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Prof E Zrenner

Zrenner "proof of concept"

German Retinal Implant Team Announce Successful Trials

02 November 2010

New advances in retinal implant technology are enabling "blind people to see", according to releases from The Royal Society today (3rd November 2010). Research published in Proceedings of the Royal Society B reveals that a group of researchers based in Germany have developed a retinal implant that has allowed three blind people to see shapes and objects within days of the implant being installed.

The report states that one blind person was even able to identify and find objects placed on a table in front of him, as well as walking around a room independently and approaching people, reading a clock face and differentiating seven shades of grey.

The device, which has been developed by the company Retinal Implant AG together with the Institute for Ophthalmic Research at the University of Tuebingen, represents a significant advance in electronic visual prostheses and could eventually revolutionise the lives of up 200,000 people worldwide who suffer from blindness as a result of retinitis pigmentosa (RP), a degenerative eye disease.

With RP, light receptors in the eye cease to function. Writing in Proceedings of the Royal Society B, Prof. Dr. Eberhart Zrenner, a founding Director of Retinal Implant AG and Director and Chairman of the University of Tuebingen Eye Hospital, states "The results of this pilot study provide strong evidence that the visual functions of patients blinded by a hereditary retinal dystrophy can, in principle, be restored to a degree sufficient for use in daily life."

The device - known as a subretinal implant - sits underneath the retina,
directly replacing light receptors lost in retinal degeneration. As such, it uses the eyes' natural image processing capabilities beyond the light detection stage to produce a visual perception in the patient that is stable and follows their eye movements. Other types of retinal implants - known as epiretinal implants - sit outside the retina and because they bypass the intact light-sensitive structures in the eyes
they require the user to wear an external camera and processor unit.

The subretinal implant described in this paper reportedly achieves greater clarity because it has a great deal more light receptors than other similar devices. Prof. Dr. Zrenner continues "The present study ... presents proof-of-concept that such devices can restore useful vision in blind human subjects, even though the ultimate goal of broad clinical application will take time to develop."

David Head, Chief Executive at RP Fighting Blindness, welcomed the report and said "This technology is very exciting; Prof Zrenner is highly respected and should be congratulated on this work. However these devices are at an early stage of development as this report notes, and it's important that we recognise that from early trials to a product that is fully proven and generally available can take a long time.

"We look forward to the results of further follow up work in Oxford and other centres and we and our members will be monitoring developments with great interest. Implants may provide a treatment for very advanced RP in the future."

RP Fighting Blindness is funding several other threads of research with the objective of preventing retinal degeneration as a result of RP. David continued "I'm optimistic we will eventually find a cure that prevents sight from deteriorating to this extent in the first place."

Oxford Eye Hospital have also released the following statement for people enquiring about taking part in clinical trials:

The Nuffield Laboratory of Ophthalmology and the Oxford Eye Hospital (John Radcliffe Hospital) will be conducting a clinical trial to assess the electronic retina implant over the course of 2011-2012.

To be eligible for the trial in Oxford, participants need to be UK citizens who are now blind but have previously had at least 12 years of vision. The implant is suitable only for people who have lost all their sight from retinitis pigmentosa. Anyone who still has enough vision to be able to see shapes or objects would not be eligible.

Potential participants who are not from the UK should contact Retina Implant AG (link provided below), which is the company that manufactures the device, to see if future trials are planned in their own country.

UK citizens who feel they may be eligible to enter the trial should arrange for a referral from their GP to the Oxford Eye Hospital. Please note that this is a trial not a treatment and there are still several unknowns about the level of vision that might be restored. Also participants should be prepared to make several visits to the Oxford Eye Hospital during the first year. For further information please contact the research team at or the designated help line 01865 572900

The device will be implanted also at King’s College Hospital by consultant Mr Tim Jackson. King’s College Hospital are asking that potential trial patients must be blind as a result of RP, but need to have had 12 years vision earlier in life (at least 12 years). Vision may be light perception but of no use for navigation. Patients must understand that a trial is not a treatment and the hospital will need to see patients regularly to get their feedback on the device and how better to improve it in future. Patients also need to be fit for a general anaesthetic.

Professor Robert MacLaren
November 2010

Original Sources: The Royal Society and Oxford Eye Hospital. Note that views expressed in an externally sourced article are not necessarily those of the charity or its Trustees and Medical Advisors. In particular the charity is not endorsing or funding these trials and cannot advise further on participation.

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