respectively, while the LOA were 58 and 46%, respectively. The N95:P50 ratio had smaller inter-session variability, was robust to changes in contrast, mean luminance and defocus, and was effective for characterization of inner-retinal dysfunction after pharmacologic block.
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Affiliation(s)
- B V Bui
- Discoveries In Sight, Legacy Clinical Research and Technology Center, Portland, OR 97208-3950, USA
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24
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Bayer AU, Maag KP, Erb C. Detection of optic neuropathy in glaucomatous eyes with normal standard visual fields using a test battery of short-wavelength automated perimetry and pattern electroretinography. Ophthalmology 2002; 109:1350-61. [PMID: 12093662 DOI: 10.1016/s0161-6420(02)01100-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
PURPOSE To evaluate the clinical use of a test battery of short-wavelength automated perimetry (SWAP), frequency-doubling technology (FDT) perimetry, and pattern-electroretinography (PERG) in patients with definite primary open-angle glaucoma (POAG) but normal results on standard automated perimetry (SAP). STUDY DESIGN Prospective, comparative, observational case series. PARTICIPANTS Thirty-six patients with POAG with standard visual field defects in one eye and normal standard visual fields in the contralateral eye and 36 normal controls were enrolled. MAIN OUTCOME MEASURES SWAP, PERG, FDT, and SAP were performed in all eyes, and global indices and amplitudes were used for statistical analysis. RESULTS When contralateral POAG eyes with asymmetric glaucomatous damage was compared, a paired t test showed significant differences in SAP mean deviation (MD) (P < 0.0001), SWAP-MD (P = 0.0003), FDT-MD (P = 0.0008), and PERG amplitudes (P < 0.0001). When comparing between POAG eyes with normal results on SAP and normal controls, Student's t test showed significant differences for SWAP-MD (P < 0.0001), FDT-MD (P = 0.0006), PERG N1P1-amplitude (P = 0.0486) and P1N2-amplitude (P < 0.0001); receiver operating characteristic analysis revealed promising accuracy for SWAP-MD of 73.6% (P < 0.0001). SWAP-MD (P < 0.0001) and FDT-MD (P < 0.0001) correlated significantly with SAP-MD and with each other (range, P < 0.0001 to P = 0.0020). Regression analysis revealed that PERG P1N2-amplitude could improve the power of SWAP-MD from 73.6% to detect early POAG in eyes with normal results on SAP to an accuracy of 81.9%. CONCLUSIONS A test battery of SWAP-MD and PERG P1N2-amplitude could detect glaucomatous optic neuropathy in POAG eyes with normal standard visual fields, whereas FDT-MD and SWAP-MD significantly correlated with each other and with SAP-MD. All tests were able to detect the eye with the more severe glaucomatous optic neuropathy in patients with asymmetric POAG.
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Affiliation(s)
- Andreas U Bayer
- Department of Ophthalmology, Hospital of Weilheim-Schongau, Puetrichstrasse 32, 82362 Weilheim, Germany
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25
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Palmowski AM, Berninger T, Allgayer R, Andrielis H, Heinemann-Vernaleken B, Rudolph G. Effects of refractive blur on the multifocal electroretinogram. Doc Ophthalmol 2000; 99:41-54. [PMID: 10947008 DOI: 10.1023/a:1002432113628] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A significant difference in the response density of the MF-ERG response has been suggested for every 2 diopter change of refraction. The influence of refractive blur on the MF-ERG was studied in 8 healthy volunteers using either the VERISTM system (Group A: n=5) or Retiscan(TM) (Group B: n=3). For each eye recordings were obtained with a corrective lens of -3 dpt, 0 dpt, +3 dpt and +6 dpt placed in front of the contact lens electrode. The viewing distance was adjusted to compensate for the induced changes in the retinal image size. When the changes in retinal image size due to the refractive lens were compensated for, no influence due to refraction was observed in either latencies or amplitudes of (KI (P > 0.05). This held true for the central response average (four degrees) as well as for the outer 6-25 degrees. In KII.1 only the peripheral amplitudes of Group B showed an influence due to refraction (P < or = 0.05). This may be due to adaptation as the recordings of group B were obtained in succession. As expected, significant differences were observed when the recordings obtained with the different systems were compared (P < or = 0.05).
