Explain why each eye is tested seperately when using the snellen eye chart?

Answer 1

Each human eye can clearly see letters of a certain size at a certain distance. The Snellen Eye Test uses this to determine that distance for each eye. The eyes do not work together to see objects clearly.

Answer 2

each eye has distinct characteristics that cannot be measured when both eyes are being used.

Answer 3

The reason is so that they can see if you have 50 50 vision. If you don't your weak eye may not work as hard and just rely on your stronger eye.

Hope this helped!