Argus II retinal prosthesis implantation with scleral flap and autogenous temporalis fascia as alternative patch graft material: a 4-year follow-up

Revisiting the Use of Deep Temporalis Fascia Grafts in Ophthalmology

PURPOSE

To report new indications for deep temporalis fascia (DTF) grafts in the ophthalmic field.

METHODS

Monocentric retrospective interventional case series study. All the patients who underwent a DTF graft in an unpublished new indication over the study period (May 2020-October 2023) were included. For each patient, gender, age, graft indication, outcomes, complications, and follow-up duration were collected. In most cases, the DTF graft was covered by a vascularized flap.

RESULTS

Eight patients underwent a DTF graft over the study period. The indications were: radiotherapy-induced scleral necrosis in three cases, tendinoplasty to replace the inferior rectus muscle tendon invaded by a locally advanced conjunctival carcinoma in one case, Ahmed glaucoma valve tube exposure in one case, intraocular lens with scleral fixation exposure in one case, orbital cerebrospinal fluid fistula (orbitorrhea) in one case, and post-traumatic complete corneal graft loss in one case. The DTF graft was successful in 87.5% of cases after a mean follow-up of 11.4 months. No complications were observed.

CONCLUSIONS

DTF graft is a highly versatile graft that can be easily harvested. New indications for DTF grafts may include the repair of radiotherapy-induced scleral necrosis, the creation of oculomotor tendon and the temporary packing of large ocular tissue loss in an emergency context. Further studies with a longer follow-up are needed to confirm our preliminary results.

Soft Devices for High-Resolution Neuro-Stimulation: The Interplay Between Low-Rigidity and Resolution

The field of neurostimulation has evolved over the last few decades from a crude, low-resolution approach to a highly sophisticated methodology entailing the use of state-of-the-art technologies. Neurostimulation has been tested for a growing number of neurological applications, demonstrating great promise and attracting growing attention in both academia and industry. Despite tremendous progress, long-term stability of the implants, their large dimensions, their rigidity and the methods of their introduction and anchoring to sensitive neural tissue remain challenging. The purpose of this review is to provide a concise introduction to the field of high-resolution neurostimulation from a technological perspective and to focus on opportunities stemming from developments in materials sciences and engineering to reduce device rigidity while optimizing electrode small dimensions. We discuss how these factors may contribute to smaller, lighter, softer and higher electrode density devices.

ADVERSE EVENTS OF THE ARGUS II RETINAL PROSTHESIS: Incidence, Causes, and Best Practices for Managing and Preventing Conjunctival Erosion

PURPOSE

To analyze and provide an overview of the incidence, management, and prevention of conjunctival erosion in Argus II clinical trial subjects and postapproval patients.

METHODS

This retrospective analysis followed the results of 274 patients treated with the Argus II Retinal Prosthesis System between June 2007 and November 2017, including 30 subjects from the US and European clinical trials, and 244 patients in the postapproval phase. Results were gathered for incidence of a serious adverse event, incidence of conjunctival erosion, occurrence sites, rates of erosion, and erosion timing.

RESULTS

Overall, 60% of subjects in the clinical trial subjects versus 83% of patients in the postapproval phase did not experience device- or surgery-related serious adverse events. In the postapproval phase, conjunctival erosion had an incidence rate of 6.2% over 5 years and 11 months. In 55% of conjunctival erosion cases, erosion occurred in the inferotemporal quadrant, 25% in the superotemporal quadrant, and 20% in both. Sixty percent of the erosion events occurred in the first 15 months after implantation, and 85% within the first 2.5 years.

CONCLUSION

Reducing occurrence of conjunctival erosion in patients with the Argus II Retinal Prosthesis requires identification and minimization of risk factors before and during implantation. Implementing inverted sutures at the implant tabs, use of graft material at these locations as well as Mersilene rather than nylon sutures, and accurate Tenon's and conjunctiva closure are recommended for consideration in all patients.