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Parmar DN, Sofat A, Bowman R, Bartlett JR, Holder GE. Visual prognostic value of the pattern electroretinogram in chiasmal compression. Br J Ophthalmol 2000; 84:1024-6. [PMID: 10966958 PMCID: PMC1723665 DOI: 10.1136/bjo.84.9.1024] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS The visual loss associated with compression of the optic chiasm by pituitary tumours may be transient or permanent, possibly related to the extent of irreversible retrograde degeneration to the retinal ganglion cells. The pattern electroretinogram (PERG) N95 component is thought to rise in relation to retinal ganglion cell function and hence may be a potential prognostic indicator for visual function following decompressive surgery. METHODS The notes and electrodiagnostic records of 72 eyes from 36 patients with chiasmal compression were retrospectively analysed. RESULTS The postoperative change in visual field was found to be associated with the PERG N95:P50 ratio (p=0.01). Improvement in visual field was shown by a greater proportion of eyes with a normal N95:P50 ratio (65%) than with an abnormal ratio (27%). No change in visual field occurred in 26% of the eyes with a normal N95:P50 ratio compared with 67% of those with an abnormal ratio. Only 8% of eyes showed a worsening of visual field following surgery, in similar proportions for eyes with normal and abnormal N95:P50 ratios. There was no significant relationship with visual acuity. CONCLUSION The PERG is a useful visual prognostic indicator in the preoperative assessment of chiasmal compression.
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Affiliation(s)
- D N Parmar
- Department of Neurosciences, King's College Hospital, London SE5 9RS, UK
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27
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Abstract
Electrophysiological research on acquired retinal disorders, both common and rare, is reviewed. Age is a major factor influencing electroretinogram (ERG) and electro-oculogram (EOG) findings. Bipolar or Müller cell death in the aging retina could account for much of the amplitude decline that is observed with age. In diabetic retinopathy, the oscillatory potentials can monitor the progression of the disease and indicate neuronal alterations rather than diabetic angiopathy of the retina. Human ERG studies on glaucoma concentrated on ERG measures that are dominated by inner retinal contributions. It has been shown that the pattern ERG can serve as a predictor of ocular hypertension's progression to glaucoma. In retinal disorders caused by endogenous intoxication, such as hepatic retinopathy, or exogenous intoxication from chronic lead exposure, ERG changes give an objective measure of the damage and allow to study the pathophysiological mechanisms that are involved. Inflammations of the choroid and the retina affect the standard ERG when they are diffuse. In central serous chorioretinopathy, functional disturbances can be revealed not only in the photoreceptors but also in the middle and inner retinal layers with the use of focal stimuli. Choroidal melanoma leads to large reductions of the EOG light peak-to-dark trough ratio through its influence on the transepithelial potential of the retinal pigment epithelium (RPE). In cancer-associated retinopathy, both the rod and cone ERGs are reduced. However, selective cone dysfunction has been described. In melanoma-associated retinopathy, the long flash ERG may reveal a specific pathophysiological mechanism, namely the affection of the ON-pathway with preservation of the OFF-pathway. ERG measurements can reveal vitamin A deficiency and are altered in cases with a mutation in the gene for the retinol binding protein in which other organs are not affected. Photochemical damage to the retina from light emission by the operating microscope can be assessed by electrophysiological methods.
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Affiliation(s)
- H P Scholl
- Department of Pathophysiology of Vision and Neuro-Ophthalmology, University Eye Hospital, Tübingen, Germany.
