Main Principles of Vitrectomy Using Intraocular Tamponades - A Basic Course in Surgery. / Grundlagen der Vitrektomie unter Verwendung intraokularer Tamponaden ­ ein chirurgischer Basiskurs.

This article is intended to clearly present the basic principles for the use of intraocular tamponades in vitreous/retinal surgery in the event of retinal detachment and other pathologies using additional video footage. It examines the various gases, silicone oils and perfluorocarbon liquids with their indications, administration and in particular intraoperative handling including pitfalls and complications. Characteristic animations show the principles of use in surgery in a comprehensible way. The two lead authors dedicate this article to their teacher Prof. Dr. V.-P. Gabel, who in the early 1990s successfully established the first vitrectomy courses for ophthalmologists at Regensburg University Eye Clinic each year. Many colleagues who still work in retinal surgery today first started learning about this segment on these courses. The other coauthors participated under his supervision in annual vitrectomy wet labs run by the German Academy of Ophthalmology.

CT Assessment of Intraorbital Cable Movement of Electronic Subretinal Prosthesis in Three Different Surgical Approaches.

Purpose: 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.

PERSEUS 24-month analysis: a prospective non-interventional study to assess the effectiveness of intravitreal aflibercept in routine clinical practice in Germany in patients with neovascular age-related macular degeneration.

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 improved by 6.3 (LOCF)/8.1 (OC) letters with regular treatment over 24 months but only by 3.3 (LOCF)/3.1 (OC) letters with irregular treatment. The proportion of treatment-naïve patients achieving a VA improvement of ≥ 15 letters was similar between regularly and irregularly treated cohorts. However, considerably more patients in the irregular cohorts experienced a VA worsening of ≥ 15 letters than in the regular cohorts (LOCF: 18.7% vs. 7.4%). CONCLUSIONS: Regular IVT-AFL treatment resulted in better VA outcomes than irregular treatment at month 24. However, only a minority of patients received regular treatment over a 2-year period.

Importance of continuous treatment with intravitreal aflibercept injections in patients with neovascular age-related macular degeneration-12-month post hoc analysis of the PERSEUS real-world evidence study.

PURPOSE: To investigate the influence of treatment regularity with intravitreal aflibercept injections (IVT-AFL injections) on visual acuity (VA) outcomes in patients with neovascular age-related macular degeneration (nAMD) enrolled in the PERSEUS trial who received at least 7 IVT-AFL injections during the first year. METHODS: This was a post hoc analysis of the PERSEUS trial, a prospective, non-interventional, multicenter cohort study, and included 370 patients with nAMD who had received ≥ 7 IVT-AFL injections during year 1. In addition to the prespecified subgroups of treatment-naïve and previously treated patients, results were compared between patients with regular (n = 209) and irregular (n = 161) treatment. Regular treatment was defined as initial dosing with monthly IVT-AFL injections for 3 months, then bimonthly IVT-AFL injections until month 12. Irregular treatment was defined as any deviation from regular treatment (provided ≥ 7 injections were received). The outcome of primary interest was the mean change in VA from baseline after 12 months. Further outcomes of interest included VA gain or loss, proportion of patients achieving reading vision, and percentage of patients with fluid. RESULTS: At month 12, the mean (± standard deviation, SD) VA improvement from baseline was 6.1 ± 15.6 Early Treatment Diabetic Retinopathy Study letters in the regular cohort and 2.5 ± 16.7 letters in the irregular cohort with ≥ 7 IVT-AFL injections (P = 0.0514). Best results were obtained in the treatment-naïve regular sub-cohort with a mean ± SD VA improvement of 8.0 ± 17.7 letters, whereas treatment-naïve patients with irregular treatment experienced a considerably lower VA gain (2.8 ± 20.0 letters). Irregular treatment consistently correlated with inferior results in treatment-naïve patients. At month 12, the proportion of treatment-naïve patients who had experienced a worsening of ≥ 5 letters was 29.6% in the irregular sub-cohort versus 13.6% in the regular sub-cohort (P = 0.0049). However, among the treatment-naïve patients, the mean number of injections was significantly higher in the irregular than in the regular sub-cohort (8.0 ± 1.2 vs. 7.4 ± 0.6; P = 0.0001). Furthermore, compared with the treatment-naïve, regular sub-cohort, patients in the irregular sub-cohort had more visits (19.1 ± 8.6 vs. 16.1 ± 5.7), VA tests (14.2 ± 6.9 vs. 12.0 ± 4.6), and optical coherence tomography examinations (5.1 ± 3.7 vs. 3.4.0 ± 3.0). CONCLUSIONS: Although irregularly treated patients received more injections and more monitoring visits during the first year of IVT-AFL treatment, they experienced worse VA outcomes than regularly treated patients.

