These dystrophies are inherited through autosomal dominant, autosomal recessive, and X-linked recessive mechanisms. Patients usually manifest with loss of acuity, central scotomata, and defective color vision. In patients with cone dystrophy, cone ERG recordings are attenuated or extinguished, however rod ERG recordings may be minimally affected in the early stages of the disease.

Patients with cone-rod dystrophies will show markedly reduced or absent cone ERGs and reduced rod ERGs. The changes in both rod and cone ERG function will be determined by the disease type (cone vs. cone-rod) and the stage of the disease.