Israeli scientists (Hebrew University of Jerusalem and Volcani Institute) used a virus to restore the sight of a herd of Awassi sheep suffering hereditary day blindness (achromatopsia). The virus replaced a missing gene. The US FDA has now approved human trials.

http://www.jewishpress.com/news/israel/promising-gene-therapy-for-visually-impaired-sheep-now-safe-for-human-trials/2018/09/18/

http://cowry.agri.huji.ac.il/Gootwine2016.mp4