Figure 1 of Wilson, Mol Vis 2012; 18:1384-1394.

Figure 1. Examples of cataract progression. A: A normal lamb eye without cataract. B: A stage 2 cataract with opacities at the suture lines. C: A stage 4 cataract with more than a third of the lens surface opaque. D: A stage 6 or mature cataract.