Early investigations of efficient coding with the linear-Gaussian model showed striking similarities to experimental data (Atick & Redlich, 1990; van Hateren, 1992). However, direct comparison with the retinal receptive fields has been hampered by three limitations:(a) Retinal ganglion cells (RGCs) are inhomogeneous, both within and between cell types (eg, Gauthier et al, 2009), as are their cone inputs, and the input-to-output cell ratio is not 1: 1. Most theoretical studies assume homogeneity and a 1: 1 cell ratio for analytical tractability (although see Li & Atick (1994), Campa et al (1995), Doi & Lewicki (2007));(b) RGC receptive fields under photopic conditions should be written in terms of weights on the cone photoreceptors, and these data were obtained only recently (Field et al, 2010);(c) Efficient coding depends on neural resource constraints, and including a cost for synaptic weights significantly alters the solution …