1
|
Smirnova TV, Budzinskaya MV, Sheludchenko VM. [Multifocal electroretinography in the diagnosis and monitoring of early and intermediate stages of age-related macular degeneration]. Vestn Oftalmol 2024; 140:172-179. [PMID: 38739148 DOI: 10.17116/oftalma2024140022172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Multifocal electroretinography is a valuable diagnostic method for the objective localization and quantitative assessment of functional disorders of the central retina in age-related macular degeneration. It is used to detect early changes, monitor the course of the disease and treatment outcomes. In many cases, multifocal electroretinography is a more sensitive method for detecting functional disorders at the early/intermediate stage of age-related macular degeneration compared to morphological (optical coherence tomography) and subjective (visual acuity, perimetry) testing methods.
Collapse
Affiliation(s)
- T V Smirnova
- Krasnov Research Institute of Eye Diseases, Moscow, Russia
| | | | | |
Collapse
|
2
|
Kitay AM, Hanson JVM, Hasan N, Driban M, Chhablani J, Barthelmes D, Gerth-Kahlert C, Al-Sheikh M. Functional and Morphological Characteristics of the Retina of Patients with Drusen-like Deposits and Systemic Lupus Erythematosus Treated with Hydroxychloroquine: A Retrospective Study. Biomedicines 2023; 11:1629. [PMID: 37371724 DOI: 10.3390/biomedicines11061629] [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: 04/24/2023] [Revised: 05/23/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
PURPOSE To evaluate the impact of drusen-like deposits (DLD) on retinal layer integrity and retinal function by optical coherence tomography (OCT) and multifocal electroretinography (mfERG) in patients with systemic lupus erythematosus (SLE). METHODS We identified 66 eyes of 33 SLE patients treated with hydroxychloroquine (HCQ) that were categorized into two groups according to whether DLDs were present (34 eyes, Group One) or absent (32 eyes, Group Two). The groups were matched for age, sex, HCQ treatment duration, daily, and cumulative dosage. OCT (retinal layer thicknesses, central retinal thickness, CRT) and mfERG concentric ring analysis were analyzed and compared. RESULTS CRT was significantly thicker in Group One compared to Group Two (273.21 ± 3.96 vs. 254.5 ± 7.62) (p = 0.023). Group One also demonstrated an overall thicker retinal pigment epithelium compared to Group Two; however, the other outer retinal layers, outer nuclear layer, and photoreceptor layer were found to be significantly thinner in Group One compared to Group Two. We found no differences in mfERG parameters between the two groups. CONCLUSIONS DLDs in SLE patients lead to abnormal central retinal layer thickness, which has no measurable impact on cone-mediated retinal function assessed by mfERG.
Collapse
Affiliation(s)
- Alice M Kitay
- Department of Ophthalmology, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland
| | - James V M Hanson
- Department of Ophthalmology, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland
| | - Nasiq Hasan
- UPMC Eye Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Matthew Driban
- UPMC Eye Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jay Chhablani
- UPMC Eye Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Daniel Barthelmes
- Department of Ophthalmology, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland
- Save Sight Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Christina Gerth-Kahlert
- Department of Ophthalmology, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland
| | - Mayss Al-Sheikh
- Department of Ophthalmology, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland
| |
Collapse
|
3
|
Messenio D, Babbi A, Guglielmi A, Airaldi M. Focal electroretinogram and microperimetry testing of photoreceptor-retinal pigment epithelium function in intermediate age-related macular degeneration. Acta Ophthalmol 2022; 100:277-284. [PMID: 34189851 PMCID: PMC9290821 DOI: 10.1111/aos.14934] [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: 02/28/2021] [Accepted: 05/20/2021] [Indexed: 11/28/2022]
Abstract
Purpose To compare the performance of focal electroretinogram (FERG) and fast mesopic microperimetry in evaluating macular function of intermediate age‐related macular degeneration (iAMD) subjects with preserved visual acuity. Methods Cross‐sectional, observational study. Participants with drusen >125 µm and VA ≥80 ETDRS letters and age‐ and sex‐comparable healthy subjects were consecutively enrolled in the study. Three photopic FERG recordings of the central 9° of the macula with luminance modulated stimuli flickering at 42.5 Hz and a fast mesopic microperimetry with a custom pattern of 3 central (CS) and 3 paracentral (pCS) stimuli at 1.2° and 6° from fixation were acquired. Results Overall, 112 eyes of 77 participants (age 73.0 ± 7.1 years, 47 iAMD eyes) were analysed. Mean FERG amplitude, CS and pCS (all p < 0.05) were lower in the iAMD group. A significant association was observed between FERG amplitude and iAMD (OR 9.58, p < 0.001) in multiple logistic regression analysis. Z‐scores of FERG were lower than microperimetry in iAMD (p = 0.002) but not for healthy participants. AUC of the ROC curve was greater for FERG than microperimetry (0.895 versus 0.644 and 0.675, both p < 0.05). Conclusion Focal ERG objectively measures a cumulative response originating from the photoreceptor‐RPE complex of the central 9° of the macula and demonstrated high accuracy in identifying decreased central macular function in iAMD patients with preserved visual acuity, performing better than fast mesopic microperimetry. Focal ERG should be considered a reliable technique for measuring retinal sensitivity of iAMD patients.
Collapse
Affiliation(s)
- Dario Messenio
- Eye Clinic Department of Biomedical and Clinical Science “Luigi Sacco” Sacco Hospital University of Milan Milan Italy
| | - Alessandro Babbi
- Eye Clinic Department of Biomedical and Clinical Science “Luigi Sacco” Sacco Hospital University of Milan Milan Italy
| | | | - Matteo Airaldi
- Eye Clinic Department of Biomedical and Clinical Science “Luigi Sacco” Sacco Hospital University of Milan Milan Italy
| |
Collapse
|
4
|
Trinh M, Kalloniatis M, Nivison-Smith L. Should clinical automated perimetry be considered for routine functional assessment of early/intermediate age-related macular degeneration (AMD)? A systematic review of current literature. Ophthalmic Physiol Opt 2021; 42:161-177. [PMID: 34843120 PMCID: PMC9300202 DOI: 10.1111/opo.12919] [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: 06/29/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 11/30/2022]
Abstract
Purpose There is growing interest in functional testing for early/intermediate age‐related macular degeneration (iAMD). However, systematic evaluation of existing clinical functional tests is lacking. This systematic review examines evidence for using clinical automated perimetry in routine assessment of early/iAMD. Recent findings PubMed, Web of Science Core Collection, and Embase were searched from inception to October 2020 to answer, is there evidence of visual field defects in early/iAMD, and if so, are early/iAMD visual field defects linked to real‐world patient outcomes? Articles using clinical automated perimetry (commercially accessible and non‐modified devices/protocols) were included. Microperimetry was excluded as this has yet to be incorporated into clinical guidelines. The primary outcome was global visual field indices including mean deviation (MD), pattern standard deviation (PSD), mean sensitivity (MS) and frequency of defects. The secondary outcome was any real‐world patient outcome including quality of life and/or activities of daily living indices. Twenty‐six studies were eligible for inclusion and all studies were observational. There was consistent evidence of worsened MD, PSD, MS and frequency of defects for early/iAMD compared to normal eyes under photopic, low‐photopic and scotopic conditions. Meta‐analysis of studies using standard automated perimetry (SAP) under photopic conditions revealed worsened MD (−1.52dB [−2.27, −0.78 dB]) and MS (−1.47dB [−2, −0.94 dB]) in early/iAMD compared to normal eyes, representing large statistical effect sizes but non‐clinically meaningful reductions. There was insufficient data for meta‐analyses regarding other clinical automated perimetry protocols. Only one study assessed a real‐world patient outcome (on‐road driving performance), with no significant link to visual field outcomes in early/iAMD. Summary Significant reduction of global visual field indices is present in early/iAMD, but not clinically meaningful using SAP under photopic conditions. Translational relevance of visual field outcomes to patient outcomes in early/iAMD remains unclear. Thus, SAP under photopic conditions is unlikely to be useful for routine assessment of early/iAMD.
