Abstract
Background
Retinal tacks, first developed for the treatment of complex retinal detachments, have more recently been used for the fixation of epiretinal electrode arrays as part of implanted visual prostheses. Here, we report on the clinical experience of extracting four such tacks after chronic implantation. The ability to safely extract retinal tacks ensures that epiretinal devices can be repositioned or removed if necessary.
Methods
Custom-built, titanium alloy retinal tacks were mechanically removed from the posterior coats after prolonged implantation (up to 19 months). The resulting wound was characterized by clinical evaluation, fundus photography, and fluorescein angiography while being monitored for stability over time. The wounds were also compared to earlier published reports of the healing response around retinal tacks in human subjects.
Results
Tack extraction was accomplished successfully, without complication, in all four subjects. The wound site was readily identified by pale scar tissue. No change in the wound size or appearance was noted over many months of post-operative observation (up to 22 months after explant). No adverse effects on overall ocular health were detected.
Conclusion
Extraction of retinal tacks from subjects implanted with epiretinal prostheses can be performed without significant complication. The long-term healing response appears to be stable and localized in eyes afflicted with retinitis pigmentosa or choroideremia. There was also minimal, if any, impact on the local circulatory system. These cases suggest that the use of retinal tacks for anchoring epiretinal visual prostheses does not preclude safe repositioning or removal of the device more than a year after implant.
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References
Ando F, Kondo J (1983) A plastic tack for the treatment of retinal detachment with giant tear. Am J Ophthalmol 95:260–261
Brown GC (1987) The use of tacks for the repair of complicated retinal detachment. Trans Pa Acad Ophthalmol Otolaryngol 39:578–582
Humayun MS, Weiland JD, Fujii GY, Greenberg R, Williamson R, Little J, Mech B, Cimmarusti V, Van Boemel G, Dagnelie G, de Juan E (2003) Visual perception in a blind subject with a chronic microelectronic retinal prosthesis. Vis Res 43:2573–2581
Gerding H, Benner F, Taneri S (2007) Experimental implantation of epiretinal implants (EPI-RET) with an IOL-type receiver. J Neural Eng 4:S38–S49
Sachs HG, Gabel VP (2004) Retinal replacement—the development of microelectronic retinal prostheses—experience with subretinal implants and new aspects. Graefes Arch Clin Exp Ophthalmol 242:717–723
Maynard EM (2001) Visual prostheses. Annu Rev Biomed Eng 3:145–168
Rizzo JF, Wyatt J, Humayun M, de Juan E, Liu W, Chow A, Eckmiller R, Zrenner E, Yagi T, Abrams G (2001) Retinal prosthesis: an encouraging first decade with major challenges ahead. Ophthalmology 108:13–14
Cottaris NP, Elfar SD (2005) How the retinal network reacts to epiretinal stimulation to form the prosthetic visual input to the cortex. J Neural Eng 2:S74
Schiefer MA, Grill WM (2006) Sites of neuronal excitation by epiretinal electrical stimulation. IEEE Trans Neural Systems Rehab Eng 14:5–13
Chen SC, Suaninga GJ, Morley JW, Lovella NH (2009) Simulating prosthetic vision: I. Visual models of phosphenes. Vis Res 49:1493–1506
Ahuja AK, Dorn JD, Caspi A, McMahon MJ, Dagnelie G, daCruz L, Stanga P, Humayun MS, Greenberg RJ (2011) Blind subjects implanted with the Argus II retinal prosthesis are able to improve performance in a spatial-motor task. Br J Ophthalmol 95:539–543
Daus W, Volcker H, Alexandridis E, Kasmann B (1989) Histopathology findings following retinal tack implantation. Ophthalmologica 199:162–164
Tripathi RC, Pon DM, Levine RA, Tripathi BJ, Falckh RCF, Moffat KP (1989) Retinal tacks: Tolerance and tissue reaction in a human eye. Ophthalmic Surg 20:658–662
Abrams GW, Williams GA, Neuwirth J, McDonald HR (1986) Clinical results of titanium tacks with pneumatic insertion. Am J Ophthalmol 102:13–19
Lewis H, Aaberg TM, Packo KH, Richmond PP, Blumenkranz MS, Blankenship GW (1987) Intrusion of retinal tacks. American J Ophthalmol 103:672–680
de Juan E, McCuen BW, Machemer R (1987) Mechanical retinal fixation using tacks. Ophthalmology 94:337–340
Harrie RP (2008) Case study 33 retinal tack. Clinical ophthalmic echography. Springer, New York, p 95
Funding
This study supported by National Institutes of Health (Bethesda, MD, USA) grant number 5R01EY12893, and Second Sight Medical Products Inc.
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Proprietary interests
EdeJ, RS, POB, and LdaC belong to institutions that receive funding from Second Sight Medical Products to support the study. The individuals themselves have no financial interest in Second Sight Medical Products. JN is an employee of and has a financial interest in Second Sight Medical Products.
The authors have full control of all primary data, and they agree to allow Graefe’s Archive for Clinical and Experimental Ophthalmology to review their data upon request.
Clinical trial
Registered at http://www.clinicaltrials.gov under identifying number NCT00407602.
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de Juan, E., Spencer, R., Barale, PO. et al. Extraction of retinal tacks from subjects implanted with an epiretinal visual prosthesis. Graefes Arch Clin Exp Ophthalmol 251, 2471–2476 (2013). https://doi.org/10.1007/s00417-013-2452-y
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DOI: https://doi.org/10.1007/s00417-013-2452-y