Hemeralopia is a the inability to see clearly in bright light. Most people have heard of night blindness, but not of this day blindness. Animals with this condition simply cannot adapt to bright light.
This condition is usually caused by a secondary issue, such as one of the following:
- Conditions affecting the cones in the retina (i.e. cone dystrophy, achromatopsia)
- Side effect from anti-epileptic drugs
- Pupils that fail to constrict in response to light
- The absence of the iris in the eye
- Albinism, where the iris is defectively pigmented
- The clouding of the lens due to cataracts
- Certain cancers
However, this condition is also often inherited. Hemeralopia is most often found in Alaskan Malamutes, but is also seen in Miniature Poodles, German Shorthaired Pointers, and Great Danes. It is often diagnosed between eight and 10 weeks of age. Dogs with hemeralopia typically do not have issues with other aspects of their vision.
Unfortunately, there is no effective treatment for hemeralopia, but it can be managed. The best way to manage this condition is to keep the pet in an environment where the light levels can be controlled and kept at a comfortable level. Trips outdoors should be taken at low light or on overcast days.
Have you ever had a pet with vision problems? How did you approach management or treatment of the condition?