Purpose:
Currently there is no effective treatment for patients with hereditary retinal diseases available. We have developed a microelectronic chip implanted subretinally to replace the function of the degenerated photoreceptor layer.
Methods:
In our current clinical trial (Nr. NCT01024803) 4 patients with an end-stage retinitis pigmentosa have received a permanent subretinal implant in one eye. Activities of daily living have been tested repeatedly in double blind implant OFF and ON condition in randomized order with the following test battery: In the first part (I in fig.) patients were presented 4 geometrical shapes. In the second part (II in fig.) they were presented a table setting containing up to 4 objects at random positions around a plate (saucer, cup, cutlery, etc.). Both parts were done on a table in 2000 lux illuminance. In each part the subjects were asked to answer following questions: How many objects do you see? (identification: a,b in fig.). Which objects do you see? (discrimination: c,d in fig.) Where can you see any objects? (localization: e,f in fig.). The number of correctly identified, discriminated and localized objects has been documented for each run ("scoring" in fig.). A paired t-Test has been applied to the performance of all tasks in both conditions.
Results:
One patient suffered a surgery complication resulting in no visual perceptions (no SAE). For the remaining patients the performance was statistically significant (*p<0.05) or highly significant (**p<0.001) if compared the in implant ON (grey bars) vs. OFF (black bars) condition, with exception of one subject’s discrimination of shapes and of the table setting (s. fig.).
Conclusions:
Subretinal visual implants are able to restore useful visual function for blind patients with hereditary retinal diseases. The subretinal implant can help to improve the visual function in activities of daily living.
Clinical Trial:
http://www.clinicaltrials.gov NCT01024803
Keywords: retinal degenerations: hereditary • perception • retina