Table 5.

Acuity levels reached on the Snellen test with three SSDs.

Device	Study	Device resolution (pixels)	Color information?	Sensory input	Acuity*
TDU	Sampaio et al., 2001	144	No	Tactile	20/860-20/430
TDU (BrainPort)	Chebat et al., 2007	100	No	Tactile	20/1800
Retinal prosthesis	Zrenner et al., 2011	1520	No	Retinal stimulation	20/1000
The vOICe	Striem-Amit et al., 2012c	25,344	No	Auditory	20/320
The vOICe	Haigh et al., 2013	11,264	No	Auditory	20/13965-20/2464
The EyeMusic	Current report	960	Yes	Auditory	20/400

^*Acuity: the highest acuity reached by users of the device, as reported in these studies; Note that the best acuity level achieved was determined using different methods in these various studies.