| Implant position |
On the surface of the retinal
nerve fiber layer |
Between the photoreceptor layer and
the retinal pigment epithelium/choroid |
Between the choroid
and sclera |
| Major target cells |
RGCs |
Bipolar cells |
Bipolar cells |
| Stimulation efficacy |
Directly stimulation
of the RGCs |
Directly interfaces the bipolar cells |
Low proximity to the target cells |
| |
Low stimulation threshold |
Low stimulation
threshold |
High stimulation threshold |
| |
|
|
Spread of current,
thereby reducing the spatial resolution |
| Surgical
method |
Transvitreal through a pars plana sclerotomy |
Vitrectomy, retinotomy |
Intravitreal surgery |
| Surgical limitations |
Possibility of
retinal detachment or hemorrhage |
Risk of damaging healthy
photoreceptor cells during insertion |
Less invasive compared
to other two and does not involve direct
contact with the retina |
| |
Requires
tacks to fix the prosthesis on the retinal surface |
Postsurgical
complications such as inflammation or proliferation
of tissue over the implant |
|
| |
Prosthesis may move or become dislodged, requiring
further
surgical intervention |
|
|