Collapse
Affiliation(s)
- Matt Trinh
- Centre for Eye Health, University of New South Wales, Sydney, New South Wales, Australia.,School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales, Sydney, New South Wales, Australia.,School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Lisa Nivison-Smith
- Centre for Eye Health, University of New South Wales, Sydney, New South Wales, Australia.,School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| |
Collapse
|
5
|
Lem DW, Davey PG, Gierhart DL, Rosen RB. A Systematic Review of Carotenoids in the Management of Age-Related Macular Degeneration. Antioxidants (Basel) 2021; 10:1255. [PMID: 34439503 PMCID: PMC8389280 DOI: 10.3390/antiox10081255] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 01/14/2023] Open
Abstract
Age-related macular degeneration (AMD) remains a leading cause of modifiable vision loss in older adults. Chronic oxidative injury and compromised antioxidant defenses represent essential drivers in the development of retinal neurodegeneration. Overwhelming free radical species formation results in mitochondrial dysfunction, as well as cellular and metabolic imbalance, which becomes exacerbated with increasing age. Thus, the depletion of systemic antioxidant capacity further proliferates oxidative stress in AMD-affected eyes, resulting in loss of photoreceptors, neuroinflammation, and ultimately atrophy within the retinal tissue. The aim of this systematic review is to examine the neuroprotective potential of the xanthophyll carotenoids lutein, zeaxanthin, and meso-zeaxanthin on retinal neurodegeneration for the purpose of adjunctive nutraceutical strategy in the management of AMD. A comprehensive literature review was performed to retrieve 55 eligible publications, using four database searches from PubMed, Embase, Cochrane Library, and the Web of Science. Epidemiology studies indicated an enhanced risk reduction against late AMD with greater dietary consumption of carotenoids, meanwhile greater concentrations in macular pigment demonstrated significant improvements in visual function among AMD patients. Collectively, evidence strongly suggests that carotenoid vitamin therapies offer remarkable synergic protection in the neurosensory retina, with the potential to serve as adjunctive nutraceutical therapy in the management of established AMD, albeit these benefits may vary among different stages of disease.
Collapse
Affiliation(s)
- Drake W. Lem
- College of Optometry, Western University of Health Sciences, Pomona, CA 91766, USA;
| | | | | | - Richard B. Rosen
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| |
Collapse
|
6
|
Asahi MG, Wallsh J, Onishi SM, Kuroyama S, Gallemore RP. Multifocal ERG and Microperimetry Changes in Response to Ranibizumab Treatment of Neovascular AMD: Randomized Phase 2 Open-Label Study. Clin Ophthalmol 2020; 14:3599-3610. [PMID: 33154619 PMCID: PMC7605973 DOI: 10.2147/opth.s270243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/05/2020] [Indexed: 11/23/2022] Open
Abstract
Purpose To compare monthly versus pro re nata (PRN) ranibizumab injections in the treatment of exudative macular degeneration (AMD) while assessing the utility of microperimetry (MP) and multifocal electroretinography (mfERG) testing when monitoring response to treatment. Methods A randomized exploratory trial comparing the efficacy of monthly versus PRN dosing of ranibizumab (0.5 mg or 2.0 mg) for patients with exudative AMD over 12 months. High-resolution optical coherence tomography (HR-OCT) studies were used to guide PRN treatment and any cystic spaces or subretinal fluid prompted retreatment. Macular function was assessed using mean sensitivity on MP and N1-P1 response density on mfERG. Best-corrected visual acuity (BCVA) was measured with Early Treatment Diabetic Retinopathy Study (ETDRS) letters and anatomic response assessed with central foveal thickness (CFT) using HR-OCT studies. Results The 12-month study was completed by 43 patients in the PRN cohort and 33 patients in the monthly cohort. Mean BCVA improved by 6.0 ± 1.3 ETDRS letters in the PRN cohort compared to 7.3 ± 2.8 ETDRS letters in the monthly cohort (p=0.68). A reduction in mean CFT of 64.5 ± 13.3 and 96.3 ± 22.0 µm occurred in the PRN and monthly cohorts, respectively (p=0.22). Macular function assessed with mfERG decreased comparably in both the PRN and monthly cohorts (p=0.33). For all patients, average mean sensitivity significantly improved by 1.7 ± 0.5 dB (p<0.05) and N1-P1 response density significantly decreased by 0.52 ± 0.21 nV/deg2 (p<0.05). Conclusion Both PRN and monthly treatment of exudative AMD with ranibizumab improve visual function as assessed by BCVA and MP. Macular thickening also improved as demonstrated by HR-OCT findings. However, the decreased retinal function noted by mfERG suggests that some loss of retinal function still occurs despite effective treatment. These measures of visual function may be useful in assessing retinal health and response to treatment in future clinical trials.
Collapse
Affiliation(s)
- Masumi G Asahi
- Clinical Research Department, Retina Macula Institute, Torrance, CA, USA
| | - Josh Wallsh
- Clinical Research Department, Retina Macula Institute, Torrance, CA, USA
| | - Spencer M Onishi
- Clinical Research Department, Retina Macula Institute, Torrance, CA, USA
| | - Shari Kuroyama
- Clinical Research Department, Retina Macula Institute, Torrance, CA, USA
| | - Ron P Gallemore
- Clinical Research Department, Retina Macula Institute, Torrance, CA, USA
| |
Collapse
|
7
|
Parisi V, Ziccardi L, Costanzo E, Tedeschi M, Barbano L, Manca D, Di Renzo A, Giorno P, Varano M, Parravano M. Macular Functional and Morphological Changes in Intermediate Age-Related Maculopathy. Invest Ophthalmol Vis Sci 2020; 61:11. [PMID: 32396630 PMCID: PMC7405611 DOI: 10.1167/iovs.61.5.11] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose The purpose of this study was to evaluate macular preganglionic function and to verify its relationship with retinal and choroidal morphology in patients with intermediate age-related macular degeneration (iAMD) patients. Methods All included patients performed multifocal electroretinogram (mfERG) for investigating on macular function from the central 15° of foveal eccentricity, spectral domain optical coherence tomography (SD-OCT) for studying retinal structure, enhanced depth imaging OCT (EDI-OCT) for the measure of choroidal vascularity index (CVI), and OCT-angiography (OCTA) for the evaluation of vessel density (VD) in the superficial and deep capillary plexus, and choriocapillaris (CC) layer. Results Twenty-seven patients with iAMD and 20 age-matched control eyes were analyzed. Significantly (P < 0.01) delayed and reduced mfERG responses in the central 0 to 2.5°, paracentral 2.5 to 5°, and overall 0 to 5° areas, as well as increased CVI values in both foveal (1 mm centered to the fovea) and fovea + parafovea areas (3 mm centered to the fovea), increased foveal and parafoveal (annular area of 1-3 mm centered to the fovea) retinal pigment epithelium thickness, and volume and parafoveal outer retinal volume were found in iAMD eyes as compared to controls. Moreover, iAMD eyes showed significantly (P < 0.01) reduced foveal and parafoveal OCTA-VD values in the CC layer when compared to controls. In the iAMD group, not significant (P > 0.01) correlations were found between morphological and functional parameters. Conclusions Our findings support a dysfunction of photoreceptors and bipolar cells in both foveal and parafoveal areas in the presence of outer retina, CC, and choroidal structural changes, however, not significantly correlated. The observed enlargement of luminal choroidal area (measured by CVI) is possibly compensatory to CC vascular insufficiency.
