Helmut Sachs - Academia.edu (original) (raw)
Papers by Helmut Sachs
Translational Vision Science & Technology
Electronic retinal implants restore some visual perception in patients blind from retinitis pigme... more Electronic retinal implants restore some visual perception in patients blind from retinitis pigmentosa. Eye movements cause mechanical stress in intraorbital power supply cables leading to cable breaks. By using computer tomography (CT) scans at the extreme positions of the four cardinal gaze directions, this study determined in vivo, which of three surgical routing techniques results in minimal bending radius variation and favors durability. Methods: Nine patients received the first-generation subretinal implant Alpha IMS (Retina Implant AG, Reutlingen, Germany) in one eye. Three techniques for intraorbital cable routing were used (straight cable route (A), parabulbar loop (B), and encircling band (C)), each in three patients. All patients underwent computer tomography of the orbital region. The bending radius of the intraorbital cable was measured with the DICOM viewer Osirix v4.1.2 (Pixmeo SARL, Bernex, Switzerland) and served as indicator for mechanical stress. Results: Average bending radius variation was 87% for method A, 11% for method B, and 16% for method C. Methods A and B (P = 0.005) and methods A and C (P = 0.007) differed significantly, while method B and C showed no statistical difference (P = 0.07). Conclusions: Compared to straight routes, arcuated cable routes significantly reduce cable movement and bending. Due to an easier surgical procedure, a parabulbar loop is the preferred method to minimize bending radius variation and prolong survival time of electronic subretinal implants. Translational Relevance: CT analysis of cable bending of implanted medical devices allows to determine which surgical routing technique favors durability in vivo.
Hintergrund: Bei durch degenerative Erkrankung erblindeten Patienten werden seit 2005 elektronisc... more Hintergrund: Bei durch degenerative Erkrankung erblindeten Patienten werden seit 2005 elektronische Chips der Wiederherstellung des Sehens eingesetzt. Wir berichten über die Zwischenergebnisse der laufenden klinischen Studien. Methode: Der subretinale Chip Alpha AMS der Firma Retina Implant[zum vollständigen Text gelangen Sie über die oben angegebene URL]
Investigative Ophthalmology & Visual Science, 2017
Investigative Ophthalmology & Visual Science, 2017
Investigative Ophthalmology & Visual Science, 2016
1. FORSCHUNGSWERKSTATT NETZHAUT, 2017
Artificial Vision, 2016
So far there are no possibilities for restitution of vision abilities in people blind from heredi... more So far there are no possibilities for restitution of vision abilities in people blind from hereditary retinal degeneration except electronic visual implants. Epiretinal and subretinal implants are already commercially available. Here the subretinal implant Alpha IMS (Retina Implant AG, Reutlingen, Germany) is presented, its technical construction, area of application, possible benefit for blind patients as well as surgical procedures including replacement, results from a clinical study in 29 patients, and safety issues. Subretinal implants are considered to have a number of advantages: the subretinal space is immunoprivileged, therefore less prone to proliferative vitreoretinal reactions; the fixation of the implant in between retina and choroid does not require scleral tacks; a retinotopically correct relation between perceived spot and retinal electrode is maintained in the visual field, thus shortening training times; natural eye movement and gaze help to localize objects; microsaccades are beneficial to avoid image fading; there are no devices attached to the face as all stimulation electronics are within the body; and resolution with 1500 pixels is the highest so far achieved.