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28
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Falsini B, Porrello G, Porciatti V, Fadda A, Salgarello T, Piccardi M. The spatial tuning of steady state pattern electroretinogram in multiple sclerosis. Eur J Neurol 1999; 6:151-62. [PMID: 10053227 DOI: 10.1111/j.1468-1331.1999.tb00008.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In normal subjects, the steady-state electroretinogram in response to contrast reversing gratings (PERG), is spatially band-pass tuned in amplitude, with a maximum at intermediate spatial frequencies and an attenuation at lower and higher ones. The amplitude attenuation at low spatial frequencies is believed to reflect centre-surround antagonistic interactions in the receptive fields of inner retinal neurons. The aim of this study was to evaluate the PERG spatial tuning in multiple sclerosis (MS) patients without a previous optic neuritis history. Steady- state PERGs in response to counterphase-modulated (8 Hz) sinusoidal gratings of variable spatial frequency (0.6, 1.0, 1.4, 2.2 and 4.8 c/deg), were recorded from 18 patients with definite or probable MS and no history of optic neuritis (ON-). Nine of them had no signs of subclinical optic nerve demyelination (asymptomatic) in either eye, while nine had symptoms or signs of optic pathways involvement (symptomatic) in one or both eyes. Results were compared with those obtained from 10 MS patients with a previous history of optic neuritis (ON+) in one or both eyes, as well as from 21 age-matched controls. The amplitudes and phases of the responses' 2nd harmonics were measured. Compared with the controls, asymptomatic ON- patients showed selective losses in mean PERG amplitudes at medium and high (1.0-4.8 c/deg) spatial frequencies. Symptomatic ON- patients and ON+ patients had reductions in mean PERG amplitudes, with respect to controls, involving the whole spatial frequency range, but with greater losses at medium-high (1.0-4.8 c/deg) than at lower spatial frequencies. In all patients' groups, the average PERG spatial tuning function differed significantly from that of the controls, assuming a low-pass instead of the normal band-pass shape. The PERG phase was delayed in ON+ but not in ON- patients, as compared to controls. However, the phase delay was independent of spatial frequency. In both ON- and ON+ patients, losses in PERG amplitude and spatial tuning tended to be associated with corresponding abnormalities in perimetric sensitivity, visual acuity, colour vision and transient visual evoked potential (VEP) latency. The results indicate that abnormalities of the spatial tuning of steady-state PERG can be found in MS patients without either optic neuritis or signs of subclinical optic nerve demyelination. These changes may reflect a retinal dysfunction, developing early in the course of MS, due to a loss of specific subpopulations of inner neurons, changes in lateral interactions of their receptive fields, or both.
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Affiliation(s)
- B Falsini
- Eye Clinic, Catholic University, Lgo F. Vito 1, Rome, Italy
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29
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Abstract
The local responses of the multifocal ERG reveal continuous changes in the second order waveforms from the nasal to the temporal retina. Scrutiny of these changes suggests the presence of an additive component whose latency increases with the distance of the stimulus from the optic nerve head. This observation led to the hypothesis of a contributing source in the vicinity of the optic nerve head whose signal is delayed in proportion to the fiber length from the stimulated retinal patch to the nerve head. The hypothesis was tested with two independent methods. In Method 1, a set of different local response waveforms was approximated by two fixed components whose relative latency was allowed to vary and the fit of this two component model was evaluated. In Method 2, two signals were derived simultaneously using different placements for the reference electrode. The placements were selected to produce a different ratio of the signal contributions from the retina and the nerve head in the two recording channels. The signals were then combined at a ratio that canceled the retinal component. Method 1 yielded an excellent fit of the two component model. Waveforms and latencies of the hypothetical optic nerve head component derived from the two methods agree well with each other. The local latencies also agree with the propagation delays measured in the nerve fiber layer of the monkey retina. In combination, these findings provide strong evidence for a signal source near the optic nerve head.
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Affiliation(s)
- E E Sutter
- Smith-Kettlewell Eye Research Institute, San Francisco, CA 94115, USA.
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30
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McCulloch DL, Van Boemel GB, Borchert MS. Comparisons of contact lens, foil, fiber and skin electrodes for patterns electroretinograms. Doc Ophthalmol 1998; 94:327-40. [PMID: 9858093 DOI: 10.1007/bf02580858] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Pattern electroretinograms are small physiologic signals that require good patient cooperation and long recording times, particularly when conditions are not optimal. Six electrodes were compared to evaluate their efficacy. Pattern electroretinograms were recorded in eight healthy volunteers to high-contrast, pattern-reversal checks (40' width) with Burian-Allen, DTL fiber, C-glide, gold foil, HK loop and skin electrodes. Raw data for 320 reversals were analyzed off-line to evaluate signal amplitude, quality, P50 and N95 peak times, artifact rate and electrical noise. Insertion time, impedance and subjective comfort were also assessed. The Burian-Allen contact lens electrode gave the largest signal and lowest impedance but was the least comfortable and had the highest artifact rate (p < 0.01). A skin electrode on the lower eyelid produced the smallest pattern electroretinogram with the poorest quality (p < 0.05). The four other electrodes were foil or fiber electrodes in contact with the tear film, conjunctiva and/or the inferior cornea. The signal from these showed only minor differences. When electrodes are compared for pattern electroretinograms recording, the foil and fiber electrodes do not differ substantially but contact lens and skin electrodes show substantial disadvantages.
