Lens transplantation. (a–e) Transplantation of a surface fish embryonic lens into the optic cup of a Pachón (b,c) or Los Sabinos (d,e) cavefish embryo after their own lens is removed rescues the eye in adults. (b,d) Lens transplant side. (c,e) Unoperated side. (f–j) Transplantation of a Pachón (g,h) or Los Sabinos (i, j) embryonic lens into the optic cup of a surface fish embryo after its own lens is removed causes retardation of eye development in adults. (g,i) Lens transplant side. (i, j) Unoperated side. From Yamamoto and Jeffery (2000) and Jeffery et al. (2003).