What will happen if there will be no cone cells in our retina?

The retina of our eye contains a large number of light-sensitive cells that respond to light. These specialized cells are known as photoreceptors (light-sensitive cells).

There are two different types of photoreceptors present within the retina:

1. Rods - They are the rod-shaped cells that are most sensitive to light and dark changes, hence function better in low light conditions (twilight vision) and get bleached quickly in bright light. They are not good for color vision. There are about 120 million rods found in the human retina.

2. Cones - They are cone-shaped cells, and they are not as sensitive as rods for light. Therefore, they function better in bright light conditions (daylight vision), and require more photons of light to become activated. It also makes us see colours, along with helps us to differentiate between various colors. That's why we are unable to see color very well in dark places. Thus, they are used for color vision and for detecting fine details. There are about 6 million cones found in the human retina. 

So, from the above explanation, we can conclude that, if there will be no cone cells in our retina then the bright light may hurt our eyes, and we'll be unable to see colors and differentiate between them. As a result, the world will appear black, white, and gray.