Deficiency in Bim or Bid do not alter adult retinal morphology. Retinal structure for both Bim and Bid deficient animals (aged 6 weeks or more) appeared to be grossly normal with no obvious increase in neuronal number in any retinal layer. Furthermore, no extra cells were obvious in adult mice that were deficient in both Bim and Bid, Bim-/- Bid-/-. At least 3 retinas for each genotype were assessed. ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer; scale bar, 50 μm.