The RETINA IMPLANT Alpha AMS is a subretinal implant. It contains a microchip, similar to a digital camera, which is implanted under the retina. In adult patients whose vision has been affected by retinal degeneration, the chip can help to partially restore functional eye sight.
One implant, three components.
The RETINA IMPLANT Alpha AMS is placed under the retina so that the function of the degenerated photoreceptors (rods and cones) can be replaced. The chip is only 3.2 x 4 mm in size with a height of 70 µm. It is equipped with 1600 photodiodes, which convert the incident light into an electrical signal. This signal is amplified and relayed via electrodes to the retinal signal processing layers which are still functional. Following the natural optical path, the signal is then transmitted to the brain via the optic nerve.
The portion of the RETINA IMPLANT Alpha AMS implanted in the eye does not have batteries or other power sources. Therefore, an external power supply is required. For this purpose, a ceramic coil for energy absorption by an external transponder is implanted behind the ear under the skin.
The transponder sends the energy from the handheld device from the outside via magnetic induction to the implanted coil. The handheld device is slightly larger than a modern mobile phone and can be carried in a pocket. The patient can adjust the brightness and contrast of the signal to the ambient light via the handheld device.
Due to the technical characteristics of the RETINA IMPLANT Alpha AMS, a theoretical maximum visual acuity of 0.07 (20/280) with a horizontal visual field of 14° is possible. The best visual acuity achieved so far by a patient has been 0.037 (20/546). The implant does not allow for colour-vision. However, some shades of grey are distinguishable.
Previous patients used their eyesight mainly for orientation: sources of light from windows or lamps in rooms, street lanterns and road markings as well as the outlines of buildings in the outdoors are used.
Experiences we value.
Since 2005, the current chip and the predecessor model have been implanted in 60 patients mostly in Europe (as of November 2016) , 20 of those received the current version of the RETINA IMPLANT Alpha AMS. The experience and feedback we receive from our patients inspire us to continue researching and developing this product. However, we must also note that the users benefit to varying degrees from the RETINA IMPLANT Alpha AMS and that it is not possible to predict at this point how well a specific patient will see with the implant.
Who is this implant suitable for?
The RETINA IMPLANT Alpha AMS is well suited for...
A prerequisite for the RETINA IMPLANT Alpha AMS is the presence of a retinal disease in which only the photoreceptors are degenerated, but where the rest of the visual system is still functional. These symptoms are associated with retinitis pigmentosa (RP). In order to implement the RETINA IMPLANT Alpha AMS in a patient suffering from RP, it is important that there are no additional eye diseases affecting the visual system or inner retina. In addition, sufficient visual ability must have been developed early in life. At most, patients may still have perception of dim light or no light perception at all. Further on, inner retinal structures must still be functional.
In order to minimise the risk of a long surgery, it is essential for the patient to be physically healthy. The duration of the inpatient stay after surgery depends on the individual recovery process . Patients should be between 18 and 78 years of age and generally in good health.
The RETINA IMPLANT Alpha AMS is not suited for...
As a rule, a retinal implant can NOT help with the following pathological causes that have led to blindness or very severe visual impairment:
Glaucoma / elevated intraocular pressure
Retinal circulatory disorders
Blindness caused by stroke
Changes in the retina due to diabetes
Optic nerve diseases / optic atrophy
Age-related macular degeneration (AMD)
The RI Competence Centre will make a reliable judgment regarding the presence of any exclusion criteria .
My path to receiving an implant
We will advise and accompany you on your path to your individual RETINA IMPLANT Alpha AMS. What exactly this entails you can learn here.