Eagle Eyes: How Much Sharper are an Eagle’s Eyes than a Human’s

Perhaps you once spotted something that no one else saw and someone responded by complimenting you on your eagle eyes. Sure, we all pretty much know that eagles, hawks, and predatory birds have excellent eyesight but how much better do they see than a human and how?

The average human has 20/20 eyesight. This is a measure of visual acuity developed using the Snellen chart. 20/20 means that a test subject sees the same line of letters at 20 feet as a normal person does at 20 feet from the chart. 20/30 vision would mean that the test subject can see the same line of letters a normal person would at 30 feet but needs to be within 20 feet to read the line of letters.

The physical properties of human eyes limits the sharpest eyesight to be somewhere around 20/10, maybe even 20/8 at best—a good trait for a fighter jet pilot. This means that a person with 20/8 vision could see a line of letters at 20 feet that would require a person with 20/20 vision to move within 8 feet to read, get it?

The vision of a bald eagle is 4 to 5 times sharper than the average human. Tests conducted on eagle’s have shown that they have 20/4 vision! If you truly had eagle eyes you could see an ant running on a sidewalk from atop of a ten story building. This is ideal for eagles as they circle overhead for prey and carrion. At a height of 300 feet an eagle can see a fish just below the surface of the water!

One of the main factors believed to give eagles such excellent eyesight is that their retinas are more densely coated with light detecting cells called cones. This allows eagles to enhance their power to resolve fine details, much like a high pixel cameras.

The other factor that enable eagles to have superior vision is cone-shaped depressions in the back of the eyes called fovea, which detect light from the center of our visual field. In humans they are shaped like a shallow bowl. In eagles they are shaped like convex pits acting like a telephoto lens.

Eagles also have superior color vision allowing them to see colors more vividly. They even have the ability to see ultra-violet light! Seeing UV light allows them to see and follow the urine trails of prey.

So you might not ever have the vision of an eagle, but there are things you can do to maintain and improve your vision. Protecting your eyes from the sun and eating healthy are the best ways to maintain your vision. For eating for optimal eye sight check out our  blog: Four Nutritional Tips for Optimum Eye Health: Eating Your Way to Healthy Eyes