Collapse
|
8
|
Savastano MC, Falsini B, Cozzupoli GM, Savastano A, Gambini G, De Vico U, Minnella AM, Placidi G, Piccardi M, Rizzo S. Retinal Pigment Epithelial and Outer Retinal Atrophy in Age-Related Macular Degeneration: Correlation with Macular Function. J Clin Med 2020; 9:jcm9092973. [PMID: 32942540 PMCID: PMC7564054 DOI: 10.3390/jcm9092973] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/30/2020] [Accepted: 09/09/2020] [Indexed: 01/19/2023] Open
Abstract
The purpose of this study was to investigate the relationship between the retinal pigment epithelium (RPE) and outer retina changes, expressed in terms of sub-RPE illumination (SRI) on optical-coherence tomography (OCT), and central retinal function, measured by visual acuity and focal electroretinogram (fERG), in patients with non-exudative age-related macular degeneration (neAMD). In this retrospective study, 29 eyes of 29 patients affected by early (24.14%), intermediate (41.38%), and advanced (34.48%) neAMD were evaluated. All enrolled eyes were studied with OCT to measure the total area of SRI, by using an automated standardized algorithm. Visual acuity and fERG were assessed. The area of SRI was negatively correlated with fERG amplitude (r ≤ −0.4, p ≤ 0.02) and best-corrected visual acuity (BCVA) (r ≤ 0.4, p ≤ 0.04). Our results indicate that the severity of retinal pigment epithelium and outer retina atrophy (RORA), indirectly quantified through the detection of SRI areas by commercial OCT algorithms, is correlated with central retinal dysfunction, as determined by visual acuity and fERG, supporting the combined use of structural exams and functional tests as valid tools to detect the extent of RPE and photoreceptors’ disruption.
Collapse
Affiliation(s)
- Maria C. Savastano
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
| | - Benedetto Falsini
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
| | - Grazia M. Cozzupoli
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
- Correspondence: ; Tel.: +39-3408292884
| | - Alfonso Savastano
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
| | - Gloria Gambini
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
| | - Umberto De Vico
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
| | - Angelo M. Minnella
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
| | - Giorgio Placidi
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
| | - Marco Piccardi
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
| | - Stanislao Rizzo
- UOC Oculistica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Largo A. Gemelli 8, 00168 Rome, Italy; (M.C.S.); (B.F.); (A.S.); (G.G.); (U.D.V); (A.M.M.); (G.P.); (M.P.); (S.R.)
- UOC Oculistica, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy
- Consiglio Nazionale delle Ricerche, Istituto di Neuroscienze, Via G. Moruzzi 1, 56124 Pisa, Italy
| |
Collapse
|
9
|
Sahay P, Kumawat D, Gupta S, Tripathy K, Vohra R, Chandra M, Venkatesh P. Detection and monitoring of subclinical ocular siderosis using multifocal electroretinogram. Eye (Lond) 2019; 33:1547-1555. [PMID: 31019264 DOI: 10.1038/s41433-019-0442-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 01/21/2019] [Accepted: 04/02/2019] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Although full-field electroretinogram (ffERG) is the gold standard test to detect physiological dysfunction in siderosis, it measures overall retinal function. This study aims to determine if multifocal electroretinogram (mfERG) can detect subclinical siderosis in eyes with an iron intraocular foreign body (IOFB). METHODS Twenty eyes of 20 patients with retained iron IOFB, clear ocular media and good visual acuity (≥20/120) were enroled in this prospective case-control study. The fellow eyes served as control. These were evaluated with ffERG and mfERG at baseline. Serial mfERG was done till six months after pars plana vitrectomy with IOFB removal. Primary outcomes measures were amplitude and peak time of P1 and N1 wave of mfERG. RESULTS The median age was 25 years (range 18-55). Most patients (n = 14/20) presented within a month of trauma. Baseline ffERG showed no difference in either 'a' or 'b' wave amplitude or peak time between cases and controls. However, on mfERG, there was a significant decrease in P1 and N1 wave amplitude and delay in P1 wave peak time in <2° retinal ring in cases as compared to controls (p = 0.001, 0.001 and 0.02 respectively) despite variability in results. At 6 months, P1 amplitude showed significant improvement from baseline in cases (p = 0.010). However, P1 peak time did not show significant recovery (p = 0.65). CONCLUSIONS mfERG may reveal subclinical electrophysiological retinal dysfunction in eyes with iron IOFB in cases with normal ffERG. P1 peak time may serve as an electrophysiological marker for past retinal damage.
Collapse
Affiliation(s)
- Pranita Sahay
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Devesh Kumawat
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Shikha Gupta
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | | | - Rajpal Vohra
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Mahesh Chandra
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Pradeep Venkatesh
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
| |
Collapse
|
10
|
Borrelli E, Mastropasqua R, Senatore A, Palmieri M, Toto L, Sadda SR, Mastropasqua L. Impact of Choriocapillaris Flow on Multifocal Electroretinography in Intermediate Age-Related Macular Degeneration Eyes. Invest Ophthalmol Vis Sci 2018; 59:AMD25-AMD30. [PMID: 29860309 DOI: 10.1167/iovs.18-23943] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the relationship between perfusion of the choriocapillaris (CC) and macular function in eyes with intermediate age-related macular degeneration. Methods In this prospective, observational, cross-sectional study, macular optical coherence tomography angiography images and multifocal electroretinograms were obtained in 20 eyes with intermediate age-related macular degeneration from 20 patients. The main outcome measures were (1) the percent nonperfused choriocapillaris area (PNPCA), which represents a measure of the total area of CC vascular dropout, and (2) the average size of the CC signal voids, which represent contiguous regions of CC dropout. Furthermore, amplitude and implicit time of multifocal electroretinograms N1 and P1 waves in the two central rings (R1 and R2) were included in the analysis. Results Of the 20 patients enrolled, only 17 eyes from 17 patients (13 women) were included in this analysis. Three patients were excluded because of poor scan quality. Mean ± SD age was 75.1 ± 7.9 years (range, 62-89 years). The best corrected visual acuity was 0.17 ± 0.13 logarithm of the minimum angle of resolution. In univariate analysis, both the PNPCA and average signal void size were found to have a significant direct relationship with N1 implicit time in the R2 ring (P = 0.006 and P = 0.035, respectively). Neither PNPCA nor the average signal void size was associated with P1 or N1 implicit times in R1. Conclusions In intermediate age-related macular degeneration eyes, PNPCA and average signal void size are related to N1 multifocal electroretinogram implicit times, which suggests an association between CC perfusion and photoreceptor function.
