Canine Multifocal Retinopathy causes blister-like defects in the retina which may gradually progress or go away. In rare instances the disease can impact vision, but most cases are minor and noted as “breeder option” on exam reports. The disease can be detected by four months of age but diagnosis by exam can be difficult. CMR may be described as retinal dysplasia or retinal folds, both of which are reported in Aussies
There are multiple forms of CMR. They type found in Aussies is CMR1. Its due to a recessive gene mutation and a DNA test is available. Owners of Aussies who have been diagnosed with either retinal dysplasia or retinal folds should consider having their dogs tested. Relatives of diagnosed dogs or dogs which have been tested and found to have the mutation should be examined so their status is known.
Most CMR dogs have normal vision but those whose vision has been reduced by the disease should not be bred. Dogs with CMR and normal vision may be bred to clear-tested mates. Ideally, dogs with the mutation should be bred to clear-tested mates.