Until that age, a puppy has blurred vision and, if you start training him earlier, offer the dog the chance to see pupil eye sight sight one ball or the rag by repeating the stimulating movement. You should not, under any circumstance, correct a puppy or an adult dog for seeing a moving object too late or not at all.
Vision is widely considered to be the most important of our senses, as it plays a crucial role in all parts of our lives. We sometimes take it for granted, but without vision, we would be struggling to read, to work, to learn, to drive and even to walk.
To understand how a dog sees, one should know that there are two types of photoreceptors in the retina: the rods and the cones. Rods register low levels of light in black and white and are responsible for night vision. Through the dilation of the pupil, the eye allows for more light to reach the retina.
Pupil Dilation and Contraction
The other photoreceptors, called cones, are needed to see in colors and in good light conditions. Dogs have good binocular vision and a reduced visual field.
Image focalization is more efficient in dog breeds with frontal eyes, compared to those with lateral eyes. In other words, the dogs in Europe can watch TV programs without any difficulty, while the dogs in the USA, where the standard consists in lines per frame, can only see moving dots and lines.