Disease overview

Achromatopsia, also known as day blindness, is a disease caused by degeneration of the cones in the eyes. It is a condition that affects a dog's light perception and color vision, but not its night vision. There are two main photoreceptor cells in the retina: rod cells and cone cells. Rod cells are responsible for vision in low light conditions and for detecting and following movement, while cone cells detect color and adjust brightness, but do not work as well in low light. The eyes of dogs have many more rods than cones. Dogs also have fewer cones in their retinas than humans, yet still have substantial color vision (primarily blue and yellow colors).

Gene name

CNGA3

Inheritance

Autosomal recessive

Signs and symptoms

Symptoms may appear as early as 8-12 weeks of age and include photophobia (intolerance of bright light) and seeking low light places, excessive blinking in daylight, and head shaking.

How is it diagnosed

Thorough examination of the eyes and clinical signs. A veterinary ophthalmologic exam can determine if there are changes in the eye that have or will lead to vision loss. Genetic testing is necessary to determine if there is an underlying genetic cause, which can assist veterinarians with diagnosis and help breeders identify affected and carrier dogs.

Breeds at higher risk

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Citations

Tanaka N, Dutrow EV, Miyadera K, Delemotte L, MacDermaid CM, Reinstein SL, Crumley WR, Dixon CJ, Casal ML, Klein ML, Aguirre GD, Tanaka JC, Guziewicz KE. Canine CNGA3 Gene Mutations Provide Novel Insights into Human Achromatopsia-Associated Channelopathies and Treatment. PLoS One. 2015 Sep 25;10(9):e0138943. doi: 10.1371/journal.pone.0138943. PMID: 26407004; PMCID: PMC4583268.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.