Argus II Retinal Prosthesis Implantation in a Patient With a History Of Strabismus Surgery:A Surgical Technique

BACKGROUND AND OBJECTIVE

The authors describe a modified surgical technique for Argus II retinal prosthesis implantation.

PATIENTS AND METHODS

The modified surgical technique was performed in a 43-year-old male with retinitis pigmentosa (RP) who underwent strabismus surgery in that eye at age 8.

RESULTS

During Argus II implantation, the lateral rectus (LR) was noted to be 10 mm posterior to its original insertion due to prior strabismus surgery. The authors placed three 5-0 nylon mattress sutures at the expected location of the LR to support the external portion of the prosthesis, specifically the coil. The band was then passed through the mattress sutures, underneath the inferior, and medial recti with temporal placement of the coil.

CONCLUSION

Placement of three mattress sutures allowed proper positioning of the device and enabled fixation of the suture tabs, thus minimizing the risk of postoperative conjunctival erosion and device exposure. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:116-119.].

Argus II retinal prosthesis system: a review of patient selection criteria, surgical considerations, and post-operative outcomes

Retinitis pigmentosa (RP) is a group of heterogeneous inherited retinal degenerative disorders characterized by progressive rod and cone dysfunction and ensuing photoreceptor loss. Many patients suffer from legal blindness by their 40s or 50s. Artificial vision is considered once patients have lost all vision to the point of bare light perception or no light perception. The Argus II retinal prosthesis system is one such artificial vision device approved for patients with RP. This review focuses on the factors important for patient selection. Careful pre-operative screening, counseling, and management of patient expectations are critical for the successful implantation and visual rehabilitation of patients with the Argus II device.

Assessment of the Electronic Retinal Implant Alpha AMS in Restoring Vision to Blind Patients with End-Stage Retinitis Pigmentosa

Purpose

To report the initial efficacy results of the Retina Implant Alpha AMS (Retina Implant AG, Reutlingen, Germany) for partial restoration of vision in end-stage retinitis pigmentosa (RP).

Design

Prospective, single-arm, investigator-sponsored interventional clinical trial. Within-participant control comprising residual vision with the retinal implant switched ON versus OFF in the implanted eye.

Participants

The Retina Implant Alpha AMS was implanted into the worse-seeing eye of 6 participants with end-stage RP and no useful perception of light vision. Eligibility criteria included previous normal vision for ≥12 years and no significant ocular or systemic comorbidity.

Methods

Vision assessments were scheduled at 1, 2, 3, 6, 9, and 12 months postimplantation. They comprised tabletop object recognition tasks, a self-assessment mobility questionnaire, and screen-based tests including Basic Light and Motion (BaLM), grating acuity, and greyscale contrast discrimination. A full-field stimulus test (FST) was also performed.

Main Outcome Measures

Improvement in activities of daily living, recognition tasks, and assessments of light perception with the implant ON compared with OFF.

Results

All 6 participants underwent successful implantation. Light perception and temporal resolution with the implant ON were achieved in all participants. Light localization was achieved with the implant ON in all but 1 participant (P4) in whom the chip was not functioning optimally because of a combination of iatrogenic intraoperative implant damage and incorrect implantation. Implant ON correct grating detections (which were at chance level with implant OFF) were recorded in the other 5 participants, ranging from 0.1 to 3.33 cycles/degree on 1 occasion. The ability to locate high-contrast tabletop objects not seen with the implant OFF was partially restored with the implant ON in all but 1 participant (P4). There were 2 incidents of conjunctival erosion and 1 inferotemporal macula-on retinal detachment, which were successfully repaired, and 2 incidents of inadvertent damage to the implant during surgery (P3 and P4).

Conclusions

The Alpha AMS subretinal implant improved visual performance in 5 of 6 participants and has exhibited ongoing function for up to 24 months. Although implantation surgery remains challenging, new developments such as OCT microscope guidance added refinements to the surgical technique.