Biomedical Engineering Reference
In-Depth Information
Ear-mounted
control unit
Electrode
Polymer
strips
Seeing straight
A power source behind
the ear creates a nega-
tive charge in the elec-
tordes, which attracts
postively-charged lithium
ions inside the polymer
strips. As a result, the
band contracts, reshap-
ing the eyeball.
Electrode
Normal shape
of eye
FIGURE 9.47
The essential operation of the active scleral band to create bionic vision.
(a)
(b)
FIGURE 9.48
The eye in (a) is myopic (long and thus short sighted; image is formed inside
the eye and does not reach the macula). The band expands the sclera outward to correct
myopia (shortens the eye length and decreases corneal curvature) as in (b).
(a)
(b)
FIGURE 9.49
The eye in (a) is hyperopic (short and thus far sighted; image is formed outside
and beyond the eye and does not reach the macula). The band contracts the sclera inward to
correct hyperopia (increases the eye length and increases corneal curvature) as in (b).