Restriction of eye motility in patients with RETINA IMPLANT Alpha AMS.

PURPOSE: To evaluate the motility of the eye in patients with the RETINA IMPLANT Alpha AMS. METHODS: Eye motility was determined in eight gaze directions in ten blind retinitis pigmentosa patients, who had received the RETINA IMPLANT Alpha AMS, before implantation of the subretinal implant and at six time-points up to one year after. RESULTS: The analysis of eye motility showed a restriction in the upgaze and gaze to the temporal side directly after surgery in eight of the nine patients included. The degree of motility restriction decreased continuously with recovery during the observation time. One year after surgery, eye motility was still restricted in the majority of patients, especially in the upgaze to the temporal side at 20° (five of seven patients). CONCLUSION: Retinal implants with intraorbital parts (e.g. connecting cables) caused restriction in the temporal and superior viewing directions in the majority of patients. Although this restriction might be cosmetically visible, this limitation in eye motility has no effects on the monocular vision and the implant's efficacy for daily use.

Implantation, removal and replacement of subretinal electronic implants for restoration of vision in patients with retinitis pigmentosa.

PURPOSE OF REVIEW: The purpose of this review is to provide an update on the efforts to restore vision through subretinal implants in patients with degenerative retinal diseases. In addition to the current technique and its latest improvements, it will focus on the surgical technique of implantation as well as explantation and reimplantation. RECENT FINDINGS: The durability of the current subretinal implant RETINA IMPLANT Alpha AMS has increased substantially compared with the predecessor model RETINA IMPLANT Alpha IMS. According to validated examinations in the laboratory, a median lifetime of 4.7 years will be reached in clinical use; in similar examinations, the previous model has reached only 8 months. Visual function has slightly increased. The surgical technique for subretinal implants is complex and demanding for ophthalmic surgeons, as it is multifaceted and combines novel surgical steps in areas, which are not commonly entered such as the suprachoroidal and the subretinal space. The surgical approach for implantation has matured considerably and has led to successful implantation in 64 patient cases. Surgical challenges are now mainly encountered with the exact subfoveal positioning of the device. The explantation procedure is relatively straight-forward because the implant can be withdrawn in a reverse direction along the already existent subretinal path. Reimplantations, however, are more challenging because some degree of scar tissue may exist along the path of the chip and around the scleral trapdoor. Nevertheless, reimplantations have now been carried out successfully in four patients. SUMMARY: The new RETINA IMPLANT Alpha AMS shows significantly improved durability compared with the predecessor model RETINA IMPLANT Alpha IMS. The subretinal implant offers excellent visual results but requires experienced surgeons. Explantation of devices is straight-forward, and reimplantations are challenging but have been successful in four patients.

Aflibercept for Patients with Neovascular Age-Related Macular Degeneration in Routine Clinical Practice in Germany: Twelve-Month Outcomes of PERSEUS.