Collapse
Affiliation(s)
- Enrico Borrelli
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D'Annunzio Chieti-Pescara, Chieti, Italy
| | - Rodolfo Mastropasqua
- Whipps Cross University Hospital, Eye Treatment Centre, London, United Kingdom.,Ophthalmology Clinic, University of Marche, Ancona, Italy
| | - Alfonso Senatore
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D'Annunzio Chieti-Pescara, Chieti, Italy
| | - Michele Palmieri
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D'Annunzio Chieti-Pescara, Chieti, Italy
| | - Lisa Toto
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D'Annunzio Chieti-Pescara, Chieti, Italy
| | - SriniVas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California, United States.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Leonardo Mastropasqua
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D'Annunzio Chieti-Pescara, Chieti, Italy
| |
Collapse
|
11
|
Rodriguez JD, Lane K, Hollander DA, Shapiro A, Saigal S, Hertsenberg AJ, Wallstrom G, Narayanan D, Angjeli E, Abelson MB. Cone photoreceptor macular function and recovery after photostress in early non-exudative age-related macular degeneration. Clin Ophthalmol 2018; 12:1325-1335. [PMID: 30100705 PMCID: PMC6067527 DOI: 10.2147/opth.s165658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Purpose To identify parameters from cone function and recovery after photostress that detect functional deficits in early non-exudative age-related macular degeneration (AMD) and to determine the repeatability of these parameters. Methods Cone-mediated visual function recovery after photostress was examined in three groups of subjects: young normal subjects (ages 20–29; N=8), older normal subjects (ages 50–90; N=9), and early non-exudative AMD subjects (ages 50–90; N=12). Eight AMD and four normal subjects were retested 1 year after the initial evaluation. Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (VA) and parameters of cone function (baseline cone sensitivity and cone recovery half-life following photobleach) were measured and compared between AMD and normal subjects. Short-term repeatability was assessed for each subject’s initial evaluation. Long-term repeatability was assessed by comparing outcomes from the initial evaluation and 1-year follow-up. Results The mean baseline cone threshold was significantly worse in subjects with early AMD compared to older normal subjects (−1.80±0.04 vs −1.57±0.06 log cd/m2p=0.0027). Moreover, the baseline cone threshold parameter exhibited good short-term (intraclass correlation coefficient [ICC]=0.88) and long-term (ICC=0.85) repeatability in all subjects. The cone intercept parameter and ETDRS VA were not significantly different between AMD and older normal subject groups. Cone recovery half-life was significantly different between older normal and AMD subject groups (p=0.041). Neither ETDRS VA nor cone function parameters were significantly different for any group at the 1-year follow-up. Conclusion The baseline cone threshold shows potential as a novel parameter to assess visual dysfunction in early AMD. This outcome consistently detected deficits in AMD subjects, and differentiated them from age-matched controls with high test–retest repeatability.
Collapse
Affiliation(s)
| | | | - David A Hollander
- Ora, Inc., Andover, MA, USA, .,Jules Stein Eye Institute, University of California, Los Angeles, CA, USA
| | | | | | | | | | | | | | - Mark B Abelson
- Ora, Inc., Andover, MA, USA, .,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
12
|
Kumar A, Midha N, Mohanty S, Chohan A, Seth T, Gogia V, Gupta S. Evaluating role of bone marrow-derived stem cells in dry age-related macular degeneration using multifocal electroretinogram and fundus autofluorescence imaging. Int J Ophthalmol 2017; 10:1552-1558. [PMID: 29062775 DOI: 10.18240/ijo.2017.10.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/20/2017] [Indexed: 02/01/2023] Open
Abstract
AIM To evaluate the role of bone marrow-derived stem cells in the treatment of advanced dry age-related macular degeneration (AMD) using multifocal electroretinogram (mf-ERG) and fundus autofluorescence imaging. METHODS Thirty patients (60 eyes) with bilateral central geographic atrophy (GA) were recruited. Worse eye of each patient received autologous bone marrow-derived hematopoietic stem cells (BM-HSCs) (group 1) and the fellow eye with better visual acuity served as control (group 2). The effect of stem cell therapy was determined in terms of visual acuity, amplitude and implicit time in mf-ERG and size of GA on fundus autofluorescence imaging. These tests were performed at presentation and first, third and sixth month follow up. Adverse events (if any) were also monitored. RESULTS At 6mo follow-up there was no statistically significant improvement in median logMAR best corrected visual acuity (BCVA) in either group. Mf-ERG revealed significant improvement in amplitude and implicit time in the intervention group. A significant decrease was also noted in greatest linear dimension (GLD) of GA in the eyes receiving stem cells [6.78±2.60 mm at baseline to 6.56±2.59 mm at 6mo (P=0.021)]. However, no such improvement was noted in the control group. CONCLUSION Electrophysiological and anatomical improvement in the intervention group sheds light on the therapeutic role of BM-HSCs. Further studies are required to determine the stage of disease at which the maximal benefit can be achieved and to standardize the dose and frequency of stem cell injection.
Collapse
Affiliation(s)
- Atul Kumar
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Neha Midha
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Sujata Mohanty
- Stem Cell Facility, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Annu Chohan
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Tulika Seth
- Department of Hematology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Varun Gogia
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Shikha Gupta
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 110029, India
| |
Collapse
|
13
|
Moschos MM, Nitoda E. The Role of mf-ERG in the Diagnosis and Treatment of Age-Related Macular Degeneration: Electrophysiological Features of AMD. Semin Ophthalmol 2017; 33:461-469. [PMID: 28328288 DOI: 10.1080/08820538.2017.1301496] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Age-related macular cegeneration (AMD) is the leading cause of visual dysfunction worldwide, affecting 9-25% of individuals between 65 and 75 years old. METHODS We have reviewed the published articles investigating the role of multifocal electroretinogram (mf-ERG) in the diagnosis and treatment of AMD. RESULTS Visual evoked potentials have revealed decreased amplitudes and higher latencies in patients with AMD, while the degeneration of photoreceptors and abnormalities of retinal pigment epithelium can be identified by electro-oculogram recordings. Moreover, ERG can detect the functional abnormalities observed in AMD and evaluate each therapeutic approach. The record of local electrophysiological responses coming from different retinal areas can be accurately performed by mfERG. CONCLUSION The accuracy of mfERG in detecting the degeneration of photoreceptors, as well the disturbances of macular function, could be useful both in the early diagnosis of AMD and the assessment of treatment efficacy.