2009 2nd International Conference on Biomedical Engineering and Informatics, 2009
Eleven patients received subretinal implants, powered and controlled via a subdermal cable ending... more Eleven patients received subretinal implants, powered and controlled via a subdermal cable ending in a thin intraocular foil, placed transsclerally between the retinal pigment epithelium and the neuroretina. The tip of this foil carries two distinct arrays, a Multiphotodiode Array (MPDA) with 1500 electrodes, each electrode being controlled by an adjacent photodiode and an amplifier within a 3times3times0.1 mm chip,
British Journal of Ophthalmology, 2005
Invest. Ophthalmol. Vis. Sci, 2006
Klinische Monatsblätter für Augenheilkunde
ZusammenfassungIn diesem Artikel sollen die Grundlagen zur Verwendung intraokularer Tamponaden in... more ZusammenfassungIn diesem Artikel sollen die Grundlagen zur Verwendung intraokularer Tamponaden in der Glaskörper-/Netzhautchirurgie bei Ablatio retinae und anderen Pathologien anhand zusätzlichen Videomaterials anschaulich dargestellt werden. Behandelt werden die verschiedenen Gase, Silikonöle und flüssigen Perfluorocarbone mit ihren Indikationen, ihrer Anwendung und insbesondere der intraoperativen Handhabung mit Fallstricken und Komplikationen. Charakteristische Animationen zeigen dabei nachvollziehbar die Prinzipien in der chirurgischen Handhabung. Seitens der beiden Erstautoren ist dieser Artikel ihrem Lehrer Herrn Prof. Dr. V.-P. Gabel gewidmet, der in den frühen 90er-Jahren die ersten Vitrektomiekurse für Augenärzte an der Universitäts-Augenklinik Regensburg erfolgreich im jährlichen Rhythmus etabliert hat und in denen viele heute noch netzhautchirurgisch tätige Kolleginnen und Kollegen ihre ersten Schritte in diesem Segment erlernt haben. Die weiteren Co-Autoren partizipierte...
Graefe's Archive for Clinical and Experimental Ophthalmology
Purpose To evaluate the real-world effectiveness of intravitreal aflibercept injections in German... more Purpose To evaluate the real-world effectiveness of intravitreal aflibercept injections in Germany in patients with neovascular age-related macular degeneration over 24 months. Methods PERSEUS was a prospective, non-interventional cohort study. The primary endpoint was the mean change in visual acuity (VA) from baseline. Secondary endpoints included the proportion of patients with a VA gain or loss of ≥ 15 letters and the frequency of injections and examinations. Patients with regular (bimonthly after 3 monthly injections during year 1 and ≥ 4 injections in year 2) and irregular (any other) treatment were analyzed. The last observation carried forward (LOCF) and the observed cases (OC) approach was applied for primary endpoint analysis to account for missing data. Results 803 patients were considered for effectivity analysis. At month 24, only 38% of the patients were still under observation. The LOCF population included 727, the OC population 279 patients. Treatment-naïve patients ...
Current Opinion in Ophthalmology
Ophthalmic Surgery, Lasers and Imaging Retina
The aim of this study was to assess changes in retinal structure and thickness after subretinal i... more The aim of this study was to assess changes in retinal structure and thickness after subretinal implantation of the Retina Implant Alpha IMS (Retina Implant AG, Reutlingen, Germany). Spectral-domain optical coherence tomography (SD-OCT) imaging was performed to assess the structure and thickness of the retina anterior to the microphotodiode array preoperatively, within 6 weeks and 6 months ± 1 month after implantation. Thickness measurements were performed using the distance tool of the built-in software. Three thickness measurements were performed in each of the four quadrants of the retina on the microchip within 6 weeks and 6 months ± 1 month after implantation. The mean ± standard deviation change in retinal thickness from within 6 weeks to 6 months ± 1 month after implantation in all four quadrants combined was 24 μm ± 68 μm. None of the tested variables (location, time, or their interaction) had a statistically significant effect on the mean retinal thickness (P = .961, P = .131, and P = .182, respectively; n = 19). The authors report on qualitative and quantitative findings in retinal structure in 27 patients after subretinal implantation of the Retina Implant Alpha IMS using OCT technology. No significant changes of retinal thickness could be observed in a period of 6 months after surgery. With more patients receiving subretinal implants and with advanced OCT technology, the data set will be extended to study possible changes in retinal structure in finer detail. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:993-999.].
Klinische Monatsblatter fur Augenheilkunde, 2017
Treatment of neovascular age-related macular degeneration (AMD) with anti-vascular endothelial gr... more Treatment of neovascular age-related macular degeneration (AMD) with anti-vascular endothelial growth factor agents has been improved since its introduction in Germany. Several observational studies have demonstrated an increased frequency of injections in parallel with improved visual outcomes during the first year of treatment over the last 7 years. These results are reflected in several case series. However, studies with a longer follow-up reported that visual function regressed to baseline vision following an initial improvement, e.g. during the first three years of treatment. A delay in treatment initiation has been reported mainly for rural areas and management models involving more than one ophthalmologist or institution. Encouragingly, recent data confirm a positive trend towards reducing treatment delay, increasing injection frequency and improving treatment outcomes. Still, further improvements are needed to attain optimal treatment outcomes achievable under routine clinic...
