What is the present state of affairs?

Seven patients successfully underwent operations which healed well. All of the patients tolerated the implant, which was operatively placed under the retina by PhD Helmut Sachs or Professor Karl-Ulrich Bartz-Schmidt, well.

The electrical stimulation brought much important and valuable knowledge about the behavioural response of the retina and thus about the optimal electronic setting of the chip. Several technical improvements could already be made during the course of the study. Due to the electrical stimulation, patients could perceive light in certain shapes and patterns. Visual perceptions via the chip itself made the recognition and localisation of sources of light (windows, lamps) possible, which is of great importance to selfsufficient orientation. The patients sometimes noticed light objects (e.g. crockery) against a dark background.

All patients viewed their participation in the study as a positive, exciting experience, despite the stress of the operation and the often protracted tests. At the end of the study they declared that, if they had to choose again, they would again decide to participate.

Study participants

Patients who are blind in at least one eye, or who can only localise light so indistinctly that it is insignificant with regard to their orientation, can take part in the study. The participants must be at least 18 years old and no older than 75 years old, and must be suffering from retinitis pigmentosa, chloroideremia or extensive cone-rod dystrophy. They must have had at least twelve years experience of vision in their lives and thereby have had at least 5 percent sharpness of vision. A retinal implant as a potential vision implant is out of the question for a wide variety of causes of blindness, e.g. glaucoma (cataract), diseased optical nerve, disorders of the blood supply to the retina, detachment of the retina or blindness due to accidental injuries.

Patients with age-related macular degeneration can also not participate in the study at present.

Questions

for further basic information please write to:

Dr. med. Barbara Wilhelm
Universitäts-Augenklinik Tübingen
Schleichstr. 12-16
72076 Tübingen
Tel.: +49 (70 71) 29 8 48 98
E-Mail: barbara.wilhelm@med.uni-tuebingen.de

The Chairmen of the University Eye Hospitals in Tübingen and in Regensburg are also happy to answer your medical questions:

Prof. Dr. med. E. Zrenner
Universitäts-Augenklinik Tübingen
Tel.: +49 (70 71) 29 8 47 86 oder 29 8 73 11

Prof. Dr. med. V.-P. Gabel
Universitäts-Augenklinik Regensburg
Tel.: +49 (09 41) 9 44 92 01