Collapse
Affiliation(s)
- Marilita M Moschos
- a First Department of Ophthalmology , Medical School, National and Kapodistrian University of Athens , Athens , Greece
| | - Eirini Nitoda
- a First Department of Ophthalmology , Medical School, National and Kapodistrian University of Athens , Athens , Greece
| |
Collapse
|
14
|
Pedersen KB, Sjølie AK, Vestergaard AH, Andréasson S, Møller F. Fixation stability and implication for multifocal electroretinography in patients with neovascular age-related macular degeneration after anti-VEGF treatment. Graefes Arch Clin Exp Ophthalmol 2016; 254:1897-1908. [PMID: 27080862 DOI: 10.1007/s00417-016-3323-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 03/02/2016] [Accepted: 03/09/2016] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To quantify fixation stability in patients with neovascular age-related macular degeneration (nAMD) at baseline, 3 and 6 months after anti-vascular endothelial growth factor (anti-VEGF) treatment and furthermore asses the implications of an unsteady fixation for multifocal electroretinography (mfERG) measurements. METHODS Fifty eyes of 50 nAMD patients receiving intravitreal anti-VEGF treatment with either bevacizumab or ranibizumab and eight eyes of eight control subjects were included. Fixation stability measurements were performed with the Eye-Link eyetracking system and the retinal area in degrees2 (deg2) containing the 68 % most frequently used fixation points (RAF68) was calculated. MfERG P1 amplitude and implicit time were analyzed in six concentric rings and as a summed response. Patients were examined at baseline, 3 and 6 months. Four different mfERG recordings were performed for the control subjects to mimic an involuntary unstable fixation: normal central fixation, 2.4°, 4.8°, and 7.1° fixation instability. RESULTS For control subjects, a fixation instability of 2.4° (corresponding to the central hexagon) did not reduce mfERG ring amplitudes significantly, whereas 4.8° and 7.1° fixation instability reduced the amplitudes significantly in rings 1 and 2 (p < 0.001) as well as in the peripheral rings in the 7.1° instability condition (p < 0.001). Fixation stability improved non-significantly for patients at 3 and 6 months. The size of the retinal area of fixation was at baseline, 3 and 6 months negatively correlated to visual acuity (VA) (rbaseline = -0.65, r3 months = -0.60, and r6 months = -0.66 respectively, p < 0.001) and mfERG amplitudes of the three innermost rings (rbaseline = -0.29, p = 0.042, r3 months = -0.43, p = 0.003 and r6 months = -0.31, p = 0.042). The VA cutoff for a fixation area less than 5 deg2 (approximately the central hexagon) was 65, 77, and 68 ETDRS letters (corresponding a maximal Snellen equivalent of 0.31) at baseline, 3 and 6 months, respectively. CONCLUSIONS MfERG amplitudes in recordings of nAMD patients are at substantial risk of being reduced due to poor fixation as a large number of patients may use a fixation area of more than 5 deg2. Fixation monitoring during recording as well as interpretation of results should be performed with care, especially in patients with poor visual acuity.
Collapse
Affiliation(s)
- K B Pedersen
- Department of Ophthalmology, Rigshospitalet-Glostrup, Nordre Ringvej 57, 2600, Glostrup, Denmark.
| | - A K Sjølie
- Department of Ophthalmology, Odense University Hospital, 5000, Odense, Denmark
| | - A H Vestergaard
- Department of Ophthalmology, Odense University Hospital, 5000, Odense, Denmark
| | - S Andréasson
- Department of Ophthalmology, Lund University, 221 00, Lund, Sweden
| | - F Møller
- Department of Ophthalmology, Vejle Hospital, 7100, Vejle, Denmark
| |
Collapse
|
15
|
Yang S, Zuo C, Xiao H, Mi L, Luo G, Xu X, Liu X. Photoreceptor dysfunction in early and intermediate age-related macular degeneration assessed with mfERG and spectral domain OCT. Doc Ophthalmol 2016; 132:17-26. [PMID: 26754967 DOI: 10.1007/s10633-016-9523-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/04/2016] [Indexed: 10/22/2022]
Abstract
PURPOSE To evaluate the changes of the photoreceptor layer (PRL) thickness with spectral domain optical coherence tomography (SD-OCT) and the retinal function by mfERG, as well as the correlation of morphology and function parameters in subjects with early and intermediate age-related macular degeneration (AMD). METHODS Subjects with clinical diagnosis of early or intermediate AMD and age-matched healthy subjects were recruited prospectively in this study. Color fundus photography, SD-OCT, and mfERG were conducted. Retinal photoreceptor thickness was measured, and first-order kernel responses were recorded. The differences between AMD group and control group were compared, and the correlations between macular photoreceptor thickness and the mfERG were analyzed. RESULTS PRL thickness (μm) in four areas including foveola and 0.5, 1.5, and 3 mm away from foveola was 192.48 ± 17.37, 163.73 ± 12.95, 130.93 ± 9.20, and 108.78 ± 7.81, respectively, in normal eyes, whereas in AMD group, they were 158.61 ± 45.25, 138.91 ± 20.92, 118.91 ± 12.85, and 95.00 ± 9.64, respectively (P < 0.001). The mean amplitude response densities of AMD patients decreased significantly compared to the control group in ring 1-6 (P < 0.001). The mean mfERG N1 and P1 latency of AMD patients prolonged compared to the control group, except the ring 1 (P = 0.588 and P = 0.084). The macular PRL thickness was significantly associated with the mfERGN1 and P1 amplitude density in ring 1-4 (r = 0.338-0.533, P < 0.01). CONCLUSIONS PRL thickness decreases are in accordance with the deterioration of retinal electrophysiological activity. The retinal PRL thickness is important parameter to assess of early and intermediate AMD severity.
Collapse
Affiliation(s)
- Shasha Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 South Xianlie Road, Guangzhou, 510060, China
| | - Chengguo Zuo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 South Xianlie Road, Guangzhou, 510060, China
| | - Hui Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 South Xianlie Road, Guangzhou, 510060, China
| | - Lan Mi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 South Xianlie Road, Guangzhou, 510060, China
| | - Guangwei Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 South Xianlie Road, Guangzhou, 510060, China
| | - Xiaoyu Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 South Xianlie Road, Guangzhou, 510060, China
| | - Xing Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 South Xianlie Road, Guangzhou, 510060, China.
| |
Collapse
|
16
|
Abstract
PURPOSE To assess the effect of intermediate age-related macular degeneration (AMD) on foveal cone-contrast thresholds. METHODS We measured L-M and S-cone-contrast thresholds in subjects with intermediate AMD (n = 10) and age-matched control subjects (n = 10). Monocular, foveal 3-degree Gaussian blobs (600-millisecond raised cosine) were presented at 16 cone ratios throughout L-, M-, and S-cone space, and threshold contours were modeled with probability summation between two independent detection mechanisms. The role that preretinal absorption plays in aging was also evaluated by simulation with FG15 and neutral-density filters. RESULTS Aging results in loss of neural sensitivity, not explained by lens changes. On average, intermediate AMD was associated with reduced sensitivity in both color and luminance channels (p < 0.05) that appeared to indicate greater involvement of S-cones. When data were normalized to age-expected values, the changes to cone sensitivity were shown to be consistent (∼200% loss) across L-M, M-L, and S-cone mechanisms. In comparison, the luminance (L + M) mechanism showed relative sparing (155% loss, p < 0.05). CONCLUSIONS Eyes with the same phenotype of intermediate AMD can have varying degrees of color threshold loss. Functional markers enhance the clinical definition of disease expression in AMD.
