1. Punita Christopher, Fred K Chen, Varalakshmi Wuyyuru, Jose Sahel,
The Argus II epiretinal prosthesis system allows letter and word reading and long-term function in patients with profound vision loss
Lyndon da Cruz, Brian F Coley, Jessy Dorn, Francesco Merlini, Eugene Filley,
Punita Christopher, Fred K Chen, Varalakshmi Wuyyuru, Jose Sahel,
Paulo Stanga, Mark Humayun, Robert J Greenberg, Gislin Dagnelie, for the
Argus II Study Group
The Argus II epiretinal prosthesis system allows
letter and word reading and long-term function
in patients with profound vision loss
Lyndon da Cruz,1 Brian F Coley,2 Jessy Dorn,3 Francesco Merlini,2 Eugene Filley,4
Punita Christopher,3 Fred K Chen,1,5 Varalakshmi Wuyyuru,3 Jose Sahel,6
Paulo Stanga,7 Mark Humayun,3,8 Robert J Greenberg,3 Gislin Dagnelie,9 for the
Argus II Study Group
Br J Ophthalmol 2013;0:1–5. doi

2. Overview Clinical Problem : RP Overview of Retinal Prosthesis
Argus II Basic Design and function
Aim
Methods
Results
Discussion
Challenges/Limitations
Conclusion
Questions

3. Retinitis Pigmentosa
Retinitis pigmentosa is a condition that can be caused by a myriad of different gene defects (about 90 for isolated RP and RP that occurs in syndromes), with different ways of inheritance (20% autosomal-dominant [50% of children of parents who carry the defect will get RP], 20% autosomal-recessive [25% of carrying parents], 10% x-linked [mothers pass it on to sons only], and 50% spontaneous without family inheritance). It affects about one in 4000 humans, and about one in 100 are carriers. Some syndromes show RP together with other symptoms, most often hearing loss. What happens in a nutshell is that dark pigments are deposited in the retina, mostly in the area of the rods, which die off by apoptosis, so the earliest symptoms tend to be increasing loss of night vision, and the development of tunnel vision. Here’s an image of a normal retina, and one with retinitis pigmentosa :

4. Retinal Prosthesis History
Charles LeRoy in 1755 discharged a large capacitor through the head of a blind person, who described “flames descending downwards” (Marg, 1991)

5. Retinal Prosthesis Concept

6. Retinal Prosthesis Options
Argus II
Visual Cortical Implant
Virtual Retinal Display (VRD)
Microsystem-based Visual Prosthesis (MIVIP)
Artificial Silicon Retina (ASR)
Tübingen MPDA Project Alpha IMS
Implantable Miniature Telescope
Dobelle Eye

7. The external equipment
The external equipment includes glasses, a video processing unit (VPU) and a cable.

8. How Is Argus® II Designed To Produce Sight?

9. Testimonials
The F.D.A. Approves a Bionic Eye: Argus II Device Helps the Blind – YouTube
Argus II, Manchester User Testimonial - Artificial Retina - Bionic Eye - YouTube

10. Aim
To determine whether a group of patients blinded by outer retinal dystrophies and fitted with the Argus II system, could identify letters and words on a computer screen.
(effective spatial resolution, in the context of a device that is stable, portable and capable of long-term function)

11. Subjects

12. Methods Test I: letter identification Test II: letter size reduction
Test III: word recognition
Conditions : System off and both eyes unpatched; system on in ‘scrambled’ mode with eyes patched and unpatched; and system in standard mode with eyes patched and unpatched

13. Results

14. Figure 2
Figure 2 Box and whisker graphs illustrating the median percentage
correct and quartiles for Test I letter Groups A, B and C comparing the
device on and off. For Groups A, B and C, n=21, 19 and 20,
respectively. (** <0.001 Wilcoxon signed rank test). Outliers, shown as
black dots, are data with values beyond the ends of the whiskers.

15. Figure 3
Figure 3 A graph showing the mean and SEs of the total number of
letters identified correctly in two test runs of letter size reduction using
the Argus II retinal prosthesis system. (*p<0.05).

16. Challenges Safety Surgery Effectiveness Suitability Cost
Contraindications
Electrodes packaging

17. Conclusion
Multiple blind subjects fitted with the Argus II system consistently identified letters and words using the device, indicating reproducible spatial resolution.
This, in combination with stable, long-term function, represents significant progress in the evolution of artificial sight.

18. Questions What is Argus II ? What are advantages of Argus II?
Argus II has therapeutic potential for what other types of retinal diseases?
Argus II vs. other Retinal Prosthesis
What experiments would you suggests to further test effectiveness of Argus II?