BDNF levels and transport are altered with age and optic nerve injury including glaucoma, and TrkB activation and transport is also reduced (Pease et al., 2000; Quigley et al., 2000; Duprey-Díaz et al., 2002; Avwenagha et al., 2006; Gupta et al., 2014; Dekeyster et al., 2015). Here, NTRK2 is linked to glaucoma.