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Affiliation(s)
- D L McCulloch
- Department of Vision Sciences, Glasgow Caledonian University, Scotland, UK
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31
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Adachi K, Fujita Y, Morizane C, Akaike A, Ueda M, Satoh M, Masai H, Kashii S, Honda Y. Inhibition of NMDA receptors and nitric oxide synthase reduces ischemic injury of the retina. Eur J Pharmacol 1998; 350:53-7. [PMID: 9683014 DOI: 10.1016/s0014-2999(98)00317-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
This study was performed to examine the roles of body temperature, NMDA receptors and nitric oxide (NO) synthase in post-ischemic retinal injury in rats. Cell loss in the ganglion cell layer and thinning of the inner plexiform layer were observed 7 days after ischemia. Cell loss in the ganglion cell layer but not thinning of the inner plexiform layer was reduced by hypothermia during ischemia. Intravenous injection of dizocilpine (MK-801) or Nomega-nitro-L-arginine methyl ester (L-NAME) prior to ischemia ameliorated retinal injury. These results suggest that activation of NO synthase following NMDA receptor stimulation is involved in ischemia-induced retinal injury.
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Affiliation(s)
- K Adachi
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan
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32
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Holder GE. The pattern electroretinogram in anterior visual pathway dysfunction and its relationship to the pattern visual evoked potential: a personal clinical review of 743 eyes. Eye (Lond) 1998; 11 ( Pt 6):924-34. [PMID: 9537157 DOI: 10.1038/eye.1997.231] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The pattern electroretinogram (PERG) has now been in routine clinical use for sufficiently long to allow a personal clinical review of its relationship to the cortically generated pattern visual evoked potential (PVEP). The PERG and PVEP findings are presented from 520 eyes with optic nerve demyelination (382 eyes), optic nerve compression (90 eyes) or heredofamilial optic atrophy (48 eyes), and these are compared with the findings obtained in 223 eyes with dysfunction anterior to the retinal ganglion cells. Dysfunction anterior to the retinal ganglion cells gives a reduction in the P50 component of the PERG, but this component is usually spared in optic nerve disease where selective loss of the N95 component is by far the most frequently occurring abnormality. A diagnostic strategy is presented.
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Affiliation(s)
- G E Holder
- Department of Clinical Neurophysiology, King's College Hospital, London, UK
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33
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Ino-ue M, Yokogawa H, Yamamoto M, Naka H, Kuriyama H. Structural impairments in optic nerve of diabetic rats ameliorated with the aldose reductase inhibitor. Exp Eye Res 1998; 66:397-401. [PMID: 9593633 DOI: 10.1006/exer.1997.0426] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Structural impairments of optic nerve fibers in the streptozotocin-induced diabetic rat were investigated using morphometric analysis. The effect of aldose reductase inhibitor (ARI) on abnormalities in myelinated nerve fibers was also evaluated. Three months after the induction of diabetes, loss of body weight and significantly elevated levels of serum glucose were observed. Light microscopic examination revealed that the mean size of the optic nerve in the diabetic rat remained unchanged. Electron microscopic morphometry showed the significantly smaller cross-sectional size of axons and myelin but no change of myelinated fiber number. Reductions of myelinated fiber size was especially remarkable in the larger fibers. ARI treatment improved structural abnormalities without any changes in body weight and blood glucose level. Reduction of axon size and myelin/axon ratio was completely inhibited by ARI treatment. These findings suggest that structural impairment may contribute to the abnormalities of psychophysical and electrophysiological measurements detected in diabetes. Moreover, ARI treatment, which can improve the polyol metabolism, may have a beneficial effect on optic nerve impairment in diabetes.
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Affiliation(s)
- M Ino-ue
- Department of Ophthalmology, School of Medicine, Kobe University, Kobe, Japan
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34
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Peppe A, Stanzione P, Pierantozzi M, Semprini R, Bassi A, Santilli AM, Formisano R, Piccolino M, Bernardi G. Does pattern electroretinogram spatial tuning alteration in Parkinson's disease depend on motor disturbances or retinal dopaminergic loss? ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1998; 106:374-82. [PMID: 9741766 DOI: 10.1016/s0013-4694(97)00075-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Systemic decrease of dopaminergic cells, such as in Parkinson's disease may produce visual alterations in humans. In order to show possible pattern electroretinogram (PERG) spatial tuning function (STF) alterations due to impaired dopaminergic transmission in humans, we studied a group of Parkinson's disease patients before and during treatment with the dopamine precursor, levodopa, and compared their performances with those of an age-matched control group. Moreover, in order to exclude the possible involvement of motor disabilities to produce PERG alterations, we also investigated PERG responses in post-traumatic parkinsonian patients who exhibited motor abnormalities as a consequence of focal lesions of basal ganglia, in the absence of systemic dopaminergic degeneration. Our results showed a clear decrease of PERG responses in Parkinson's disease patients particularly at medium spatial frequency range (2.7-4.0 cycles/degree) with a substantial preservation of responses at low frequencies. Levodopa therapy reversed these alterations in Parkinson's disease patients, resulting in the recovery of a normal tuning function shape. In contrast to Parkinson's disease, the tuning function appeared to be preserved in post-traumatic parkinsonian patients. Our results clearly establish a relationship between retinal alteration in PD patients and dopaminergic retinal function.