Collapse
|
17
|
Ogino K, Tsujikawa A, Yamashiro K, Ooto S, Oishi A, Nakata I, Miyake M, Takahashi A, Ellabban AA, Yoshimura N. Multimodal evaluation of macular function in age-related macular degeneration. Jpn J Ophthalmol 2013; 58:155-65. [DOI: 10.1007/s10384-013-0295-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 10/29/2013] [Indexed: 11/29/2022]
|
18
|
Panorgias A, Zawadzki RJ, Capps AG, Hunter AA, Morse LS, Werner JS. Multimodal assessment of microscopic morphology and retinal function in patients with geographic atrophy. Invest Ophthalmol Vis Sci 2013; 54:4372-84. [PMID: 23696601 DOI: 10.1167/iovs.12-11525] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To correlate retinal function and visual sensitivity with retinal morphology revealed by ultrahigh-resolution imaging with adaptive optics-optical coherence tomography (AO-OCT), on patients with geographic atrophy. METHODS Five eyes from five subjects were tested (four with geographic atrophy [66.3 ± 6.4 years, mean ± 1 SD] and one normal [61 years]). Photopic and scotopic multifocal electroretinograms (mfERGs) were recorded. Visual fields were assessed with microperimetry (mP) combined with a scanning laser ophthalmoscope for high-resolution confocal retinal fundus imaging. The eye tracker of the microperimeter identified the preferred retinal locus that was then used as a reference for precise targeting of areas for advanced retinal imaging. Images were obtained with purpose-built, in-house, ultrahigh resolution AO-OCT. Fundus autofluorescence (FAF) and color fundus (CF) photographs were also acquired. RESULTS The AO-OCT imaging provided detailed cross-sectional structural representation of the retina. Up to 12 retinal layers were identified in the normal subject while many severe retinal abnormalities (i.e., calcified drusen, drusenoid pigment epithelium detachment, outer retinal tubulation) were identified in the retinae of the GA patients. The functional tests showed preservation of sensitivities, although somewhat compromised, at the border of the GA. CONCLUSIONS The images provided here advance our knowledge of the morphology of retinal layers in GA patients. While there was a strong correlation between altered retinal structure and reduction in visual function, there were a number of examples in which the photoreceptor inner/outer segment (IS/OS) junctions lost reflectivity at the margins of GA, while visual function was still demonstrated. This was shown to be due to changes in photoreceptor orientation near the GA border.
Collapse
Affiliation(s)
- Athanasios Panorgias
- Department of Ophthalmology and Vision Science, University of California, Davis, Davis, California 95817, USA.
| | | | | | | | | | | |
Collapse
|
19
|
Acton JH, Smith RT, Hood DC, Greenstein VC. Relationship between retinal layer thickness and the visual field in early age-related macular degeneration. Invest Ophthalmol Vis Sci 2012; 53:7618-24. [PMID: 23074210 DOI: 10.1167/iovs.12-10361] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
PURPOSE To quantify and compare the structural and functional changes in subjects with early age-related macular degeneration (AMD), using spectral-domain optical coherence tomography (SD-OCT) and microperimetry. METHODS Twenty-one eyes of 21 subjects with early AMD were examined. MP-1 10-2 visual fields (VFs) and SD-OCT line and detail volume scans were acquired. The thicknesses of the outer segment (OS; distance between inner segment ellipsoid band and upper retinal pigment epithelium [RPE] border) and RPE layers and elevation of the RPE from Bruch's membrane were measured using a computer-aided manual segmentation technique. Thickness values were compared with those for 15 controls, and values at locations with VF total deviation defects were compared with values at nondefect locations at equivalent eccentricities. RESULTS Sixteen of 21 eyes with AMD had VF defects. Compared with controls, line scans showed significant thinning of the OS layer (P = 0.006) and thickening and elevation of the RPE (P = 0.037, P = 0.002). The OS layer was significantly thinner in locations with VF defects compared with locations without defects (P = 0.003). There was a negligible difference between the retinal layer thickness values of the 5 eyes without VF defects and the values of normal controls. CONCLUSIONS In early AMD, when VF defects were present, there was significant thinning of the OS layer and thickening and elevation of the RPE. OS layer thinning was significantly associated with decreased visual sensitivity, consistent with known photoreceptor loss in early AMD. For AMD subjects without VF defects, thickness values were normal. The results highlight the clinical utility of both SD-OCT retinal layer quantification and VF testing in early AMD.
Collapse
Affiliation(s)
- Jennifer H Acton
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom
| | | | | | | |
Collapse
|
20
|
|
21
|
Berrow EJ, Bartlett HE, Eperjesi F, Gibson JM. The electroretinogram: a useful tool for evaluating age-related macular disease? Doc Ophthalmol 2010; 121:51-62. [PMID: 20232109 DOI: 10.1007/s10633-010-9226-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 03/02/2010] [Indexed: 10/19/2022]
Abstract
With an ageing population, the number of age-related macular disease (ARMD) cases will inevitably rise. This gives greater impetus for the need to identify the disease earlier and assess treatments to slow disease progression. Differing electroretinogram (ERG) modalities have been reviewed in relation to the objective assessment of retinal function in ARMD and for monitoring the effectiveness of clinical interventions. Conflicting results have been found with regard to the efficacy of ERG findings in the investigation of ARMD in previous years. The newer multifocal ERG paradigm provides spatial topographical information about retinal function in ARMD. It has shown promising results in monitoring effectiveness of clinical interventions and studies are continuing in this area. Better knowledge of retinal function in ARMD may lead to enhanced treatments at each phase of the disease.
Collapse
Affiliation(s)
- Emma J Berrow
- Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, United Kingdom.
| | | | | | | |
Collapse
|
22
|
Perceived Color of Hallucinations in the Charles Bonnet Syndrome Is Related to Residual Color Contrast Sensitivity. J Neuroophthalmol 2009; 29:192-6. [DOI: 10.1097/wno.0b013e3181b1b2bf] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
23
|
Feigl B. Age-related maculopathy – Linking aetiology and pathophysiological changes to the ischaemia hypothesis. Prog Retin Eye Res 2009; 28:63-86. [PMID: 19070679 DOI: 10.1016/j.preteyeres.2008.11.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Beatrix Feigl
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059 QLD, Australia.
| |
Collapse
|
24
|
Abstract
BACKGROUND It is of interest to examine paracentral functional deficits in early age-related maculopathy (ARM), as histopathological studies indicate that this is where the earliest changes occur. The purpose of this study is to detect the sensory functional deficits at chosen retinal areas around the fovea and at the fovea itself in patients with early age-related maculopathy and to determine the type of functional losses that are more pronounced in early ARM. METHODS Ten participants with early ARM and 10 age-matched controls took part. Crowded and uncrowded visual acuity and static and transient contrast sensitivity were measured in the same selected eye of each participant at eight predetermined retinal locations plus the fovea in patients with early ARM and controls. All measurements were made using computer-generated targets. RESULTS A significant difference between the controls and subjects with ARM was found in low spatial frequency static contrast sensitivity (p = 0.05) but not for transient contrast sensitivity (p = 0.586). Visual acuity (uncrowded VA and crowded VA) showed a borderline difference (p = 0.072 and p = 0.084, respectively). Compared to controls, there was no evidence of increased contour interaction effects in early ARM (p = 0.595). CONCLUSION The subjects with very early ARM showed significant loss of low spatial frequency static contrast sensitivity before the loss of high contrast VA, indicating that static contrast sensitivity may be one of the earliest functional losses in early ARM and this loss was found to extend across the central 10 degrees of the retina.
Collapse
Affiliation(s)
- Feng Qiu
- School of Optometry, University of Waterloo, Waterloo, Ontario, Canada
| | | |
Collapse
|
25
|
Gerth C. The role of the ERG in the diagnosis and treatment of Age-Related Macular Degeneration. Doc Ophthalmol 2008; 118:63-8. [PMID: 18536949 DOI: 10.1007/s10633-008-9133-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 05/23/2008] [Indexed: 11/24/2022]
Abstract
Age-related macular degeneration (AMD) is affecting an increasing number of people, with 2.95 million people estimated to be affected in the USA by 2020. Possible preventive agents, such as vitamins and supplements have been studied and new treatment options for AMD have been developed in recent years. What role does electrophysiology play as a sensitive outcome measure? The most commonly used tests are the full-field electroretinogram (ffERG) and the multifocal ERG (mfERG). Test results from patients with AMD and reduced central vision need special attention in respect to fixation pattern, age-matched control data, and retinal luminance. Advantages, disadvantages and limitations of techniques will be considered, together with a review of published studies.
