Compensatory growth renders Tcf7l1a dispensable for eye formation despite its requirement in eye field specification. - Young RM; Hawkins TA; Cavodeassi F; Stickney HL; Schwarz Q; Lawrence LM; Wierzbicki C; Cheng BY; Luo J; Ambrosio EM; Klosner A; Sealy IM; et al. (ELife, 2019)