Saturday, November 14, 2009

Retinal Implants: The Artificial Retina Project

" 'Bionic' eye restores vision after three decades of darkness"
 by Larry Greenmeier. Scientific American News Blog. Mar 4, 2009.










Winning the prestigious "2009 R&D 100" 100, the Argus Retinal Prosthesis is a collaborative effort among the academia, private institutions, and the government. The project is funded by  the US Department of Energy along with the National Institute of Health. It is similar to the Artificial Silicon Retina in that it requires surgery, but it is different in that it is placed epiretinally rather than subretinally. Patients need to wear a pair of eyeglasses which hold a camera that captures images and passes the information along to a video processor, which then converts the image into electronic signals. These signals are sent to a receiver attached to the surface of the eye, which are then passed on to the artificial retina, stimulating it to transmit electronic pulses to the brain through the optic nerve. The basis of this project is exactly the same as that of the Artificial Silicon Retina developed by Dr. Vincent Chow. However, the Argus Retinal Prosthesis seems to hold more promise in that the numerous electrodes on the epiretinal prosthesis (up to 200 electrodes in the current model) are capable of conjuring up images that are clearer and bigger than any other artificial retinal devices have done before. In fact, as the article mentioned, eleven of the study participants reported they could locate a door up to six meters away, which have previously not been shown. 



Creating a retinal prosthetic device is no easy task. Not only does the device have to be safe and effective, it also needs to be durable enough to last for a lifetime for the individual.
The device must be biocompatible with the delicate eye tissue, yet tough enough to withstand the corrosive, salty environment. It needs to be powered at a high enough level to generate a response, but it cannot generate enough heat that would damage the remaining functioning retinal cells. It also needs to stay put on the retinal macula. Another important aspect is that image processing needs to be instantaneous so that there is no delay in interpreting an object in view.

The article also mentions a few other artificial vision projects. It is obvious that this area is gaining speed; when reading about the numerous projects out there, I found myself getting confused by the subtle differences between each "innovation". I believe part of the reason why the Artificial Silicon Project is the leader in the field is that it is a collaborative, multi-institutional effort. By pooling talents and resources, it has been able to emerge with convincing clinical results. Although commercial profit provides a great incentive for innovation, I can't help but think that if research groups were to consolidate and focus on a few projects, artificial vision would become a reality much sooner. The flip-side of the argument, of course, is that this stifles creativity and does not give new ideas a chance to be developed. The outcome of this, most probably, is that we will end up with a plethora of artificial vision devices that ultimately achieve the same goal. The job of the FDA is therefore to set up clear guidelines to applying for new device approval. It is also crucial that in the future, when the field of artificial vision becomes even more advanced, that the FDA provide of set of standards that new artificial devices must achieve in order for them to be approved. 

No comments:

Post a Comment