Neuro-Eye Therapy was researched and developed at the University of Aberdeen. The concept grew from the realisation that the only options available to patients with vision loss were designed to help develop coping strategies rather than to help stimulate changes within the visual system.
Professor Arash Sahraie and colleagues demonstrated that visual sensitivity can be improved by the systematic stimulation of blind areas using visual stimuli. They hypothesised that this improvement occurs via two possible ways. First, there may be parallel routes for nerves to take visual information to different brain areas; therefore, processing by other routes can be encouraged if one route is damaged. Alternatively, the brain may be able to be trained to use surviving functioning nerves within the damaged areas. NeET was designed by researchers to encourage the use of remaining nerve pathways to compensate for the damaged areas. The therapy ultimately relies on the intrinsic ability of the brain to adapt to changing circumstances, a process called neuroplasticity.
Clinical studies published in peer reviewed scientific journals have shown that after a three-month training period on the program, clients experience improvements in their visual sensitivity within the damaged area of their visual field and the size of the affected area is often reduced. At the end of therapy, clients have reported on the practical advantages of NeET. These include better detection of moving, flickering objects such as traffic, improvements in reading and visual attention, improved navigational skills, and greater concentration and confidence—all of which can lead to improved quality of life. However, despite the improvements reported, we cannot guarantee a specific outcome—including the return of a driving licence—because both the extent of damage and response to therapy are unique to each person.
VRT and NeET – The Science Behind The Different Approaches
Previous studies of residual visual processing in the blind field of patients with post-geniculate lesions have shown evidence for the following: A luminance flux channel that signals presence/absences of light patches and a spatial channel which signals the presence/absence of spatial patterns, objects, etc (Barbur et al. 1993; Weiskrantz et al., 1992). Both these mechanisms have overlapping as well as distinct properties. For example the light flux channel has a broader temporal tuning than the spatial channel and may reflect the activity of neurones in subcortical/mid-brain areas. The spatial channel on the other hand has specific spatial tuning properties probably being mediated by neuronal projections to intact extra-striate areas, by-passing the damaged geniculo-striate route (Weiskrantz 1986; Cowey 2004).
The VRT approach relies on stimulation of the light-flux channel whereas NeET targets the spatial channel. The pattern of recovery after VRT and NeET are also different. VRT is specifically targeting the blind/sighted border regions and is proposed to stimulate the interconnectivity between the neighbouring neurones (Poggel et al., 2008). NeET has shown to change sensitivity deep within the blind regions, and recovery is attributed mostly to increased activity in the remaining intact projections (Sahraie 2007, Trevethan & Sahraie in press).
With VRT therapy, the patient first focuses on a fixation point on a display screen. Then, a series of light stimuli are presented along the border of the patient’s visual field loss. These programmed light sequences stimulate the border zone between the “seeing” and “blind” visual fields, repetitively challenging the visual cortex in the border zone with thousands of stimuli over the course of the therapy. With NeET, the patient responds to the images that appear on the screen, initially in the border area of the patient’s visual field loss and over time deeper within the damaged field of vision.
Both therapies are able to demonstrate improvements in both visual sensitivity and activities of daily living.
Neuro-Eye Therapy Clinical Studies
- Improved detection following Neuro-Eye Therapy in patients with post-geniculate brain damage.
Sahraie A, Macleod MJ, Trevethan CT, Robson SE, Olson JA, Callaghan P, Yip B (2010).
Read more (http://www.ncbi.nlm.nih.gov/pubmed/20721542)
- Temporal properties of spatial channel of processing in hemianopia.
Sahraie A, Trevethan CT, MacLeod MJ (2008).
Read more (http://www.ncbi.nlm.nih.gov/pubmed/18158164)
- Induced visual sensitivity changes in chronic hemianopia.
Sahraie A (2007).
Read more (http://www.ncbi.nlm.nih.gov/pubmed/17992086)
- Increased sensitivity after repeated stimulation of residual spatial channels in blindsight.
Sahraie A, Trevethan CT, MacLeod MJ, Murray AD, Olson JA, Weiskrantz L (2006).
Read more (http://www.pnas.org/content/103/40/14971.full)
- Spatial channels of visual processing in cortical blindness.
Sahraie A, Trevethan CT, Weiskrantz L, Olson J, MacLeod MJ, Murray AD, Dijkhuizen RS, Counsell C, Coleman R (2003).
Read more (http://www.ncbi.nlm.nih.gov/pubmed/12956717)