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Affiliation(s)
- A Peppe
- I.R.C.C.S. Clinica, S. Lucia, Rome, Italy
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35
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Otto T, Bach M. Retest variability and diurnal effects in the pattern electroretinogram. Doc Ophthalmol 1998; 92:311-23. [PMID: 9476598 DOI: 10.1007/bf02584085] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pattern electroretinograms were recorded to phase-reversing checkerboard stimuli with DTL electrodes under conditions close to those of the ISCEV pattern electroretinogram guidelines. Both transient (2 reversals/s) and steady-state (16 reversals/s) stimulation was used. The check sizes were 0.4 degree, 0.8 degree and 16 degrees; the mean luminance 45 cd/m2, the contrast 98%, and the field size 32 degrees x 27 degrees. In 42 eyes of 21 subjects, measurements were repeated at the same time of day after 1 week. For each eye, the intersession coefficient of variation was calculated as a measure of reproducibility. We found a coefficient of variation (+/- standard deviation) of 7% +/- 5% for the amplitude of the steady-state pattern electroretinogram, 9.5% +/- 7% for the transient pattern electroretinogram and 1.5% +/- 2% for the latency of the transient pattern electroretinogram. To assess the diurnal variability, during a 15-h period, three pattern electroretinograms were recorded in 10 subjects. No relationship was found between the P50 latency and the time of day. However, the mean amplitude showed a maximum in the morning (9:30 am) and a minimum in the afternoon (2:30 pm). This small effect (about 7%, p < 0.001) was more pronounced for N95 and steady-state amplitudes than for P50 amplitudes (p < 0.01). Diurnal contributions to the pattern electroretinogram ranged between 3% and 10%. We conclude that pattern electroretinogram amplitude reproduces within +/- 10% with a probability of 70%. The effect size of the diurnal variation is similar and might be relevant for longitudinal studies.
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Affiliation(s)
- T Otto
- Universitäts-Augenklinik, Freiburg, Germany
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36
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Vingrys AJ, Weisinger HS, Sinclair AJ. Reply to Vaegan. Clin Exp Optom 1997. [DOI: 10.1111/j.1444-0938.1997.tb04865.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Algis J Vingrys
- Department of Optometry and Vision Sciences, The University of Melbourne
| | | | - Andrew J Sinclair
- Department of Food Technology Royal Melbourne Institute of Technology
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37
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Benardete EA, Kaplan E. The receptive field of the primate P retinal ganglion cell, II: Nonlinear dynamics. Vis Neurosci 1997; 14:187-205. [PMID: 9057279 DOI: 10.1017/s0952523800008865] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The receptive-field properties of retinal ganglion cells (RGCs) provide information about early visual processing. In the primate retina, P cells form the largest class of RGCs (Rodieck, 1988). A detailed exploration of the dynamics of the two subdivisions of the P-cell receptive field--the center and the surround--was undertaken. In the preceding paper (Benardete & Kaplan, 1996), the first-order responses of the center and the surround of P cells were described, which were obtained with a new technique, the multiple m-sequence stimulus (Benardete & Victor, 1994). In this paper, the investigation of P-cell responses measured as S-potentials in the lateral geniculate nucleus (LGN) is continued, and significant nonlinear, second-order responses from the center and the surround are described. These responses are quantified by fitting a mathematical model, the linear-nonlinear-linear (LNL) model (Korenberg, 1973; Korenberg & Hunter, 1986; Victor, 1988) to the data. In a second series of experiments, demonstration that steady illumination of the surround modifies the gain of the center to contrast signals (see also Kaplan & Shapley, 1989) is made. In P ON cells, increasing the steady illumination of the surround decreases the gain and speeds up the center's first-order response. In P OFF cells, increasing the steady illumination of the surround increases the gain of the center while speeding up the response. The results of both sets of experiments are related to the known anatomy and physiology of the P cell.
