Inclusion/exclusion criteria.

<p>Inclusion/exclusion criteria.</p

The intraocular electrode array of the suprachoroidal device (A) and the entire device (B), showing the array connected to the percutaneous connector via a helical lead wire.

<p>The electrodes on the intraocular array (C) were numbered for analysis, with the black electrodes (21a to 21m) being ganged to provide an external ring for common ground and hexagonal stimulation parameter testing. Note electrodes 9, 17 and 19 were smaller (400 µm vs. 600 µm). The percutaneous connector protruded through the skin behind the ear (D), allowing direct connection to the neurostimulator via a connecting lead (E). The scleral incision was made 9 mm to 10 mm posteriorly from the sclero-corneal limbus.</p

Different monopolar electrode stimulations used in the psychophysical testing of the implanted subjects (A & B), where the active electrodes are shown in red and the return electrodes in black.

<p>Table (C) shows the number of electrodes that were capable of eliciting a visual percept using the given stimulation parameters in each subject. PW =  phase width, IPG =  interphase gap, pps =  pulses per second. Stimulus duration was 2 seconds in all cases.</p

Time series of IR images of the electrode array in all subjects, showing no significant lateral movement of the array over a twelve-month period.

<p>The leading edge of the array is marked with a white arrow in the 3-day images. The position of the fovea is marked with a white cross in the 6-month images.</p

OCT scan of the electrode array in situ, taken 2 months postoperatively in Patient 1.

<p>The horizontal arrow on the infrared image indicates the direction of the OCT scan (A). The cross-sectional OCT image (B) shows the silicone and platinum electrode components of the array, the retina structure and choroidal vasculature, and the electrode to retina distance used for analysis (double-headed arrow). Scale bars  =  200 µm.</p

Impedances for the 600 µm platinum electrodes over time in the three subjects.

<p>Impedances were measured with charge-balanced biphasic current pulses (pulse phase width: 25 µs; amplitude: 75 µA). The dotted lines represent the date of first stimulation. In P1 & P2, the impedances were stable over the implantation and stimulation period. Impedances measured in P3 decreased over the course of the implantation period. Outliers are identified by open circles, and the numbers represent the electrode location (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115239#pone-0115239-g002" target="_blank">Fig. 2</a>).</p

Time course of subretinal hemorrhage in P1, as documented with retinal fundus photography.

<p>Complete resolution of the hemorrhage occurred in this subject by 55 days post-operatively. Note the electrode array with individual electrodes can be seen more clearly over time as the blood clears in the temporal retina (arrow).</p

Potential anatomical locations for retinal prosthesis implantation.

<p>To date, clinical trials have been performed with devices in the A: epiretinal position <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115239#pone.0115239-Humayun3" target="_blank">[15]</a>, B: subretinal space <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115239#pone.0115239-Zrenner2" target="_blank">[7]</a> and D: intrascleral space <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115239#pone.0115239-Fujikado2" target="_blank">[19]</a>. Image modified with permission from Bionic Vision Australia.</p

Stability of the intraocular array (arrow) and helical lead wire (star) over the initial 12 months of implantation, as documented by X-ray images.

<p>Additional scans were taken to monitor the percutaneous connector (not shown), which also stayed stable over this time period.</p

Results of the BaLM light localisation task, showing that using the device (with a Lanczos2 vision-processing filter) gave significant visual improvement compared with device off, p<0.0001 for all three subjects.

<p>Results of the BaLM light localisation task, showing that using the device (with a Lanczos2 vision-processing filter) gave significant visual improvement compared with device off, p<0.0001 for all three subjects.</p