Translational Vision Science & Technology
Electronic retinal implants restore some visual perception in patients blind from retinitis pigme... more Electronic retinal implants restore some visual perception in patients blind from retinitis pigmentosa. Eye movements cause mechanical stress in intraorbital power supply cables leading to cable breaks. By using computer tomography (CT) scans at the extreme positions of the four cardinal gaze directions, this study determined in vivo, which of three surgical routing techniques results in minimal bending radius variation and favors durability. Methods: Nine patients received the first-generation subretinal implant Alpha IMS (Retina Implant AG, Reutlingen, Germany) in one eye. Three techniques for intraorbital cable routing were used (straight cable route (A), parabulbar loop (B), and encircling band (C)), each in three patients. All patients underwent computer tomography of the orbital region. The bending radius of the intraorbital cable was measured with the DICOM viewer Osirix v4.1.2 (Pixmeo SARL, Bernex, Switzerland) and served as indicator for mechanical stress. Results: Average bending radius variation was 87% for method A, 11% for method B, and 16% for method C. Methods A and B (P = 0.005) and methods A and C (P = 0.007) differed significantly, while method B and C showed no statistical difference (P = 0.07). Conclusions: Compared to straight routes, arcuated cable routes significantly reduce cable movement and bending. Due to an easier surgical procedure, a parabulbar loop is the preferred method to minimize bending radius variation and prolong survival time of electronic subretinal implants. Translational Relevance: CT analysis of cable bending of implanted medical devices allows to determine which surgical routing technique favors durability in vivo.
Hintergrund: Bei durch degenerative Erkrankung erblindeten Patienten werden seit 2005 elektronisc... more Hintergrund: Bei durch degenerative Erkrankung erblindeten Patienten werden seit 2005 elektronische Chips der Wiederherstellung des Sehens eingesetzt. Wir berichten über die Zwischenergebnisse der laufenden klinischen Studien. Methode: Der subretinale Chip Alpha AMS der Firma Retina Implant[zum vollständigen Text gelangen Sie über die oben angegebene URL]
Investigative Ophthalmology & Visual Science, 2017
Investigative Ophthalmology & Visual Science, 2017
Investigative Ophthalmology & Visual Science, 2016
1. FORSCHUNGSWERKSTATT NETZHAUT, 2017
Artificial Vision, 2016
So far there are no possibilities for restitution of vision abilities in people blind from heredi... more So far there are no possibilities for restitution of vision abilities in people blind from hereditary retinal degeneration except electronic visual implants. Epiretinal and subretinal implants are already commercially available. Here the subretinal implant Alpha IMS (Retina Implant AG, Reutlingen, Germany) is presented, its technical construction, area of application, possible benefit for blind patients as well as surgical procedures including replacement, results from a clinical study in 29 patients, and safety issues. Subretinal implants are considered to have a number of advantages: the subretinal space is immunoprivileged, therefore less prone to proliferative vitreoretinal reactions; the fixation of the implant in between retina and choroid does not require scleral tacks; a retinotopically correct relation between perceived spot and retinal electrode is maintained in the visual field, thus shortening training times; natural eye movement and gaze help to localize objects; microsaccades are beneficial to avoid image fading; there are no devices attached to the face as all stimulation electronics are within the body; and resolution with 1500 pixels is the highest so far achieved.