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38
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Porciatti V, Pizzorusso T, Cenni MC, Maffei L. The visual response of retinal ganglion cells is not altered by optic nerve transection in transgenic mice overexpressing Bcl-2. Proc Natl Acad Sci U S A 1996; 93:14955-9. [PMID: 8962163 PMCID: PMC26244 DOI: 10.1073/pnas.93.25.14955] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/1996] [Accepted: 10/04/1996] [Indexed: 02/03/2023] Open
Abstract
Attempts to rescue retinal ganglion cells from retrograde degeneration have had limited success, and the residual function of surviving neurons is not known. Recently, it has been found that axotomized retinal ganglion cells die by apoptotic mechanisms. We have used adult transgenic mice overexpressing the Bcl-2 protein, a powerful inhibitor of apoptosis, as a model for preventing injury-induced cell death in vivo. Several months after axotomy, the majority of retinal ganglion cells survived and exhibited normal visual responses. In control wild-type mice, the vast majority of axotomized retinal ganglion cells degenerated, and the physiological responses were abolished. These results suggest that strategies aimed at increasing Bcl-2 expression, or mimicking its function, might effectively counteract trauma-induced cell death in the central nervous system. Neuronal survival is a necessary condition in the challenge for promoting regeneration and eventually restoring neuronal function.
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Affiliation(s)
- V Porciatti
- Istituto di Neurofisiologia del Consiglio Nazionale delle Ricerche, Pisa, Italy
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39
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Affiliation(s)
- J F Acheson
- Department of Neuro-Ophthalmology, National Hospital for Neurology and Neurosurgery, London, UK
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40
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Graham SL, Goldberg I, Buckland L, Hollows FC. Flash and pattern electroretinogram changes with optic atrophy and glaucoma. Exp Eye Res 1995; 60:697-706. [PMID: 7641852 DOI: 10.1016/s0014-4835(05)80011-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We investigated recent reports that, contrary to common belief, glaucoma can affect flash as well as pattern electroretinograms. An extensive flash and pattern electroretinogram test protocol was used in a large sample of glaucoma patients and age-matched controls who were either visually normal or had other optic nerve diseases. All electroretinogram parameters were reduced and delayed in normal people > 55 years of age. The effect did not increase in later decades. In patients aged < or = 55 years, flash electroretinograms showed mild reductions and delays from optic atrophy alone. Glaucomatous ERG changes were larger and increased with disease severity. Pattern electroretinograms and oscillatory potentials were almost equally reduced in optic atrophy and all degrees of glaucoma. Mildly affected patients > 55 years of age had similar electroretinogram change to age-matched normals in most conditions. Advanced glaucoma patients showed similar differences from normal irrespective of age. This suggests that direct diagnostic application of these results to older patients will be difficult, that the ERG changes in glaucoma cannot be attributed simply to optic atrophy and that additional widespread outer retinal damage occurs in glaucoma.
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41
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Gündüz K, Zengin N, Okudan S, Okka M, Ozbayrak N. Pattern-reversal electroretinograms and visual evoked potentials in branch retinal vein occlusion. Doc Ophthalmol 1995; 91:155-64. [PMID: 8813495 DOI: 10.1007/bf01203695] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We recorded pattern electroretinograms and visual evoked potentials in a group of selected patients with unilateral uncomplicated branch retinal vein occlusion. To document the effects of preexisting risk factors, patients were divided into three groups: diabetes mellitus, hypertension with hyperlipidemia and no systemic disease. The transient and steady-state pattern electroretinogram and visual evoked potential amplitudes were significantly reduced and visual evoked potential peak times were delayed relative to the fellow eyes and age-matched normal subjects. There was a second amplitude reduction relative to the other patient groups in both the affected and fellow eyes of the diabetes mellitus group, which was indicative of an additive effect of diabetes mellitus.
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Affiliation(s)
- K Gündüz
- Department of Ophthalmology, Selçuk University, Konya, Türkiye
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42
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Analysis of evoked potentials. Clin Neurophysiol 1995. [DOI: 10.1016/b978-0-7506-1183-1.50028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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43
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Porciatti V, Morrone MC, Fiorentini A, Burr DC, Bisti S. The pattern electroretinogram in response to colour contrast in man and monkey. Int J Psychophysiol 1994; 16:185-9. [PMID: 8089037 DOI: 10.1016/0167-8760(89)90045-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Steady-state pattern-reversal electroretinograms (PERG) were recorded from both monkeys and humans in response to tartan patterns modulated in both space and time in either luminance contrast or chromatic contrast. In both species, all types of patterns cause a strong modulation of the second-harmonic of the PERG. There was no measurable dependency of the PERG on the colour of the stimulus per se: both in humans and monkeys, stimuli with green-black, red-black or yellow-black modulation of the same mean luminance and of the same contrast, produced identical results. However, chromatic stimuli with modulation between equiluminant red and green produced a qualitatively different PERG: the amplitude was lower, particularly at high temporal frequencies, and there was a clear phase lag corresponding to a difference in processing time of about 20 ms.
