A computer software device that enables a disabled person to operate a computer via an eye blink, eyebrow twitch, or similar activity qualifies as a “prosthetic device” that is exempt from sales and use tax.  Advisory Opinion, TSB-A-14(28)S (N.Y.S. Dep’t of Taxation & Fin., Aug. 20, 2014).  The Department of Taxation and Finance concluded that the software meets the three requirements for “prosthetic devices” under 20 NYCRR 528.5(b):  (i) the software replaces the disabled person’s motor skills to type or control a computer’s buttons or mouse; (ii) is primarily used for that purpose; and (iii) is not useful in the absence of a user’s disability.