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

Akos Kusnyerik, Udo Greppmaier, Robert Wilke, Florian Gekeler, Barbara Wilhelm, Helmut G. Sachs, Karl Ulrich Bartz-Schmidt, Uwe Klose, Katarina Stingl, Miklos D. Resch, Anusch Hekmat, Anna Bruckmann, Kristof Karacs, Janos Nemeth, Ildiko Suveges, Eberhart Zrenner

Research output: Contribution to journalArticle

19 Citations (Scopus)


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 aweighted 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.

Original languageEnglish
Pages (from-to)3748-3755
Number of pages8
JournalInvestigative Ophthalmology and Visual Science
Issue number7
Publication statusPublished - Jun 1 2012


ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Kusnyerik, A., Greppmaier, U., Wilke, R., Gekeler, F., Wilhelm, B., Sachs, H. G., Bartz-Schmidt, K. U., Klose, U., Stingl, K., Resch, M. D., Hekmat, A., Bruckmann, A., Karacs, K., Nemeth, J., Suveges, I., & Zrenner, E. (2012). Positioning of electronic subretinal implants in blind retinitis pigmentosa patients through multimodal assessment of retinal structures. Investigative Ophthalmology and Visual Science, 53(7), 3748-3755. https://doi.org/10.1167/iovs.11-9409