This results in astigmatism and distorted images. The lens is larger and unable to change its shape as well as in humans. Thus, accommodation , or focusing, is also poorer in most animals. The light-sensitive retina is not as well developed in pets, except in birds. The retina contains visual cells called rods and cones.
Birds have more cones in their retinas than do humans and thus have excellent color vision.
They also have well-developed maculas, so most birds have better central vision than humans. Except for birds, most domestic animals have mainly rod cells with few cones in their retinas. Their maculas are not as developed as in humans. Thus, color vision and central vision in these animals is not good. But most animals have better peripheral vision and can spot something immediately if it moves even slightly to the side.