Almost all iris colobomas in Aussies were seen in merle dogs, however they will occasionally be found in non-merles. (ashgi.org)
The prevalence of CRD increased significantly from 54.2 per cent to 68.1 per cent (P < 0.001) from 1989 to 1997, while the prevalence of coloboma did not (8.3 per cent to 8.5 per cent, P = 0.4). (optigen.com)
Some dogs also have optic nerve coloboma in which a portion of the optic nerve where it enters the back of the eyeball has failed to develop. (ashgi.org)