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Affiliation(s)
- V Porciatti
- Istituto di Neurofisiologia CNR, Pisa, Italy
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44
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Bartel PR, Vos A. Induced refractive errors and pattern electroretinograms and pattern visual evoked potentials: implications for clinical assessments. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1994; 92:78-81. [PMID: 7508855 DOI: 10.1016/0168-5597(94)90009-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Refractive errors were induced in normal subjects by means of positive dioptre lenses to reduce visual acuity (VA) from an initial level of 20/20 to 20/100 and then to 20/200. Pattern electroretinograms (PERGs) and pattern visual evoked potentials (PVEPs) were simultaneously recorded at each of these 3 levels of VA using high contrast checkerboard stimuli subtending 11' and 42' of visual arc. Attention was paid to PERG and PVEP variables used for clinical assessments. The findings confirmed the need to take refractive errors into account because, in some cases, latencies and particularly PERG amplitudes fell outside normal limits with decreased VA, especially when using smaller checks.
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Affiliation(s)
- P R Bartel
- Neurophysiology Laboratory, University of Pretoria, South Africa
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45
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Ofri R, Dawson WW, Foli K, Gelatt KN. Chronic ocular hypertension alters local retinal responsiveness. Br J Ophthalmol 1993; 77:502-8. [PMID: 8025048 PMCID: PMC504585 DOI: 10.1136/bjo.77.8.502] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Electrophysiological responses of the retina and visual cortex to a series of grating stimuli (6-768 minutes of arc) were recorded in seven sessions using normal beagles, 21 sessions using beagles afflicted with inherited ocular hypertension, and 12 sessions using rhesus monkeys. A 15 degrees field centred around the animal's area centralis or fovea was used to stimulate the central retina. A 30 degrees field, centred on the same spot, was then used to stimulate the larger area. Two recording series were completed on each animal, with both field sizes presented in each recording session. The first recording took place 30 minutes after and the second 2 hours after the injection of thiamylal sodium. Only the signals from the toroidal 15 degrees of the retina of the hypertensive dogs were remarkably larger during the second recording (p = 0.001). No significant differences were found between the two recordings from the retinas of normal dogs or monkeys, nor were there any significant differences between the two recordings from above the cortex in any group. Several hypotheses are proposed to explain the basis for the interaction of thiamylal with the more peripheral retinal function in clinically glaucomatous dogs.
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Affiliation(s)
- R Ofri
- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, University of Florida, Gainesville
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46
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Logan P, Eustace P, Robinson R. Hypertensive retinopathy: a cause of decreased visual acuity in children. J Pediatr Ophthalmol Strabismus 1992; 29:287-9. [PMID: 1432515 DOI: 10.3928/0191-3913-19920901-07] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hypertensive retinopathy may present atypically in children. Delays in diagnosis may result in permanent visual loss, as demonstrated in three cases we saw.
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Affiliation(s)
- P Logan
- Department of Ophthalmology, Mater Misericordiae Hospital, Dublin, Republic of Ireland
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47
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Stanzione P, Traversa R, Pierantozzi M, Semprini R, Marciani MG, Bernardi G. An electrophysiological study of D2 dopaminergic actions in normal human retina: a tool in Parkinson's disease. Neurosci Lett 1992; 140:125-8. [PMID: 1407691 DOI: 10.1016/0304-3940(92)90697-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A peculiar deficit of electrophysiological retinal responses to pattern reversal grating stimuli has been reported in Parkinson's disease (PD) patients. A similar abnormality has been reproduced by means of non-selective dopaminergic antagonists in normal humans. Aim of this study was to verify, by means of a selective D2 antagonist (sulpiride) administered to normal subjects, whether a D2 blockade affects the visual electrophysiological performances with the same trend as observed in PD patients. Patterns electroretinogram (PERG) responses to 1 cycle per degree (c/d) of spatial frequency at 1 (transient) and 7.5 (steady state) Hz of temporal modulation of a square-wave grating pattern reversal have been recorded in 19 healthy volunteers before and after the administration of 100 mg i.m. of sulpiride. The data are consistent for the following conclusion: a selective D2 antagonist reduces steady state and delays transient retinal responses as expected for a PD mimicking agent.