PURPOSE: To explore real-world effectiveness of intravitreal aflibercept injection (IAI) for neovascular age-related macular degeneration (nAMD) in Germany. DESIGN: A 24-month, prospective, noninterventional, noncontrolled, multicenter observational cohort study. PARTICIPANTS: Patients (n = 848) with nAMD treated with IAI. METHODS: Patients (n = 988) were screened at 67 study sites. Therapeutic decisions were made by the treating physician. Primary end point analysis was performed after 12 months for the entire study cohort and for predetermined subgroups of treatment-naïve and previously treated patients. Additionally, outcomes with regular injection intervals (bimonthly after 3 monthly injections) were compared with those of patients with irregularities in their treatment regimen. MAIN OUTCOME MEASURES: The primary end point was the mean change in visual acuity (VA) from baseline after 12 months. Other key end points included the proportions of patients gaining 15 letters or more and patients with reading vision (≥70 letters). Furthermore, the number of injections, anatomic measurements, and safety data were recorded. RESULTS: Mean ± standard deviation VA improvement was 5.3±17.4 letters in treatment-naïve patients and -0.1±15.6 letters in previously treated patients (P ≤ 0.0001), and that of the total study group was 2.9±16.8 letters. Baseline VA was 53.4±17.9 letters for treatment-naïve patients, 52.9±18.4 letters for previously treated patients, and 53.2±18.1 letters for the total patient population. Treatment pattern was associated with VA outcome: best outcomes-an average VA gain of 8.0±17.7 letters-were seen in treatment-naïve patients in the regularly treated population, whereas irregularly treated, treatment-naïve patients achieved a mean VA gain of only 4.0±17.1 letters. Among previously treated patients, regular treatment also was associated with better outcomes (+3.1±10.7 vs. -1.1±16.8 letters). For the total study group, the mean VA gain was the following: regularly treated population, 6.1±15.6 letters; irregularly treated population, 1.5±17.1 letters (P = 0.008). No cases of endophthalmitis were observed during the first 12 months of the study. Adverse events were in line with the known safety profile of IAI. CONCLUSIONS: After 12 months of treatment with IAI, treatment-naïve patients showed substantial functional benefit, whereas previously treated patients maintained their VA. With regular IAI treatment, it seems that similar results as those in pivotal IAI studies can be achieved in routine clinical practice.

Optical Coherence Tomography in Patients With the Subretinal Implant Retina Implant Alpha IMS.

BACKGROUND AND OBJECTIVE: 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). PATIENTS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.].

[The Conundrum of Relationships in the Multivariate Dataset of nvAMD Treatment]. / Die Frage nach Zusammenhängen in multivariaten Datensätzen zur Behandlung der nvAMD.

Background The evaluation of relationships in clinical case series is complicated by statistical pitfalls, one of which is spurious correlation. In this case, one or more potential factors are actually not related to a target measure, yet it may be wrongly inferred that they are. This may be due to either coincidence or the presence of a one or more confounding unregarded factors. In randomised clinical trials, it is attempted to eliminate such confounding factors or to control them by randomisation. However, this approach is not applicable in retrospective case series, and other statistical methods must be applied, such as multivariate analyses, taking into account all known variables. Patients/Material and Methods Statistical evaluation of the impact of different variables on the change in visual acuity after year 2 in a cohort of 1300 cases of nvAMD. The investigated variables are: visual acuity (VA) at baseline, central retinal thickness at baseline, age at baseline, mean interval between visits, number of injections, initial gain in VA after upload, and a change of the anti-VEGF compound. The target outcome measure was the change in VA as letter score at the end of year 2. Results All investigated variables have a marked impact on VA outcome when only single regression analysis is performed. Initial analysis of a switch in therapy gives a seemingly large effect on VA. However, multivariate analysis to avoid spurious correlations shows that only the following variables influence VA outcome with statistical significance: VA at baseline, initial gain in VA after upload, number of injections, mean interval between visits, and central retinal thickness at baseline. A switch in therapy had no statistically significant effect on VA outcome. Conclusion A switch in anti-VEGF therapy is not causally related to better VA outcome. In the statistical evaluation of non-randomised, retrospective case series, special attention must be given to potential confounding variables. When subgroups under investigation are not well balanced for confounding factors, misleading spurious correlations can result, leading to incorrect inferences.

[Real-life Data on the Treatment of Diabetic Macular Oedema in Germany]. / Daten zur Behandlungsrealität des diabetischen Makulaödems mit Ranibizumab.

