Hi there! This is Md.Ashik from Creative Designer. And today we're going to learn how to color eyes in Photoshop in Just One Minute!
Now, since this is a dark eye, we need to first brighten it. So create a Curves Adjustment Layer. Take it all up, just like that. Now, select the mask. Press Ctrl/Command + I. Take the brush, make sure the foreground color is White. And just paint on the eye, just like that. Now, let's create a Hue/Saturation Adjustment Layer. Choose whatever color you like, but first, check 'Colorize'.
So, I'm gonna choose Blue. Let's increase the Saturation. Select the Mask, Press Ctrl/Command + I. Take the brush, make sure the foreground color is white. And just paint on the eye, just like that. Be careful! Don't paint on the outside. Now, create one more Hue/Saturation Adjustment Layer. This time, again, check on 'Colorize'.
Whatever color you want on the inside, I'm going to select that. I'm going to increase the saturation. Select the mask, press Ctrl/Command + I. Take the brush. Make sure the foreground color is White. And just paint on the inside. Now, you can play with the Hue/Saturation later as well. Let's go back to this. You can choose whatever color you like. You can choose Red, you can choose Blue, Yellow, whatever you want. I'm going to keep it at Blue. And You can add even more than two colors! Isn't that fun?

If you have any doubts, Please let me know :)