- Health Library - PetMD U The retina is the tissue that lines
the inner surface of the eye, and is the light sensitive part of
the eye that acts as the brain's camera, transmitting images
through the rods and cones that are part of its structure, thus
enabling the experience of vision. The retina is part of the
central nervous system (CNS) and the only part of the CNS that
can be easily imaged and examined. In retinal degeneration, the
cells of the retina begin to decline in function, thereby
leading to impaired vision or even blindness. There are many
causes for retinal degeneration. Mean Age and Range You will
need to give a thorough history of your dog's health, onset of
symptoms, and possible incidents that might have led to this
condition, such as trauma or exposure to toxic substances. Your
dog's diet will also be taken into consideration, since this may
be a supporting cause. Your veterinarian will perform a complete
physical exam on your dog, taking into consideration your dog's
lineage and whether t