Background Controlled prospective clinical trials on the treatment of diabetic macular oedema (DME) using anti-VEGF compounds show very good results in visual acuity gain over several years. To date, only limited data are available from comparable studies under real-life settings in clinical routine. However, real-life data from other indications for anti-VEGF treatment suggest that, in clinical routine, gain in visual acuity is less pronounced and cannot be maintained over a longer period of time, which is related to the significantly lower number of injections administered in clinical routine. Here we report a case series from our clinical routine of patients treated with ranibizumab for visual significant DME. Patients/Material and Methods Retrospective case series of 335 cases with follow-up of up to 3 years. All cases in our clinic treated for visual significant DME with at least one injection of ranibizumab were evaluated for the course of visual acuity gain and number of injections received. Results A mean gain in visual acuity (VA) of + 5.6 and + 3.7 letters was found in years one and two, respectively, with a median VA of logMAR 0.52 (decimal 0.3) at baseline. The steepest increase in VA is found during the first 4 months, with a less pronounced increase up to month 16. The mean number of injections was 5.7, 3.2 and 1.1 for years one, two, and three, respectively. Conclusions Results of real life treatment in clinical routine are found to fall behind controlled, prospective trials, as found to the findings in other anti-VEGF indications: mean gain in VA is lower than in prospective trials, and the initial gain cannot be fully maintained over a prolonged time period. Similarly, the number of injections received is markedly lower than in controlled trials. This can partially be explained by differences in study populations and a negative selection bias in longer term results. However, additional barriers that hamper timely treatment tailored to disease activity requirements must be identified and circumvented where possible.

[Time Course of Changes in Visual Acuity After a Single Injection of Aflibercept or Ranibizumab in Neovascular Age-related Macular Degeneration - Analysis of Aggregated Real Life Data]. / Der zeitliche Verlauf der Visusentwicklung nach einer Injektion von Aflibercept oder Ranibizumab bei der neovaskulären altersbedingten Makuladegeneration.

Background Treatment of neovascular age-related macular degeneration (nvAMD) under real life conditions may differ from controlled prospective trials with respect to the number of injections and long term preservation of visual acuity. In many instances, intervals for controls and re-injection cannot be maintained as frequently as required. This case series examines actual intervals for control and re-injection visits, in order to estimate how prolonged intervals have an impact on momentary visual acuity and how long term visual outcome is affected. Patients/Material and Methods Retrospective case series of 1,324 eyes with nvAMD, treated with a total of 8,150 ranibizumab injections (according to the PRN regimen) or 1,725 aflibercept injections (according to a fixed regimen), during the observation period of up to 3 years. The evaluation covered the time interval between visits, impact of this on the course of visual acuity, as well as the number of injections throughout treatment. Results Planned intervals of 4 or 8 weeks between visits were more often exceeded in the PRN regimen than with the fixed regimen. Visual acuity does not peak after 4 weeks, but only between 6 and 8 weeks. No statistically significant difference between aflibercept and ranibizumab was found. If the mean interval for re-injection was maintained at 4 - 6 weeks, this gave the greatest gains in visual acuity at end of years 1 and 2, respectively. Any prolongation of these intervals was accompanied by worse long term visual acuity. The fixed regimen is associated with consistently briefer re-treatment intervals during years 2 and 3, than with the PRN regimen. Conclusion Our data point to the importance of frequent controls accompanied by timely retreatment, as these have a major impact on visual outcome. It therefore appears to be more important to choose a treatment plan that facilitates frequent re-injections than to select either of the two compounds.

[Real-life Evidence on Treatment Outcomes of Neovascular Age-related Macular Degeneration in Germany]. / Real-Life-Evidenz zur Therapie der neovaskulären altersabhängigen Makuladegeneration in Deutschland.

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 clinical conditions in Germany.

Interim Results of a Multicenter Trial with the New Electronic Subretinal Implant Alpha AMS in 15 Patients Blind from Inherited Retinal Degenerations.