2009 2nd International Conference on Biomedical Engineering and Informatics, 2009
Eleven patients received subretinal implants, powered and controlled via a subdermal cable ending... more Eleven patients received subretinal implants, powered and controlled via a subdermal cable ending in a thin intraocular foil, placed transsclerally between the retinal pigment epithelium and the neuroretina. The tip of this foil carries two distinct arrays, a Multiphotodiode Array (MPDA) with 1500 electrodes, each electrode being controlled by an adjacent photodiode and an amplifier within a 3times3times0.1 mm chip,
British Journal of Ophthalmology, 2005
Invest. Ophthalmol. Vis. Sci, 2006
Klinische Monatsblätter für Augenheilkunde
ZusammenfassungIn diesem Artikel sollen die Grundlagen zur Verwendung intraokularer Tamponaden in... more ZusammenfassungIn diesem Artikel sollen die Grundlagen zur Verwendung intraokularer Tamponaden in der Glaskörper-/Netzhautchirurgie bei Ablatio retinae und anderen Pathologien anhand zusätzlichen Videomaterials anschaulich dargestellt werden. Behandelt werden die verschiedenen Gase, Silikonöle und flüssigen Perfluorocarbone mit ihren Indikationen, ihrer Anwendung und insbesondere der intraoperativen Handhabung mit Fallstricken und Komplikationen. Charakteristische Animationen zeigen dabei nachvollziehbar die Prinzipien in der chirurgischen Handhabung. Seitens der beiden Erstautoren ist dieser Artikel ihrem Lehrer Herrn Prof. Dr. V.-P. Gabel gewidmet, der in den frühen 90er-Jahren die ersten Vitrektomiekurse für Augenärzte an der Universitäts-Augenklinik Regensburg erfolgreich im jährlichen Rhythmus etabliert hat und in denen viele heute noch netzhautchirurgisch tätige Kolleginnen und Kollegen ihre ersten Schritte in diesem Segment erlernt haben. Die weiteren Co-Autoren partizipierte...
Graefe's Archive for Clinical and Experimental Ophthalmology
Purpose To evaluate the real-world effectiveness of intravitreal aflibercept injections in German... more Purpose To evaluate the real-world effectiveness of intravitreal aflibercept injections in Germany in patients with neovascular age-related macular degeneration over 24 months. Methods PERSEUS was a prospective, non-interventional cohort study. The primary endpoint was the mean change in visual acuity (VA) from baseline. Secondary endpoints included the proportion of patients with a VA gain or loss of ≥ 15 letters and the frequency of injections and examinations. Patients with regular (bimonthly after 3 monthly injections during year 1 and ≥ 4 injections in year 2) and irregular (any other) treatment were analyzed. The last observation carried forward (LOCF) and the observed cases (OC) approach was applied for primary endpoint analysis to account for missing data. Results 803 patients were considered for effectivity analysis. At month 24, only 38% of the patients were still under observation. The LOCF population included 727, the OC population 279 patients. Treatment-naïve patients ...
Current Opinion in Ophthalmology
Ophthalmic Surgery, Lasers and Imaging Retina
The aim of this study was to assess changes in retinal structure and thickness after subretinal i... more The aim of this study was to assess changes in retinal structure and thickness after subretinal implantation of the Retina Implant Alpha IMS (Retina Implant AG, Reutlingen, Germany). Spectral-domain optical coherence tomography (SD-OCT) imaging was performed to assess the structure and thickness of the retina anterior to the microphotodiode array preoperatively, within 6 weeks and 6 months ± 1 month after implantation. Thickness measurements were performed using the distance tool of the built-in software. Three thickness measurements were performed in each of the four quadrants of the retina on the microchip within 6 weeks and 6 months ± 1 month after implantation. The mean ± standard deviation change in retinal thickness from within 6 weeks to 6 months ± 1 month after implantation in all four quadrants combined was 24 μm ± 68 μm. None of the tested variables (location, time, or their interaction) had a statistically significant effect on the mean retinal thickness (P = .961, P = .131, and P = .182, respectively; n = 19). The authors report on qualitative and quantitative findings in retinal structure in 27 patients after subretinal implantation of the Retina Implant Alpha IMS using OCT technology. No significant changes of retinal thickness could be observed in a period of 6 months after surgery. With more patients receiving subretinal implants and with advanced OCT technology, the data set will be extended to study possible changes in retinal structure in finer detail. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:993-999.].
Klinische Monatsblatter fur Augenheilkunde, 2017
Treatment of neovascular age-related macular degeneration (AMD) with anti-vascular endothelial gr... more Treatment of neovascular age-related macular degeneration (AMD) with anti-vascular endothelial growth factor agents has been improved since its introduction in Germany. Several observational studies have demonstrated an increased frequency of injections in parallel with improved visual outcomes during the first year of treatment over the last 7 years. These results are reflected in several case series. However, studies with a longer follow-up reported that visual function regressed to baseline vision following an initial improvement, e.g. during the first three years of treatment. A delay in treatment initiation has been reported mainly for rural areas and management models involving more than one ophthalmologist or institution. Encouragingly, recent data confirm a positive trend towards reducing treatment delay, increasing injection frequency and improving treatment outcomes. Still, further improvements are needed to attain optimal treatment outcomes achievable under routine clinic...