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Affiliation(s)
- P Stanzione
- Clinica Neurologica II Università di Roma Tor Vergata, Italy
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48
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Peppe A, Stanzione P, Pierelli F, Stefano E, Rizzo PA, Tagliati M, Morocutti C. Low contrast stimuli enhance PERG sensitivity to the visual dysfunction in Parkinson's disease. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1992; 82:453-7. [PMID: 1375553 DOI: 10.1016/0013-4694(92)90051-i] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The pattern electroretinogram (PERG) was recorded at different contrast levels (96%, 71%, 47%) in 10 Parkinson's disease patients before and during dopaminergic monotherapy. The data were compared to a control group of 8 normal subjects recorded with the same procedure. PERG P50 latency progressively increased as contrast was decreased both in normal subjects and patients; however, this trend was much more pronounced in PD patients without therapy; consequently in this group the difference between P50 latency obtained with 96% and 47% contrast was statistically significant (P = 0.01, analysis of variance corrected by post-hoc Tukey test). By contrast this was not seen in the control group. Statistical analysis (Bonferroni's t test) showed at the 47% contrast level a significant P50 latency increase (P less than 0.01) in PD patients without therapy if compared with the control group. Dopaminergic monotherapy induced a P50 latency recovery in PD patients. We conclude that low contrast stimuli enhance PERG sensitivity to the visual dysfunction of PD patients. Moreover, the effects observed after therapy confirm that abnormal contrast response functions in PD patients are linked to dopaminergic deficiency.
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Affiliation(s)
- A Peppe
- Istituto di Clinica delle Malattie Nervose e Mentali, Università La Sapienza, Rome, Italy
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49
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Pallas S, Schmidt W, Dodt E. Scotopic versus photopic pattern onset-offset electroretinograms. Doc Ophthalmol 1992; 81:239-52. [PMID: 1468354 DOI: 10.1007/bf00156013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We investigated the contribution of rods and cones to the human pattern electroretinogram to onset and offset checkerboards of different spatial frequency and wavelength in a 39 degrees x 39 degrees field. Under strictly scotopic conditions, there was a negative potential at onset and a positive potential at offset, whereas under photopic conditions, there was a positive potential at onset and a negative/positive potential at offset. Thus, the waveform to pattern onset (offset) was that of the luminance electroretinogram to decreasing (increasing) luminances. For pattern onset, the sensitivity difference 486-601 nm under scotopic and photopic conditions closely followed the luminosity function of rods and cones. The amplitude of the scotopic onset response increased with check size up to 3 degrees 30' and that of the photopic onset response, up to 30'. With larger checks, the scotopic and photopic onset response markedly decreased. This indicates antagonistic center-surround organization of the receptive fields under both scotopic and photopic conditions. By contrast, the offset response monotonically increased with check size under scotopic and photopic conditions, which suggests a luminance component in the pattern electroretinogram. Consequently, the pattern electroretinogram to reversing checkerboards has to be regarded as a mixture of both pattern- (contrast) and luminance-specific components.
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Affiliation(s)
- S Pallas
- Max-Planck-Institute for Physiological and Clinical Research, W. G. Kerckhoff-Institute, Bad Nauheim, Germany
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50
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Holder GE. The incidence of abnormal pattern electroretinography in optic nerve demyelination. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1991; 78:18-26. [PMID: 1701710 DOI: 10.1016/0013-4694(91)90014-u] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
This report describes the pattern electroretinogram (PERG) findings in 141 patients with optic nerve demyelination in one or both eyes. The overall incidence of PERG abnormality in the 199 eyes with abnormally delayed pattern visual evoked potential (PVEP) P100 component was 39.2%, with 84.6% of these PERG abnormalities being confined to the N95 component. The incidence of abnormal PERG was greater (53.3%) in those eyes with a history of retrobulbar neuritis than in those with sub-clinical demyelination (22.8%). The importance of stimulus parameters is noted. The value of the PERG in the improved interpretation of an abnormal PVEP is discussed.
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Affiliation(s)
- G E Holder
- Regional Dept. of Clinical Neurophysiology, Brook General Hospital, London, U.K
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