Purpose: We assessed the safety and efficacy of a technically advanced subretinal electronic implant, RETINA IMPLANT Alpha AMS, in end stage retinal degeneration in an interim analysis of two ongoing prospective clinical trials. The purpose of this article is to describe the interim functional results (efficacy). Methods: The subretinal visual prosthesis RETINA IMPLANT Alpha AMS (Retina Implant AG, Reutlingen, Germany) was implanted in 15 blind patients with hereditary retinal degenerations at four study sites with a follow-up period of 12 months (www.clinicaltrials.gov NCT01024803 and NCT02720640). Functional outcome measures included (1) screen-based standardized 2- or 4-alternative forced-choice (AFC) tests of light perception, light localization, grating detection (basic grating acuity (BaGA) test), and Landolt C-rings; (2) gray level discrimination; (3) performance during activities of daily living (ADL-table tasks). Results: Implant-mediated light perception was observed in 13/15 patients. During the observation period implant mediated localization of visual targets was possible in 13/15 patients. Correct grating detection was achieved for spatial frequencies of 0.1 cpd (cycles per degree) in 4/15; 0.33 cpd in 3/15; 0.66 cpd in 2/15; 1.0 cpd in 2/15 and 3.3 cpd in 1/15 patients. In two patients visual acuity (VA) assessed with Landolt C- rings was 20/546 and 20/1111. Of 6 possible gray levels on average 4.6 ± 0.8 (mean ± SD, n = 10) were discerned. Improvements (power ON vs. OFF) of ADL table tasks were measured in 13/15 patients. Overall, results were stable during the observation period. Serious adverse events (SAEs) were reported in 4 patients: 2 movements of the implant, readjusted in a second surgery; 4 conjunctival erosion/dehiscence, successfully treated; 1 pain event around the coil, successfully treated; 1 partial reduction of silicone oil tamponade leading to distorted vision (silicon oil successfully refilled). The majority of adverse events (AEs) were transient and mostly of mild to moderate intensity. Conclusions: Psychophysical and subjective data show that RETINA IMPLANT Alpha AMS is reliable, well tolerated and can restore limited visual functions in blind patients with degenerations of the outer retina. Compared with the previous implant Alpha IMS, longevity of the new implant Alpha AMS has been considerably improved. Alpha AMS has meanwhile been certified as a commercially available medical device, reimbursed in Germany by the public health system.

Subretinal Visual Implant Alpha IMS--Clinical trial interim report.

A subretinal visual implant (Alpha IMS, Retina Implant AG, Reutlingen, Germany) was implanted in 29 blind participants with outer retinal degeneration in an international multicenter clinical trial. Primary efficacy endpoints of the study protocol were a significant improvement of activities of daily living and mobility to be assessed by activities of daily living tasks, recognition tasks, mobility, or a combination thereof. Secondary efficacy endpoints were a significant improvement of visual acuity/light perception and/or object recognition (clinicaltrials.gov, NCT01024803). During up to 12 months observation time twenty-one participants (72%) reached the primary endpoints, of which thirteen participants (45%) reported restoration of visual function which they use in daily life. Additionally, detection, localization, and identification of objects were significantly better with the implant power switched on in the first 3 months. Twenty-five participants (86%) reached the secondary endpoints. Measurable grating acuity was up to 3.3 cycles per degree, visual acuities using standardized Landolt C-rings were 20/2000, 20/2000, 20/606 and 20/546. Maximal correct motion perception ranged from 3 to 35 degrees per second. These results show that subretinal implants can restore very-low-vision or low vision in blind (light perception or less) patients with end-stage hereditary retinal degenerations.

Extraocular Surgical Approach for Placement of Subretinal Implants in Blind Patients: Lessons from Cochlear-Implants.