Collapse
Affiliation(s)
- Christina Gerth
- Department of Ophthalmology, University of Rostock, Doberaner Str. 140, 18055, Rostock, Germany.
| |
Collapse
|
26
|
Hashizume K, Hirasawa M, Imamura Y, Noda S, Shimizu T, Shinoda K, Kurihara T, Noda K, Ozawa Y, Ishida S, Miyake Y, Shirasawa T, Tsubota K. Retinal dysfunction and progressive retinal cell death in SOD1-deficient mice. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 172:1325-31. [PMID: 18372426 DOI: 10.2353/ajpath.2008.070730] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The superoxide dismutase (SOD) family is a major antioxidant system, and deficiency of Cu,Zn-superoxide dismutase (SOD1) in mice leads to many different phenotypes that resemble accelerated aging. The purpose of this study was to examine the morphology and physiology of the sensory retina in Sod1(-/-) mice. The amplitudes of the a- and b-waves of electroretinograms elicited by stimuli of different intensity were reduced in senescent Sod1(-/-) mice, and this reduction in amplitude was more pronounced with increasing age. Retinal morphometric analyses showed a reduced number of nuclei in both the inner nuclear cell layer and outer nuclear cell layer. Electron microscopy revealed swollen cells and degenerated mitochondria in the inner nuclear cell and outer nuclear cell layer of senescent Sod1(-/-) mice indicating necrotic cell death. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling revealed no significant differences in the number of apoptotic cells between Sod1(-/-) and wild-type mice, and activated caspase-3 could not be detected in the retina of Sod1(-/-) mice. In addition to the age-related macular degeneration-like phenotypes previously reported, Sod1(-/-) mice also present progressive retinal degeneration. Our results indicate that Sod1(-/-) mice may be a good model system in which to study the mechanism of reactive oxygen species-mediated retinal degeneration.
Collapse
Affiliation(s)
- Kouhei Hashizume
- Department of Ophthalmology, Inaida Laboratory, Keio University School of Medicine, 35-Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Lai TYY, Ngai JWS, Lam DSC. Multifocal electroretinography: update on clinical application and future development. EXPERT REVIEW OF OPHTHALMOLOGY 2008. [DOI: 10.1586/17469899.3.1.85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
28
|
Feigl B, Zele AJ. A method for investigating the temporal dynamics of local neuroretinal responses. J Neurosci Methods 2008; 167:207-12. [PMID: 17913236 DOI: 10.1016/j.jneumeth.2007.08.006] [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: 07/06/2007] [Revised: 08/15/2007] [Accepted: 08/15/2007] [Indexed: 11/25/2022]
Abstract
Visual sensitivity improves with prolonged exposure to light. Global neuroretinal responses increase, but little is known about the dynamics of local retinal responses over brief time intervals after changes in light level. This study applies the time-slice multifocal electroretinogram (TS mfERG) paradigm for the measurement of local electrical responses of the human eye over brief time intervals. Sixty-one, localised retinal areas were assessed over 25 degrees of the visual field. Cone-mediated contributions to the time-slice waveform were established. The time-slice mfERG waveforms were similar in shape and timing for pre- and post-photopigment bleach conditions after saturation of rod-mediated responses, suggesting there was no rod-mediated intrusion in the waveform. The temporal dynamics of the mfERG components show that N1P1 amplitudes decrease with each successive time-slice probe, with larger amplitude responses in the central retina compared to nasal and temporal retina. The time-slice mfERG waveform is a technique for assessing the temporal dynamics of cone-generated neural responses over time. The data are interpreted in terms of the vascular supplies and lower-level visual adaptation mechanisms.
Collapse
Affiliation(s)
- Beatrix Feigl
- Institute of Health and Biomedical Innovation and the School of Optometry, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, 4059 Qld, Australia.
| | | |
Collapse
|
29
|
Parisi V, Perillo L, Tedeschi M, Scassa C, Gallinaro G, Capaldo N, Varano M. Macular function in eyes with early age-related macular degeneration with or without contralateral late age-related macular degeneration. Retina 2007; 27:879-90. [PMID: 17891012 DOI: 10.1097/iae.0b013e318042d6aa] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate psychophysical and electrophysiologic responses in eyes with early age-related macular degeneration (AMD) without a decrease in visual acuity and with or without late AMD in the fellow eye. METHODS Fifteen patients (mean age: 67.9 +/- 7.20 years) with early AMD in both eyes (AMD1 group, 15 eyes) and 15 patients (mean age: 71.40 +/- 7.06 years) with early AMD in one eye and late AMD in the fellow eye (AMD2 group, 15 eyes) were enrolled. They were compared to 15 age-similar normal control subjects. LogMAR visual acuity (VA), macular sensitivity by MP-1 microperimetry, and multifocal electroretinograms (mfERG) were assessed in control, AMD1, and AMD2 eyes. mfERG response amplitude density (RAD, nV/deg2) of the N1-P1 component of first order binary kernels was measured. RESULTS When compared to controls, AMD1 and AMD2 eyes showed a significant (analysis of variance, P < 0.01) decrease in MP-1 microperimetry assessed in the 0-2.5 and 2.5-5 degrees of the macula, significantly correlated (Pearson test, P < 0.01) to the corresponding significant decrease (P < 0.01) in mfERG N1-P1 RADs assessed in the 0-2.5 and 2.5-5 degrees. In AMD1 and AMD2 eyes, VA and mfERG N1-P1 RADs assessed in the 5-20 degrees were similar (P > 0.01) to controls. VA, MP-1, and mfERG values were not significantly different in AMD1 and AMD2 eyes. CONCLUSION In eyes with early AMD there is a dysfunction of preganglionic elements in the central 0-5 retinal degrees detectable by mfERG or MP-1 microperimetry. This impairment is not further influenced by the presence of late AMD in the fellow eye.
Collapse
Affiliation(s)
- Vincenzo Parisi
- Fondazione per l'Oftalmologia G B Bietti-IRCCS, Rome, Italy.