In hereditary retinal diseases photoreceptors progressively degenerate, often causing blindness without therapy being available. Newly developed subretinal implants can substitute functions of photoreceptors. Retina implant extraocular surgical technique relies strongly on cochlear-implant know-how. However, a completely new surgical approach providing safe handling of the photosensor array had to be developed. The Retina Implant Alpha IMS consisting of a subretinal microphotodiode array and cable linked to a cochlear-implant-like ceramic housing was introduced via a retroauricular incision through a subperiosteal tunnel above the zygoma into the orbit using a specially designed trocar. Implant housing was fixed in a bony bed within a tight subperiosteal pocket in all patients. Primary outcomes were patient short term safety as well as effectiveness. Nine patients participated in the first part of the multicenter trial and received the subretinal visual implant in one eye. In all cases microphotodiode array pull-through procedure and stable positioning were possible without affecting the device function. No intraoperative complications were encountered. The minimally invasive suprazygomatic tunneling technique for the sensor unit as well as a subperiosteal pocket fixation of the implant housing provides a safe extraocular implantation approach of a subretinal device with a transcutaneous extracorporeal power supply.

Safety evaluation of "retina implant alpha IMS"--a prospective clinical trial.

BACKGROUND: To restore vision in patients with retinitis pigmentosa, several types of electronic devices have been developed to stimulate neurons at different levels along the visual pathway. Subretinal stimulation of the retina with the Retina Implant Alpha IMS (Retina Implant AG, Reutlingen, Germany) has been demonstrated to provide useful vision in daily life. Here we evaluated the safety of this device. METHODS: An interventional, prospective, multi-center, single-arm study was conducted in patients with retinitis pigmentosa with the Retina Implant Alpha IMS. The results from the first nine patients of a single center regarding safety of the device are reported. Any untoward medical occurrence related or unrelated to the tested device was documented and evaluated. RESULTS: Nine adult subjects were included in the study at the Tübingen site. Seventy-five adverse events occurred in total, and 53 affected the eye and its adnexa. Thirty-one ocular adverse events had a relationship to the implant that was classified as "certain" while 19 had a probable or possible relationship; three had no relationship to the implant. Thirty-nine ocular adverse events resolved without sequelae, two resolved with sequelae, 11 remained unresolved, and in one the status was unknown. The intensity of ocular adverse events was mild in the majority of cases (n = 45), while six were of moderate and two of severe intensity. There was no non-ocular adverse event with certain relationship to the device. One subject lost light perception (without light localization) in her study eye. CONCLUSIONS: In conclusion, this prospective study, "Safety and Efficacy of Subretinal Implants for Partial Restoration of Vision in Blind Patients," shows that the Retina Implant Alpha IMS is an option for restoring vision using a subretinal stimulation device with a clinically acceptable safety profile.

Functional outcome in subretinal electronic implants depends on foveal eccentricity.

PURPOSE: An active microelectronic subretinal implant, developed to replace the photoreceptive function in hereditary degenerations of the outer retina, has been applied in a pilot and clinical study in patients with end-stage retinal degeneration. METHODS: The study population comprised 20 blind patients, all of whom lost vision as result of a hereditary retinal disease. An active visual implant was placed surgically within the subretinal space of each patient: subfoveal placement in eight patients (group 1) and parafoveal placement in 12 (group 2). Standardized low-vision tests, including light perception, light localization, movement detection, grating acuity, and visual acuity by Landolt C-rings, were used under masked, randomized implant-OFF and implant-ON conditions. For the chip-mediated vision functional results of both subject groups were compared. RESULTS: Three of 20 patients were excluded from analysis because of surgical or technical implant issues. Among patients with nonfoveal placement of the implant, 80% could perceive light, 10% recognized location, and 10% correctly distinguished stripe patterns up to a resolution of 0.33 cycles/degree. No nonfoveal placement patient passed the motion or Landolt C-ring tests. When the implant was placed subfoveally, 100% of patients could perceive light and determine light localization, 75% could resolve motion up to 35°/s, 88% correctly distinguished stripe patterns up to a resolution of 3.3 cycles/degree, and 38% passed a Landolt C-ring test with a decimal visual acuity of up to 20/546 (logMAR 1.43). CONCLUSIONS: Subfoveal placement of active subretinal visual implants allows superior measurable outcomes compared to para- or nonfoveal placement locations. (ClinicalTrials.gov numbers, NCT01024803, NCT00515814.).

Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS.