| | | | | | | | | | | | | |
Collapse
|
30
|
Parisi V, Tedeschi M, Gallinaro G, Varano M, Saviano S, Piermarocchi S. Carotenoids and antioxidants in age-related maculopathy italian study: multifocal electroretinogram modifications after 1 year. Ophthalmology 2007; 115:324-333.e2. [PMID: 17716735 DOI: 10.1016/j.ophtha.2007.05.029] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Revised: 05/03/2007] [Accepted: 05/04/2007] [Indexed: 01/27/2023] Open
Abstract
OBJECTIVE To evaluate the influence of short-term carotenoid and antioxidant supplementation on retinal function in nonadvanced age-related macular degeneration (AMD). DESIGN Randomized controlled trial. PARTICIPANTS Twenty-seven patients with nonadvanced AMD and visual acuity > or =0.2 logarithm of the minimum angle of resolution were enrolled and randomly divided into 2 age-similar groups: 15 patients had oral supplementation of vitamin C (180 mg), vitamin E (30 mg), zinc (22.5 mg), copper (1 mg), lutein (10 mg), zeaxanthin (1 mg), and astaxanthin (4 mg) (AZYR SIFI, Catania, Italy) daily for 12 months (treated AMD [T-AMD] group; mean age, 69.4+/-4.31 years; 15 eyes); 12 patients had no dietary supplementation during the same period (nontreated AMD [NT-AMD] group; mean age, 69.7+/-6.23 years; 12 eyes). At baseline, they were compared with 15 age-similar healthy controls. METHODS Multifocal electroretinograms in response to 61 M-stimuli presented to the central 20 degrees of the visual field were assessed in pretreatment (baseline) conditions and, in nonadvanced AMD patients, after 6 and 12 months. MAIN OUTCOME MEASURES Multifocal electroretinogram response amplitude densities (RAD, nanovolt/deg(2)) of the N1-P1 component of first-order binary kernels measured from 5 retinal eccentricity areas between the fovea and midperiphery: 0 degrees to 2.5 degrees (R1), 2.5 degrees to 5 degrees (R2), 5 degrees to 10 degrees (R3), 10 degrees to 15 degrees (R4), and 15 degrees to 20 degrees (R5). RESULTS At baseline, we observed highly significant reductions of N1-P1 RADs of R1 and R2 in T-AMD and NT-AMD patients when compared with healthy controls (1-way analysis of variance P<0.01). N1-P1 RADs of R3-R5 observed in T-AMD and NT-AMD were not significantly different (P>0.05) from controls. No significant differences (P>0.05) were observed in N1-P1 RADs of R1-R5 between T-AMD and NT-AMD at baseline. After 6 and 12 months of treatment, T-AMD eyes showed highly significant increases in N1-P1 RADs of R1 and R2 (P<0.01), whereas no significant (P>0.05) change was observed in N1-P1 RADs of R3-R5. No significant (P>0.05) changes were found in N1-P1 RADs of R1-R5 in NT-AMD eyes. CONCLUSIONS In nonadvanced AMD eyes, a selective dysfunction in the central retina (0 degrees -5 degrees ) can be improved by the supplementation with carotenoids and antioxidants. No functional changes are present in the more peripheral (5 degrees -20 degrees ) retinal areas.
Collapse
Affiliation(s)
- Vincenzo Parisi
- Fondazione G. B. Bietti-Istituto di Ricovero e Cura a Carattere Scientifico, Roma, Italy.
| | | | | | | | | | | |
Collapse
|
31
|
Feigl B, Stewart I, Brown B. Experimental hypoxia in human eyes: Implications for ischaemic disease. Clin Neurophysiol 2007; 118:887-95. [PMID: 17307390 DOI: 10.1016/j.clinph.2006.12.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2006] [Revised: 11/14/2006] [Accepted: 12/11/2006] [Indexed: 11/24/2022]
Abstract
OBJECTIVE This study investigated neuroretinal activity under normoxic and hypoxic conditions with the multifocal electroretinogram (mfERG). METHODS We used two mfERG paradigms, the fast flicker and slow flash stimulation modes, to measure neuroretinal activity in five healthy participants who breathed room air and a reduced oxygen mixture (14% oxygen, balance nitrogen). We analysed concentric ring N1P1 and P1N2 response density amplitudes, the P1 implicit times as well as the local scalar product (SP) response densities. RESULTS During hypoxia there was a significant reduction of the scalar product response density for the fast flicker (p<0.001) and for the slow flash mfERG (p<0.001). The N1P1 and P1N2 response densities were lower especially for the central three rings; although these reductions were not significant between the two oxygen conditions, they indicated an overall distortion of the mfERG waveform. CONCLUSIONS It is demonstrated that a post-receptoral, primarily ON and OFF bipolar cell deficit is evident in the central retina of healthy young people during short term hypoxia. SIGNIFICANCE Our findings suggest that persons with pre-existing ischaemic eye disease may be at risk when exposed to hypoxic conditions.
Collapse
Affiliation(s)
- Beatrix Feigl
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia.
| | | | | |
Collapse
|
32
|
Feigl B, Brown B, Lovie-Kitchin J, Swann P. Postreceptoral adaptation abnormalities in early age-related
maculopathy. Vis Neurosci 2007; 23:863-70. [PMID: 17266778 DOI: 10.1017/s0952523806230190] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 08/09/2006] [Indexed: 11/05/2022]
Abstract
Age-related maculopathy (ARM) has become the major cause of blindness
in the Western World. Currently its pathogenesis and primary site of
functional damage is not fully understood but ischemia is believed to play
a major role. Early detection and precise monitoring of progression of ARM
are main goals of current research due to lack of sufficient treatment
options, especially in the dry, atrophic form of this disease. We applied
the multifocal electroretinogram (mfERG) that can detect any local
functional deficit objectively in the central retina. We recorded two
paradigms in early ARM patients, the fast flicker and the slow flash
paradigm which both represent fast adaptation processes of the proximal
retina but under differing photopic conditions and stimulation rates. By
subtracting the waveform responses we extracted a late component in the
difference waveform that was significantly reduced in the early ARM group
compared to a healthy control group (p ≤ 0.05). We propose
that this multifocal nonlinear analysis permits the detection of
adaptative deficits and provides topographic mapping of retinal
dysfunction in early ARM. The difference waveform component we extracted
with this novel approach might indicate early functional loss in ARM
caused by ischemia in postreceptoral layers such as bipolar cells and
inner plexiform regions.
Collapse
Affiliation(s)
- B Feigl
- Institute of Health and Biomedical Innovation, School of Optometry, Queensland University of Technology, Victoria Park Road, Kelvin Grove Q 4059, Australia.
| | | | | | | |
Collapse
|
33
|
Ronan S, Nusinowitz S, Swaroop A, Heckenlively JR. Senile panretinal cone dysfunction in age-related macular degeneration (AMD): a report of 52 amd patients compared to age-matched controls. TRANSACTIONS OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY 2006; 104:232-40. [PMID: 17471344 PMCID: PMC1809916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
PURPOSE To test if patients with age-related macular degeneration (AMD) have normal panretinal function using standardized full-field electroretinograms (ERGs). METHODS This is a retrospective study evaluating electroretinographic studies performed in patients with AMD to assess their panretinal function. Fifty-two individuals 55 years or older had standardized ERG testing and fundus photographs. RESULTS The study group was aged 57 to 93 years old with a mean of 75.7, and the controls ranged from 79 to 87 years with a mean of 81.4. On average, the photopic, scotopic, dark-adapted bright-flash, and flicker function response amplitudes are lower with longer implicit times in the study group than the controls. The most pronounced differences were seen with the bright-flash dark-adapted a-waves and the photopic b-wave amplitudes. Forty-three of 104 eyes had abnormal photopic b-wave ERGs of more than 2 SD compared to controls. The mean of the photopic b-wave amplitudes for the study group was 76.7 +/- 36.2 muV (1 SD) compared to 91.4 +/- 16.9 muV (1 SD) for the control group. This finding was statistically significant with P = .0269 by the Student t test and P = .0336 by the Wilcoxon test. CONCLUSIONS There is a subgroup of AMD patients with a panretinal cone dysfunction on ERG in association with their macular degeneration. Previous studies have shown varied results when looking at ERG changes in AMD, likely reflecting the underlying complexity of this disorder. Using standardized ERG to identify a more homogeneous subgroup of AMD patients with panretinal dysfunction will aid in better characterizing subtypes clinically and is likely to be valuable in identifying new genes contributing to AMD.
Collapse
Affiliation(s)
- Shawn Ronan
- Department of Ophthalmology and Visual Science, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, USA
| | | | | | | |
Collapse
|