This study aims at substituting the essential functions of photoreceptors in patients who are blind owing to untreatable forms of hereditary retinal degenerations. A microelectronic neuroprosthetic device, powered via transdermal inductive transmission, carrying 1500 independent microphotodiode-amplifier-electrode elements on a 9 mm(2) chip, was subretinally implanted in nine blind patients. Light perception (8/9), light localization (7/9), motion detection (5/9, angular speed up to 35 deg s(-1)), grating acuity measurement (6/9, up to 3.3 cycles per degree) and visual acuity measurement with Landolt C-rings (2/9) up to Snellen visual acuity of 20/546 (corresponding to decimal 0.037° or corresponding to 1.43 logMAR (minimum angle of resolution)) were restored via the subretinal implant. Additionally, the identification, localization and discrimination of objects improved significantly (n = 8; p < 0.05 for each subtest) in repeated tests over a nine-month period. Three subjects were able to read letters spontaneously and one subject was able to read letters after training in an alternative-force choice test. Five subjects reported implant-mediated visual perceptions in daily life within a field of 15° of visual angle. Control tests were performed each time with the implant's power source switched off. These data show that subretinal implants can restore visual functions that are useful for daily life.

Positioning of electronic subretinal implants in blind retinitis pigmentosa patients through multimodal assessment of retinal structures.

PURPOSE: To optimize methods for positioning subretinal visual implants, customizing their cable length, guiding them to the predetermined retinal position, and evaluating their performance. METHODS: Ten eyes of 10 patients (6 male, 4 female, mean age 46.4 years) were investigated before implantation of a subretinal visual implant. The structural characteristics of the retina as well as the ocular dimensions were determined. Topographic images of the prospective implantation site were subdivided into grids of squares. Each square received a weighted score for suitability. The sum of the scores was calculated, and the region with the highest score was chosen for the implant. In each case, the implant's power supply cable length was calculated by means of magnetic resonance imaging. The planned and achieved positions before and after implantation were compared. RESULTS: The mean light sensitivity ratio between the area actually covered by the chip and that of the planned position was 90.8% with an SD of 11.4%. In two cases with almost perfect positioning, the computed ratio was 100%. Measurements showed that to achieve a 95% sensitivity rate the difference between the planned and achieved chip position must be less than 1.7 mm. Preoperative calculations of the intraocular cable length proved accurate in all cases. CONCLUSIONS: Preoperative evaluation of retinal structures and eye morphology is useful for guiding a retinal implant to the designated area. It is a meaningful tool for planning and performing retinal chip implantation, and it optimizes personalized implantation. (ClinicalTrials.gov numbers, NCT00515814, NCT01024803.).

Spatial resolution and perception of patterns mediated by a subretinal 16-electrode array in patients blinded by hereditary retinal dystrophies.

PURPOSE: The perception of 11 persons blinded by hereditary retinal degeneration elicited by a subretinally implanted 16-electrode array used for light-independent direct stimulation of the retina is described. This device is part of the Tübingen retina implant, which also employs a light-sensitive, multiphotodiode array (MPDA). The ability to reliably recognize complex spatial percepts was investigated. METHODS: Eleven blind volunteers received implants and participated in standardized psychophysical tests investigating the size and shape of perceptions elicited by single-electrode activation, multiple-electrode activation, and activation of compound patterns such as simplified letters. RESULTS: Visual percepts were elicited reliably in 8 of 11 patients. On single-electrode activation, percepts were generally described as round spots of light of distinguishable localization in the visual field. On activation of a pattern of electrodes, percepts matched that pattern when electrodes were activated sequentially. Patterns such as horizontal or vertical bars were identified reliably; the most recent participant was able to recognize simplified letters presented on the 16-electrode array. The smallest distance between sites of concurrent retinal stimulation still yielding discernible spots of light was assessed to be 280 µm, corresponding to a logMAR of 1.78. CONCLUSIONS: Subretinal electric stimulation can yield reliable, predictable percepts. Patterned perception is feasible, enabling blind persons to recognize shapes and discriminate different letters. Stimulation paradigms must be optimized, to further increase spatial resolution, demanding a better understanding of physical and biological effects of single versus repetitive stimulation (ClinicalTrials.gov number, NCT00515814).